Measuring system and measuring method

Abstract

The invention provides a measuring system and a measuring method, the measuring system comprises a light emitting module, a modulation module and a detection module, the light emitting module is used for generating first pump light and detection light; the modulation module comprises a first light splitting assembly used for splitting the first pump light into a first light beam and a second light beam; the optical switch is used for controlling on-off of an optical path of the first light beam and / or an optical path of the second light beam; the beam combining assembly is used for combining the first light beam and the second light beam which pass through the optical switch to form second pump light and irradiating the second pump light to the surface of the to-be-detected object, sound waves are formed in the to-be-detected object, and the detection light is reflected to form signal light after reaching the surface of the to-be-detected object; the detection module is used for detecting the signal light and obtaining to-be-detected information of the to-be-detected object according to the signal light. Compared with the prior art, the modulation mode in the invention can make the modulation depth of the pump light reach 100%, so that the signal-to-noise ratio of the pump light signal can be improved, and the measurement precision of the object to be measured can be improved.

Description

technical field [0001] The invention relates to the technical field of optical measurement, and more specifically, to a measurement system and a measurement method. Background technique [0002] With the development of modern technology, the size of semiconductor chips is decreasing day by day, and the processing technology of semiconductor chips is being updated day by day. However, since there are many processing steps for semiconductor chips, and any unqualified chip produced by any processing step may lead to the failure of the entire chip, therefore, in the prior art, a detection process is often introduced after the key processing steps, by detecting the film of the chip. Information such as layer thickness can be used to eliminate unqualified chips in time and improve the pass rate of chip products. [0003] An existing method for measuring the thickness of a metal thin film is a measurement method based on the photoacoustic effect and pump detection technology, whic...

AI Technical Summary

Problems solved by technology

In the prior art, the intensity of the pump light is modulated. However, since the modulation depth of the pump light often does not reach 100%, it will affect the signal-to-noise ratio of the pump light signal and affect the thickness of the film to be measured. measurement accuracy

Images