WO2013067395A2

WO2013067395A2 - Method and apparatus for improving ink deposition

Info

Publication number: WO2013067395A2
Application number: PCT/US2012/063381
Authority: WO
Inventors: Albert K. Henning; Raymond Roger Shile; Joseph S. Fragala; Sergey V. Rozhok
Original assignee: Nanoink, Inc.
Priority date: 2011-11-04
Filing date: 2012-11-02
Publication date: 2013-05-10
Also published as: WO2013067395A3

Abstract

A device comprising different microcantilevers in structural design to determine best printing of inks from the cantilevers in direct write nanolithography. A method comprising: providing at least one passive array of a plurality of microcantilevers wherein each microcantilever has at least one nanoscopic tip thereon; disposing on the microcantilevers a single ink composition comprising a patterning material; depositing the patterning materials onto a substrate to provide a substrate comprising a plurality of deposits; inspecting the deposits to determine which of the cantilevers provides a preferred deposition.

Description

METHOD AND APPARATUS FOR IMPROVING INK DEPOSITION

RELATED APPLICATIONS

This application claims priority to US provisional application serial no. 61/556,117 filed November 4, 2011 and US provisional application serial no. 61/602,493 filed February 23, 2012.

BACKGROUND

Surface nanolithography tools include, for example, nanoscopic tips made from a variety of hard and soft materials such as silicon, silicon nitride, and elastomeric polymers. If desired, the tips can be attached to microcantilevers. For example, scanning probe and atomic force microscopy (SPM and AFM, respectively) cantilevers and tips can be used in a variety of technologies where material is deposited from the tip to a substrate. For example, DPN lithography is a direct write technique that utilizes, for example, sharp tips such as, for example, AFM tips as a pen for micron and nanoscale deposition of molecules, materials, and chemical and biological fluids (often referred to as "inks"). AFM tips have been used for DPN applications to generate a variety of nanoscale patterns.

If desired, multiples cantilevers and tips can be used in one-dimensional or two- dimensional arrays. Pen arrays, however, have generally contained only one design for the pen per array in order to promote uniformity.

Improvement of ink deposition often required altering properties of the ink, such as viscosity or solvent which can be cumbersome, time-consuming, and expensive.

Improved arrays and methods for improving and optimizing ink delivery are needed, particularly for commercial applications. For example, reproducibility is an important parameter for which improvement is needed.

SUMMARY

Embodiments described herein include devices and articles, as well as methods of making devices and articles and also methods of using devices and articles. Instruments can be used with the devices and to practice the methods.

For example, one embodiment provides a method comprising: providing at least one passive array of a plurality of microcantilevers wherein each micro cantilever has at least one nanoscopic tip thereon; disposing on the microcantilevers a single ink composition comprising a patterning material; depositing the patterning materials onto a substrate to provide a substrate comprising a plurality of deposits; inspecting the deposits to determine which of the cantilevers provides a preferred deposition.

In one embodiment, the array of microcantilevers comprises at least two different microcantilevers which are structurally different.

In one embodiment, the array of microcantilevers comprises at least three different microcantilevers which are structurally different.

In one embodiment, the array of cantilevers comprises eleven different cantilevers which are structurally different.

In one embodiment, the at least one tip is a solid tip without a hole or aperture.

In one embodiment, the cantilevers are A-frame cantilevers or diving board cantilevers.

In one embodiment, the array of cantilevers comprises at least two different cantilevers which contain different dimensions in at least one of the following parameters: tail width, throat width, throat-to-tip distance, channel depth, and tip radius.

In one embodiment, the array of cantilevers comprises at least five different cantilevers which contain different dimensions in at least one of the following parameters: tail width, throat width, throat-to-tip distance, channel depth, and tip radius.

In one embodiment, each tip in the array deposits the ink containing patterning materials on the substrate at the essentially the same time.

In one embodiment, each tip in the array is composed of the same material.

Another embodiment provides a method comprising: providing at least one array of microcantilevers, wherein each micro cantilever has a nanoscopic tip thereon; depositing at least one ink composition comprising at least one patterning material on at least two of the tips, depositing the patterning material from the tip to a substrate, wherein the array of microcantilevers comprises at least two different cantilevers that are structurally different.

In one embodiment, the array of cantilevers comprises at least five different cantilevers which are structurally different.

In one embodiment, the tip is a solid tip without a hole or aperture.

In one embodiment, all of the tips are contacted with the same ink composition. In one embodiment, the cantilevers are A-frame cantilevers and/or diving board cantilevers.

In one embodiment, the array of cantilevers comprises a passive array of cantilevers.

