Abstract:
A process for making a microelectromechanical device having a moveable component defined by a gap pattern in a semiconductor layer of a silicon-on-insulator wafer (10) involves the use of a plurality of deep reactive ion etching steps at various etch depths that are used to allow a buried oxide layer (14) of the silicon-on-insulator wafer (10) to be exposed in selected areas before the entire moveable component of the resulting device is freed for movement. This method allows wet release techniques to be used to remove the buried oxide layer (14) without developing stiction problems. This is achieved by utilizing deep reactive ion etching to free the moveable component after a selected portion of the buried oxide layer (14) has been removed by wet etching.
Abstract:
A technique for manufacturing silicon structures includes etching a cavity into a first side of an epitaxial wafer (506). A thickness of an epitaxial layer is selected, based on a desired depth of the etched cavity and a desired membrane thickness. The first side of the epitaxial wafer is then bonded to a first side of a handle wafer (510). After thinning the epitaxial wafer until only the epitaxial layer remains, desired circuitry is formed on a second side of the remaining epitaxial layer (516), which is opposite the first side of the epitaxial wafer.
Abstract:
A microfluidic valve structure (10 or 10') is provided. The valve structure (10) includes a valve body (15) having a fluid flow passage (22) formed therein for allowing fluid to flow therethrough. A valve boss (24) is configured to move relative to a valve seat (26) to open and close the fluid flow passage. A plurality of flexible support arms (30A-30D) extend between a wall (20) of the valve body (15) and the valve boss (24) for supporting the valve boss (24) relative to the valve body (15) such that the valve boss (24) engages and disengages the valve seat (26) to close and open the passage.
Abstract:
A technique (400) for manufacturing a microelectromechanical (MEM) device includes a number of steps. Initially, a first wafer (402) is provided. Next, a bonding layer is formed on a first surface of the first wafer. Then, a portion of the bonding layer is removed to provide a cavity including a plurality of spaced support pedestals within the cavity (404). Next, a second wafer is bonded to at least a portion of the bonding layer (406). A portion of the second wafer provides a diaphragm over the cavity and the support pedestals support the diaphragm during processing. The second wafer is then etched to release the diaphragm from the support pedestals.
Abstract:
An integrated sensor (10) comprising a thermopile transducer (12) and signal processing circuitry (4) that are combined on a single semiconductor substrate (20), such that the transducer output signal is sampled in close vicinity by the processing circuitry (14). The sensor (10) comprises a frame (18) formed of a semiconductor material that is not heavily doped, and with which a diaphragm (16) is supported. The diaphragm (16) has a first surface for receiving thermal (e.g., infrared) radiation, and comprises multiple layers that include a sensing layer containing at least a pair of interlaced thermopiles (22). Each thermopile (22) comprises a sequence of thermocouples (24), each thermocouple (24) comprising dissimilar electrically-resistive materials that define hot junctions (26) located on the diaphragm (16) and cold junctions (28) located on the frame (18). The signal processing circuitry (14) is located on the frame (18) and electrically interconnected with the thermopiles (22). The thermopiles (22) are interlaced so that the output of one of the thermopiles (22) increases with increasing temperature difference between the hot and cold junctions (26,28) thereof, while the output of the second thermopile (22) decreases with increasing temperature difference between its hot and cold junctions (26,28).
Abstract:
A linear accelerometer (10) is provided having a support substrate (14), fixed electrodes (22A-22D) having fixed capacitive plates (30A-30D), and a movable inertial mass (12) having movable capacitive plates (20A-20D) capacitively coupled to the fixed capacitive plates (30A-30D). Adjacent capacitive plates vary in height. The accelerometer (10) further includes support tethers (16A-16B) for supporting the inertial mass (12) and allowing movement of the inertial mass upon experiencing a linear acceleration along a sensing axis. The accelerometer (10) has inputs (26, 28) and an output (34) for providing an output signal which varies as a function of the capacitive coupling and is indicative of both magnitude and direction of vertical acceleration along the sensing Z-axis. A microsensor fabrication process (100) is also provided which employs a top side mask and etch module (70).