Spectroscopic scatterometer system

An instrument for measuring one or more parameters of a periodic diffracting structure located adjacent to a structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the periodic diffracting structure, said instrument comprising:

• a reference database that includes a plurality of ellipsometric functions, each ellipsometric function corresponding to a set of values of said one or more parameters, said values including at least values of line width, height and side wall angle of periodic diffracting structures;
• a source of broadband radiation;
• a polarizer polarizing said radiation to provide a sampling beam towards the sample;
• an analyzer for receiving radiation from the sampling beam diffracted by the periodic diffracting structure to provide an output beam;
• a spectrometer for detecting intensity data from the output beam simultaneously at a plurality of wavelengths;
• a device measuring data related to at least an index of refraction of the adjacent structure;
• a processor for controlling said polarizer and analyzer so that ellipsometric functions are measured, and determining at least the line width, height and side wall angle of the periodic diffracting structure by comparison of said measured ellipsometric functions to said ellipsometric functions in the reference database, said periodic diffracting structure located on a surface of a sample, wherein said adjacent structure is away from said periodic diffracting structure so that said data related to at least the index of refraction of the adjacent structure is measured without measuring said periodic diffracting structure, and the processor uses said data related to at least the index of refraction of the adjacent structure to reduce number of parameters of the database and processing time for determining said parameters of the periodic diffracting structure.

A scatterometer for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the periodic diffracting structure, said scatterometer comprising:

• a reference database that includes a plurality of ellipsometric functions, each ellipsometric function corresponding to a set of values of said one or more parameters, said values including at least values of line width, height and side wall angle of periodic diffracting structures;
• a source which emits broadband radiation;
• a polarizer that polarizes the broadband radiation to produce a sampling beam sampling the periodic diffracting structure;
• means for detecting ellipsometric parameters of a diffraction from the periodic diffracting structure of said broadband radiation over a range of wavelengths;
• means for comparing said detected ellipsometric parameters to said plurality of ellipsometric functions in the database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the periodic diffracting structure, wherein said comparing means determines at least the line width, height and side wall angle of the periodic diffracting structure;
• and
• a device measuring data related to at least an index of refraction of a structure adjacent to the periodic diffracting structure.

A scatterometer for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said scatterometer comprising:

• a reference database that includes a plurality of signature curves, each signature curve corresponding to a set of values of said one or more parameters, said values including at least values of line width, height and side wall angle of periodic diffracting structures;
• a source which emits broadband radiation;
• a polarizer that polarizes the broadband radiation to produce a sampling beam at an oblique angle to the sample sampling the periodic diffracting structure;
• a detector detecting intensity data of a diffraction from the periodic diffracting structure of said broadband radiation over a range of wavelengths;
• and
• a processor comparing said detected intensity data to said plurality of signature curves in the reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the periodic diffracting structure, wherein said processor determines at least the line width, height and side wall angle of the periodic diffracting structure;
• said reference database constructed using information related to film thickness of an adjacent structure that is obtained without measuring said periodic diffracting structure.

A scatterometer for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said scatterometer comprising:

• a reference database that includes a plurality of signature curves, each signature curve corresponding to a set of values of said one or more parameters, said values including at least values of line width, height and side wall angle of periodic diffracting structures;
• a source which emits broadband radiation;
• a polarizer that polarizes the broadband radiation to produce a sampling beam at an oblique angle to the sample sampling the periodic diffracting structure;
• a detector detecting intensity data of a diffraction from the periodic diffracting structure of said broadband radiation over a range of wavelengths;
• and
• a processor comparing said detected intensity data to said plurality of signature curves in the reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the periodic diffracting structure, wherein said processor determines at least the line width, height and side wall angle of the periodic diffracting structure;
• said reference database constructed using an index of refraction of an adjacent structure that is obtained without measuring said periodic diffracting structure to reduce the number of signature curves in the reference database.

A scatterometer for measuring one or more parameters of a periodic diffracting structure of a sample, said one or more parameters comprising shape of lines, linewidth, pitch, height and/or side wall angle of the structure, said scatterometer comprising:

• a reference database that includes a plurality of signature curves, each signature curve corresponding to a set of values of said one or more parameters, said values including at least values of line width, height and side wall angle of periodic diffracting structures;
• a source which emits broadband radiation;
• a polarizer that polarizes the broadband radiation to produce a sampling beam at an oblique angle to the sample sampling the periodic diffracting structure;
• a detector detecting intensity data of a diffraction from the periodic diffracting structure of said broadband radiation over a range of wavelengths;
• and
• a processor comparing said detected intensity data to said plurality of signature curves in the reference database to determine said shape of lines, linewidth, pitch, height and/or side wall angle of the periodic diffracting structure, wherein said processor determines at least the line width, height and side wall angle of the periodic diffracting structure;
• said sample comprising an adjacent structure having at least an index of refraction, said scatterometer further comprising a device measuring data related to said at least the index of refraction of the adjacent structure without measuring said periodic diffracting structure.