Photolithography Structures and Methods
This disclosure provides systems, methods and apparatus including processes that use two layers of resist, with a layer of etch stop material in between. The two layers of resist may be etched in separate processes to form devices having vias with sidewalls that extend through both layers of resist
1 . A method for manufacturing a electromechancial system (EMS) device, comprising:
depositing on a substrate, a first layer of sacrificial material, a layer of etch stop material resistant to a first etch process, and a second layer of the sacrificial material,
etching the second layer of sacrificial material using the first etch process to form a first pattern within the second layer of sacrificial material,
applying a mask to the patterned layer of sacrificial material that exposes at least a portion of the etch stop material, and
etching with a second etch process the etch stop material and the first layer of sacrificial material to form a mold having features that extend through the first and second layers of sacrificial material.
2 . The method of claim 1 , further comprising selecting the thickness of the second layer of sacrificial material to select a feature size of a component in the EMS device.
3 . The method of claim 1 , wherein depositing the first layer of sacrificial material and the second layer of sacrificial material includes depositing layers of between 1 and 10 μm (microns).
4 . The method of claim 1 , wherein depositing at least one of the first and second layer of sacrificial material includes depositing a layer of resist material.
5 . The method of claim 1 , wherein depositing the layer of etch stop material includes depositing a layer of material between about 25 and 5000 Å (angstroms).
6 . The method of claim 1 , wherein depositing a layer of etch stop material includes depositing a layer of material selected from the group consisting of amorphous silicon, Titanium, silicon oxide, silicon carbide, and silicon nitride.
7 . The method of claim 1 , wherein applying the mask includes applying a hard mask.
8 . The method of claim 7 , wherein applying the hard mask includes sputtering a pattern of material selected from the group consisting of metals, silicon dioxide, and geranium.
9 . The method of claim 1 , wherein etching using the first etch process includes anisotropic etching with oxygen ions.
10 . The method of claim 1 , wherein etching with the second process includes anisotropic etching with oxygen.
11 . The method of claim 1 , wherein etching with a first process includes anisotropic etching to form a sidewall substantially perpendicular to the substrate.
12 . The method of claim 1 , further including depositing a layer of semiconductor material over the etched first and second layers of sacrificial material to form features of the EMS device and removing the first and second layers of sacrificial material and etch stop layer to release the features for use within the EMS device.
13 . The method of claim 12 , wherein removing the first and second layers of sacrificial material and etch stop layer includes etching with a fluorine compound and oxygen.
14 . An electromechanical system (EMS) device, having
a substrate having a first surface,
an anchor attached to the first surface and having a sidewall with a first portion and a second portion, and a junction joining the first portion with the second portion, wherein the first portion is in contact with the first surface of the substrate and the second portion of the sidewall is spaced away from the first surface.
15 . The EMS device of claim 14 , further comprising
a beam connected to the second portion of the sidewall and extending substantially parallel to the first surface of the substrate.
16 . The EMS device of claim 15 , wherein the beam includes elements movable between a first position and a second position.
17 . The EMS device of claim 14 , wherein the substrate includes a transparent material.
18 . The EMS device of claim 14 , wherein the anchor has a height between 2 and 20 μm (microns).
19 . The EMS device of claim 14 , wherein the first portion of the sidewall has a first inclination relative to the first surface of the substrate and the second portion of the sidewall has a second, different inclination relative to the first surface of the substrate.
20 . The EMS device of claim 14 , wherein the first portion of the sidewall and the second portion of the sidewall are inclined substantially orthogonally relative to the first surface of the substrate.
21 . The EMS device of claim 14 , wherein the anchor includes a second sidewall having a first portion and second portion and a junction joining the first portion with the second portion.
22 . The EMS device of claim 14 , wherein the junction includes a coupling of semiconductor material having a first end joined to the first portion of the sidewall and a second end being laterally spaced from the first end and joined to the second portion of the sidewall.
23 . An apparatus comprising the EMS device of claim 14 , wherein the substrate includes a plurality of anchors and a plurality beams having movable elements for modulating light to provide a display,
a processor capable of communicating with the display, the processor being capable of processing image data; and
a memory device capable of communicating with the processor.
24 . The apparatus of claim 23 , further comprising:
a driver circuit capable of sending at least one signal to the display; and
a controller capable of sending at least a portion of the image data to the driver circuit.
25 . The apparatus of claim 23 , further comprising:
an image source module capable of sending the image data to the processor, wherein the image source module includes at least one of a receiver, transceiver, and transmitter.
26 . The apparatus of claim 23 , further comprising:
an input device capable of receiving input data and communicating the input data to the processor.