Calibration and alignment of X-ray reflectometric systems

A method of measuring the reflectivities of a thin film layer on the surface of a sample including the steps of generating a probe beam of X-rays;

• focusing said probe beam on the surface of said sample such that various X-rays within the focused probe beam create a range of angles of incidence with respect to said surface;
• measuring the intensity of various X-rays as a function of position within the probe beam as reflected with the positions of the X-rays within said reflected probe beam corresponding to specific angles of incidence with respect to said surface;
• and separately measuring the tilt of said sample in order to either adjust said tilt or to correct the X-ray measurements to account for said tilt, said tilt measuring comprising the steps of:
• generating a beam of light;
• directing said beam of light to the surface of said sample;
• reflecting said beam of light from said sample;
• measuring the reflected beam of light with a position sensitive detector;
• and
• determining changes in the tilt of said sample based on the measurements made by the position sensitive detector.

A method for measuring the tilt of a sample for use in an X-ray reflectometry system comprising the steps of:

• generating a beam of light;
• focusing said beam of light on the surface of said sample;
• measuring the reflected beam of light with a position sensitive detector;
• determining changes in the tilt of said sample based on the measurements made by the position sensitive detector;
• and
• making X-ray measurements where the determined changes in the vertical position of the said sample are used to improve the accuracy of the measurement.

A method for measuring the tilt of a sample in a system for measuring characteristics of sample, comprising:

• directing X-rays to the surface of the sample such that the X-rays are reflected off sample;
• determining characteristics of the sample based on the X-rays reflected off the sample;
• generating a beam of light;
• passing said beam of light through a beam splitter;
• using a lens to focus said beam of light on the surface of said sample;
• returning at least a portion of the reflected beam back through said lens to said beam splitter and reflecting it to a position sensitive detector;
• using said position sensitive detector to measure the beam of light;
• and
• determining changes in the tilt of said sample based upon the measurements of the position sensitive detector.

A method for measuring changes in the vertical position of a sample for use in an X-ray reflectometry system comprising the steps of:

• generating a beam of light;
• passing said beam through a beam splitter;
• using a lens to focus said beam of light on the surface of said sample;
• returning at least a portion of the reflected beam back through said lens to said beam splitter and reflecting it from said beam splitter;
• using a second lens to bring the beam reflected from said beam splitter to a focus near a chopper;
• measuring the movement of the shadow cast by said chopper using a position sensitive detector;
• determining changes in the vertical position of said sample based upon the measurements of said shadow;
• and
• making X-ray reflectometry measurements where the determined changes in the vertical position of the said sample are used to improve the accuracy of the measurement.

An X-ray reflectometer for evaluating characteristics about a sample comprising:

• an X-ray source for generating a first probe beam of X-rays directed to reflect off of the sample;
• a first detector for measuring the intensity of the reflected first probe beam and generating first output signals in response thereto;
• a processor for evaluating the sample based on the first output signals;
• a light source for generating a second probe beam directed to reflect off the sample;
• and
• a second detector for monitoring the second probe beam after it reflects off the sample and generating second output signals in response thereto, said second output signals being indicative of the orientation or vertical position of the sample and wherein said processor utilizes the second output signals to improve the evaluation of the sample.

An X-ray reflectometer for evaluating characteristics about a sample comprising:

• an X-ray source for generating a first probe beam of X-rays directed to reflect off of the sample;
• a first detector for measuring the intensity of the reflected first probe beam and generating first output signals in response thereto;
• a processor for evaluating the sample based on the first output signals;
• a light source for generating a second probe beam directed to reflect off the sample;
• and
• a second detector for monitoring the second probe beam after it reflects the sample and generating second output signals in response thereto, said second output signals being indicative of the orientation of the sample with respect to the first probe beam and the first detector and wherein said processor utilizes the second output to measure the orientation of the sample.

A method for measuring changes in the vertical position of a sample for use in an X-ray reflectometry system comprising the steps of:

• generating a beam of light;
• using a lens to focus said beam of light on the surface of said sample;
• directing at least a portion of the reflected beam to a second lens;
• using said second lens to bring the reflected beam to a focus near a chopper;
• measuring the movement of the shadow cast by said chopper using a position sensitive detector;
• determining changes in the vertical position of said sample based upon the measurements of said shadow;
• and
• making X-ray reflectometry measurements where the determined changes in the vertical position of the said sample improve the accuracy of the measurement.

A method for improving measurements in an x-ray reflectometry system comprising:

• generating a probe beam;
• directing the probe beam toward the sample such that the probe beam is reflected off the sample;
• detecting the probe beam reflected off the sample;
• determining the position of the sample based on the detected probe beam;
• and
• utilizing the determined position of the sample to improve x-ray reflectometry measurements of the sample.

A method for improving measurements in an x-ray reflectometry system comprising:

• generating a beam of light;
• directing said beam of light to the surface of said sample;
• reflecting said beam of light from said sample;
• detecting the reflected beam of light;
• determining changes in the tilt of said sample based on the reflected beam of light;
• and
• utilizing the determined position of the sample to improve x-ray reflectometry measurements of the sample.