Micromachining of diamond probes for atomic force microscopy applications

We realized IC-compatible diamond atomic force microscope (AFM) probe technology using our newly developed anodic bonding technique of 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 500 degreesC, with an electric voltage of 600 V, and a bonding time of 3 h in atmosphere. Moreover, by depositing Ti film as an adhesive layer between the diamond film and the Al him, a bond strength of 1-2 MPa was obtained. Based on the batch fabrication process proposed here, we demonstrate diamond AFM probes for contact mode measurements consisting of two kinds of V-shaped cantilever integrated with a pyramidal tip. The cantilevers were optimally designed by a finite element analysis, giving spring constants of approximately 1 and 5 N/m. The diamond cantilevers and diamond tips were fabricated on a Si substrate by a selective deposition of diamond film and a Si mold technique, respectively. Through anodic bonding of a glass backing plate to a diamond base followed by removing the unnecessary Si substrate, diamond probes were successfully obtained. The fabrication process described here would allow the production of large quantities of diamond AFM probes, resulting in a high cost performance. (C) 2001 Elsevier Science B.V. All rights reserved.