Abstract:
A MEMS device, for example a capacitive microphone, comprises a flexible membrane 11 that is free to move in response to pressure differences generated by sound waves. A first electrode 13 is mechanically coupled to the flexible membrane 11, and together form a first capacitive plate of the capacitive microphone device. A second electrode 23 is mechanically coupled to a generally rigid structural layer or back-plate 14, which together form a second capacitive plate of the capacitive microphone device. The capacitive microphone is formed on a substrate 1, for example a silicon wafer. A back-volume 33 is provided below the membrane 11, and is formed using a “back-etch” through the substrate 1. A first cavity 9 is located directly below the membrane 11, and is formed using a first sacrificial layer during the fabrication process. Interposed between the first and second electrodes 13 and 23 is a second cavity 17, which is formed using a second sacrificial layer during the fabrication process. A plurality of bleed holes 15 connect the first cavity 9 and the second cavity 17. Acoustic holes 31 are arranged in the back-plate 14 so as to allow free movement of air molecules, such that the sound waves can enter the second cavity 17. The first and second cavities 9 and 17 in association with the back-volume 33 allow the membrane 11 to move in response to the sound waves entering via the acoustic holes 31 in the back-plate 14. The provision of first and second sacrificial layers has the advantage of protecting the membrane during manufacture, and disassociating the back etch process from the definition of the membrane. The bleed holes 15 aid with the removal of the first and second sacrificial layers. The bleed holes 15 also contribute to the operating characteristics of the microphone.
Abstract:
A multi-layer fabrication method for making three-dimensional structures is provided. In one embodiment, the formation of a multi-layer three-dimensional structure comprises: 1) fabricating a plurality of layers with each layer comprising at least two materials; 2) aligning the layers; 3) attaching the layers together to form a multi-layer structure; and 4) removing at least a portion of at least one of the materials from the multi-layer structure. Fabrication methods for making the required layers are also disclosed. In another embodiment, the formation of a multi-layer three-dimensional structure comprises: 1) attaching a layer of a material to a substrate or a previously formed layer; 2) machining the attached layer to form a layer that comprises at least two materials; and 3) repeating the operations of 1) and 2) a plurality of times to form a multi-layer structure; and 4) removing at least a portion of at least one of the materials from the multi-layer structure to form a desired three-dimensional structure.
Abstract:
A microfabricated structure and method of making that includes forming a first layer of material on a substrate, forming patterned sacrificial material having a predetermined shape on the first layer of material, and forming a second layer of material over the first layer and the patterned sacrificial material, which is then removed to form an encapsulated cavity. Ideally, the first and second layers are formed of the same type material. A structural support layer can be added to the second layer. Openings can be formed in the cavity, and the cavities can be layered side by side, vertically stacked with interconnections via the openings, and a combination of both can be used to construct stacked arrays with interconnections throughout.
Abstract:
The invention provides a microfabrication process which may be used to manufacture a MEMS device. The process comprises depositing one or a stack of layers on a base layer, said one layer or an uppermost layer in said stack of layers being a sacrificial layer; patterning said one or a stack of layers to provide at least one aperture therethrough through which said base layer is exposed; depositing a photosensitive layer over said one or a stack of layers; and passing light through said at least one aperture to expose said photosensitive layer.
Abstract:
A method comprising over an area of a substrate, forming a plurality of three dimensional first structures; following forming the first structures, conformally introducing a sacrificial material over the area of the substrate; introducing a second structural material over the sacrificial material; and removing the sacrificial material. An apparatus comprising a first structure on a substrate; and a second structure on the substrate and separated from the first structure by an unfilled gap defined by the thickness of a removed film.
Abstract:
New devices having horizontally-disposed nanofabric articles and methods of making same are described. A discrete electro-mechanical device includes a structure having an electrically-conductive trace. A defined patch of nanotube fabric is disposed in spaced relation to the trace; and the defined patch of nanotube fabric is electromechanically deflectable between a first and second state. In the first state, the nanotube article is in spaced relation relative to the trace, and in the second state the nanotube article is in contact with the trace. A low resistance signal path is in electrical communication with the defined patch of nanofabric. Under certain embodiments, the structure includes a defined gap into which the electrically conductive trace is disposed. The defined gap has a defined width, and the defined patch of nanotube fabric spans the gap and has a longitudinal extent that is slightly longer than the defined width of the gap. Under certain embodiments, a clamp is disposed at each of two ends of the nanotube fabric segment and disposed over at least a portion of the nanotube fabric segment substantially at the edges defining the gap. Under certain embodiments, the clamp is made of electrically-conductive material. Under certain embodiments, the contact between the nanotube patch and the trace is a non-volatile state. Under certain embodiments, the contact between the nanotube patch and the trace is a volatile state. Under certain embodiments, the at least one electrically conductive trace has an interface material to alter the attractive force between the nanotube fabric segment and the electrically conductive trace.
Abstract:
In fabricating a microelectromechanical structure (MEMS), a method of forming a narrow gap in the MEMS includes a) depositing a layer of sacrificial material on the surface of a supporting substrate, b) photoresist masking and at least partially etching the sacrificial material to form at least one blade of sacrificial material, c) depositing a structural layer over the sacrificial layer, and d) removing the sacrificial layer including the blade of the sacrificial material with a narrow gap remaining in the structural layer where the blade of sacrificial material was removed.
Abstract:
The invention provides a microfabrication process which may be used to manufacture a MEMS device. In one embodiment, the process comprises depositing at least one first layer on a substrate. The process further comprises patterning said first layer to define at least a first portion of said microelectromechanical system device. The process further comprises depositing a second layer on said first layer. The process further comprises patterning said second layer using said first layer as a photomask. The process further comprises developing said second layer to define at least a second portion of the microelectromechanical system device.
Abstract:
RF and microwave radiation directing or controlling components are provided that may be monolithic, that may be formed from a plurality of electrodeposition operations and/or from a plurality of deposited layers of material, that may include switches, inductors, antennae, transmission lines, filters, hybrid couplers, antenna arrays and/or other active or passive components. Components may include non-radiation-entry and non-radiation-exit channels that are useful in separating sacrificial materials from structural materials. Preferred formation processes use electrochemical fabrication techniques (e.g. including selective depositions, bulk depositions, etching operations and planarization operations) and post-deposition processes (e.g. selective etching operations and/or back filling operations).
Abstract:
Electro-mechanical switches and memory cells using vertically-disposed nanofabric articles and methods of making the same are described. An electro-mechanical device, includes a structure having a major horizontal surface and a channel formed therein. A conductive trace is in the channel; and a nanotube article vertically suspended in the channel, in spaced relation to a vertical wall of the channel. The article is electro-mechanically deflectable in a horizontal direction toward the conductive trace. Under certain embodiments, the vertically suspended extent of the nanotube article is defined by a thin film process. Under certain embodiments, the vertically suspended extent of the nanotube article is about 50 nanometers or less. Under certain embodiments, the nanotube article is clamped with a conducting material disposed in porous spaces between some nanotubes of the nanotube article. Under certain embodiments, the nanotube article is formed from a porous nanofabric. Under certain embodiments, the nanotube article is electromechanically deflectable into contact with the conductive trace and the contact is either a volatile state or non-volatile state depending on the device construction. Under certain embodiments, the vertically oriented device is arranged into various forms of three-trace devices. Under certain embodiments, the channel may be used for multiple independent devices, or for devices that share a common electrode.