We report about our progress in developing a process for the manufacture of carbon nanotube (CNT) atomic force microscopy (AFM) cantilevers. Due to their exceptional mechanical properties, CNT are among the most promising materials for high aspect ratio critical dimension metrology (CDM) AFM probes. Our goal is to produce well-defined long lasting CNT probes for CDM measurements in the <100 nm pitch range. Our efforts currently focus on manufacturing precisely aligned CNT having defined locations, diameters and lengths. The CNT are grown using plasma enhanced chemical vapor deposition (PECVD). The CNT growth process is enabled by the presence of a catalyst, which allows precise definition of the growth location. Experimental data from CNT grown on Si AFM probes and catalyst patterns prepared by focused ion beam (FIB) and electron beam lithography (EBL) is being shown. Furthermore, first results from scanning experiments with CNT-AFM cantilevers are shown.
Carbon nanotubes (CNT) have exceptional mechanical strength at small diameters needed for measuring high aspect ratio features. Manually attached carbon nanotube atomic force microscopy probes have demonstrated exceptional longevity. Unfortunately, due to the manual attachment process, and the usually arbitrary diameter and length of the used CNT, such probes are not suitable for high aspect ratio critical dimension metrology (CDM). For reproducible and accurate CDM measurements precisely defined CNT probes are necessary. We are reporting about the progress made growing carbon nanotubes (CNT) directly on top of standard Si probes. The goal is to produce well-defined long lasting probes for CDM measurements in the <100 nm pitch range. Our efforts currently focus on manufacturing precisely aligned CNT having defined locations, diameters and lengths. This is accomplished by using plasma assisted chemical vapor deposition in combination with focused ion beam (FIB) patterned catalyst films. Our results demonstrate that it is possible to manufacture 1:10 aspect ratio CNT probes at <100 nm diameters.
Carbon nanotubes (CNT) are among the candidates for atomic force microscopy probes for use in high aspect ratio critical dimension metrology (CDM). Their mechanical strength at small diameters makes them ideal probes for narrow and deep features. The synthesis of CNT has been making great progress in recent years. The use of CNT in scanning probe microscopy, however, has been limited due to a number of problems. While the CNT probes generally appear to be long lasting, the manufacture of precisely aligned CNT of defined length, diameter and number of walls poses a number of challenges. Yet, such precisely defined CNT probes seem to be required if the cantilevers are to be used for CDM. Our result demonstrate, for example, that the attachment angle of CNT with respect to the cantilever beam is crucial for their application in CDM. We report about our efforts to overcome these problems by growing well-defined CNT on standard Si cantilevers using chemical vapor deposition in combination with focused ion-beam machining techniques.