Method and system for optical inspection of a structure formed with a surface relief

A method for in-process inspecting of a semiconductor wafer comprising a surface relief of a developed photoresist layer, the method comprising:

• (i) providing reference data indicative of a spectrum of photometric intensities of broad band light components of different wavelengths returned from the wafer;
• (ii) continuously applying spectrophotometric measurements with broad band illumination to successive locations within the surface relief on the wafer along a measurement slice thereon;
• (iii) detecting measured data in the form of a single spectrum indicative of photometric intensities of light components of different wavelengths returned from the successive locations within the slice;
• and
• (iv) analyzing the measured data to determine whether it correlates with said reference data in accordance with predetermined criteria results.

A method for carrying out a photolithography process applied to a semiconductor wafer, the method comprising:

• coating the wafer with a photoresist layer;
• exposing the photoresist layer;
• developing the exposed layer, thereby creating a pattern in the form of a surface relief;
• and
• continuously applying spectrophotometric measurements with broad band illumination to successive locations within a surface relief of the wafer, detecting measured data in the form of a single spectrum indicative of photometric intensities of light components of different wavelengths returned from the successive locations along a slice, and analyzing the measured data so as to determine whether it correlates with reference data in accordance with predetermined criteria results.

A method for controlling a process consisting of creating a pattern in the form of a surface relief on a structure, the method comprising:

• providing reference data indicative of photometric intensities of broad band light components of different wavelengths returned from a structure having a pattern similar to the pattern to be created;
• continuously applying spectrophotometric measurements with broad band illumination to successive locations within the surface relief on the structure along a measurement slice thereon;
• detecting measured data in the form of a single spectrum indicative of photometric intensities of light components of different wavelengths returned from the successive locations within the slice;
• analyzing the measured data to determine whether it correlates with said reference data in accordance with predetermined criteria results;
• and
• utilizing analysis results for closed loop control of the pattern creation process.

A system comprising a pattern-creating tool to be applied to a structure to create a pattern thereon in the form of a surface relief, and a measurement unit operable for applying optical measurements to the patterned structure and carrying quality control of the surface relief, the system comprising:

• a translation unit operable to carry out a relative displacement between the patterned structure and an optical arrangement of the measurement unit;
• a spectrophotometer operable to apply spectrophotometric measurements by illuminating the structure with broad band light, detecting light returned from the illuminated structure, and generating a measured spectral data indicative thereof;
• and
• a control unit that operates said translation unit to provide said relative displacement to sequentially bring to the measurements successive locations along a slice on the structure, and operates said spectrophotometer to continuously apply the spectrophotometric measurements during said displacement, said measured data being thereby indicative of a single spectrum of photometric intensities of light components of different wavelengths returned from the successive locations along the slice, the control unit operating to be responsive to the measured data and analyzes it with respect to reference data indicative of photometric intensities of light components of different wavelengths returned from a structure having a pattern similar to said pattern of the structure under inspection, so as to determine a correlation between the measured data and reference data in accordance with predetermined criteria results.

A photolithography tools arrangement to be applied to a semiconductor wafer to create a pattern thereon in the form of a surface relief of a developed photoresist, the arrangement being provided with an optical measurement unit and a translation unit operable to carry out a relative displacement between the wafer and an optical arrangement of the measurement unit, the measurement unit comprising:

• a spectrophotometer operable to apply spectrophotometric measurements to the structure by illuminating the structure with broad band light, detect light returned from the illuminated structure, and generate a measured data indicative thereof;
• and
• a control unit that operates said translation unit to provide said relative displacement so as to sequentially bring to the measurements successive locations along a slice on the structure, and operates said spectrophotometer to continuously apply the spectrophotometric measurements during said displacement, said measured data being thereby indicative of a single spectrum of photometric intensities of light components of different wavelengths returned from the successive locations along the slice, the control unit operating to be responsive to the measured data and analyzes it with respect to reference data indicative of photometric intensities of light components of different wavelengths returned from a structure having a pattern similar to said pattern of the structure under inspection, and determine a correlation between the measured data and reference data in accordance with predetermined criteria results.