The emerging GUI standard
06/01/1999
A standard for graphical user interfaces (GUIs) on all semiconductor manufacturing equipment is expected to be endorsed by Semi members in time for Semi West next month, followed by formal committee approval at the July show. This draft document 2873B has been over two years in the making, including changes from two balloting cycles, and culminates a 10-year effort driven by manufacturers, equipment suppliers, Sematech, J300, I300I, and others.
It has become critically important to develop a simple, ergonomically sound, common user interface centered on ease of use and aimed at making production tasks more uniform and less error-prone. Up to now on the fab floor, disparate GUI implementations have resulted in exorbitant training costs, difficulty in moving personnel between areas, and misprocessing and other operator errors. For equipment suppliers, the investment required to reinvent, implement, test, maintain, and enhance constantly evolving GUIs has become a significant burden, often delaying product release and escalating post-installation software support and maintenance costs.
Despite the need, problems have haunted previous GUI standardization efforts. Fabs wanted interfaces with a common look and feel across all types of equipment, but OEMs felt unique GUIs powerfully project corporate identity and differentiate products. Also, the proliferation of GUI development tools reinforced the mistaken perceptions of software engineers and company management that interfaces were easy, could be done by almost anyone, and did not have to be addressed until near the end of a project.
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The first comprehensive attempt to rationalize the chaotic interface design and implementation process came in 1992 with Sematech`s Strategic Cell Controller User-Interface Style Guide 1.0 (SCC1). This guide has been a pioneering and precedent-setting document resulting from years of Herculean research into ergonomics, user-centered design, task analysis, and practical manufacturing requirements. SCC1 techniques and information have had a lasting influence on this segment of the industry.
SCC1, however, did not become the de facto interface for several reasons. First, it was written for a cell controller, not equipment. In addition, it was based on UNIX Motif tools that were unacceptable to proponents of other operating systems and its document graphics quality was limited (some said "unattractive"). But many OEMs and system integrators have proven SCC1`s lasting value by looking beyond its cosmetic issues and successfully adapting and applying many of its advanced concepts and methods.
Much of the pending new GUI standard is based on SCC1, incorporating its strengths and extending its reach to modern production equipment. For example, its look and feel are not dependent on any one operating system; it has updated terminology and names, a greatly expanded display capability, and additions enabling efficient equipment monitoring and control.
Early on, the international task forces established principles and goals to promote acceptance and adoption of the new standard. This standard would need to:
Even with these principles and goals, the process of going from a style guide to a standard was difficult. The recommendations of the former became the requirements of the latter, with a very real potential to be overly restrictive, stifling innovation and creativity or even hindering implementation. The avoidance of unreasonable strictures clashed with making the standard detailed enough so its concepts and requirements were clear and straightforward. The structure and screen organization had to be simple, yet flexible enough for all types of equipment and input devices. The last hurdle proved the most onerous; existing GUI implementations had to be considered, at least to the extent of not making them completely and instantly obsolete.
The standard specifies a shallow, easily navigated hierarchy supporting a large number of views. Users spend less time interacting with the interface and more time performing productive work. Rapid access to critical information and control enables quick response to warnings and alarms, improved system monitoring, and more reliable operation.
The screen is organized into four panels: title, information, command, and navigation (see figure on p. 184). The top title display has information and controls that must be visible at all times. A bottom display provides buttons for one-touch access to the major functional areas in the interface, each of which can display multiple views, one at a time, in the center information panel. Within a functional area, a user may select another view to display or use the navigation panel to go to another functional area and its views. Associated with each view is a command panel with buttons for global commands that are specific to that view. Selecting another view also displays its command panel. Other sections of the standard include categorization of dialog boxes and their contents and a compliance checklist.
The balance between the specific and the general necessary for a useful standard means its scope must be limited. Real-world manufacturing automation needs more than a standard can provide. To this end, GUI task forces have started work on a Graphical User Interface Style Guide (draft document 2990) that will provide practical guidance for defining and designing user-centered, task-oriented graphical user interfaces at all levels of semiconductor and flat panel display manufacturing, not just equipment. This is a very large task. To ensure this guide meets the needs of device manufacturers and their hardware, software, and services suppliers, our task forces invite others to participate.
Frank Summers is chair of the Semi North American Human/Computer Interface Task Force and president and CTO of Industrial-Strength Graphics Inc., 327 Old Street Rd., Peterborough, NH 03458; ph 603/924-6252, fax 603/924-2311; e-mail [email protected].