Systems for measuring periodic structures

An apparatus for measuring one or more parameters of a periodic structure, comprising:

• an instrument directing a polychromatic beam of electromagnetic radiation to the structure;
• optics collecting radiation from the beam after it has been modified by the structure;
• a device dividing the collected radiation into two collected rays having different polarization states;
• detectors detecting the two rays to provide two outputs;
• and
• a processor deriving the one or more parameters from the two outputs.

A method for measuring one or more parameters of a periodic structure, comprising:

• (a) directing a polychromatic beam of electromagnetic radiation to the structure in a plane of incidence;
• (b) collecting radiation from the beam after it has been modified by the structure;
• (c) passing the collected radiation through a first polarizing element having a polarization plane at a first angle to the plane of incidence;
• (d) detecting the collected radiation passing through the element to provide an output;
• (e) altering the first angle between the two planes to a different value and repeating (a), (b), (c) and (d), wherein said different value remains substantially stationary when (a), (b), (c) and (d) are repeated to provide at least an additional output;
• and
• (f) deriving the one or more parameters from the outputs.

An apparatus for measuring one or more parameters of a periodic structure, comprising:

• a source directing a polychromatic beam of electromagnetic radiation to the structure in a plane of incidence;
• optics collecting radiation from the beam after it has been modified by the structure;
• a first polarizing element having a polarization plane at a first angle to the plane of incidence passing the collected radiation;
• a detector detecting the collected radiation that has passed through the element to provide an output;
• an instrument rotating the first element relative to the plane of incidence to alter the value(s) of the first angle to one or more different value(s) that remain substantially stationary when said detector is detecting the collected radiation, so that the detector provides at least one output before and alter the first angle is altered;
• and
• a processor deriving the one or more parameters from the outputs.

An apparatus for measuring one or more parameters of a periodic structure, comprising:

• an optical device including a first element directing a polychromatic beam of electromagnetic radiation to the structure in a plane of incidence and a second optical element passing radiation from the beam after it has been modified by the structure, said two elements attached together to form an integrated unit or being an integral unit;
• said second element having a plane of polarization;
• and
• at least one detector detecting the collected radiation that has passed through the second element to provide at least one output.

An apparatus for inspecting a sample having a periodic structure thereon, comprising:

• (a) a detection system including:
• a device directing a polychromatic beam of electromagnetic radiation to the structure;
• optics collecting radiation from the beam after it has been modified by the structure;
• and
• at least one detector detecting the collected radiation to provide at least one output;
• (b) a first instrument causing translational motion of the sample in a first direction;
• (c) a second instrument causing translational motion between the first instrument and the system in a second direction transverse to the first direction;
• and
• (d) a processor deriving one or more parameters of the periodic structure from the at least one output.

An apparatus for inspecting a sample having a structure thereon, comprising:

• (a) a detection system including:
• a device directing a polychromatic beam of electromagnetic radiation to illuminate a spot on the structure;
• optics collecting radiation from the beam after it has been modified by the structure;
• and
• at least one detector detecting the collected radiation to provide at least one output, said detector comprising a spectrometer detecting the collected radiation at a plurality of distinct wavelengths simultaneously;
• (b) first instrument causing first motion of the sample, and
• (c) a second instrument causing second motion between the first instrument and the system to move location of the illuminated spot on the structure, wherein one of the two motions is translational and the remaining motion is translational or rotational.

An integrated processing and detection apparatus for processing a sample having structures thereon, comprising:

• (a) a detection system for finding one or more parameters of a structure, wherein the system detects the structure by directing a polychromatic beam of electromagnetic radiation to the structure, collecting radiation from the beam after it has been modified by the structure;
• said system including:
• a device dividing the collected radiation into two collected rays having different polarization states;
• detectors detecting the two rays to provide two outputs;
• and
• a processor deriving the one or more parameters from the two outputs;
• and
• (b) a processing system processing the sample, said processing system responsive to said one or more parameters for adjusting a processing parameter.

An integrated processing and detection apparatus for processing a sample having structures thereon, comprising:

• (a) a detection system for finding one or more parameters of a structure, wherein the system detects the structure by directing a polychromatic beam of electromagnetic radiation to the structure in a plane of incidence, collecting radiation from the beam after it has been modified by the structure;
• said detection system including:
• a first polarizing element having a polarization plane at a first angle to the plane of incidence passing the collected radiation;
• a detector detecting the collected radiation that has passed through the element to provide an output;
• an instrument rotating the first element relative to the plane of incidence to alter the value(s) of the first angle to one or more different value(s) that remain substantially stationary when said detector is detecting the collected radiation, so that the detector provides at least one output before and after the first angle is altered;
• and
• a processor deriving the one or more parameters from the outputs;
• (b) a processing system processing the sample, said processing system responsive to said one or more parameters for adjusting a processing parameter.

An integrated processing and detection apparatus for processing a sample having a structure thereon, comprising:

• (a) a detection system including:
• a device directing a polychromatic beam of electromagnetic radiation to the structure;
• optics collecting radiation from the beam after it has been modified by the structure;
• and
• at least one detector detecting the collected radiation to provide at least one output;
• (b) a first instrument causing motion of the sample;
• (c) a second instrument causing relative motion between the first instrument and the system so that the beam has access to any location of the sample;
• and
• (d) a processing system processing the sample, said processing system responsive to said at least one output for adjusting a processing parameter.

A scatterometry instrument integrated within a wafer measurement station that forms one station of wafer process tool, the wafer measurement station having a spectrometry instrument and a wafer support with a capacity for locating a wafer at a measurement position, wherein the scatterometry instrument comprises:

• a movable stage;
• an optical measurement system mounted on said stage for movement by said stage to one or more specified locations over a wafer held by a wafer support in the measurement position, the measurement system being in optical communication with a light source for directing a light beam as a spot onto patterned features on a wafer on the wafer support, the measurement system having collection optics associated with a detector for collecting and detecting light scattered from the portion of the wafer illuminated by the light beam, whereby features on the wafer yield characteristic optical signatures with independent optical parameters of the signatures;
• and
• a data processor in communication with the detector, the data processor analyzing the characteristic optical signatures using a scattering model for possible periodic structures on a wafer to obtain a measure of the patterned features on the wafer such that a process carried out by the wafer process tool can be analyzed.

A wafer measurement method for cooperative use with a wafer process tool, comprising:

• within the wafer process tool after completion of a process step carried out in processing stations of the process tool, receiving in an integrated measuring station of the process tool a wafer in the measurement station relative to a moveable optical measurement system;
• moving an optical measurement system to a plurality of locations over the wafer;
• directing a beam of light normally onto the wafer surface as a light spot at each of said plurality of locations;
• detecting light reflected from the wafer surface to obtain data for an optical characteristic of surface pattern features on the wafer at said plurality of locations;
• and
• analyzing the optical characteristic data using a scattering model of possible periodic structures on a wafer to obtain a measure of critical dimensions of the surface pattern features on the wafer.

A method of measuring a wafer within a wafer process tool, comprising:

• transferring a wafer from a process station of the process tool to a measurement station of the process tool;
• positioning a measurement spot of an optical head of a scatterometry measurement instrument within the measurement station over a first location of the wafer;
• rotating the wafer and translating the optical head to position the measurement spot over a second location of the wafer;
• repeating the wafer rotation and optical head translation to successively position the measurement spot over different locations of the wafer;
• and
• measuring an optical characteristic of the wafer by detecting radiation scattered from patterned features on the wafer at each of the successive measurement locations.