Abstract: A method for determining the thickness of a thin sample is described. The method includes the step of exciting time-dependent acoustic waveguide modes in the sample with an excitation radiation field. The acoustic waveguide modes are detected by diffracting probe radiation off a ripple morphology induced on the sample's surface by the acoustic waveguide modes. The diffracted probe radiation is then analyzed to measure phase velocities or frequencies of the acoustic waveguide modes. A thickness of the thin sample is determined by comparing the measured phase velocities or frequencies to the phase velocities or frequencies calculated from a mathematical model.

Abstract: A method for measuring a structure that contains overlying and underlying films in a region where the overlying film's thickness rapidly decreases until the underlying film is exposed (e.g., an edge-exclusion structure). The method includes the steps of: (1) exciting acoustic modes in a first portion of the region with at least one excitation laser beam; (2) detecting the acoustic modes with a probe laser beam that is either reflected or diffracted to generate a signal beam; (3) analyzing the signal beam to determine a property of the structure (e.g., the thickness of the overlying layer) in the first portion of the region; (4) translating the structure or the excitation and probe laser beams; and (5) repeating the exciting, detecting, and analyzing steps to determine a property of the structure in a second portion of the region.

Abstract: A method and apparatus that determines a concentration of ions implanted in a material is described. The method includes the steps of: 1) generating at least two excitation laser sub-pulses and a probe pulse from a single pulse emitted from a laser; 2) irradiating a region of the material with a grating pattern formed by overlapping at least two excitation laser sub-pulses to initiate a time-dependent response in the region; 3) diffracting a probe laser pulse off the region to generate at least one time-dependent signal beam; 4) detecting at least one time-dependent signal beam to generate a signal waveform; and 5) processing the signal waveform to determine the concentration of ions implanted in the material.

Abstract: A method for determining the thickness of a thin sample is described. The method includes the step of exciting time-dependent acoustic waveguide modes in the sample with an excitation radiation field. The acoustic waveguide modes are detected by diffracting probe radiation off a ripple morphology induced on the sample's surface by the acoustic waveguide modes. The diffracted probe radiation is then analyzed to measure phase velocities or frequencies of the acoustic waveguide modes. A thickness of the thin sample is determined by comparing the measured phase velocities or frequencies to the phase velocities or frequencies calculated from a mathematical model.

Abstract: The invention provides an apparatus for measuring a property of a sample (using, e.g., ISTS) that includes: 1) an excitation laser that generates an excitation laser beam; 2) an optical system aligned along an optical axis that separates the excitation laser beam into at least three sub-beams; 3) an imaging system aligned along the optical axis that collects the sub-beams and focuses them onto the sample to form an optical interference pattern that generates a time-dependent response in the sample; 4) a probe laser that generates a probe laser beam that diffracts off the time-dependent response to form a signal beam; 5) a detector that detects the signal beam and in response generates a radiation-induced electronic response; and 6) a processor that processes the radiation-induced electronic response to determine the property of the sample.

Abstract: An apparatus for measuring a property of a structure comprising at least one layer, the appratus including a light source that produces an optical pulse having a duration of less than 10 ps; a diffractive element that receives the optical pulse and diffracts it to generate at least two excitation pulses; an optical system that spatially and temporally overlaps at least two excitation pulses on or in the structure to form an excitation pattern, containing at least two light regions, that launches an acoustic wave having an out-of-plane component that propagates through the layer, reflects off a lower boundary of the layer, and returns to a surface of the structure to modulate a property of the structure; a light source that produces a probe pulse that diffracts off the modulated property to generate at least one signal pulse; a detector that receives at least one signal pulse and in response generates a light-induced electrical signal; and an analyzer that analyzes the light-induced electrical signal to measur

Abstract: A method and apparatus that determines a concentration of ions implanted in a material is described. The method includes the steps of: (1) passing an excitation pulse through a diffracting mask (e.g., a phase or amplitude mask) to generate at least two excitation laser sub-pulses; (2) irradiating a region of the material with a grating pattern, formed by overlapping two excitation laser sub-pulses in time and space to initiate a time-dependent response (e.g., a change in refractive index) in the region; (3) diffracting a probe laser pulse having a duration that is at least long as the time-dependent response off the region to generate a time-dependent signal beam; (4) detecting the time-dependent signal beam to generate a signal waveform; and (5) processing the signal waveform to determine the concentration of ions implanted in the material.

Abstract: A method for determining the thickness of a thin sample is described. The method includes the step of exciting time-dependent acoustic waveguide modes in the sample with an excitation radiation field. The acoustic waveguide modes are detected by diffracting probe radiation off a ripple morphology induced on the sample's surface by the acoustic waveguide modes. The diffracted probe radiation is then analyzed to measure phase velocities or frequencies of the acoustic waveguide modes. A thickness of the thin sample is determined by comparing the measured phase velocities or frequencies to the phase velocities or frequencies calculated from a mathematical model.