Observation

 

This question was fairly attempted by candidates.
The expected answers are:
(a) Reballing kit items

• Ball Grid Array (BGA) solder balls
• BGA stencil plates
• Spatula
• Liquid soldering flux
• PCB holder
• Lacquer thinner
• Cotton buds
• blades          
• ESD cleaning brush
• Tweezers                                                     

                      (b) Functions of Reballing kit items

• Ball Grid Array (BGA) solder balls: to hold the terminal connection of every chip
• BGA stencil plates: to properly align the solder ball on every bumps of the chip
• Spatula: to gather the solder balls on each hole of the stencil plate
• Liquid soldering flux: to make the solder balls remain firm and adhesive
• PCB holder: to ensure firm grip of PCB for proper alignment of solder balls
• Lacquer thinner: to clean the board
• Cotton buds : to clean the board                              
•  blades: to clean the board      
• ESD cleaning brush: to clear the residues

Tweezers: to pick/hold tiny objects or to align pins