Devices having a cavity structure and related methods
A structure having a cavity or enclosed space is fabricated by forming a recessed region in a surface of a substrate, and providing a first layer adjacent the recessed region. A liquid mixture including first and second components is supplied to the recessed region. The first component has a higher chemical affinity to the first layer than the second component such that the first component separates from the second component and adheres to an edge portion of the first layer. The substrate may then be heated to remove the second component from the recessed region through evaporation. As a result, the first component remains as a second layer adhering to the edge portion of the first layer and covering the recessed region, thereby defining a cavity or enclosed space with the recessed region. Unique structures including such cavities may be employed to realize a capacitor having a fluid, as opposed to solid, dielectric material, in order to increase the capacitance of the capacitor. Alternatively, such cavities may confine the flow of gases within narrow grooves of a substrate to realize a fuel cell having reduced size.
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1. Field of the Invention
The present invention is directed toward devices and structures having a cavity formed therein and related methods.
2. Background of the Invention
Miniature devices and structures can be fabricated with conventional semiconductor processing techniques. These techniques typically involve depositions of insulative and conductive materials, as well as photolithography and etching steps, in a desired sequence. The resulting structure is thus a series of patterned layers, one on top of another.
Many different device structures can be fabricated with conventional semiconductor processing techniques. For example, in fabricating a memory cell capacitor, trenches may be formed in a substrate and then filled with a desired dielectric material. The top of a trench, however, often cannot simply be covered with a material to form a cavity or enclosed space, because the deposited material fills the bottom and coats the sides of the trench instead. Accordingly, device structures including cavities or enclosed spaces have been difficult to achieve with conventional semiconductor processing techniques. Such structures may be beneficial in obtaining capacitors and fuel cells, for example, having reduced size or improved performance.
SUMMARY OF THE INVENTIONConsistent with an aspect of the present invention, a device is provided which comprises a substrate having a recessed surface portion and a protruding surface portion spaced from the recessed surface portion. A first layer including a first material is provided on the protruding surface portion, and an edge portion of the first layer is aligned with an edge portion of the protruding surface portion. In addition, a second layer including a second material is provided over the recessed surface portion. The second layer has an edge portion contacting the edge portion of the first layer. The first material has a chemical affinity toward the second material such that the edge portion of the second layer adheres to the edge portion of the first layer, the second layer and recessed surface portion defining a cavity.
Consistent with an additional aspect of the present invention, a method of making a device is provided, which comprises providing a first layer including a first material on a surface of a substrate, and removing a portion of the first layer and a corresponding portion of the substrate to form an opening in the first layer and a recessed portion in the surface of the substrate. The method further comprises supplying a liquid mixture to the opening in the first layer and the recessed portion in the surface of the substrate. The liquid mixture includes a first component having a first chemical affinity to the first material and a second component having a second chemical affinity to the first material, the first chemical affinity being greater than the second chemical affinity. In addition, the method includes removing the second component and forming a second layer including the first component. The second layer covers the recessed portion and adheres to an edge portion of the first layer adjacent the opening in the first layer. The second layer and the recessed portion define a cavity.
Consistent with a further aspect of the present invention, an electronic device is provided which comprises a substrate. A first conductive layer is provided on the substrate, and an insulative layer is provided on the conductive layer. In addition, a second conductive layer provided on the insulative layer, and a first layer including a first material is provided on the second conductive layer. A cavity extends through the first layer, the first conductive layer, and the insulative layer. A second layer is also provided, such that an edge portion of the second layer contacts an edge portion of the first layer. The second layer includes a second material having a chemical affinity toward the first material so that the second layer adheres to the first layer. Further, a fluid, having a higher dielectric constant than a dielectric constant of the insulative layer, is provided in the cavity.
Consistent with an additional aspect of the present invention, a method of manufacturing an electronic device is provided in which a first conductive layer is provided on a substrate, and an insulative layer is provided on the first conductive layer. The method also includes providing a second conductive layer on the insulative layer, and providing a first layer including a first material on the second conductive layer. In addition, the method includes etching a portion of the first layer, a portion of the second conductive layer and a portion of the insulative layer to form a recessed region, and supplying a liquid mixture to the recessed region. The liquid mixture includes a first component having a first chemical affinity to the first material and a second component having a second chemical affinity to the first material, the first chemical affinity being greater than the second chemical affinity. Moreover, the method includes removing the second component, and forming a second layer including the first component. The second layer covers the recessed region and adheres to an edge portion of the first layer adjacent to the opening in the first layer. The second layer and the recessed region define a cavity. The method also includes supplying a dielectric liquid to the cavity, the dielectric fluid having a dielectric constant greater than a dielectric constant associated with the insulative layer.
