Abstract:
A method of manufacturing a semiconductor device wherein a laminate structure comprising a sacrificial layer is sandwiched between two etch stop layers (8,11) and which separates a semiconductor membrane (9) from a bulk substrate (1) is used to provide an underetched structure. Access trenches (4) and support trenches (5) are formed in the layered structure through the thickness of the semiconductor layer (9) and through the upper etch stop layer (8). The support trenches extend deeper through the sacrificial layer (12) and the lower etch stop layer and are filled. The sacrificial layer is exposed and etched away selectively to the etch stop layers to form a cavity (30) and realise a semiconductor membrane which is attached to the bulk substrate via a vertical support structure comprising the filled support trenches.
Abstract:
Micro-electromechanical systems (MEMS) pre-fabrication products and methods for forming MEMS devices using silicon-on-metal (SOM) wafers. An embodiment of a method may include the steps of bonding a patterned SOM wafer to a cover wafer (46), thinning the handle layer of the SOM wafer (48), selectively removing the exposed metal layer (50), and either continuing with final metallization (64) or cover bonding to the back of the active layer (62).
Abstract:
A method of manufacturing an external force detection sensor in which a sensor element is formed by through-hole (20) dry etching of an element substrate (3), and an electrically conductive material is used as an etching stop layer (18) during the dry etching.
Abstract:
A new bulk resonator may be fabricated by a process that is readily incorporated in the traditional fabrication techniques used in the fabrication of monolithic integrated circuits on a wafer. The resonator is decoupled from the wafer by a cavity etched under the resonator using selective etching through front openings (vias) in a resonator membrane. In a typical structure the resonator is formed over a silicon wafer by first forming a first electrode, coating a piezoelectric layer over both the electrode and the wafer surface and forming a second electrode opposite the first on the surface of the piezoelectric layer. After this structure is complete, a number of vias are etched in the piezoelectric layer exposing the surface under the piezoelectric layer to a selective etching process that selectively attacks the surface below the piezoelectric layer creating a cavity under the resonator.
Abstract:
The current invention provides for encapsulated release structures, intermediates thereof and methods for their fabrication. The multi-layer structure has a capping layer (211) that preferably comprises silicon oxide and/or silicon nitride and which is formed over an etch resistant substrate (203). A patterned device layer (206), preferably comprising silicon nitride, is embedded in a sacrificial material (205, 209), preferably comprising polysilicon, and is disposed between the etch resistant substrate (203) and the capping layer (211). Access trenches or holes (219) are formed into the capping layer (211) and the sacrificial material (205, 209) is selectively etched through the access trenches (219) such that portions of the device layer (206) are released from the sacrificial material (205, 209). The etchant preferably comprises a noble gas fluoride NgF2x (wherein Ng = Xe, Kr or Ar: and where x = 1, 2 or 3). After etching that sacrificial material (205, 209), the access trenches (219) are sealed to encapsulate (241) released portions the device layer (206) between the etch resistant substrate (203) and the capping layer (211). The current invention is particularly useful for fabricating MEMs devices, multiple cavity devices and devices with multiple release features.
Abstract:
A method for fabricating a MEMS device having a fixing part, driving part, electrode part, and contact parts on a substrate. A driving electrode is formed on the substrate, and then an insulation layer is formed thereon. The insulation layer is patterned, and the regions of the insulation layer in which the fixing part and the contact parts are formed are etched. A metal layer is formed on the substrate. The metal layer is planarized down to the insulation layer, and the driving electrode is formed. A sacrificial layer is formed on the substrate, and a groove-shaped space is formed in a region in which the fixing part is formed. A MEMS structure layer is formed on the sacrificial layer. Sidewalls are formed in the groove-shaped space, and the fixing part and driving part are formed, leaving the sacrificial layer underneath the fixing part.
Abstract:
A method of providing microelectromechanical structures (MEMS) that are compatible with silicon CMOS electronics is provided. The method providing for processes and manufacturing sequences limiting the maximum exposure of an integrated circuit upon which the MEMS is manufactured to below 35O°C, and potentially to below 25O°C, thereby allowing direct manufacturing of the MEMS devices onto electronics, such as Si CMOS circuits. The method further providing for the provisioning of MEMS devices with multiple non-conductive structural layers such as silicon carbide separated with small lateral gaps. Such silicon carbide structures offering enhanced material properties, increased environmental and chemical resilience whilst also allowing novel designs to be implemented taking advantage of the non-conductive material of the structural layer. The use of silicon carbide being beneficial within the formation of MEMS elements such as motors, gears, rotors, translation drives, etc where increased hardness reduces wear of such elements during operation.
Abstract:
Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung eines mikromechanischen Bauelements mit mindestens einer freitragenden Struktur, bei dem eine Leiterbahnebene (11) und eine Opferschicht (4) aus einem elektrisch nicht leitenden Material so auf ein Substrat (2) aufgebracht werden, dass die Leiterbahnebene (11) zwischen Substrat (2) und Opferschicht (4) oder innerhalb der Opferschicht (4) liegt, auf die Opferschicht (4) eine die freitragende Struktur bildende Schicht (3) abgeschieden wird und die Opferschicht (4) zur Fertigstellung der freitragenden Struktur durch einen Ätzprozess teilweise entfernt wird. Bei dem vorgeschlagenen Verfahren wird oberhalb eines zu schützenden Bereichs der Leiterbahnebene (11) eine elektrisch leitfähige Schutzschicht (15) in die Opferschicht (4) eingebettet, die als Ätzstoppschicht beim Ätzprozess für die Entfernung der Opferschicht (4) dient. Die Schutzschicht (15) wird in einem nachfolgenden Prozess wieder entfernt, wobei eine darunter liegende dünne Opferschicht (17) als Passivierungsschicht auf den Leiterbahnen verbleibt. Das Verfahren ermöglicht den Schutz der Leiterbahnebene in sensiblen Bereichen und lässt sich einfach mit bestehenden Oberflächen-mikromechanischen Prozessen umsetzen.
Abstract:
Method for fabricating ultrathin gaps producing ultrashort standoffs (26) in array structures includes sandwiching a patterned device layer (12) between a silicon standoff layer (26) and a silicon support layer (38), providing that the back surfaces (46, 48) of the respective silicon support layer and the standoff layer are polished to a desired thickness corresponding to the desired standoff height on one side and to at least a minimum height for mechanical strength on the opposing side, as well as to a desired smoothness. Standoffs and mechanical supports are then fabricated by etching to produce voids with the dielectric oxides (20, 40) on both sides of the device layer serving as suitable etch stops. Thereafter, the exposed portions of the oxide layers are removed to release the pattern, and a package layer is mated with the standoff voids to produce a finished device. The standoff layer can be fabricated to counteract curvature.