# A Novel Approach for Temperature-Induced Ball Grid Array Collapse Observation

## TL;DR

This paper introduces a new method to observe how repeated heating affects ball grid array solder balls, helping prevent short circuits in electronics.

## Contribution

A novel in situ method to measure BGA solder ball collapse during reflow cycles is developed and validated.

## Key findings

- TMA measurements revealed distinct collapse behaviors of Sn63Pb37 and SAC305 solder alloys at different temperatures.
- Short circuits between BGA leads were detected and confirmed using TMA and X-ray analysis.
- The method successfully provided insights into solder ball behavior during repeated reflow cycles.

## Abstract

This study presents a new approach to investigating the impact of repeated reflow on the failure of ball grid array (BGA) packages. The issue with the BGA package collapse is that the repeated reflow can lead to short circuits, particularly for BGAs with a very fine pitch between leads. A novel approach was developed to measure the collapse of BGA solder balls during the melting and solidification process, enabling in situ measurements. The study focused on two types of solders: Sn63Pb37 as a reference, and the commonly used SAC305, with measurements taken at various temperatures. The BGA samples were subjected to three different heating/cooling cycles in a thermomechanical analyzer (TMA) at temperatures of 250 °C, 280 °C, and 300 °C, with a subsequent cooling down to 100 °C. The results obtained from the TMA indicated differences in the collapse behavior of both BGA solder alloys at various temperatures. Short circuits between neighboring leads (later confirmed by an X-ray analysis) were also recognizable on the TMA. The novel approach was successfully developed and applied, yielding clear insights into the behavior of solder balls during repeated reflow.