Authors:

Brendan Duffy

Date Created:

Not specified

Course Title:

Professor:

Not specified

About Paper:

Solder joint reliability is a critical contributor to the longevity of electronic assemblies. With the ban on lead- based solder alloys, there exists a critical need to characterize alternatives. Furthermore, with the increasing use of large-area advanced electronic packages, there is a need for newer, Bi-based lead-free solder alloys that may be assembled at temperatures less than 180 degrees Celsius. However, the stress-strain profiles of these alloys vary significantly with strain rates and operating temperature. To provide a standardized process of lead-free solder joint material characterization, a custom micro-precision tester is used to apply double shear loading to solder joint samples. The tester leverages closed-loop feedback control and uniformly designed samples to mitigate measurement errors and enable repeatable experimentation. Monotonic and creep tests were conducted with aged and unaged solder joint samples of three Sn-Bi (tin bismuth) alloys with different microalloying elements. In addition, different sample-holding designs were modeled and fabricated. Component models were developed through Fusion360, a computer-aided design software. Fusion360's computer-aided manufacturing functionality was then leveraged to elicit code for a programmable milling machine. Monotonic experimental results evidenced that the saturation stress of tested alloys increased with aging. Moreover, creep test data outlined that all aged alloys exhibited lower strain rates and, therefore, more creep resistance than their unaged counterparts.

Source:

Purdue University / 2023

Topics:

No topics listed

Co-authors:

Brendan Duffy