This guide with show you how to remove the rear case of your phone in order to reach the motherboard.
Slide your fingernail into the slit at the bottom of the phone to remove the back cover.
Place your finger in either of the bottom corner of the battery slot and lift to remove the battery.
Remove six 5 mm Phillips #0 screws from the back of the phone.
Insert a plastic opening tool into the seam between the back case and the rest of the phone.
Working along the seam, pry the back from the phone.