SMD components are getting smaller and more complex, with extreme package densities and increased I/O counts. At the same time, they are supposed to shine with ever more functionalities and boosted performance. A trend which makes no exception when it comes to ball grid arrays (BGA), such as processor units (CPU) or graphics chips (GPU). With solder sphere sizes and pitch shrinking and thermal characteristics becoming more challenging, a reliable rework solutions should incorporate high accuracy and perfect heat management.
The more premium priced electronic products become, the more economically worthwhile the rework of CPU/GPU components will be - as opposed to getting rid of the whole PCB in case of a defect. It's no coincidence that for years all major OEM have been implementing SMD rework cycles right into their development and production stages - to correct misplaced components or insufficient soldering results. And we must not forget manufacturer-certified EMS companies providing manufacturer warranty repair services or all the field rework centers offering after-sales-repair, device upgrade services, and more.
As diverse as the range of customers and their budget may be, they're all united in their need for user independent, safe, reproducible and economic rework solutions which comply with offical specifications (i.e. as stated by JEDEC/IPC).
What are the Challenges?
- Large variety of CPU and GPU components (dimensions, design, interconnection)
- Large variety of boards (design, shape, number and complexity of layers, materials, population)
- Component sizes (thermal mass), weight and interior packaging density
- Small diameter solder balls and fine pitch hamper the rework process (placement, self-alignment of the component by floating into position)
- Tensions caused by thermal influences in production and rework processes put stress on components and joints
- Pins might detach after months or years
- Sub-assemblies are characterized by dense populations, with many adjacent components prone to damage during rework
- Use of underfill materials can hamper the rework process
- Higher PCB values raise the demand for reliable processes and better yield
Typical Process steps
The Finetech solution allows performing the entire rework cycle on the same rework system:
- Pre-inspection - Visual and functional inspection of the board/PCB
- Preparation - Prepare board and relevant components with regard to calibration measurings (needed for profiling)
- Profiling - Create profiles for de-soldering, soldering and special processes (i.e. residual solder removal, reballing, etc.)
- De-soldering - Remove the component from the board
- Residual solder removal - Remove residual solder from board and component pads
- Reballing - Attach new soldering balls if the component is to be re-used
- Special processes - If required, add special working steps (i.e. solder paste printing or dispensing, double ball / hard ball reballing, etc.)
- Soldering - Assemble the component to board
- Follow-up inspection - Optical inspection of the soldering joints (i.e. by x-ray, microscopy)
Learn more here