Abstract:
A microelectromechanical systems (MEMS) device utilizing an aluminum fluoride layer as an etch stop is disclosed. In one embodiment, a MEMS device (80) includes a first electrode (81) having a first surface; and a second electrode (82) having a second surface facing the first surface and defining a gap (85) therebetween. The second electrode (82) is movable in the gap (85) between a first position and a second position. At least one of the electrodes includes an aluminum fluoride layer (83) facing the other of the electrodes. During fabrication of the MEMS device, a sacrificial layer is formed between the first and second electrodes and is released to define the gap. The aluminum fluoride layer (83) serves as an etch stop to protect the first or second electrode during the release of the sacrificial layer.
Abstract:
A buried etch stop layer (208) for fabricating stepped etched structures has a patterned recess (211). The etch stop layer is buried between etchable first (201) and second (202) layers. The recessed patterned buried etch stop layer can be made by forming a portion of the etch stop layer (204) on one of the etchable layers, etching the recess into it, then wafer bonding the etch stop layer (208) between the first (201) and second (202) layers. Once the buried etch stop layer has been formed, the process for fabricating stepped structures starts with patterning the first layer (201) and etching it to reveal a portion of the recessed area of the etch stop (211). Selective removal by etching of the revealed area is done to remove its entire thickness in the recessed area (211) but only to remove a partial thickness of the remaining revealed area (212). This is followed by selective etching of the revealed area of the second layer, masked by the remaining revealed area (212), so as to transfer a portion of the recess pattern into the second layer, optionally down to a membrane layer (214). This provides improved etch uniformity for stepped etched structures, including those with membranes.
Abstract:
A microelectromechanical systems device having support structures formed of sacrificial material surrounded by a protective material. The microelectromechanical systems device includes a substrate having an electrode formed thereon. Another electrode is separated from the first electrode by a cavity and forms a movable layer, which is supported by support structures formed of a sacrificial material.
Abstract:
In one embodiment, the invention provides a method for fabricating a microelectromechanical systems device. The method comprises fabricating a first layer comprising a film having a characteristic electromechanical response, and a characteristic optical response, wherein the characteristic optical response is desirable and the characteristic electromechanical response is undesirable; and modifying the characteristic electromechanical response of the first layer by at least reducing charge build up thereon during activation of the microelectromechanical systems device.
Abstract:
Die Erfindung betrifft einen mikrostrukturierter Sensor, der mindestens aufweist: ein Substrat (1), eine in das Substrat geätzte Kaverne (6), eine Membran (7), die oberhalb der Kaverne freitragend ausgebildet und in einer Membrankante (11) lateral angebunden ist und eine Sensorschicht (3) mit Sensorstrukturen aufweist, wobei die Membrankante (11) von Ätzflächen (10) der Kaverne getrennt ist. Erfindungsgemäß wird die Membrankante von den unregelmäßigen Ätzflanken der Ätzflächen entkoppelt, so dass die Membranstabilität verbessert wird. Hierzu kann die Membrankante (11) in einer lateralen Vertiefung (9) der Seitenwand (10) der Kaverne (6) ausgebildet und von einer Oberkante (10a) der Seitenwand getrennt sein. Alternativ hierzu kann die Seitenwand der Kaverne durch eine sich vertikal erstreckende Ringschicht gebildet sein, wobei die Ringschicht und eine untere Membranschicht der Membran Teile einer auf dem Substrat ausgebildeten Füllschicht sind, und die Membrankante in der Füllschicht im Übergang zwischen der Ringschicht und der unteren Membranschicht ausgebildet ist.
Abstract:
Es wird ein Verfahren vorgeschlagen, mit dem sich unter Einsatz von Standard-verfahren der Mikrosystemtechnik einfach und kostengünstig Hohlräurne (7) mit einer optisch transparenten Wandung in einem Bauelement (10) erzeugen lassen. Dazu wird zunächst ein Siliziumbereich erzeugt, der allseitig von einer optisch transparenten Mantelschicht umgeben ist. Dann wird mindestens eine Öffnung (6) in der Mantelschicht erzeugt. Über these Öffnung (6) wird das von der Mantelschicht umgebene Silizium herausgelöst, so dass ein Hohlraum (7) innerhalb der Mantelschicht entsteht. Dabei wirkt die Mantelschicht als Ätzstoppschicht.
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 N g F 2x (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 of making a micro electro-mechanical gyroscope. A cantilevered beam structure, firstportions of side drive electrodes and a mating structure are defined on a first substrate or wafer;and at least one contact structure, second portions of the side drive electrodes and a matingstructure are defined on a second substrate or wafer, the mating structure on the second substrateor wafer being of a complementary shape to the mating structure on the first substrate or waferand the first and second portions of the side drive electrodes being of a complementary shape to each other. A bonding layer, preferably a eutectic bonding layer, is provided on at least one of the mating structures and one or the first and second portions of the side drive electrodes. The matingstructure of the first substrate is moved into a confronting relationship with the mating structureof the second substrate or wafer. Pressure is applied between the two substrates so as to cause a bond to occur between the two mating structures at the bonding or eutectic layer and alsobetween the first and second portions of the side drive electrodes to cause a bond to occurtherebetween. Then the first substrate or wafer is removed to free the cantilevered beam structurefor movement relative to the second substrate or wafer. The bonds are preferably eutectic bonds.
Abstract:
A microelectromechanical (MEM) switch is fabricated inexpensively by using processing steps which are standard for fabricating multiple metal layer integrated circuits, such as CMOS. The exact steps may be adjusted to be compatible with the process of a particular foundry, resulting in a device which is both low cost and readily integrable with other circuits. The processing steps include making contacts for the MEM switch from metal plugs which are ordinarily used as viasto connect metal layers which are separated by a dielectric layer. Such contact vias are formed on either side of a sacrificial metallization area, and then the interconnect metallization is removed from between the contact vias, leaving them separated. Dielectric surrounding the contacts is etched back so that they protrude towards each other. Thus, when the contacts are moved towards each other by actuating the MEM switch, they connect firmly without obstruction. Tungsten is typically used to form vias in CMOS processes, and it makes an excellent contact material, but other via metals may also be employed as contacts. Interconnect metallization may be employed for other structural and interconnect needs of the MEM switch, and is preferably standard for the foundry and process used. Various metals and dielectric materials may be used to create the switches, but in a preferred embodiment the interconnect metal layers are aluminum and the dielectric material is Si>O2
Abstract:
The invention comprises a method for fabricating a monolithic chip containing integrated circuitry as well as a suspended polysilicon microstructure. The inventive method comprises 67 processes which are further broken down into approximately 330 steps. The processes and their arrangement allow for compatible fabrication of transistor circuitry and the suspended polysilicon microstructure on the same chip.