– Layers:
– Polysilicon used as substrate layer
– Silicon dioxide used as sacrificial layer
– Added layers vary from 2-5 micrometres
– Ability to build electronic and mechanical components on same substrate
– Surface micro-machined components are smaller than bulk counterparts
– Fabrication process:
– Starts with silicon wafer or substrate
– Layers grown and selectively etched by photo-lithography
– Wet etch involving acid or dry etch involving ionized gas
– Surface micro-machining involves multiple layers with different masks
– Modern integrated circuit fabrication can use up to 100 layers
– Sacrificial layers:
– Used to build complicated components like movable parts
– Suspended cantilever example of component built using sacrificial layer
– Structural layer deposited on sacrificial layer
– Sacrificial layer removed to release beams
– Combination of layers chosen based on process requirements
– Examples:
– Surface Micro-machined Accelerometers
– 3D Flexible Multichannel Neural Probe Array
– Nanoelectromechanical relays
– See also:
– Bulk micromachining
– Magnetic nanoparticles
– MEMS
– Semiconductor device fabrication
This article includes a list of general references, but it lacks sufficient corresponding inline citations. (February 2018) |
Surface micromachining builds microstructures by deposition and etching structural layers over a substrate. This is different from Bulk micromachining, in which a silicon substrate wafer is selectively etched to produce structures.
