BGA (Ball Grid Array) has become a widely used packaging form in modern electronic devices. BGA rework refers to removing a BGA device from a PCB and then re-soldering it to the PCB when it fails.
But it’s hard to observe solder joints. Reworking BGAs is complex, so the BGA chip rework is still a challenge for some unskilled repair personnel. Fortunately, the BGA rework station can solve this problem. This article will introduce how to use correctly the BGA rework station for BGA repair, helping you better master this technology.
What does BGA meaning?
A BGA (Ball Grid Array) chip is integrated circuit packaging. Solder joints on the bottom of the chip are in circular or cylindrical arrays. The solder balls connect to the PCB pads through a reflow soldering process.
BGA packaging has many advantages, such as small size, high density, and good heat dissipation performance, and is widespread in consumer electronics, communication equipment, industrial control, and other fields.
According to the type of BGA packaging material, You can divide BGA components into Plastic Ball Grid Array ( PBGA ), Ceramic Ball Grid Array ( CBGA ), Ceramic Column Grid Array ( CCGA ), and Tape Ball Grid Array ( TBGA )
BGA chip
What are the reasons for BGA rework?
1)Device fault
Failure in Ball Grid Array connections can cause a device to stop working or performance degradation.
2)Temperature issues
The stability of BGA connections is affected by temperature changes. If the temperature is too high or too low, it may lead to the solder falling off or deforming.
3)Stress issues
Due to mechanical stress and vibration, etc., stress may occur in the BGA connection, causing the solder to break.
Solder crack
4)Production and design defects
During the manufacturing process, there may be problems with the location and layout of BGA components, resulting in poor connections.
5)Maintenance and Repair
During maintenance or repair, incorrect operation or use of inappropriate tools may damage the Ball Grid Array connection.
Advantages of BGA Rework
Low rework cost: reworking a BGA chip is cheaper than replacing the entire circuit board.
• Fast repair
It usually takes less time than remanufacturing the PCB and replacing surface mount components.
• Reliability improvement
Through rework, problematic BGA connections can be repaired, improving the reliability and performance of the device.
• Environmental protection
Through repair, We can reduce electronic equipment waste. It will also lessen the burden of electronic garbage on the environment.
BGA Rework flow
BGA rework stations
BGA repair is a complex process that requires strict compliance with the corresponding processes and operating specifications to ensure soldering quality. Now, technicians use BGA rework stations for repairs. Because it includes tools such as hot air guns, hot plates, microscopes, etc, it can help maintenance personnel accurately control the temperature and soldering process.
The BGA rework process mainly includes the following steps:
1) Preparation
Drying: Dry the circuit boards and chips to remove moisture. It prevents product defects during the rework, such as bubbles or open circuits.
Product protection: Protect components on circuit boards susceptible to heat damage, such as plastic parts, LEDs, batteries, etc.
Preparation of nozzles and supports: Choose the suitable nozzles and supports. Do this based on the size and thickness of the circuit board. It will prevent the board from deforming.
Disassembly or soldering curve: Pick the right disassembly or soldering curve. Do this based on the type and spec of the chip. It prevents damage to the chip or board.
2) Disassembly
Select the appropriate temperature curve and remove the BGA device from the circuit board.
Cleaning solder pads: Remove residual solder paste and solder balls on the PCB.
3) Ball Planting
Select appropriate solder balls and auxiliary materials, and implant the solder balls onto the pads of the BGA parts.
4) BGA soldering
Choose appropriate auxiliary materials ( tin or flux paste ) and apply them evenly on the pad.
Solder the BGA device to the circuit board.
After the surface mount inspection, choose the temperature curve for the chip. Heat the BGA with it. Then, remove the PCB after it cools.
5) Detection
Use X-ray detection to check for defects such as cold welding, open circuits, short circuits, etc. It ensures the welding quality is qualified.
BGA Rework FAQ
Chip warping: Control the temperature and time during disassembly, pad cleaning, and ball planting to prevent the chip from overheating and deformation.
PCB warping: Lower the temperature and increase the bottom heating temperature. Also, watch the support position and height to prevent PCB deformation.
Warped PCB
Welding open circuit: Check welding curve, auxiliary materials, drying, and coplanarity to ensure welding quality.
Welding short circuit: Check the stencil opening, drying, solder mask, and temperature curve to prevent welding short circuits.
BGA Rework Notes
• Strictly follow the repair process and operating specifications to prevent repair failure.
• Use appropriate equipment and materials to ensure welding quality.
• Be familiar with common problems in BGA chip rework and prepare countermeasures.
Summary
BGA repair is a complex process that requires a few skills and experience.
Although BGA technology is more advanced, the chip performance will decrease under multiple stress impacts. Therefore, PCBA manufacturers should strengthen supervision and management when packaging chips to minimize the probability of BGA rework.
