Patent ID: 7880485

Claim:
A high-sensitive resistance measuring device of solder bumps comprising: a package having a rear surface on which plural solder bumps are arranged; a circuit board on which the solder bumps of the package are mounted by soldering; a monitored bump connection unit which is selected as a solder connection unit which is readily damaged by deforming stress; a reference bump connection unit which is selected as a solder connection unit which is not readily damaged by deforming stress; a first constant current source which is connected to the monitored bump connection unit in series and causes a constant current to flow, and a second constant current source which commonly connects the series circuit of the first constant current source and the monitored bump connection unit by common sides; and a resistance variation detection unit which detects a differential voltage (ΔV=V 1 −V 2 ), which is obtained by subtracting a second voltage (V 2 ) generated in the reference bump connection unit by the constant current (I) from the second constant current source from a first voltage (V 1 ) generated in the monitored bump connection unit by the constant current I from the first constant current source, as a resistance variation voltage representing the resistance variation (ΔR) of the monitored bump connection unit.