Semiconductor test apparatus

A semiconductor test apparatus in which a light beam emitted from a light source irradiates a measured part of a measured device via an electrooptic element arranged above the measured device and the electrical field distribution or the voltage distribution in the measured part of said measured device is calculated by electrically detecting the change in the state of the polarization of this reflected beam, comprising:

• a first optical system wherein light emitted from said light source is shaped into a line-shaped light beam and irradiates a desired measurement line on said measured device via said electrooptic element,
• a second optical system that maintains as-is the shape of the line-shaped light beam reflected from the desired measurement line on said measured device after transiting said electrooptic element, and modulates the change in polarization of said line-shaped light beam to a change in the intensity of the light,
• a light receiving device that receives the line-shaped light beam emitted from said second optical system and converts the light beam at each measured point to an electrical signal depending on the strength of each light beam reflected at each measured point on the desired measurement line on the measured device and outputs the result, and
• a signal processing device that calculates the voltage or electrical field at each of the measured points on the measured device from the output signal of said light receiving device and calculates the electrical field distribution or the voltage distribution at the measured part on the measured device.