Design and fabrication of diamond probe for atomic force microscope

We realized IC-compatible diamond AFM probe technology using our newly developed anodic bonding technique for diamond film to glass together with microfabrication techniques employing CVD diamond film. Using Al film as an intermediate layer, diamond film can be anodically bonded to Pyrex 7740 glass at a bonding temperature of 400-500 degrees C, with an electrostatic voltage of 600V, and a bonding time of 1-2 h in atmosphere. Based on the batch fabrication process proposed here, we demonstrate diamond AFM probes for contact mode measurements consisting of two kind of V-shaped cantilevers integrated with a pyramidal tip. They were optimally designed by FEA, giving spring constants of approximately 1 N/m and 5 N/m. The diamond cantilevers and diamond tips were fabricated by the selective deposition of diamond film and a Si mold technique, respectively. A diamond base, to which the diamond probes have been attached, was then anodically bonded to a glass backing plate to facilitate handling. This bonding technique was found to provide high accuracy and good repeatability. Finally, diamond probes attached with high accuracy to one end of the glass backing plate were obtained by removing the unnecessary Si substrate. They were then successfully mounted in a Si frame by means of four thin diamond brackets, making a chip array in the substrate. These results indicate that this fabrication process would allow the production of large quantities of diamond AFM probes, resulting in a high cost performance.