Nanometrics Inc.

American Optical Corporation

Duane C Holmes

Guillermo L Toro-Lira

John D Heaton

Vincent J Coates

An optical measurement instrument that detects and analyzes reflected light includes a sample support, such as a wafer supporting chuck, with a sample bearing surface that is configured so as to not reflect light back to the optical measurement instrument. In one embodiment, the sample bearing surface of the sample support is a layer of material that absorbs light in the wavelength or wavelengths being used by the optical measurement instrument. For example, a hard plastic, such as poly-ether-ether-ketone (PEEK), may be used to absorb light in the infrared wavelengths. In another embodiment, the entire sample support may be manufactured from the light absorbing material. In yet another embodiment, the top surface of the sample support is configured with light scattering depressions, which prevent light that is incident on the sample bearing surface from being reflected back to the optical measurement instrument.

Sample support with a non-reflecting sample supporting surface

A measuring instrument with a parfocal combination of an ultra-violet to near-infrared (UV-NIR) spectrophotometer and a Fourier Transform Infrared (FTIR) spectrometer is disclosed. The parfocal configuration of metrology tools obviates lateral movement of the sample between two separate measurement instruments. Consequently, the area occupied by the parfocal measuring instrument is reduced. Moreover, throughput is increased because there is no need to reposition the sample to properly align the measurement area for the separate measurements. The measuring instrument also includes an imaging apparatus, such as a camera or microscope ocular, to accurately position the measurement area of the sample. Beam directing elements, such as a mirror and objective lenses, are mounted on a common movable member. The common movable member, which may be, e.g., a linear or rotating turret, moves to properly align the desired beam directing element, thereby selecting the specific metrology mode. In addition, the measurement instrument includes a purging shroud along the FTIR spectrometer optical path to efficiently purge any atmospherical gases that may interfere with the FTIR measurement technique.

Integrated optical measurement instruments

A computerized stage assembly for a Scanning Electron Microscope including a support frame, a tilt frame pivotally coupled to the support frame, an X carriage engaged with the tilt frame for movement in an X direction, a Y carriage engaged with the X carriage for movement in a Y direction, and a pedestal carried by the Y carriage and capable of rotation around an axis substantially normal to both the X and Y directions. The tilt frame, X and Y carriages, and pedestal are moved by computer controlled step motors. The tilting and rotating of a specimen secured to the pedestal is non-eucentric, i.e. the axis of rotation or tilt is not necessarily through the point of inspection on the specimen. A method is disclosed for automatically returning an inspection point to the viewing field of the microscope after a non-eucentric rotation or tilt.

Microscope stage assembly and control system

In scanning electron microscopes the field established between the focusing lens housing at ground potential and the secondary emission electron detector at a positive potential attracts and carries the secondary electrons to the detector. This field is often displaced from the secondary emission source so that much of the emission is attracted to other areas of the microscope and is lost to the detector. To greatly improve detection efficiency, an electron attracting grid at a potential between that on the detector and the focusing lens housing ground reference potential is interposed between the detector and the specimen and positioned so that the new field established between grid and lens housing dips down toward the specimen surface and thus collects substantially all of the secondary emission electrons which then are attracted to higher potential on the detector.

Three-stage secondary emission electron detection in electron microscopes

In a scanning charged particle microprobe such as a scanning electron microscope, means for generating an exponentially decaying electrical signal and means for generating a step function signal to be summed and applied to the microprobe to cause it to deflect in a step function compensated for the effects of eddy current induced fields.

Scanning electron microscope with eddy-current compensation

A scanning electron microprobe and display system adaptable to stereoscoptic or side-by-side viewing of an image for comparison on a television type monitor. The apparatus includes means for scanning the microprobe beam in a raster over a specimen and displaying the image on the cathode ray tube viewer. The microprobe beam scan is synchronized to the beam of the cathode ray tube and the cathode ray tube horizontal scan is blanked over a portion of its extent for sequential fields. For stereo viewing, the angle of incidence of the microprobe is varied in relation to the blanking sequence to provide side-by-side images on the cathode ray tube, each of which are generated from different microprobe incidence angles.

Growing community of inventors

San Jose, CA, United States of America

Duane C Holmes