SMTA International Conference Proceedings


Author: Cynthia Garcia
Company: Raytheon Company
Date Published: 10/24/2010   Conference: SMTA International

Abstract: As part of the NASA-DoD Lead-Free Electronics project, combined environments testing was performed to validate and demonstrate lead-free solders as potential replacements for conventional tin-lead solders against aerospace and mili-tary electronics industry requirements for circuit card as-semblies.

Solder alloys Sn3.0Ag0.5Cu, Sn0.7Cu0.05Ni (=0.01Ge) and Sn37Pb were used to assemble components on two different printed wiring board test vehicles: manufactured and re-work. The rework test vehicles included BGA-225, CSP-100, PDIP-20, and TSOP-50 components that were removed and replaced.

The test vehicles were subjected to thermal cycling from -55 to 125 degrees Celsius, a ramp rate of 20 degrees Celsius per minute, and dwelling at each temperature extreme for 15 minutes in a HALT (highly accelerated life test) chamber. Pseudorandom vibration was applied continuously through-out the life test beginning at 10 grms and increased by 5 grms after 50 cycles until a maximum of 55 grms was reached. The test vehicles were electrically monitored for 650 cycles us-ing event detectors.

Solder joint failure data of a given component type, compo-nent finish and solder alloy were evaluated using 2-parameter Weibull analysis. The reliability of each lead-free solder alloy tested was compared to the baseline Sn37Pb solder alloy.

Key words: Lead-free, tin-lead, solder, reliability testing

Members download articles for free:

Not a member yet?

What else do you get when you join SMTA? Read about all of the benefits that go along with membership.

Notice: Sharing of articles is restricted to just your immediate work group. Downloaded papers should not be stored on an external network or shared on the internet.


SMTA Headquarters
6600 City West Parkway, Suite 300
Eden Prairie, MN 55344 USA

Phone +1 952.920.7682
Fax +1 952.926.1819