Components
By Michael Kennedy
Practical Components
10867 Portal Drive
Los Alamitos, CA 90720-1037

Which lead-free component packages are seeing a significant growth in demand?

The electronics industry’s tighter environmental requirements is fueling a demand for Land Grid Array (LGA) components which offer a practical solution for lead-free soldering systems, where one component design fits into almost every solder alloy system.  LGA IC-packages are gaining popularity among portable electronics; where the key drivers for the technology implementation are low cost, mechanical reliability, direct lead-free assembly process compatibility, and their low profile on the PWB.  LGA technology can be considered as an excellent choice for future environmental requirements in thin and compact products.

The use of electronic components that are compatible with the higher temperatures used in a lead-free assembly process requires extensive process evaluations which are prohibitively costly using “live” components. 

The industry is still far from a common standard with lead-free solders.  Compared to the situation with lead containing solders, special care is needed when combining the soldering systems of component vendors and OEMs. For this purpose, Land Grid Array (LGA) components offer a practical solution for lead-free soldering systems, where one component design fits into almost every solder alloy system.

We’re experimenting with different formulations of solder component and board finishes maximizing our lead-free reliability.  How can we test and refine our process?

Dummy components and test boards are available in nearly all available component and board finishes making them the ideal vehicle. 
  
Tin/silver/copper (SAC) alloys that have formulations of 3 to 4% silver, 0.5 to 1.0% copper with the rest as tin have become the most common component finishes.

Many end users are settling on 3% silver, 0.5% copper and 96.5% tin as the alloy for optimized processes and reliability performance. This alloy often is abbreviated as SAC305 and is supported by a considerable body of data; and the work continues.

Here are some Amkor® Dummy component SAC formulations currently available. 

Test boards for lead-free include FR4, Polyimide, FR5, BT and IS-410 with pad finishes of lead-free HASL, IMSN, IMAG and ENIG.