Impedance measuring apparatus of package substrate and method for the same

A method of measuring RF (radio frequency) impedances, comprising:

• measuring package RF signals between terminals formed on front and back surfaces of a package substrate;
• measuring calibration RF signals between terminals formed on front and back surfaces of at least one calibration substrate;
• determining RF impedances of said package substrate from the package RF signals;
• determining phase differences corresponding to a thickness of said package substrate and distances between said terminals on a front or back surface of said package substrate from the calibration RF signals;
• and
• calibrating said RF impedances based on said phase differences.

An impedance measuring apparatus which corrects phase differences in a direction of a thickness of a package substrate and in a same plane and measures impedance between terminals formed on front and back surfaces of said package substrate, comprising:

• a plurality of RF probes;
• and
• a plurality of rotation mechanisms,
• wherein said plurality of RF probes are connected with said plurality of rotation mechanisms and measure the impedance between the terminals formed on the front and back surfaces of said package substrate on a first rotation position, and
• measure the phase differences corresponding to distances between the terminals in the direction of the thickness of said package substrate and in the same plane of said package substrate by using RF calibration substrates arranged in a vertical direction or in a horizontal direction to a arrangement direction of said package substrate in said first rotation position and a second rotation position, and
• said impedance value is calibrated based on said phase differences.