New methods for fast, accurate, and inexpensive identification of failed integrated circuits (ICs) on electronic circuit boards have been recently a subject of intensive research. Presently, testing of these boards is accomplished through the use of automatic test equipment (ATE) controlled by test programs. The circuit board interfaces with the ATE through the use of a hardware device called an interface test adapter (ITA), which is developed in conjunction with the test program. The non-recurring costs for the development of ATE and test program sets (TPSs) and the recurring costs for their operation and maintenance runs into the billions of dollars each year.
This paper describes progress in development efforts pertaining to creation of nanotechnology-based molecular test equipment (MTE) performing the ATE functions in an IC substrate level. Application of nanotechnology techniques into automatic test equipment area creates an opportunity to significantly reduce or entirely eliminate ATE and TPS costs associated with the maintenance of shop replaceable unit (SRU) circuit boards by designing a means for ICs to continuously test themselves during normal operation and to provide a visual indication that they have failed (as it is presented on the attached figure). Moreover, using for that purpose nano-scale sensor devices, several orders smaller than conventional integrated circuit elements, allows for occupying only minimal area of valuable IC chip real estate.
We will present original research and development in the use of nanotube-based chemical and electronic sensors as embedded test equipment within the architecture of integrated circuits to detect failures that may affect IC reliability and performance. This R&D focuses on the monitoring of electromigration processes occurring within integrated circuits as well as electrical performance of the ICs to provide a reliable identification of failures.
Results are presented from the development of two carbon nanotube-based devices: a metal migration sensor and a nanotube rectifier diode sensor. The metal migration sensor 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. Design of the sensor and research related to forming a viable contact between the carbon nanotube probe and electro-migrated (or melted) metal are being discussed in the paper. We will also present our research results associated with the design of a nanotube diode-based MTE sensor and discuss the feasibility of fabrication of CNT diode sensor using an electrical breakdown of multiwalled nanotubes technique.1
We will describe our methods of testing the electrical conductance of the metal-CNT junctions as well as present our research related to creation of nanoscale-diode based on CNT-CNT heterojunctions. We will convey any experimental results associated with the presented research achieved to date, and discuss lessons learned in the process.
Philip G. Collins et al., Science 2001, 292, pp. 706-709