Machine Vision, NDT and UV Lasers Top Semicon West '97

Barbara Grant

SAN JOSE, Calif. -- Semicon West '97, an international exposition highlighting innovations in the semiconductor equipment and materials
industry, brought the latest developments in wafer processing and integrated circuit test, assembly and packaging to San Francisco and San Jose from July 14 to 22.
Photonics technologies, long established as a key part of the $55 billion-a-year industry, are finding new applications in inspection, device failure analysis and shorter wavelength photolithography.

Digital Instruments' scanning probe microscopes allow companies to study the active region of semiconductor lasers Courtesy of D.V. Lang, T. Tanbun-Ek and A.M. Sergent of Lucent Bell Laboratories.

Vision systems abound
Measuring package lead dimensions, verifying product markings, tracking individual parts and automating wafer inspections are just a few of the semiconductor manufacturing tasks that benefit from photonics technology. Complex machine vision and optical inspection systems address these tasks with the help of charge-coupled device cameras, lasers, light-emitting diodes and other photonic components.
August Technologies of Edina, Minn., demonstrated an innovation for automating a second optical inspection on complex wafer and die structures. Its NSX-80 Automated Wafer and Die Defect Inspection System provides a machine-based alternative to manual inspection, which requires a human operator viewing thousands of images a day under a microscope. Besides increasing process throughput and providing consistency in the pass/fail decision process, the new system facilitates data gathering so that, at some point in the future, engineers will be able to conduct detailed failure analyses.
Other innovations provide high-resolution imaging for complex failure analysis. Digital Instruments Inc. of Santa Barbara offers a new approach to profiling carrier concentration in semiconductors: its NanoScope Dimension Series scanning probe microscopes configured for scanning capacitance microscopy. This approach provides a new analytical tool to evaluate both silicon and compound semiconductor processes and devices.
As the microchip components continue to shrink in size, systems such as the 3D Microtomographic X-ray Imaging System demonstrated by CR Technology of Laguna Niguel, Calif., which constructs three-dimensional representations from a series of two-dimensional images, will allow users to obtain detailed defect information without cutting apart the small devices.
Several efforts under way at the National Institute of Standards and Technology (NIST) in Gaithersburg, Md., reflect the industry push toward shorter-wavelength photolithography. In the National Semiconductor Metrology Program, NIST is developing stable linewidth sources and measurement techniques for optical materials characterization at 193 nm and below. Also discussed at Semicon West was the institute's efforts in conjunction with Massachusetts Institute of Technology's Lincoln Laboratories in Cambridge, Mass., to refine the refractive index values of UV-transmitting materials in support of smaller linewidths.