Methods And Systems For In-Situ Discovery Of Illumination Angles In Semiconductor Measurements

A semiconductor measurement system comprising:

• an illumination source configured to generate an amount of illumination radiation incident on a surface of a semiconductor wafer at a measurement site, wherein one or more structures are fabricated on the semiconductor wafer at the measurement site;
• a specimen positioning system configured to orient the semiconductor wafer about a first axis and a second axis at the measurement location, wherein the first and second axes are aligned with the surface of the semiconductor wafer and the second axis is orthogonal to the first axis;
• a detector configured to detect a first amount of collected radiation from the semiconductor wafer in response to the incident amount of illumination radiation at a plurality of azimuth angles and a first nominal angle of incidence while the specimen positioning system scans the semiconductor wafer about the first axis and the second axis simultaneously such that the surface of the semiconductor wafer is oriented with respect to the incident amount of illumination radiation over a range of azimuth angles at the first nominal angle of incidence;
• and
• a computing system configured to:
• estimate a value of an tilt azimuth angle associated with an alignment between the incident amount of illumination radiation and a feature of the one or more structures fabricated on the semiconductor wafer based on the first amount of collected radiation.

A method comprising:

• generating an amount of illumination radiation incident on a semiconductor wafer at a measurement site at one or more nominal angles of incidence, wherein one or more structures are fabricated on the semiconductor wafer at the measurement site;
• detecting a first amount of collected radiation from the semiconductor wafer in response to the incident amount of illumination radiation at each of the one or more nominal angles of incidence;
• estimating values of one or more actual angles of incidence of the incident amount of illumination radiation with respect to the semiconductor wafer associated with each of the one or more nominal angles of incidence;
• and
• estimating a value of a parameter of interest characterizing the one or more structures fabricated on the surface of the semiconductor wafer based at least in part on the detected first amount of collected radiation and the values of the one or more actual angles of incidence.

A method comprising:

• generating an amount of illumination radiation incident on a surface of a semiconductor wafer at a measurement site, wherein one or more structures are fabricated on the semiconductor wafer at the measurement site;
• orienting the semiconductor wafer about a first axis and a second axis at the measurement location, wherein the first and second axes are aligned with the surface of the semiconductor wafer and the second axis is orthogonal to the first axis;
• detecting a first amount of collected radiation from the semiconductor wafer in response to the incident amount of illumination radiation at a plurality of azimuth angles and a first nominal angle of incidence while orienting the semiconductor wafer about the first axis and the second axis simultaneously;
• and
• estimating a value of an tilt azimuth angle associated with an alignment between the incident amount of illumination radiation and a feature of the one or more structures fabricated on the semiconductor wafer based on the first amount of collected radiation.