Etching a substrate: processes – Nongaseous phase etching of substrate – Etching using radiation
Reexamination Certificate
2000-01-28
2004-09-14
Wong, Edna (Department: 1753)
Etching a substrate: processes
Nongaseous phase etching of substrate
Etching using radiation
C216S012000, C216S056000
Reexamination Certificate
active
06790377
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to forming structures by electrochemical deposition. Microfabrication processes (also referred to as micromachining) are being developed and refined for eventual application to the manufacture of complex devices including machines and instrumentation. These processes are being directed to the production of machines of miniaturized devices having features in the range of a few microns and in some cases features in the submicron range, some of which currently exist on a macroscopic scale.
Microfabrication processes include: bulk micromachining, in which material is removed from regions of a substrate; surface micromachining, in which a thin conformal structural layer and one or more sacrificial layers are deposited onto a substrate; and LIGA, which generates 2.5-D extruded shapes by molding materials around metals molds which were formed by the metals being electrodeposited within openings in thick synchrotron-processed photoresists. These processes are used to produce structures of simple geometries (e.g., they can be defined by 1-4 different cross sections), and are usually customized for each application.
Solid freeform fabrication, which is also referred to as rapid prototyping, is used to manufacture macroscopic parts from hundreds of layers by generating one layer at a time. These processes produce features typically greater than 50-100 um in width using layers typically greater than 50-150 um thick. These processes typically generate a layer serially. These processes employ structures for supporting the part being manufactured. The support structures are often customized to the part.
SUMMARY OF THE INVENTION
In one aspect, the invention features an electroplating method that includes: a) contacting a first substrate with a first article, which includes a substrate and a conformable mask disposed in a pattern on the substrate; b) electroplating a first metal from a source of metal ions onto the first substrate in a first pattern, the first pattern corresponding to the complement of the conformable mask patted; and c) removing the first article from the first substrate.
In preferred embodiments, the method further includes electroplating a second metal from a second metal ion source onto the first substrate. In one embodiment, the step of electroplating the second metal includes: a) contacting the first substrate with a second article including a substrate and a conformable mask disposed in a pattern on the substrate; b) electroplating a second metal onto the first substrate in a second pattern, the second pattern corresponding to the complement of the conformable mask pattern of the second article; and c) removing the second article from the first substrate. The method can further include building additional layers.
In one embodimnent, the invention features an electroplating method that includes repeatedly contacting a substrate with a patterned conformable mask; electroplating a first metal form a source of ions onto the substrate in a pattern, the pattern corresponding to the complement of the conformable mask pattern; and removing the mask from the substrate.
In another embodiment, the invention features a method for manufacturing an element that includes forming a multi-layer structure by repeatedly forming layers according to the above-described electroplating methods.
In another aspect, the invention features an electroplating article that includes a substrate having a first major surface and a conformable mask disposed in a pattern on the first major surface of the substrate. The article is capable of electroplating a pattern of metal complementary to the pattern of the conformable mask onto an electrode when the article is placed in contact with the electrode in the presence of a metal ion source and subjected to an electric field.
In other aspects, the invention features an electroplating apparatus that includes an electrolyte, which includes ions of a first metal and ions of a second metal, an anode in contact with the electrolyte, a cathode in contact with the electrolyte, and a first article (e.g., the above described electroplating article) in contact with the electrolyte.
In one embodiment, the electroplating apparatus includes a first electroplating reservoir that includes an electrolyte, which includes a first metal ion, disposed within the first reservoir, an anode in contact with the electrolyte, a cathode in contact with the electrolyte, and an article (e.g., an article described above) in contact with the electrolyte; a second electroplating reservoir that includes an electrolyte, which includes ions of a second metal, disposed within the second reservoir, and an anode in contact with the electrolyte.
In another aspect, the invention features a method for manufacturing an electroplating article. The method includes: a) applying a conformable mask to an article comprising a first substrate and a patterned resist disposed on the first substrate; b) contacting a second substrate to said conformable mask such that the conformable mask obtains a pattern complemnentary to the resist pattern; c) separating the first substrate from the conformable mask (the conformable mask remaining adhered to the article); and d) removing the resist.
In one embodiment, the method for manufacturing an electroplating article includes providing a porous medium having a first surface; b) treating said porous medium to create one or more nonporous regions; c) applying a film to said first surface of said porous medium; d) patterning the film to create a patterned mask; and e) removing at least a portion of the one or more nonporous regions.
In other aspects, the present invention is directed to the calculation, storage and retrieval of cross section geometry of a three dimensional object for generation of patterned masks reflecting that geometry and for use in an electroplating method. The data and control processes of various embodiments of the invention can be implemented by a software application program executed in a general purpose computing system.
The data and control processes of various embodiments of the invention can be embodied in an electroplating method implemented via the application program and also in an article of manufacture, in the form of a data storage medium, that stores application program code arranged to carry out that method upon execution by a processor.
The electroplating methods and articles allow fabrication of devices from thin layers of materials such as, e.g., metals, polymers, ceramics, and semiconductor materials. The electroplating methods produce relatively homogeneous, isotropic elements (e.g., devices) without interlayer junctions. The electroplating methods can be performed at low temperatures, thus allowing substrates such as integrated circuits and silicon wafers to be used as plating substrates.
The electroplating methods of various embodiments of the invention can be used to fabricate devices of freeform geometry including high aspect ratio devices, hollow devices with internal features, devices with cantilevered and “chandelier” geometries, and functional assemblies of interconnected, stationary or moving parts (i.e., devices fabricated in an assembled state). The electroplating articles, apparatus, and methods also are particularly useful in mass production of devices.
Other features and advantages of various aspects of the invention will be apparent from the following description of the preferred embodiments thereof , and from the claims.
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Smalley Dennis R.
University of Southern California
Wong Edna
LandOfFree
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