Position sensitive detection optimization

摘要

An automatically adjustable method for use in opto-acoustic metrology or other types of metrology operations is described. The method includes modifying the operation of a metrology system that uses a PSD style sensor arrangement. The method may be used to quickly adjust the operation of a metrology system to ensure that the data obtained therefrom are of the desired quality. Further, the method is useful in searching for and optimizing data that is or can be correlated to substrate or sample features or characteristics that of interest. Apparatus and computer readable media are also described.

主权项

1. A method for optimizing signal to noise ratio in an optical sensor comprising:
a. directing a beam of light onto a surface of a sample such that at least one characteristic of the sample is encoded in the beam of light as it interacts with the surface of the sample, the beam of light being at least partially reflected from the surface of the sample; b. directing the reflected beam of light onto an optical sensor having at least two discrete light sensitive surfaces; c. modifying an apportionment of radiant power of the reflected beam of light between the at least two discrete light sensitive surfaces; d. obtaining information from the optical sensor that is at least partially based on the apportionment of radiant power between the at least two discrete light sensitive surfaces and at least partially based on at least one of the characteristics of the sample encoded in the reflected beam of light; and, e. determining based at least in part on the information the at least one characteristic of the sample.