An electronic wafer traveler system for an academic microchip fabrication facility

Abstract

Even in a university microchip fabrication facility, the process by which bare silicon wafers are transformed into wafers with working devices consists of a complex sequence involving many steps, each of which must be performed by the students precisely as designed by the instructor. In order to assure such processing conformance, each wafer is accompanied by a "wafer traveler" that tells the student exactly what to do. These travelers have historically been paper documents. In an attempt to model modern commercial fabrication facilities, and in order to provide electronic data to the students for use in their laboratory reports, we are developing an electronic wafer traveler system (EWTS). This system accomplished two main user functions. First, it allows instructors to develop wafer travelers specific to a given process flow, and second, it produces wafer travelers for that process that will allow students to electronically record and use all data associated with fabricating a wafer by the given process. This paper presents the design of the EWTS using advanced object-oriented software engineering techniques such as use case modeling to show how users interact with the system and class diagramming that shows the structural relationships among data elements as required by the Unified Modeling Language (UML). The resulting third normal form data model will be implemented in SQL 2000 and interfaced to the existing laboratory information management system (LIMS) now in use in our facility. User interaction with the EWTS will be via Visual Basic and Active Server pages using SQL.