Consistent with a further aspect of the present invention, a fuel cell is provided which comprises a substrate, as well as an anode electrode and a cathode electrode formed on first and second portions, respectively, of the substrate. A third portion of the substrate is provided between the first and second portions. A polymer electrolyte membrane is provided on the third portion of the substrate, and a first film having a sidewall surface is provided on the anode electrode. In addition, a second film having a sidewall surface is provided on the cathode electrode. A first porous layer is provided adjacent a first side of the polymer electrolyte membrane and is spaced from the sidewall surface of the first film, and a second porous layer is provided adjacent a second side of the polymer electrolyte membrane and is spaced from the sidewall surface of the second film. Moreover, a first recessed region is defined by the first porous layer and the sidewall of the first film, and a second recessed region is defined by the second porous layer and the sidewall of the second film. A first layer is provided on the first film, and a second layer is provided over the first recessed region. The second layer has a chemical affinity toward the first layer such that an edge portion of the second layer adheres to an edge portion of the first layer. Further, a third layer is provided on the second film, and a fourth layer is provided over the second recessed region. The fourth layer has a chemical affinity toward the third layer such that an edge portion of the fourth layer adheres to an edge portion of the second layer.
Consistent with another aspect of the present invention, a method of making a fuel cell is provided which comprises depositing a conductive layer on a substrate, and patterning the conductive layer to form an anode electrode and a cathode electrode. The method also includes providing a first porous layer on the anode electrode and a second porous layer on the cathode electrode, and providing a polymer electrolyte membrane between the first and second porous layer. In addition, the method includes depositing a film on the substrate about the first and second porous layers, and depositing a first layer including a first material on the film. The method further includes etching the film to form a first sidewall surface spaced from the first porous layer and a second sidewall surface spaced from the second porous layer. The first sidewall surface and the first porous layer define a first recessed region and the second sidewall surface and the second porous layer define a second recessed region. Moreover, the method includes etching the first layer to form a first opening in correspondence with the first recessed region and a second opening in correspondence with the second recessed region, and supplying a liquid mixture to the first and second recessed regions. The liquid mixture includes a first component having a first chemical affinity to the first material and a second component having a second chemical affinity to the first material less than the first chemical affinity. The method also includes removing the second component to form a second layer over the first recessed region and a third layer over the second recessed region such that an edge of the second layer adheres to a first edge of the first layer and an edge of the third layer adheres to a second edge of the first layer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGSFIGS. 1(a)-1(i) illustrate process steps in manufacturing a device consistent with an aspect of the present invention;
FIGS. 2(a)-2(l) illustrate process steps in manufacturing a capacitor consistent with an additional aspect of the present invention;
FIGS. 3(a)-3(t) illustrate process steps in manufacturing a fuel cell consistent with a further aspect of the present invention; and
A structure having a cavity or enclosed space is fabricated by forming a recessed region in a surface of a substrate, and providing a trap or first layer adjacent the recessed region. A liquid mixture including first and second components is supplied to the recessed region. The first component has a higher chemical affinity to the trap layer than the second component such that the first component separates from the second component and adheres to an edge portion of the trap layer. The substrate may then be heated, and the second component is removed from the recessed region through evaporation. As a result, the first component remains as a dried film or second layer adhering to the edge portion of the trap layer and covering the recessed region, thereby defining a cavity or enclosed space within the recessed region. Structures including such cavities may be employed to realize a capacitor having a fluid, as opposed to solid, dielectric material, thereby increasing the capacitance of the capacitor. Alternatively, such cavities may confine the flow of gases within narrow grooves of a substrate to realize a fuel cell having reduced size.
