Optomec Aerosol Jet metal deposition for Printed Electronics

This is the fourth in the series of Printed Electronics patents granted in 2011.  I was alerted to this via the Boliven patent alert system which sends me an automatic update for any new granted patents with the search terms used in my original PE patent search.

US7987813:

Patent Title: Apparatuses and methods for maskless mesoscale material deposition
Filing Date: 6 Jan 2009
Issue Date: 2 Aug 2011
Inventor(s): Michael J. Renn, Bruce H. King, Marcelino Essien, Gregory J. Marquez, Manampathy G. Giridharan, Jyh-Cherng Sheu
Assignee(s): Optomec Inc.

Abstract

Apparatuses and processes for maskless deposition of electronic and biological materials. The process is capable of direct deposition of features with linewidths varying from the micron range up to a fraction of a millimetre, and may be used to deposit features on substrates with damage thresholds near 100° C. Deposition and subsequent processing may be carried out under ambient conditions, eliminating the need for a vacuum atmosphere. The process may also be performed in an inert gas environment. Deposition of and subsequent laser post processing produces linewidths as low as 1 micron, with sub-micron edge definition. The apparatus nozzle has a large working distance—the orifice to substrate distance may be several millimetres—and direct write onto non-planar surfaces is possible.

Phil’s Comments

This is the latest granted patent covering Optomec’s Maskless Mesoscale Material Deposition (originally termed M3D).  Their recent applications seem to use the Aerosol Jet Printing system description and that is consistent with Optomec’s current website.  There is quite a lot of technical information available on this approach and the reader is referred to their website for more details.  An extract from their website gives a good overview of the system and its applications:

Aerosol Jet systems have the unique ability to produce a wide range of electronic, structural and biological patterns onto almost any substrate. The proprietary process, which is completely different from ink jet industrial printing, utilizes aerodynamic focusing to precisely deliver fluid and nano-material formulations that as required can be optionally post-treated with a highly focused laser or other sintering methods. The resulting patterns can have features that are less than 10 microns wide, with layer thicknesses from 10’s of nanometers to several microns. A recently announced Aerosol Jet Wide Nozzle print head is also available which enables efficient patterning of millimeter scale conductive features (bus bars, backplanes), large area thin film coatings, and selective coatings (insulators, cross-over circuits, encapsulation). Example applications for Aerosol Jet Wide Nozzle deposition capabilities are fuel cells, conformal antennae and Molded Interconnect Devices.

This patent further strengthens Optomec’s patent portfolio which already has close to 20 granted US patents in this field.  A look at the granted patent trends over the past few years shows that while there has been a steady rate of on average 2 patents per year this number is already significantly higher for 2011.

Optomec Granted Patent Trend

 

The Aerosol Jet deposition method has been investigated by a number of companies interested in using this approach for printed electronics including the PETEC organisation in the UK.

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Printed Electronics Patents Granted in 2011 – Kovio Inc

This is the third in the series covering patents granted during 2011 in the printed electronics field.

US7977240: Metal Inks For Improved Contact Resistance

Inventor(s)
Joerg Rockenberger, Yu Chen, Fabio Zürcher, Scott Haubrich

Assignee(s)
Kovio, Inc.

Filing date: 13 Feb 2009; Issue date: 12 Jul 2011

Abstract

Metal ink compositions, methods of forming such compositions, and methods of forming conductive layers are disclosed. The ink composition includes a bulk metal, a transition metal source, and an organic solvent. The transition metal source may be a transition metal capable of forming a silicide, in an amount providing from 0.01 to 50 wt. % of the transition metal relative to the bulk metal. Conductive structures may be made using such ink compositions by forming a silicon-containing layer on a substrate, printing a metal ink composition on the silicon-containing layer, and curing the composition. The metal inks of the present invention have high conductivity and form low resistivity contacts with silicon, and reduce the number of inks and printing steps needed to fabricate integrated circuits.

Phil’s Comments:

Kovio Inc. is one of the leading companies involved in printed electronics devices and have made significant progress in printing complex electronic devices such as RFID’s in which not only the antenna but also the associated electronics is printed by a solution deposition process.

Here is an extract from the patent which explains the problem faced in any printing method for electronic devices:

In integrated circuits, the devices (e.g., TFT, capacitors, diodes, etc.) are generally connected to each other with metal lines (i.e., interconnects). Integrated circuits with good performance generally include interconnects with low resistivity, and thus not all metals are suitable for use as interconnects. Typical examples of suitable metals are Al, Cu, Au and Ag. Often, metals used for interconnects in integrated circuits do not form low resistivity contacts with the device electrodes (e.g., gate and source/drain electrodes), which are usually made with n+ and/or p+ doped silicon. Therefore, in order to fabricate integrated circuits with good performance, a contact layer formed between the n+/p+ silicon and the metal lines often provides relatively low resistivity between the devices and the interconnects. Typically, silicides are the preferred contact layers used in microelectronic devices, because they can provide ohmic contacts to heavily doped semiconductors (e.g. n+/p+ silicon and/or germanium).

This patent describes metal ink compositions that have high conductivity and low contact resistance and can therefore reduce the number of inks and printing steps required to manufacture a device.  The patent also describes a method which comprises (a) forming a layer comprising silicon and/or germanium on a substrate, (b) depositing (e.g., by printing) a metal ink composition on the silicon-containing layer, and (c) curing the metal composition. In general, the metal ink compositions comprise a bulk metal and a silicide-forming transition metal source.

More details are available in the full patent specification which can be found here.  Email me or leave a comment if you would like any further details.