WARF TECHNOLOGIES

Processing techniques similar to those used to manufacture integrated circuits can also be used to make a variety of microelectromechanical and nanoelectromechanical systems (MEMS and NEMS), including pressure sensors, micromechanical electrical switches, resonators and filters. A typical step in the manufacturing process involves depositing a patterned structure on a sacrificial layer, and then wet etching the sacrificial layer to free the NEMS structure and suspend it as a bridge or cantilever. A major drawback of this technique is that the wet etchants used to dissolve the sacrificial layer may also attack and damage the NEMS structure – a problem that is especially acute when the features of the NEMS structure are only a few hundred nanometers or less in size.

UW-Madison researchers have developed a method to protect nanoelectromechanical systems during wet etching, resulting in much higher yield of usable devices from the manufacturing process. The method involves depositing a carbon layer of diamond-like hardness (i.e., a protective mask) over the NEMS structure. The mask is deposited by electron beam deposition (EBD) using residual carbon atoms in the vacuum chamber. After the main processing steps, including wet etching, the carbon/mask layer is removed using plasma etching to reveal the usable NEMS structure.

• Production of NEMS

• Increases the yield of usable NEMS devices from 10 percent to 85 percent
• Enables large scale manufacturing of NEMS with suspended structural features of 500 nm or less in size
• Allows production of NEMS with much finer and more complex features than those made with conventional techniques
• Particularly well suited to devices formed on semiconductor substrates, such as silicon
• Facilitates integration of NEMS structures with conventional electronic devices formed on silicon substrates

Tech Fields

• Engineering : Micro & nanotechnologies