Indium 8.9HF Pb Free Solder Paste
• Halogen-free per EN14582 test method
• High transfer efficiency through small apertures (≤ 0.66AR)
• Eliminates hot and cold slump
• High oxidation resistance
• Wets well to oxidized BGA and pad surfaces
• Excellent soldering performance under high temperature and long reflow processes
• Clear, probe testable flux residue
• Backward compatible with SnPb alloys
Indium8.9HF is an air reflow, no-clean solder paste specifically formulated to accommodate the higher processing temperatures required by the SnAgCu, SnAg, and other alloy systems favored by the electronics industry to replace conventional Pb-bearing solders. Indium8.9HF offers unprecedented stencil print transfer efficiency to work in the broadest range of processes. In addition, the high probe testability of Indium8.9HF minimizes false failures in ICT.
Indium Corporation manufactures low-oxide spherical powder composed of a variety of Pb-free alloys that cover a broad range of melting temperatures. Type 4 and Type 3 powders are standard offerings with SAC alloys. The metal percent is the weight percent of the solder powder in the solder paste and is dependent upon the powder type and application. Standard product offerings are detailed in the following table.
88.5% (Type 4)
89% (Type 3)
88.5% (Type 4)
Indium8.9HF is currently available in 500g jars or 600g cartridges. Packaging for enclosed print head systems is also readily available. Alternate packaging options may be available upon request.
Storage and Handling
Refrigerated storage will prolong the shelf life of solder paste. The shelf life of Indium8.9HF is 6 months when stored at <10°C. Solder paste packaged in cartridges should be stored tip down.
Solder paste should be allowed to reach ambient working temperature prior to use. Generally, paste should be removed from refrigeration at least two hours before use. Actual time to reach thermal equilibrium will vary with container size. Paste temperature should be verified before use. Jars and cartridges should be labeled with date and time of opening.
BELLCORE AND J-STD TESTS & RESULTS
• Flux Type (per J-STD-004A) ROL0
• Flux Induced Corrosion
(Copper Mirror) Type L
• Presence of Halide
Oxygen Bomb Followed by
Ion Chromatography <100ppm
• SIR Pass
• Typical Solder Paste Viscosity 1700 poise
Malcom (10 rpm)
• Slump Test Pass
• Solder Ball Test Pass
• Typical Tackiness 35 grams
• Wetting Test Pass
• SIR Pass
• Electromigration Pass
Electroformed and laser cut/electropolished stencils produce the best printing characteristics among stencil types. Stencil aperture design is a crucial step in optimizing the print process. The following are a few general recommendations:
• Discrete components — A 10–20% reduction of stencil aperture has significantly reduced or eliminated the occurrence of mid-chip solder beads. The “home plate” design is a common method for achieving this reduction.
• Fine pitch components — A surface area reduction is recommended for apertures of 20 mil pitch and finer. This reduction will help minimize solder balling and bridging that can lead to electrical shorts. The amount of reduction necessary is process dependent (5–15% is common).
• For optimum transfer efficiency and release of the solder paste from the stencil apertures, industry standard aperture and aspect ratios should be adhered to.
Printer Operation: The following are general recommendations for stencil printer optimization. Adjustments may be necessary based on specific process requirement:
• Solder Paste Bead Size: 20–25mm diameter
• Print Speed: 25–100mm/sec
• Squeegee Pressure: 0.018–0.027kg/mm of blade length
• Underside Stencil Wipe: Start at once every 5 prints then decrease frequency until an optimum value is determined.
• Solder Paste Stencil Life: >8 hrs. @ 30–60% RH & 22°–28°C
Indium8.9HF is designed for no-clean applications, however the flux can be removed if necessary by using a commercially available flux residue remover.
Stencil Cleaning is best performed using isopropyl alcohol (IPA) as a solvent. Most commercially available stencil cleaners work well.
• Rework Flux: TACFlux® 020B, TACFlux® 089HF
• Cored Wire: CW-802
• Wave Flux: WF-7742, WF-9945
The stated profile recommendations apply to most Pb-free alloys in the SnAgCu (SAC) alloy system, including SAC 305 (96.5Sn/3.0Ag/0.5Cu). This can be used as a general guideline in establishing a reflow profile when using Indium8.9HF Solder Paste. Deviations from these recommendations are acceptable, and may be necessary, based on specific process requirements, including board size, thickness, and density.
Heating Stage: The use of a linear ramp rate or ramp-to-spike (RTS) type profile assists in minimizing the greatest overall number of defects associated with the reflow process. If the ramp rate
is too fast, it can cause solder balling, solder beading, and aggravated hot slump which can lead to bridging. The ramp rate in the preheat stage of the profile can range from
0.5°–2.5°C/second (0.5°–1°C/second is ideal). A short soak of 20–30 seconds just below the melting point of the solder alloy can help minimize tombstoning when using
a RTS type profile. If necessary, a ramp-soak-spike (RSS) profile can be implemented to minimize voiding on BGA and CSP type packages. A soak zone between 200°–210°C for up to 2 minutes is acceptable.
Liquidus Stage: To achieve acceptable wetting and form a quality solder joint, the acceptable temperature range above the melting point of the solder alloy is 12°–50°C (15°–30°C is
ideal). The acceptable range for time above liquidus (TAL) is 30–100 seconds (45–60 seconds is ideal). A peak temperature and TAL above these recommendations can result in excessive intermetallic formation that can decrease solder joint reliability.
Cooling Stage: A rapid cool down is desired to form a fine grain structure. Slow cooling will form a large grain structure, which typically exhibits poor fatigue resistance. The acceptable cooling range is 0.5°C–6.0°C/second (2.0°–6.0°C/second is ideal).
This product data sheet is provided for general information only. It is not intended, and shall not be construed, to warrant or guarantee the performance of the products described which are sold subject exclusively to written warranties and limitations thereon included in product packaging and invoices.