Surface properties detection by reflectance metrology

A method of measuring a selected surface property of a surface of a semiconductor substrate, the method comprising:

• directing electromagnetic radiation having a plurality of selected wavelengths from each of a plurality of slave reflectometers to a respect slave area on a surface of a test semiconductor substrate, where a selected surface property of the surface of the test semiconductor substrate is known;
• measuring the quantity and variation thereof of electromagnetic radiation at each of the selected wavelengths that is reflected off the respective slave areas of the surface of the test semiconductor substrate from each of the plurality of slave reflectometers, each said slave reflectometers communicating the respective measured quantity and variation thereof of electromagnetic radiation at each of the selected wavelengths to as signal data to a master data channel;
• receiving said signal data from the master data channel communicated by said plurality of slave reflectometers, and for each of said slave areas:
• determining a target wavelength from among the plurality of selected wavelengths that has substantially the highest the change in the ratio of reflected electromagnetic radiation off the slave area of surface of the test semiconductor substrate divided by incident electromagnetic radiation to the slave area of the surface of the test semiconductor substrate;
• directing electromagnetic radiation at the target wavelength for each respective slave reflectometer to a respective slave area of a surface of a production semiconductor substrate for which the selected surface property is unknown;
• measuring the quantity of electromagnetic radiation at the target wavelength that is reflected off the respective slave area of the surface of the production semiconductor substrate from the respective slave reflectometer of the plurality of slave reflectometers, each said slave reflectometers communicating the respective measured quantity of reflected electromagnetic radiation at the target wavelength for each respective slave area as signal data to a master data channel;
• receiving said signal data from the master data channel communicated by said plurality of slave reflectometers, and
• determining with the selected surface property for each said slave areas of the surface of the production semiconductor substrate when the numerical difference between a selected target amount and the signal data from the master data channel communicated by said plurality of slave reflectometers is within a selected master numerical range.

An apparatus for determining a selected surface property of a surface on a semiconductor substrate, said apparatus comprising:

• a plurality of slave reflectometers for each performing a slave reflectometer process comprising:
• directing electromagnetic radiation at a target wavelength to a slave area on the surface of the semiconductor substrate for which a selected surface property is unknown;
• measuring the quantity of electromagnetic radiation at the target wavelength that is reflected off the slave area on the surface of the semiconductor substrate, and communicating same as signal data to a master data channel;
• and
• determining the selected surface property for each of the slave areas on the surface of the semiconductor substrate from said signal data from the master data channel communicated by said plurality of slave reflectometers when the numerical difference between a selected target amount and the signal data from the master data channel communicated by said plurality of slave reflectometers is within a selected master numerical range.

A method of forming a contact plug comprising:

• forming an electrically conductive material on a semiconductor substrate, said electrically conductive material being formed in between and adjacent to a pair of raised structures on the semiconductor substrate;
• directing electromagnetic radiation at a target first wavelength towards an area adjacent to the electrically active area where a top surface of each of the raised structures is desired to be situated;
• measuring the quantity and variation thereof of electromagnetic radiation at the target first wavelength that is reflected,
• determining the selected first surface property for a surface from which the electromagnetic radiation at the target first wavelength was reflected when the numerical difference between a target first amount and the quantity of electromagnetic radiation at the target first wavelength that was reflected is within a selected first numerical range;
• directing electromagnetic radiation at a target second wavelength towards the electrically active area where a top surface of the electrically conductive material is desired to be situated;
• measuring the quantity of electromagnetic radiation at the second target wavelength that is reflected;
• and
• determining the selected second surface property for a surface from which the electromagnetic radiation at the second target wavelength was reflected when the numerical difference between a target second amount and the quantity of electromagnetic radiation at the target second wavelength that was reflected is within a selected second numerical range.

A method of measuring a selected surface property of a surface of a semiconductor substrate, the method comprising:

• directing electromagnetic radiation having a plurality of selected wavelengths to a surface of a test semiconductor substrate, where a selected surface property of the surface of the test semiconductor substrate is known;
• measuring the quantity and variation thereof of electromagnetic radiation at each of the selected wavelengths that is refracted from the surface of the test semiconductor substrate;
• determining a target wavelength from among the plurality of selected wavelengths that has substantially the highest the change in the ratio of refracted electromagnetic radiation off the surface of the test semiconductor substrate divided by incident electromagnetic radiation to the surface of the test semiconductor substrate;
• directing electromagnetic radiation at the target wavelength to a surface of a production semiconductor substrate for which the selected surface property is unknown;
• measuring the quantity of electromagnetic radiation at the target wavelength that is refracted from the surface of the production semiconductor substrate;
• and
• determining the selected surface property for the surface of the production semiconductor substrate when the numerical difference between the measured quantity of electromagnetic radiation at the target wavelength that is refracted from the surface of the test semiconductor substrate and the measured quantity of electromagnetic radiation at the target wavelength that is refracted from the surface of the production semiconductor substrate is within a selected numerical range.

A method of measuring a selected surface property of a surface of a semiconductor substrate, the method comprising:

• directing electromagnetic radiation having a plurality of selected wavelengths to a surface of a test semiconductor substrate, where a selected surface property of the surface of the test semiconductor substrate is known;
• measuring the quantity and variation thereof of electromagnetic radiation at each of the selected wavelengths that is reflected or refracted from the surface of the test semiconductor substrate;
• determining a target wavelength from among the plurality of selected wavelengths that has substantially the highest the change in the ratio of reflected or refracted electromagnetic radiation off the surface of the test semiconductor substrate divided by incident electromagnetic radiation to the surface of the test semiconductor substrate;
• directing electromagnetic radiation at the target wavelength to a surface of a production semiconductor substrate for which the selected surface property is unknown;
• measuring the quantity of electromagnetic radiation at the target wavelength that is reflected or refracted from the surface of the production semiconductor substrate;
• and
• determining the selected surface property for the surface of the production semiconductor substrate when the numerical difference between the measured quantity of electromagnetic radiation at the target wavelength that is reflected or refracted from the surface of the test semiconductor substrate and the measured quantity of electromagnetic radiation at the target wavelength that is reflected or refracted from the surface of the semiconductor substrate is within a selected numerical range.