Estimated reading time: 4 minutes

Knocking Down the Bone Pile: Revamp Your Components with BGA Reballing

Ball grid array (BGA) components evolved from pin grid array (PGA) devices, carrying over many of the same electrical benefits while introducing a more compact and efficient interconnect format. Instead of discrete leads, BGAs rely on solder balls on the underside of the package to connect to the PCB. In some advanced designs, solder balls are on both the PCB and the BGA package. In stacked configurations, such as package-on-package (PoP), these solder balls also interconnect multiple packages, enabling higher functionality in a smaller footprint.

BGA Advantages
BGAs offer several advantages compared to other package types:

• High circuit density: Their compact layout supports advanced miniaturization trends in electronics
• Improved heat conductivity: Short thermal paths reduce internal chip overheating
• Low inductance: The shorter interconnects minimize signal distortion at high frequencies

Because of these benefits, BGAs have become the backbone of advanced electronics, including smartphones, automotive ECUs, aerospace systems, and defense-grade modules.

Lack of Compliance
One tradeoff with BGAs is their lack of mechanical compliance. Unlike packages with leads that flex, solder balls are rigid. This makes BGAs susceptible to stress from:

• Thermal cycling (differences in coefficient of thermal expansion between the package and PCB)
• Vibration and mechanical flexing in demanding environments

To mitigate this, underfill materials are commonly applied to redistribute stress and improve mechanical reliability, particularly in mission-critical systems such as avionics, military processors, and automotive controllers.

The Need for BGA Reballing
There are several reasons BGAs require reballing during manufacturing or refurbishment:

1. Conversion of solder alloys: Many defense and aerospace applications mandate SnPb finishes for reliability, requiring conversion from standard lead-free solder.
2. Refurbishment and repair: Reballing extends the service life of expensive components that would otherwise be scrapped.
3. Rework for quality assurance: Damaged or contaminated solder balls discovered during incoming inspection can be replaced via reballing

The Reballing Process

Selecting a Reballing Service Provider

When outsourcing reballing, buyers and engineers should look for compliance with IPC J-STD-001, IPC-7711, GEIA-STD-0006, and IEC TS 62647-4 standards. Critical capability ranges to verify include:

• Package sizes from 3 × 3 mm to 60 × 60 mm
• Pitch from 0.20 mm to 1.5 mm
• Ball diameters from 8 mil to 35 mil
• Methods supported: fixture-based reballing and preform/stencil systems

Thorough post-process inspection is non-negotiable. Providers should be equipped for coplanarity checks, ball volume measurement, debris detection, and short/open analysis.

Risks Associated With BGA Reballing
While reballing is an effective method for extending the usability of BGA components, it carries several inherent risks if not performed under tightly controlled conditions. Excessive heat during deballing or reflow can lead to pad delamination, lifted pads, or substrate warpage, all of which may render the device unusable. Inadequate cleaning between processes increases the likelihood of residual flux entrapment or ionic contamination, which can compromise long-term reliability and cause electrochemical migration.

Misalignment of solder balls or uneven solder distribution may result in coplanarity issues, bridging, or head-in-pillow defects that are difficult to detect without advanced X-ray inspection. Additionally, repeated thermal exposure during multiple rework cycles can degrade the component’s metallization and reduce its overall mechanical strength. For these reasons, BGA reballing should only be performed by trained technicians using controlled equipment, validated processes, and comprehensive inspection protocols to minimize risk and ensure compliance with IPC and industry standards.

Best Practices for Mitigating Reballing Risks

• Thermal management: Use tightly controlled reflow profiles to avoid overheating that can cause pad delamination, lifted pads, or substrate warpage
• Process cleanliness: Ensure thorough cleaning between deballing and reballing steps to eliminate flux residues and prevent ionic contamination
• Precise ball placement: Use fixtures, stencils, or preforms to guarantee accurate alignment and uniform solder distribution
• Inspection protocols: Perform both visual and X-ray inspection per IPC-A-610 and IPC-7095 standards to detect coplanarity issues, solder bridging, voids, or hidden defects
• Cycle limitation: Minimize the number of reballing or rework cycles to reduce metallization fatigue and extend component longevity
• Standards compliance: Validate that all processes meet applicable requirements such as IPC J-STD-001, IPC-7711, GEIA-STD-0006, and IEC TS 62647-4
• Qualified personnel and equipment: Use only trained technicians and calibrated, automated equipment to maintain repeatability and reliability

Inspection Challenges

Visual Inspection
Following IPC-A-610 standards, inspectors use microscopes or borescopes to check for missing balls, solder bridging, and ball size uniformity. Proper lighting, magnification selection, and operator training are essential to ensure consistency.

X-ray Inspection
Since most BGA joints are hidden, X-ray inspection is critical for uncovering defects such as head-in-pillow, voids, or shorts that visual inspection cannot detect. Multi-angle imaging increases defect detection reliability.

Conclusion
BGA reballing is a proven and reliable process for extending the life and usability of high-value components. Whether the goal is to convert solder alloys for defense and aerospace compliance, refurbish parts for continued use, or restore components to their original specifications, reballing offers manufacturers a cost-effective alternative to scrapping.

When performed correctly—with controlled thermal profiles, precise ball placement, and thorough inspection—reballing ensures components meet the stringent requirements of commercial, military, and aerospace applications. By adhering to industry standards and employing robust inspection practices, engineers and buyers can confidently incorporate reballing into their rework strategies, maintaining both performance and reliability in advanced electronic assemblies. 

As electronic devices continue to shrink while demanding higher reliability and processing power, reballing will play an increasingly important role in sustaining supply chains, meeting compliance needs, and extending the service life of critical components.

This column originally appeared in the October 2025 issue of SMT007 Magazine.