APPLICATION BRIEFS
`
`Semiconductor Process Analysis Software
`Incorporates Graphics Package
`
`Enhansys, Inc., is using a device-
`and machine-independent graphics
`tools package to adapt a data
`analysis software system for the
`widely different data processing
`environments of large semiconductor
`manufacturers.
`The DI-3000 graphics package
`from Precision Visuals, Inc., of
`Boulder, Colorado, gives the
`ENHANSYS system the flexibility to
`produce graphs of semiconductor
`and electronics factory data on a
`variety of output devices without
`modifying the application. The
`package supports the major main-
`frame and minicomputers used in
`industrial installations.
`In addition, Enhansys is also using
`Precision Visuals' contouring
`package, which "sits on top of' Dl-
`3000, in an application that pinpoints
`low-yield areas on wafers.
`The system enables engineers to
`retrieve and analyze the manufac-
`turing data needed for controlling
`semiconductor processes and im-
`proving product yields. The software
`provides data access, management,
`analysis, and presentation facilities to
`simplify quantitative problem solving
`in semiconductor process control.
`"We needed a graphics package
`with a high degree of both machine
`
`8
`
`Scattergram/plot produced by the ENHANSYS system, developed for semicon-
`ductor manufacturers and other industries and incorporating the DI-3000 graphics
`tools package from Precision Visuals. The package enables Enhansys to support
`more than 80 graphics devices, including raster displays, pen plotters, and film
`recorders.
`
`IEEE CG&A
`
`

`
`and device independence," says Tim
`Sherrod, vice president of develop-
`ment for the company. "By incor-
`porating DI-3000, we can accommo-
`date the variety of computers and
`graphics devices within each cus-
`tomer site and within the industry."
`
`Productivity enhancement
`
`Enhansys, of Cupertino, Cali-
`fornia, was started in 1982 to provide
`consulting and educational services in
`quantitative problem solving to the
`semiconductor manufacturing indus-
`try. The firm soon noticed that no
`common denominator existed to
`merge databases residing on different
`computers.
`According to Sherrod, factory data
`analysis has been hampered in the
`past by this isolation. Accessing that
`data and using it in a different
`computing environment often re-
`quires more computing expertise than
`most engineers and managers have.
`"It's usually too difficult for a
`manager to move data from, say, the
`company's HP-3000 and Tandem
`computers onto a VAX, because the
`two operating environments have
`nothing in common," says Sherrod.
`"As a result, a great deal of impor-
`tant data never gets used, because it
`resides in a vacuum."
`The only recourse up to now has
`been either multiple data entry or the
`use of custom programs to merge the
`different databases. Likewise, a
`summary of the data in graphics
`form has been difficult to produce,
`because such an application must
`accommodate the idiosyncrasies of
`multiple output devices.
`
`Merging data
`
`The ENHANSYS system provides
`four basic functions: data access, data
`sorting and preview, statistical
`analysis, and graphic presentation. A
`natural-language interface enables
`users to enter simple English state-
`ments to access data transparently
`from any number of workstations,
`mainframes, or minicomputers in the
`company's network. Users can then
`sort, analyze, and query a data
`subset, and obtain a hard-copy
`report.
`
`December 1985
`
`A cumulative sum chart produced by the ENHANSYS system, showing tolerance
`levels in semiconductor and other manufacturing applications.
`
`The system simplifies all phases of
`data analysis with a single user inter-
`face that has a straightforward
`syntax. The system allows the user to
`phrase the command in a number of
`ways, from a full sentence to a few
`terse words.
`The ENHANSYS statistical-
`analysis and data-presentation
`utilities facilitate problem solving in
`the factory. The system shows trends
`and potential problem areas by pro-
`viding a graphic report of factory
`information. Trends revealed in
`graphic form help engineers identify
`potential problems and their causes
`early enough to take corrective
`action.
`
`Flexibility through machine
`and device independence
`
`Enhansys recognized that
`machine independence was only half
`the battle in developing a common
`interface between several computers.
`To provide graphics on a variety of
`color raster terminals, monochrome
`
`displays, pen plotters, and raster
`printers, some kind of graphics tools
`package was needed. Enhansys
`managers assessed the cost of
`developing such a package in-house
`and decided against this approach.