Reference will now be made in detail to the present exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
FIGS. 1(a)-1(i) illustrate process steps in manufacturing a device 140 (see
In
The first (120) and second (122) components are typically selected based on the choice of first layer 102. For example, if first layer 102 includes silicon nitride, first component 120 may be an acidic nitride derivative and second component 122 may be water. Alternatively, if first layer 102 includes an organo-metallic material, such as tetramethylsilane, first component 120 may include cellular fiber, carbon particles or carbon fibers, and second component 122 may include an alcohol.
When substrate 100 is heated sufficiently, for example, in a dry gas flow or low power plasma, as represented by arrows 124 in
As noted above, cavity structures may be provided in capacitors to increase the capacitance thereof, consistent with a further aspect of the present invention. A process for fabricating an exemplary metal-insulator-metal (MIM) capacitor in accordance with an aspect of the present invention will next be described with reference to FIGS. 2(a)-2(l). As shown in
As further shown in
Next, in
A third layer 230, typically including an insulative material, is next provided on first (210) and second (226) layers in
Next, in
The dielectric fluid discussed above may be either in liquid or gaseous form and may be a high-k dielectric fluid have a higher dielectric constant than that of insulative layer 208 or substrate 200. In addition, by using a liquid or gas dielectric fluid, flexible capacitor designs, which are not limited to conventional structures based on solid dielectric materials, can be achieved.
As further noted above, cavity structures consistent with the present invention may be also be implemented in a fuel cell. Such a fuel cell and related manufacturing method in accordance with further aspects of the present invention will next be described with reference to FIGS. 3(a)-(t).
In
Next, in
In
First (319) and second (318) films are next deposited, as shown in
As further shown in
In
A first layer 338 is next deposited on films 318 and 319, as well as PEM 336, as shown in
In
A cap or protective layer is next deposited as layer 376, which includes an insulative material (
In operation, hydrogen gas is supplied to regions of PEM 366 exposed by openings 348 in porous layer 324. Catalyst layer 306 adjacent porous layer 324 interacts with the hydrogen to yield protons and electrons. The protons migrate through openings 348 of porous layer 324, pass through PEM 336, and reach recessed region 346. Meanwhile, the electrons form an electrical current that flows from anode 304-2 to cathode 304-1. This electrical current flow has a corresponding voltage which can be used to drive a desired circuit (not shown). In recessed region 346, the electrons combine with the protons and the oxygen to form water, which can be removed by flushing additional oxygen gas, for example, through recessed region 346.
Fuel cell 390 may be manufactured using semiconductor processing techniques, such as photolithography, and thus can be made relatively small. Moreover, fuel cell 390 can be integrated onto a semiconductor chip so that the chip is self-powered, thereby obviating the need for an external power supply.
Although a hydrogen-based fuel cell is described above, other fuel cells are contemplated involving other input materials, such as methanol. Moreover, the cavity or recessed region structures discussed above are applicable to other devices in addition to capacitors and fuel cells.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
Claims
1. A device comprising:
- a substrate having a recessed surface portion and a protruding surface portion spaced from the recessed surface portion;
- a first layer including a first material disposed on the protruding surface portion, an edge portion of the first layer being aligned with an edge portion of the protruding surface portion; and
- a second layer including a second material disposed over the recessed surface portion, the second layer having an edge portion contacting the edge portion of the first layer, the first material having a chemical affinity toward the second material such that the edge portion of the second layer adheres to the edge portion of the first layer, the second layer extending over the recessed surface portion.
2. A device in accordance with claim 1, further comprising a third layer, the third layer extending over the first layer and the second layer.
3. A device in accordance with claim 1, wherein the first layer includes silicon nitride and the second layer includes an acidic nitride derivative.
4. A device in accordance with claim 1, wherein the first layer includes an organo-metallic compound and the second layer includes carbon particles.
5. A device according to claim 4, wherein the organo-metallic compound includes tetramethylsilane.
6. A device according to claim 1, further including a third material in the cavity having a dielectric constant greater than a dielectric constant associated with the substrate.
7. An electronic device, comprising:
- a substrate;
- a first conductive layer disposed on the substrate;
- an insulative layer disposed on the conductive layer;
- a second conductive layer disposed on the insulative layer;
- a first layer including a first material disposed on the second conductive layer, a recessed region extending through the first layer, the first conductive layer, the second conductive layer, and the insulative layer;
- a second layer disposed over the recessed region, an edge portion of the second layer contacting an edge portion of the first layer, the second layer including a second material having a chemical affinity toward the first material such that the second layer adheres to the first layer; and
- a fluid provided in the recessed region, the fluid having a higher dielectric constant than a dielectric constant of the insulative layer.
