Apparatus for characterization of microelectronic feature quality
AssigneesLam Research Corporation, Verity Instruments, Inc.
InventorsRandall S. Mundt, Albert J. Lamm, Mike Whelan, Andrew Weeks Kueny
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Abstract
Apparatus characterizes the quality of microelectronic features using broadband white light. A highly collimated light source illuminates an area of a first wafer using broadband multi-spectral light. The angular distribution of the light scattered from the first wafer is then measured. Generally, the angle of the light source, detector, or both is altered and an angular distribution measurement taken at each angle, producing a scatter signature for the first wafer. Finally, the scatter signature of the first wafer is compared with a known scatter signature of a second wafer of good quality to determine the quality of the first wafer.
Claims29
An apparatus for monitoring feature characteristics of etched wafers, comprising:
- a broadband collimated light source suitable for illuminating a surface of a first wafer with a light beam;
- a light detector suitable for sensing light scattered from the illuminated surface of the first wafer;
- a motor for independently controlling an incident angle at which the light beam intersects the surface of the wafer;
- a control system capable of independently controlling and monitoring the angular orientation of the incident angle;
- and
- a computer for comparing a scattered signature of the first wafer with a known signature of a second wafer.
An apparatus for monitoring feature characteristics of etched wafers comprising:
- a broadband collimated light source, said collimated light source for illuminating an area of a first wafer utilizing one light beam, wherein the one light beam from the light source is broadband multi-spectral light, wherein the entire one beam illuminates the area from one angle to a surface of the wafer at any one time and the one beam is scattered from the illuminated area, wherein the one angle of the light beam illuminating the illuminated area is varied at different times in the range of about normal to the surface of the wafer to about seventy degrees to the surface;
- a measurement means for measuring an angular distribution of the light scattered from the illuminated area of the first wafer, the measurement of the distribution being gathered at variable angles, each of the variable angles having a fixed angle of offset from a respective one of the varied angles of the one light beam illuminating the illuminated area;
- and
- a comparison means for comparing a scatter signature of the first wafer obtained from the measuring of the one beam with a known scatter signature of a second wafer in order to determine a quality of the first wafer.
An apparatus for monitoring feature characteristics of etched wafers comprising:
- a broadband collimated light source, said collimated light source for illuminating an area of a first wafer, wherein light from the light source that is incident on the illuminated area is broadband multi-spectral light that is scattered from the illuminated area to form scattered light at various scattering angles, the size of the illuminated area being no less than 50% of a repeating unit size of a feature characteristic of the wafer;
- a measurement means for measuring the intensity of the light scattered from the illuminated area of the first wafer;
- and
- a comparison means for comparing a scatter signature of the first wafer with a known scatter signature of a second wafer.
An apparatus for monitoring feature characteristics of etched wafers, the feature characteristics including a plurality of die on the surface of the wafer, the die having an average size, the apparatus comprising:
- a broadband collimated light source for illuminating an area of a first wafer, wherein the size of the illuminated area has a value approximately equal to the average die size, wherein light from the light source that is incident on the illuminated area is broadband multi-spectral light that is scattered from the illuminated area to form scattered light;
- a measurement means for measuring the intensity of the light scattered from the illuminated area of the first wafer;
- and
- a comparison means for comparing a scatter signature of the first wafer with a known scatter signature of a second wafer.
An apparatus for monitoring feature characteristics of etched wafers, comprising:
- a broadband collimated light source suitable for illuminating an area on a surface of a wafer with a light beam;
- a movable source arm coupled to the broadband collimated light source for repositioning the broadband collimated light source relative to the wafer, said movable source arm suitable for altering a magnitude of an incident angle, wherein said incident angle defined as an angle between the light beam and the surface of the wafer;
- a light detector suitable for sensing a scattering light beam from the illuminated area on the surface of the wafer;
- a movable detector arm coupled to the light detector for repositioning the light detector relative to the wafer, said movable detector arm suitable for altering a magnitude of a scattering angle, wherein said scattering angle defined as an angle between the scattering light beam and the surface of the wafer;
- and
- a data acquisition and control computer for analyzing light intensity data of the scattering light beam sensed by the light detector.
Dependencies are inferred from the claim text.