Technology

TECHNOLOGICAL BACKGROUND

LFSMD has developed a Lead-Free solder alloy based on the Tin-Zinc system. The melting point of LFSMD’s alloy is slightly higher than that of the conventional Tin-Lead alloy, but still in a range that allows for the use of most existing electronic components and the utilization of the same manufacturing equipment and processes.

Although the Tin-Zinc system is known to be of relative low melting temperature (199ºC, compared to 183ºC of conventional Tin-Lead alloys and 217ºC - 220ºC for Tin-Silver-Copper alloys), its inherent problematic attributes of oxidation and poor wettability (how well it flows when liquid) have prevented until now its successful utilization as a viable Lead-Free alternative.

LFSMD has succeeded in overcoming these problematic attributes of Tin-Zinc by incorporating Manganese into the alloy, utilizing a new method of micro-alloying. Israeli and USA patents have been granted in 2005 covering the IKAlloy development by LFSDM.

In order to implement a solder alloy in an SMT mass production process, a paste form must be developed. No off-shelf polymeric media available suited Tin-Zinc alloys. LFSMD’s second significant achievement was to develop this complex media specifically adapted to its Tin-Zinc-Manganese composition. The polymer media contains many different components that add to the paste the complex properties it should have in order to create consistent and sound joints in mass SMT production.

Tests conducted by LFSMD, as well as independent tests carried out by Soldertec UK (a world leading research institute for Lead-Free technologies) and by a leading manufacturer of semi-conductors, suggest that LFSMD’s alloy performs as well or better than available Lead-Free alternatives.

The immediate advantages of the LFSMD paste, when compared with commonly used SAC soldering pastes are,

• The melting temperature is 199ºC, 18ºC lower than that of SAC, and
• The metal component costs substantially less.