Hybrid Integrated Circuit Manufacturing Process as Controlled by Shop Information Systems

Hybrid integrated circuits (HIC's) used in Bell System transmission equipment are rapidly increasing in numbers, type, and complexity. An efficient and effective system of controlling and monitoring the HIC manufacturing process is therefore of prime importance if scheduling, inventory, product yield, and operator performance are to be accurately determined. The major sequence of operations is described of both thin- and thick-film technologies required in the fabrication of a typical transmission equipment HIC and how this process is integrated with information systems. The basic process sequence includes the application of thick-film crossunders, deposition of resistor and conductor thin films, pattern generation of passive components, laser trimming of resistors, circuit separation, HIC assembly, and functional testing. Incorporated within this fabrication process is a computer-based data storage and retrieval system known as the universal shop information system (USIS). This system provides three basic functions, namely dynamic inventory control and scheduling, operator efficiency, and engineering analyses. Particular emphasis is placed on engineering applications of the USIS for evaluating the HIC process and product performance. As an engineering tool it offers numerous active on-line programs which assist in the pinpointing of operator/facility caused defectiveness. Critical operations are monitored and product yields can be tracked over any requested time interval. In addition to monitoring overall product performance, the USIS provides the capability of investigating individual lot histories, analyzing the effectiveness of HIC repair cycles, monitoring quality control information, and computing product costs.