8. An electronic device in accordance with claim 7, wherein the electronic device is a capacitor.
9. An electronic device in accordance with claim 7, wherein a first opening extends through the insulative layer and overlies a portion of the first conductive layer, and a second opening extends through the first layer and overlies a portion of the second conductive layer, the electronic device further comprising:
- a third conductive layer disposed in the first opening, the third conductive layer being electrically coupled to the first conductive layer; and
- a fourth conductive layer disposed in the second opening, the fourth conductive layer being electrically coupled to the second conductive layer.
10. An electronic device in accordance with claim 7, further comprising:
- a third conductive layer constituting a first electrical connection to the first conductive layer; and
- a fourth conductive layer constituting a second electrical connection to the second conductive layer.
11. An electronic device in accordance with claim 7, wherein said insulative layer is a first insulative layer, said electronic component further comprising a second insulative layer overlying the first and second layers.
12. An electronic device in accordance with claim 7, wherein the first material is selected from the group consisting of silicon nitride, fluorine doped silicate glass, silicon oxynitride, an organo-metallic compound, and silicon carbide.
13. An electronic device in accordance with claim 7, wherein the first material is silicon nitride and the second material includes an acidic nitride derivative.
14. An electronic device in accordance with claim 7, wherein the first material is an organo-metallic compound and the second material includes carbon particles.
15. A device according to claim 1, wherein the first material is selected from the group consisting of silicon nitride, fluorine doped silicate glass, silicon oxynitride, an organo-metallic compound, and silicon carbide.
16. A device according to claim 7, wherein the first material is selected from the group consisting of silicon nitride, fluorine doped silicate glass, silicon oxynitride, an organo-metallic compound, and silicon carbide.
17. A fuel cell, comprising:
- a substrate;
- an anode electrode disposed on a first portion of the substrate;
- a cathode electrode disposed on a second portion of the substrate spaced from the anode electrode, a third portion of the substrate being disposed between the first and second portions of the substrate;
- a polymer electrolyte membrane disposed on the third portion of the substrate;
- a first film disposed on the anode electrode, the first film having a sidewall surface;
- a second film disposed on the cathode electrode, the second film having a sidewall surface;
- a first porous layer disposed adjacent a first side of the polymer electrolyte membrane and being spaced from the sidewall surface of the first film;
- a second porous layer disposed adjacent a second side of the polymer electrolyte membrane and being spaced from the sidewall surface of the second film;
- a first recessed region being defined by the first porous layer and the sidewall of the first film;
- a second recessed region being defined by the second porous layer and the sidewall of the second film;
- a first layer disposed on the first film;
- a second layer disposed over the first recessed region and having a chemical affinity toward the first layer such that an edge portion of the second layer adheres to an edge portion of the first layer;
- a third layer disposed on the second film; and
- a fourth layer disposed over the second recessed region and having a chemical affinity toward the third layer such that an edge portion of the fourth layer adheres to an edge portion of the second layer.
18. A fuel cell in accordance with claim 17, wherein the first and second porous layers include a plurality of openings configured to expose portions of the polymer electrolyte membrane to the first and second recessed portions.
19. A fuel cell in accordance with claim 17, further comprising a first groove formed in the first film and a second groove formed in the second film, the first recessed region constituting a part of the first groove and the second recessed region constituting part of the second groove.
20. A fuel cell in accordance with claim 19, wherein the first groove is configured to receive a first gas and the second groove is configured to receive a second gas.
21. A fuel cell in accordance with claim 20, wherein the first gas is hydrogen and the second gas is oxygen.
Type: Application
Filed: Apr 13, 2006
Publication Date: Oct 18, 2007
Applicant:
Inventors: You-Hua Chou (Taipei City), Hsiang Ko (Tainan County), Hung Chang (Changhua County), Yi Chen (Tainan City), Hsien-Wei Lin (Tainan)
Application Number: 11/402,906
International Classification: H01L 23/52 (20060101);