Improving yield, productivity, and quality in test assembly and packaging through direct part marking and unit level traceability

Identifying and tracking individual devices throughout test, assembly and packaging using directly marked 2D data matrix symbols is a viable application and the basis of several SEMI traceability standards. Recently, it has been utilized more extensively in high-volume manufacturing. Advancements such as package-less strip designs make traceability challenges more acute and lead to the development of new methodologies for assembly and test, such as strip testing and mapping. In these applications, 2D symbology marked on lead frames, strips or individual devices provides unit level traceability, prevents mixed lots, and allows defect tracking - ultimately improving yield, productivity and quality. This paper highlights the basic advantages of directly marked 2D data matrix symbols versus conventional 1D bar codes. It describes representative traceability applications in test, assembly and packaging, and the benefits derived from implementation in each business case. A system-level methodology for implementing unit level traceability is presented, including the four basic elements: symbol marking, mark verification, symbol reading and communication of results. Finally, recognizing that a variety of options are often required for effective implementation and integration in a production line, it addresses alternative reading and verification systems ranging from board-level products to intelligent cameras and hand-held readers.