Abstract:
A MEMS device is disclosed comprising: a substrate; a movable micromechanical element movable relative to the substrate; a connector and a hinge for allowing movement of the micromechanical element, wherein the connector is made of a material different than the hinge. In another embodiment of the invention, the connector has a conductivity greater than the hinge. In a further embodiment of the invention, the hinge provides at least 90% of the restoring force to the MEMS device, and the connector provides 10% or less of the restoring force. In a further embodiment of the invention, the connector and the hinge have different spring constants. In a still further embodiment of the invention, the connector experiences a lower strain at maximum deflection of the micromechanical element than the hinge.
Abstract:
Processes for the addition or removal of a layer or region from a workpiece material by contact with a process gas in the manufacture of a microstructure are enhanced by the use of recirculation of the process gas. Recirculation is effected by a pump that has no sliding or abrading parts that contact the process gas, nor any wet (such as oil) seals or purge gas in the pump. Improved processing can be achieved by a process chamber that contains a baffle, a perforated plate, or both, appropriately situated in the chamber to deflect the incoming process gas and distribute it over the workpiece surface. In certain embodiments, a diluent gas is added to the recirculation loop and continuously circulated therein, followed by the bleeding of the process gas (such as an etchant gas) into the recirculation loop. Also, cooling of the process gas, etching chamber and/or sample platen can aid the etching process. The method is particularly useful for adding to or removing material from a sample of microscopic dimensions.
Abstract:
The etching of a sacrificial silicon portion in a microstructure such as a microelectromechanical structure by the use of etchant gases that are noble gas fluorides or halogen fluorides is performed with greater selectivity toward the silicon portion relative to other portions of the microstructure by slowing the etch rate. The etch rate is preferably 30 um/hr or less, and can be 3 um/hr or even less. The selectivity is also improved by the addition of non-etchant gaseous additives to the etchant gas. Preferably the non-etchant gaseous additives that have a molar-averaged formula weight that is below that of molecular nitrogen offer significant advantages over gaseous additives of higher formula weights by causing completion of the etch in a shorter period of time while still achieving the same improvement in selectivity. The etch process is also enhanced by the ability to accurately determine the end point of the removal step. A vapor phase etchant is used to remove a material that has been deposited on a substrate, with or without other deposited structure thereon. By creating an impedance at the exit of an etching chamber (or downstream thereof), as the vapor phase etchant passes from the etching chamber, a gaseous product of the etching reaction is monitored, and the end point of the removal process can be determined. The vapor phase etching process can be flow through, a combination of flow through and pulse, or recirculated back to the etching chamber. Also, the etch selectivity can be improved by doping the sacrificial material.
Abstract:
A method for forming a MEMS device is disclosed, where a final release step is performed just prior to a wafer bonding step to protect the MEMS device from contamination, physical contact, or other deleterious external events. Without additional changes to the MEMS structure between release and wafer bonding and singulation, except for an optional stiction treatment, the MEMS device is best protected and overall process flow is improved. The method is applicable to the production of any MEMS device and is particularly beneficial in the making of fragile micromirrors.
Abstract:
A method is disclosed for forming a micromechanical device. The method includes fully or partially forming one or more micromechanical structures multiple times on a first substrate. A second substrate is bonded onto the first substrate so as to cover the multiple areas each having one or more micromechanical structures, so as to form a substrate assembly. The substrate assembly is then separated into individual dies, each die having the one or more micromechanical structures held on a portion of the first substrate, with a portion of the second substrate bonded to the first substrate portion. Finally, the second substrate portion is removed from each die to expose the one or more micromechanical structures on the first substrate portion. The invention is also directed to a method for forming a micromechanical device, including: forming one or more micromechanical structures in one or more areas on a first substrate; bonding caps onto the first substrate so as to cover the one or more areas each having one or more micromechanical structures, so as to form a substrate assembly; after a period of time, removing the caps to expose the one or more micromechanical structures. During the period of time between bonding the caps and later removing the caps, the substrate assembly can be singulated, inspected, irradiated, annealed, die attached, shipped and/or stored.
Abstract:
A method for forming a MEMS device is disclosed, where a final release step is performed just prior to a wafer bonding step to protect the MEMS device from contamination, physical contact, or other deleterious external events. Without additional changes to the MEMS structure between release and wafer bonding and singulation, except for an optional stiction treatment, the MEMS device is best protected and overall process flow is improved. The method is applicable to the production of any MEMS device and is particularly beneficial in the making of fragile micromirrors.
Abstract:
A spatial light modulator is disclosed, along with a method for making such a modulator that comprises an array of micromirror devices. The center-to-center distance and the gap between adjacent micromirror devices are determined corresponding to the light source being used so as to optimize optical efficiency and performance quality. The micromirror device comprises a hinge support formed on a substrate and a hinge that is held by the hinge support. A mirror plate is connected to the hinge via a contact, and the distance between the mirror plate and the hinge is determined according to desired maximum rotation angle of the mirror plate, the optimum gap and pitch between the adjacent micromirrors. In a method of fabricating such spatial light modulator, one sacrificial layer is deposited on a substrate followed by forming the mirror plates, and another sacrificial layer is deposited on the mirror plates followed by forming the hinge supports. The two sacrificial layers are removed via the small gap between adjacent mirror devices with spontaneous vapor phase chemical etchant. Also disclosed is a projection system that comprises such a spatial light modulator, as well as a light source, condensing optics, wherein light from the light source is focused onto the array of micromirrors, projection optics for projecting light selectively reflected from the array of micromirrors onto a target, and a controller for selectively actuating the micromirrors in the array.
Abstract:
A method and spatial light modulator are provided herein. The spatial light modulator has a higher resolution and an increased fill factor. The spatial light modulator also provides an increased contrast ratio. Furthermore, the spatial light modulator of the present invention can be operated in the absence of polarized light and that has improved electro-mechanical performance and robustness with respect to manufacturing. A method and its alternative are disclosed herein by the present invention for manufacturing the spatial light modulator.
Abstract:
A sacrificial layer and a method for applying said sacrificial layer in fabricating microelectromechanical devices are disclosed herein. The sacrificial layer comprises an early transition metal. Specifically, the sacrificial layer comprises an early transition metal element, an early transition metal alloy or an early transition metal silicide.
Abstract:
A spatial light modulator is disclosed, along with methods for making such a modulator, that comprises an array of micromirrors each having a hinge and a micromirror plate held via the hinge on a substrate, the micromirror plate being disposed in a plane separate from the hinge and having a diagonal extending across the micromirror plate, the micromirror plate being attached to the hinge such that the micromirror plate can rotate along a rotation axis that is parallel to, but off-set from the diagonal of the micromirror plate. Also disclosed is a projection system that comprises such a spatial light modulator, as well as a light source, condensing optics, wherein light from the light source is focused onto the array of micromirrors, projection optics for projecting light selectively reflected from the array of micromirrors onto a target, and a controller for selectively actuating the micromirrors in the array.