THE EFFECTS OF VARIOUS PROCESS AND DESIGN PARAMETERS ON ULTRA-SMALL PASSIVE DEVICES"

The long-standing trend in the electronics industry has been the miniaturization of electronic components. It is projected that this trend will continue as Original Equipment Manufacturers (OEMs) and Electronic Manufacturing Service (EMS) providers strive to reduce "real estate " on printed circuit boards. Typically, the miniaturization of components can be achieved by integration or size reduction. At present, size reduction is considered to be more cost effective and flexible than integration. Passive components, which are used in limiting current, terminating transmission lines and de-coupling switching noise, are the primary focus in size reduction due to their variety of uses [4]. From a manufacturing stand point, the sizes of the ultra-small components pose significant challenges to the capability of the manufacturing equipment and the control over various process parameters. Plexus Electronic Assembly has investigated some of these issues, particularly associated with 0402/0201 devices and their tendencies to form tombstone defects. The purpose of this paper is to discuss: 1) the mechanism of tombstoning and design considerations, 2) the potential process parameters affecting tombstoning and 3) the results of a multi-level Design of Experiment (DoE) conducted using a Plexus-designed test substrate