Features

•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

Alloys

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.

Printing 

Stencil Design:

Electroformed and laser cut/electro polished 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.

• Indium 8.9HF PDF