Retronix Blog

Apr 15, 2016

Problems Associated with the use of large BGAs’


The electronics industry is driven by demand. 20 years ago in a typical town perhaps a few companies accessed the internet, and others sent communications down a phone line by fax etc. Now it’s changed. There is a huge increase in wired and wireless communications, and it’s not just in communications, it’s in car technology, where vehicles self diagnose, it’s in roadsigns with solar panels which send information back to a base without having cables to do so.
 
Advances in semiconductor technology including smaller geometries have allowed more processing power to be added to the IC’s. Increasing requirements in speed and power of communications have led to an increase in the use of large BGAs (typically 50 x 50 or larger) This creates some issues, which Retronix has solutions for:
 
Placement Issues
 
Due to their size, they can require a large amount of heat and time to reflow properly, and when limiting the amount of heat into other components, this can often lead to misplacement issues. Typically these would be open circuits, short circuits. Very often the cost of the BGA is many times the cost of the PCBA, so Retronix use a process to safely recover the BGA while scrapping the PCB.
 
This is done by :
 
  • Heating from underneath to remove BGA at lowest body temperature (This causes delamination in the PCB, effectively scrapping it)
  • Removal of old solder using a hot air knife to avoid abrasive damage to solder mask or pads.
  • Reball using a laser pulse to avoid a reflow cycle.
 
These processes are completely repeatable and avoid reflow cycles, thereby meeting the manufacturers warranty.
 
If on an Expensive PCB
 
If the PCB is expensive, then both the BGA & PCB should be reused. This requires from Retronix an additional cycle to remove the BGA from above. This process is instead of the bottom heat mentioned above, however the next two processes remain the same. Removing (and placing) components using this process is a standard rework process adopted all over the world.
 
Large BGA's
 
If the BGA overheats
 
When the large devices are performing at capacity, they often create large amounts of heat, which if not dissipated away, can cause overheating within the BGA and subsequent failure. Retronix can replace the spheres with high melting point (HMP) spheres which will not reflow during assembly and therefore maintain their height. This increases the height of the BGA from the PCB, thereby avoiding failure. Alternatively the HMP spheres can be replaced by columns.
 

Know More –


Safe Component Recovery Process – Click Here

Coefficient of Thermal Expansion – Click Here

Laser BGA Reballing Process – Click Here

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