Apparatus and method for measuring the orientation of a single crystal surface
AssigneeLucent Technologies Inc.
InventorMuhammed Afzal Shahid
Life of this patent
Estimating the term…
Abstract
An apparatus and method for measuring the misorientation of a polished surface of a single crystal wafer with respect to a set of low index crystal planes utilizes both an optical beam and an X-ray beam that are directed along the same axis at the wafer. The optical beam is reflected by the polished surface of the wafer, but the X-ray beam penetrates the surface and is diffracted by the low index crystal planes located below the surface. The separation between the diffracted and reflected beams is measured with a detection device. The separation between the reflected and diffracted beams is an indication of the magnitude and sense of the misorientation between the surface and the crystal planes.
Claims26
A method for identifying the misorientation of a polished surface of an immobilized monocrystalline substrate with respect to a set of low index crystalline planes aligned in parallel relationship and formed beneath said surface, said method including the steps of:
- establishing a reference beam along a predetermined path to non-destructively penetrate said surface and diffract from said set of planes at a predictable angle to define a diffraction beam;
- guiding an optical beam along said predetermined path collinear with said reference beam to reflect from said misoriented surface of said substrate and define a reflected beam ;
- and
- determining a relative separation and position of said reflected beam from said diffraction beam, said relative separation and position representing the magnitude and sense of the misorientation between said polished surface and said crystal planes.
A system for measuring the misorientation of the polished surface of a monocrystalline substrate with respect to a vicinal low index crystal plane formed in said substrate, said system comprising:
- means for generating and directing a reference beam along a path to a point on the surface of said substrate, through said surface to the crystal plane located below said surface, and diffracted away from said crystal plane;
- means for generating and directing an optical beam collinear with the path of said reference beam so as to impinge on said point on the surface of said substrate and be reflected therefrom;
- means for receiving the optical beam reflected from said substrate;
- means for receiving the reference beam diffracted from the crystalline plane;
- and
- means for determining the angle between said reflected and diffracted beams.
A detection device for use with a measurement system for measuring the misorientation of a monocrystalline substrate surface, said system having a reference beam and an optical beam source collinearly directed to a substrate, and reflected and diffracted beams for subsequent detection, said detection device comprising:
- a multi-axis platform for providing adjustable support in multiple directions;
- a scale mounted to said platform and having an adjustment track, said track formed along a track path disposed radially equidistant from a predetermined point;
- a multi-detector mechanism mounted on said scale and including respective reference beam and optical beam detectors disposed in measurably adjustable relative relation, one of said detectors of said detection device being at said predetermined point and the other being located on a bar extending from said predetermined point to the track of said scale, said bar being adjustable along said track and said other detector being adjustable along said bar so said detectors align with said diffracted and reflected beams and define a relative spacing therebetween representing the sense and magnitude of misorientation of said polished surface with respect to a vicinal low index crystal plane.
A misorientation system for measuring the misorientation of the polished surface of a monocrystalline substrate with respect to a vicinal low index crystal plane formed in said substrate, said system comprising:
- a reference beam source for generating an energy beam;
- an optical beam source for generating an optical beam collinear with said reference beam;
- a substrate fixture disposed in-line with said reference beam and said optical beam for immobilizing said substrate in an adjusted position;
- and
- a detection device including:
- a multi-axis platform for providing adjustable support in multiple directions;
- a scale mounted to said platform and having an adjustment track, said track formed along a track path disposed radially equidistant from a predetermined point;
- and
- a multi-detector mechanism mounted adjustably to said track and including respective reference beam and light beam detectors disposed in measurably adjustable relative relation on said mechanism to determine angular separation between said reflected optical and diffracted reference beams from said substrate.
A method for measuring the misorientation of a polished surface of a substrate with respect to a set of low index crystal planes aligned in parallel relationship and formed beneath said polished surface, said method including the steps of:
- generating respective reference and optical beams;
- directing said reference beam along a predetermined path to penetrate said polished surface of said substrate and intersect at least one of said crystal planes of said substrate at an angle of incidence such that said reference beam diffracts from said set of planes at a diffraction angle equivalent to said angle of incidence;
- guiding said optical beam along said predetermined path collinear with said reference beam to intersect said polished surface such that said optical beam reflects from said surface at a reflection angle to define a reflected beam;
- and
- detecting the relative angle between said diffraction angle and said reflection angle to identify the misorientation of said polished surface.
A method for measuring the misorientation of a polished surface of a monocrystalline substrate with respect to a set of low index crystal planes formed beneath said polished surface, said method for use with a measurement system including an X-ray beam source, a visible light beam source, and a beam detection device, said method including the steps of:
- generating respective X-ray and visible light beams with said X-ray beam and light beam sources;
- directing said X-ray beam along a predetermined path to penetrate said polished surface and intersect said set of crystal planes at an angle of incidence sufficient to satisfy the Bragg condition;
- guiding said light beam along said predetermined path co-linear with said X-ray beam to intersect said polished surface such that said light beam reflects from said surface at a reflection angle to define a reflected beam;
- detecting the relative angle between said diffraction angle and said reflection angle with said beam detection device to identify the misorientation of said polished surface;
- and
- determining the relative position of said reflected beam and said diffracted beam with said beam detection device to establish a sense of said misorientation.
Dependencies are inferred from the claim text.