Abstract: A method and apparatus for the etching of variable depth features in a substrate is described. Movement of the substrate relative to an etchant (e.g. into or out of the etchant) during the etching process is utilised to provide a varying etch time, and hence depth, across the substrate, and in various examples this is enabled without requiring a varying mask.

Abstract: A method of reactive ion etching a substrate 46 to form at least a first and a second etched feature (42, 44) is disclosed. The first etched feature (42) has a greater aspect ratio (depth:width) than the second etched feature (44). In a first etching stage the substrate (46) is etched so as to etch only said first feature (42) to a predetermined depth. Thereafter in a second etching stage, the substrate (46) is etched so as to etch both said first and said second features (42, 44) to a respective depth. A mask (40) may be applied to define apertures corresponding in shape to the features (42, 44). The region of the substrate (46) in which the second etched feature (44) is to be produced is selectively masked with a second maskant (50) during the first etching stage, The second maskant (50) is then removed prior to the second etching stage.

Abstract: A method of reactive ion etching a substrate 46 to form at least a first and a second etched feature (42, 44) is disclosed. The first etched feature (42) has a greater aspect ratio (depth:width) than the second etched feature (44). In a first etching stage the substrate (46) is etched so as to etch only said first feature (42) to a predetermined depth. Thereafter in a second etching stage, the substrate (46) is etched so as to etch both said first and said second features (42, 44) to a respective depth. A mask (40) may be applied to define apertures corresponding in shape to the features (42, 44). The region of the substrate (46) in which the second etched feature (44) is to be produced is selectively masked with a second maskant (50) during the first etching stage, The second maskant (50) is then removed prior to the second etching stage.

Abstract: An accelerometer having a plate-like proof mass (1), flexible mounting legs (2) each co-planar with the proof mass (1), a ring-like support (3), in which the proof mass (1) is moveably mounted, with each mounting leg (2) being connected at one end to the proof mass (1) and connected at another end to the support (3) and with the mounting legs (2) extending substantially perpendicularly to the sensing direction, a plurality of interdigitated capacitor fingers mounted, in a gaseous medium, in the ring-like support (3) for sensing linear movement of, and for providing gaseous medium squeeze damping for the proof mass (1) in the sensing direction, with the fingers, proof mass (1), mounting legs (2) and support (3) being co-planar and formed from a single plate of mono-crystalline silicon, which fingers comprise fixed first, second, third and fourth arrays (5, 6, 7, 8) of laterally spaced fingers extending substantially perpendicularly to the sensing direction and away from the support (3) towards to the proof mas

Abstract: An accelerometer having a plate-like proof mass (1), flexible mounting legs (2) each co-planar with the proof mass (1), a ring-like support (3), in which the proof mass (1) is moveably mounted, with each mounting leg (2) being connected at one end to the proof mass (1) and connected at another end to the support (3) and with the mounting legs (2) extending substantially perpendicularly to the sensing direction, a plurality of interdigitated capacitor fingers mounted, in a gaseous medium, in the ring-like support (3) for sensing linear movement of, and for providing gaseous medium squeeze damping for the proof mass (1) in the sensing direction, with the fingers, proof mass (1), mounting legs (2) and support (3) being co-planar and formed from a single plate of mono-crystalline silicon, which fingers comprise fixed first, second, third and fourth arrays (5, 6, 7, 8) of laterally spaced fingers extending substantially perpendicularly to the sensing direction and away from the support (3) towards to the proof mas