A Study on the Development of Computer Aided Die Design System for Lead Frame of Semiconductor Chip

This paper describes the development of computer-aided design of a very precise progressive die for lead frame of semiconductor chip. The approach to the system is based on knowledge-based rules. Knowledge for the system is formulated from plasticity theories, experimental results, and the empirical knowledge of field experts. This system has been written in AutoLISP using AutoCAD on a personal computer and the I-DEAS drafting programming Language on the I-DEAS master series drafting with on HP9000/715(64) workstation. Data exchange between AutoCAD and I-DEAS master series drafting is accomplished using DXF(drawing exchange format) and IGES(initial graphics exchange specification) files. This system is composed of six main modules, which are input and shape treatment, production feasibility check, strip layout, data conversion, die layout, and post processing modules. Based on knowledge-based rules, the system considers several factors, such as V-notches, dimple, pad chamfer, spank, cavity punch, camber, coined area, cross bow, material and thickness of product, complexities of blank geometry and punch profiles, specifications of available presses, and the availability of standard parts. As forming processes and the die design system using 2D geometry recognition are integrated with the technology of process planning, die design, and CAE analysis, the standardization of die parts for lead frames requiring a high precision piercing process is possible. The die layout drawing generated by the die layout module is displayed in graphic form. The developed system makes it possible to design and manufacture lead frame of a semiconductor more efficiently.