Device and method for measuring via hole of silicon wafer

A device for measuring a via hole of a silicon wafer, the device comprising a light source unit, and an interferometer that irradiates a light generated from the light source unit to the silicon wafer and measures a depth of the via hole formed in the wafer from an interference signal of a light reflected by the silicon wafer,

• wherein the light source unit generates a broadband infrared light,
• the interferometer senses an interference signal that is generated as the broadband infrared light is reflected by interfaces of a bottom surface of the via hole and a front surface or a rear surface of the silicon wafer, and
• optical path differences for a plurality of frequency components are simultaneously acquired through spectrum period analysis for the interference signal to measure a depth and a diameter of the via hole, and
• wherein the interferometer includes:
• a collimation lens that converts the broadband infrared light output from the light source unit to a parallel light;
• a condenser lens that is arranged to face the collimation lens with the silicon wafer interposed therebetween, and condenses the infrared light transmitted through the silicon wafer after passing through the collimation lens;
• a detector that is arranged to face the condenser lens and detects an interference signal caused by an optical path difference between an infrared light passing through the via hole formed in the silicon wafer and an infrared light transmitted through a portion of the silicon wafer in which a via hole has not been formed.