Two-dimensional optical scatterometer apparatus and process

An optical scatterometer system comprising:

• a sample material having periodic and diffractive microstructure characteristics to be analyzed;
• light source means for transmitting an incident light beam to illuminate a point on the sample material;
• screen means positioned between said sample material and said light source means to receive and scatter a pattern representative of light specularly reflected from said sample material and light scattered from said sample material, said screen means including an aperture therein through which said incident light beam is directed to illuminate said point on said sample material;
• camera means positioned on the same side of said screen means as said light source means;
• specularly reflecting curved element positioned on the same side of said screen means as said sample material for directing light scattered from said screen means through said aperture to said camera means for recording thereby;
• and
• microprocessor means coupled to said camera means for processing electrical signals received therefrom to provide a two-dimensional intensity distribution of the light scattered from said screen means and directed through said aperture by said specularly reflecting curved element that is recorded by said camera means, said two-dimensional intensity distribution being indicative of the periodic and diffractive microstructure characteristics of said sample material.

An optical scatterometer system comprising:

• a sample material having periodic and diffractive microstructure characteristics to be analyzed;
• light source means for transmitting an incident light beam to illuminate a point on the sample material;
• reflector means positioned for receiving said incident light beam and for directing it onto said sample material to illuminate said point on said sample material and for receiving light specularly reflected from said sample material and for directing said light specularly reflected from said sample material away from said optical scatterometer system;
• screen means positioned to receive and display a pattern representative of light scattered from said sample material;
• camera means positioned to record the pattern displayed on said screen means;
• and
• microprocessor means coupled to said camera means for processing electrical signals received therefrom to provide a two-dimensional intensity distribution of the pattern recorded by said camera means, said two-dimensional intensity distribution being indicative of the periodic and diffractive microstructure characteristics of said sample material.

An optical scatterometer system comprising:

• a sample material having periodic and diffractive microstructure characteristics to be analyzed;
• light source means for transmitting an incident light beam to illuminate a point on the sample material;
• reflector means positioned for receiving said incident light beam and for directing it onto said sample material to illuminate said point on said sample material;
• additional reflector means for receiving light specularly reflected from said sample material and for directing said light specularly reflected from said sample material away from said optical scatterometer system;
• screen means positioned to receive and display a pattern representative of light scattered from said sample material;
• camera means positioned to record the pattern displayed on said screen means;
• and
• microprocessor means coupled to said camera means for processing electrical signals received therefrom to provide a two-dimensional intensity distribution of the pattern recorded by said camera means, said two-dimensional intensity distribution being indicative of the periodic and diffractive microstructure characteristics of said sample material.

An optical scatterometry process for analyzing periodic and diffractive microstructure characteristics of a sample material, the process comprising the steps of:

• transmitting an incident light beam to illuminate a point on the sample material;
• positioning a screen to receive and display a pattern representative of light specularly reflected from the sample material and light scattered from the sample material, the screen including one or more apertures therein for passing the incident light beam and a selected one or both of the light specularly reflected from the sample material and a portion of the light scattered from the sample material, to thereby prevent the selected one or both of the light specularly reflected from the sample material and said portion of the light scattered from the sample material from being received and displayed on the screen;
• recording the pattern displayed on the screen;
• and
• processing information representative of the pattern recorded to provide a two-dimensional intensity distribution of the pattern recorded, the two-dimensional intensity distribution being indicative of the periodic and diffractive microstructure characteristics of the sample material.

An optical scatterometer system comprising:

• a sample material having periodic and diffractive microstructure characteristics to be analyzed;
• light source means for transmitting an incident light beam to illuminate a point on the sample material;
• screen means positioned between said sample material and said light source means to receive and display a pattern representative of light specularly reflected from said sample material and light scattered from said sample material, said screen means being constructed of a material that permits the pattern displayed thereon to be viewed from a side of the screen means opposite said sample material, said screen means including an aperture therein through which said incident light beam is directed to illuminate said point on said sample material;
• camera means positioned on the same side of said screen means as said light source means to record the pattern displayed on said screen means;
• and
• microprocessor means coupled to said camera means for processing electrical signals received therefrom to provide a two-dimensional intensity distribution of the pattern recorded by said camera means, said two-dimensional intensity distribution being indicative of the periodic and diffractive microstructure characteristics of said sample material.