GMA Industries, Inc. has continued its efforts toward creating its original concept of molecular test equipment (MTE)1. Fast, accurate, and inexpensive identification of failed integrated circuits (ICs) on electronic circuit boards has been identified as an urgent issue for the electronic testing industry. Presently, testing of these boards is accomplished through the use of expensive and time-consuming process involving automatic test equipment (ATE) controlled by test program sets (TPS). The non-recurring costs for the development of ATE and TPS and the recurring costs for their operation and maintenance runs into the billions of dollars each year. An opportunity exists to significantly reduce or entirely eliminate ATE and TPS costs by applying nanoscale sensor devices continuously monitoring IC performance.
In this paper, we describe progress in development efforts pertaining to creation of carbon nanotube-based molecular test equipment (MTE) performing the ATE functions in an IC substrate level. We have thoroughly investigated previous research reports pertaining to various types of IC failures and prioritize them based on the occurrence frequencies. Electromigration turned out to be the unquestionable "leader" among those ICs malfunctions causes. The phenomenon of electromigration, which is the current induced transport of conducting material, is responsible for more than 50% of all the IC failure incidences. During this process, electron movement causes the conducting material to be depleted at its original location and accumulated "down stream". This, in turn, results in formation of voids (at depletion areas) and material build-ups (where the accumulation occurs).
In order to give early warning about possible IC failures caused by open or short circuit created as a result of such processes, GMA Industries is developing a type of sensor device to detect electromigration movement of conducting material. Due to the ingenious simplicity of the metal migration sensor (MMS) design, we foresee that this type of a device will be the primary (although not the only) type of sensor applied in the molecular test equipment system. MMS probe consists of a conductive carbon nanotube (CNT) and uses its properties to detect a small change in current density caused by an increased area in contact with the metal. The paper elaborates also on other types of nanoscale sensors that are being considered for the IC monitoring system as well as describes the entire MTE architecture.
We present up-to-date experimental results associated with the ongoing development of the metal migration sensor, and discuss lessons learned in the process of interfacing the MMS with the remaining elements of the MTE. Advances in the design development of the sensor and research related to forming a viable contact between the carbon nanotube probe and electro-migrated metal are also being discussed in the paper.