BGA Sample Preparation Plan- Trojan (Suzhou) material technology Co., Ltd.

BGA Sample Preparation Plan

28-10-2025

As electronic products continue to evolve towards miniaturization and high-density integration, ball grid array (BGA) packaging has become the core packaging form for devices such as smartphones and aerospace systems due to its ability to achieve high I/O pin density connections. Although the solder joints between BGA and printed circuit boards (PCBs) are of tiny size (with diameters typically ranging from 0.3 to 0.8 mm), they are crucial nodes that maintain electrical signal conduction and mechanical structure stability. Their quality directly determines the long-term reliability of electronic devices. Therefore, PCBA slicing analysis has become the core method for inspecting BGA solder joint quality.

This analysis focuses on detecting the following three types of indicators:

IMC layer: Generally, the thickness is 2-5 μm. An overly thick layer may cause thermal cycling cracks, and an uncontinuous layer may have a risk of detachment;
Solder joint voids: Caused by insufficient evaporation of flux, with a proportion exceeding 15% will reduce heat conduction and load-bearing capacity, or cause signal interruption;
Interface cracks: Triggered by thermal/ mechanical stress, they will cut off the current, and are an important cause of equipment freezing and fatal failures.

PCBA slicing analysis can precisely trace the quality of solder joints, and is used not only for mass production screening but also for failure location assistance, serving as the core support for ensuring the functionality and integrity of electronic devices.

Here is an example of a BGA sample preparation plan for a solder joint approximately 80 μm in size. Please refer to the following plan for your reference:

1️⃣ : Use P1200 metallographic sandpaper to polish to the target position edge

2️⃣ : Use P2000 metallographic sandpaper to polish to the target position

3️⃣ : Use SC-JP polishing cloth and 3 μm diamond polishing liquid for polishing.

4️⃣ : Use ET-JP polishing cloth and 1 μm diamond polishing liquid for polishing.

5️⃣ : Use ZN-ZP polishing cloth and SO-A439 50-nanometer silica polishing liquid for final polishing.