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Patent Issued for Methods of Fabricating Devices by Low Pressure Cold Welding

February 12, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- The Trustees Of Princeton University (Princeton, NJ) has been issued patent number 8637345, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Kim, Changsoon (Princeton, NJ); Forrest, Stephen R. (Princeton, NJ).

This patent was filed on June 18, 2012 and was published online on January 28, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Nearly all electronic and optical devices require patterning. Patterned metals are used in forming a variety of such devices. For example, patterned metals may be used in forming transistors, as electrodes in various devices, and as shadow masks in the patterning of various materials. One possible use for patterned metals is as electrodes in organic light emitting devices (OLEDs), which make use of thin films that emit light when excited by electric current. Popular OLED configurations include double heterostructure, single heterostructure, and single layer, and may be stacked, as described in U.S. Pat. No. 5,707,745, which is incorporated herein by reference in its entirety.

"Patterning of sub-micrometer structures is preferable for the realization of new and improved types of devices such as flat panel displays.

"For OLEDs from which the light emission is only out of the bottom of the device, that is, only through the substrate side of the device, a transparent anode material such as indium tin oxide (ITO) may be used as the bottom electrode. Since the top electrode of such a device does not need to be transparent, such a top electrode, which is typically a cathode, may be comprised of a thick and reflective metal layer having a high electrical conductivity. In contrast, for transparent or top-emitting OLEDs, a transparent cathode such as disclosed in U.S. Pat. Nos. 5,703,436 and 5,707,745 may be used. As distinct from a transparent or bottom-emitting OLED, a top-emitting OLED is one which may have an opaque and/or reflective substrate, such that light is produced only out of the top of the device and not through the substrate, or can be a fully transparent OLED that may emit from both the top and the bottom.

"As used herein, the term 'organic material' includes polymers as well as small molecule materials that may be used to fabricate OLEDs. The organic materials of an OLED are very sensitive, and may be damaged by conventional semiconductor processing. For example, any exposure to high temperature or chemical processing may damage the organic layers and adversely affect device reliability."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "An embodiment of the invention is directed to a method of fabricating a device by depositing a metal layer over a patterned stamp, and then transferring the metal layer from the patterned stamp onto a substrate. Preferably, the patterned stamp is a soft, elastomeric stamp.

"An embodiment of the invention is also directed to a method of fabricating a device by depositing one or more organic layers over a patterned stamp, and then transferring the organic layer(s) from the patterned stamp onto a substrate. Preferably, the patterned stamp is a soft, elastomeric stamp. A combination of metal and organic layers may also be transferred from a patterned stamp onto a substrate.

"An embodiment of the invention includes transferring a deposited metal layer from a patterned stamp onto a substrate by cold-welding. According to this embodiment, a strike layer is optionally deposited over a substrate and a patterned stamp is obtained having a metal layer deposited over the stamp. The stamp is then pressed onto the substrate, such that the metal layer over the patterned stamp contacts portions of the strike layer or other underlying layer, and sufficient pressure is applied to cold-weld the metal layer to the strike layer or other underlying layer. The patterned stamp is removed and the portions of the metal layer that are cold-welded to the strike layer or the substrate break away from the stamp and remain cold-welded to the strike layer or the substrate, in substantially the same pattern as the patterned stamp.

"Another embodiment of the invention includes transferring a deposited organic layer from a patterned stamp onto a substrate by 'cold-welding'. According to this embodiment, a strike layer is optionally deposited over a substrate and a patterned stamp is obtained having an organic layer deposited over the stamp. The stamp is then pressed onto the substrate, such that the organic layer over the patterned stamp contacts portions of the strike layer or the substrate, and sufficient pressure is applied to 'cold-weld' the organic layer to the strike layer or the substrate. The patterned stamp is removed and the portions of the organic layer that are 'cold-welded' to the strike layer or the substrate break away from the stamp and remain adhered to the strike layer or the substrate, in substantially the same pattern as the patterned stamp."

For the URL and additional information on this patent, see: Kim, Changsoon; Forrest, Stephen R.. Methods of Fabricating Devices by Low Pressure Cold Welding. U.S. Patent Number 8637345, filed June 18, 2012, and published online on January 28, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=67&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=3322&f=G&l=50&co1=AND&d=PTXT&s1=20140128.PD.&OS=ISD/20140128&RS=ISD/20140128

Keywords for this news article include: The Trustees Of Princeton University.

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Source: Journal of Engineering


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