`"My people are primarily applica-
`tions programmers, not graphics
`programmers," says Sherrod. "The
`purchase of DI-3000 saved us
`considerable development time and
`money."
`The company's principal criterion
`was a graphics package that could
`run on most major computers.
`Enhansys also demanded that the
`package be able to generate graphics
`on a large selection of graphics
`devices.
`"Our customers may have pen
`plotters and monochrome and color
`terminals from different manufac-
`turers all at one site," says Sherrod.
`An outside consultant recom-
`mended the purchase of the DI-3000
`graphics tools package. DI-3000 is
`an integrated system of more than
`200 callable, Fortran-compatible
`
`9
`
`

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`partitioned histograms, cumulative
`sum charts, and V-mask charts.
`Viewing the charts, the user
`determines the behavior of a certain
`parameter over time and identifies
`trends that could send a process out
`of control limits.
`
`Wafer contouring application
`uses mapping package
`Enhansys has also developed a
`wafer contouring facility based on
`Precision Visuals' contouring
`package, which works in conjunction
`with DI-3000.
`The facility provides a maplike
`contour drawing of a measured
`parameter over the surface of a semi-
`conductor wafer. When a tester
`measures oxide thickness at pre-
`defined points across the wafer, for
`example, ENHANSYS retrieves that
`data and prepares it in a grid form.
`The software then calls the contour-
`ing package, which draws a map of
`the data. Curves connect values on
`the wafer that are equal, forming a
`drawing that resembles a map of land
`elevation.
`The contour drawing helps
`engineers to see low-yield areas of the
`wafer and pinpoint processing steps
`that could contribute to the problem
`in those areas. Users can map oxide
`thickness, sheet resistance, or any
`other parameter that could vary over
`the wafer surface.
`"By viewing a contour drawing, an
`engineer can discern a problem
`caused, say, by the thumbprint of an
`inexperienced operator," says
`Sherrod. "He can also see whether it's
`an entire processing step that's going
`out of control or a machine that is
`not processing a certain section of the
`wafer properly. It's difficult to spot
`these problems because the yield over
`an otherwise good wafer may show
`up as average, though local areas
`may have serious processing defects.
`Alleviating the causes of these local
`problems can cause substantial
`increases in yield."
`Sherrod adds that the ENHAN-
`SYS system, including the contouring
`facility, could be applied to industries
`other than semiconductor manu-
`facturing.
`
`IEEE CG&A
`
`The ENHANSYS statistical and data presentation package is designed to facilitate
`problem solving in the factory through vivid graphics output.
`
`graphics subroutines that runs on
`most minicomputers, mainframes,
`and on several Unix-based micros.
`The package eliminates the need for
`programmers to support the specific
`features of each graphics peripheral;
`instead, they address a single virtual
`device that represents the combined
`characteristics of most terminals,
`plotters, film recorders, storage
`tubes, raster-scan displays, and
`calligraphic displays.
`DI-3000 is both machine and
`device independent, supporting the
`DEC VAX minicomputer and the
`IBM, Hewlett-Packard, and
`Tandem mainframes targeted by
`ENHANSYS. More than 80 dif-
`ferent graphics devices are sup-
`ported, with new drivers released
`monthly.
`Graphics package integrated
`
`DI-3000 gives Enhansys the flexi-
`bility to configure its software for
`different combinations of computers
`and graphics devices at different
`manufacturing sites.
`
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`
`Enhansys configures its system by
`installing a version of DI-3000, a
`selection of appropriate device
`drivers, and the ENHANSYS soft-
`ware on each computer in the cus-
`tomer's network. Included in each
`ENHANSYS version is a selection of
`device drivers that accommodate the
`terminals and hard-copy devices used
`by the particular installation. When a
`user logs on and specifies the type of
`device being used, the ENHANSYS
`software loads the appropriate driver.
`Enhansys programmers take ad-
`vantage of DI-3000's flexibility to
`provide users with a graphics
`environment that can be tailored for
`virtually any configuration of output
`devices. An engineer can request
`graphs from any terminal in the
`system or hard copy from any plotter
`or matrix printer. ENHANSYS
`supports any mixture of up to 12
`models of monochrome and color
`terminals from a large number of
`manufacturers.
`The ENHANSYS system produces
`scatterplots with curve fittings,