It is shown that silicon microstructures and microsystems of high complexity can be effectively fabricated in any research lab with sub-micrometer accuracy and high aspect ratio values (about 100), which is well beyond any up-to-date wet or dry microstructuring approach, using a wet etching, low-cost technology, namely silicon electrochemical micromachining (ECM). As an example, two silicon microgrippers electrically actuable by means of comb-finger batteries driving a spring system and fabricated by ECM technology are shown in Fig. 1. ECM technology capitalizes on the experimental and theoretical results reported in the literature over the last two decades on back-side electrochemical etching of silicon in HF-aqueous electrolytes. A novel dynamic control of the electrochemical etching anisotropy (from 1 to 0) as the etching progresses allows the silicon dissolution to be switched in real-time from the anisotropic to the isotropic regime and enables advanced silicon microstructuring to be achieved through the use of high-aspect-ratio functional and sacrificial structures, the former being functional to the microsystem operation and the latter being sacrificed for accurate microsystem fabrication. World-wide dissemination of the ECM technology for silicon microstructuring is envisaged in the near future, due to its low cost and high flexibility, with high-potential impact on, though not limited to, the broad field of microelectronics and microfabrication.
ELECTROCHEMICAL MICROMACHINING AS AN ENABLING TECHNOLOGY FOR ADVANCED SILICON MICROSTRUCTURING: APPLICATION TO PHOTONIC CRYSTAL OPTOFLUIDIC MICROSYSTEMS FOR (BIO)SENSING
BARILLARO, GIUSEPPE
2013-01-01
Abstract
It is shown that silicon microstructures and microsystems of high complexity can be effectively fabricated in any research lab with sub-micrometer accuracy and high aspect ratio values (about 100), which is well beyond any up-to-date wet or dry microstructuring approach, using a wet etching, low-cost technology, namely silicon electrochemical micromachining (ECM). As an example, two silicon microgrippers electrically actuable by means of comb-finger batteries driving a spring system and fabricated by ECM technology are shown in Fig. 1. ECM technology capitalizes on the experimental and theoretical results reported in the literature over the last two decades on back-side electrochemical etching of silicon in HF-aqueous electrolytes. A novel dynamic control of the electrochemical etching anisotropy (from 1 to 0) as the etching progresses allows the silicon dissolution to be switched in real-time from the anisotropic to the isotropic regime and enables advanced silicon microstructuring to be achieved through the use of high-aspect-ratio functional and sacrificial structures, the former being functional to the microsystem operation and the latter being sacrificed for accurate microsystem fabrication. World-wide dissemination of the ECM technology for silicon microstructuring is envisaged in the near future, due to its low cost and high flexibility, with high-potential impact on, though not limited to, the broad field of microelectronics and microfabrication.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