In one embodiment, each tip in the array is composed of the same material.

In one embodiment, the method further comprises a step comprising inspecting the deposits to determine which of the cantilevers provides a preferred deposition.

Another embodiment provides a device for optimizing ink deposition onto a substrate, comprising: at least one passive array of three or more cantilevers comprising a plurality of different dimensions wherein each cantilever has tip thereon and a free end and wherein the cantilevers are affixed to a handle so as to allow the cantilever tips to contact a substrate at essentially the same time.

In one embodiment, the at least one array of cantilevers comprises five or more cantilevers.

In one embodiment, the at least one array of cantilevers comprises eleven or more cantilevers.

In one embodiment, each of the cantilevers comprises an area adapted to hold and control delivery of a fluid.

In one embodiment, each of the cantilevers comprises an area adapted to hold and control delivery of a fluid, wherein the area is a channel.

In one embodiment, each of the cantilevers comprises a channel extending towards the free end adapted to hold and control delivery of a fluid, wherein the area is a channel wherein each channel comprises a plurality of different dimensions.

In one embodiment, the plurality of different dimensions comprises at least one of the following dimensions: width of the channel at the channel terminus located closest to the free end; width of the channel at the channel terminus located furthest from the free end, distance from the channel terminus located closest to the free end to the tip thereon, and distance from the channel terminus located furthest from the free end to the tip thereon.

In one embodiment, at least one additional cantilever consisting of identical dimensions to at least one of the cantilevers comprising a plurality of different dimensions is affixed to the handle.

Another embodiment provides a device comprising: at least one array of

microcantilevers wherein the microcantilevers display different distinct deposition patterns when a single ink is loaded onto the array and the ink is deposited from the array of microcantilevers to a substrate. In one embodiment, at least one array of micro cantilevers comprises five or more microcantilevers.

In one embodiment, the at least one array of microcantilevers comprises eleven or more microcantilevers.

In one embodiment, the ink is deposited from each microcantilever at substantially the same time.

In one embodiment, the array comprises a passive array of microcantilevers.

In one embodiment, the microcantilevers comprise a plurality of different dimensions.

In one embodiment, every microcantilever of the array comprises a channel.

In one embodiment, every microcantilever comprises a channel of varying dimensions or of varying distance from a terminus of the channel to a tip located on the same cantilever.

Another embodiment provides a kit for optimizing ink deposition from a

microcantilever comprising at least one device as described herein.

Another embodiment provides a device comprising: at least one cantilever comprising a front surface, a first side edge, a second side edge, and a first end which is a free end, and a second end which is a non-free end, wherein the front surface comprises: at least one first sidewall disposed at the first cantilever side edge and at least one second sidewall disposed at the second cantilever side edge opposing the first cantilever side edge; at least one channel, adapted to hold a fluid, disposed between the first and second sidewalls, wherein the channel, the first sidewall, and the second sidewall extend toward the cantilever free end but do not reach the free end, and a base region having a boundary defined by the first edge, the second edge, and the cantilever free end and also the first sidewall, second sidewall, and the channel, wherein the base region comprises a tip extending away from the cantilever front surface, and wherein the device has a distance between the terminus of the at least one channel and the tip extending away from the cantilever front surface which is about 1 micron to about 10 microns.

In one embodiment, the distance is about 1 micron to about 20 microns, or about 9 to 13 microns.

In one embodiment, the distance is about 2 microns to about 13 microns, or about 9 to 13 microns.

In one embodiment, the distance is about 11 microns.

Another embodiment provides a microcantilever comprising a tip and a microfluidic channel thereon for delivery of ink to the tip, wherein the microcantilever has a tail width, a throat-to-tip distance, and a throat width adapted to provide an improved ink delivery from the tip to a substrate.

In one embodiment, the improved ink delivery is measured by measuring a dot size diameter change as a plurality of dots is patterned.

At least one advantage for at least one embodiment is to improve deposition of inks to substrates, whether at the micron or nanoscale, including improved uniformity of dot size as deposition progresses over the substrate.

At least one additional advantage for at least one embodiment is improved, faster testing of the suitability of an ink formulation.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 shows an embodiment for the microfabrication mask design which implements the pens specified in Table 1.

FIG. 2 shows, in one embodiment, a close-up of the 12 pens in the ID array of FIG. 1.

FIG. 3 A shows, in one embodiment, a 12 pen array system wherein all the pens are substantially similar.

FIG. 3B shows, in one embodiment, a 12 pen array system wherein eleven of the pens (pens 1-11) are different from each other, but two pens (pens 1 and 12) are the same.

FIG. 4 shows examples of printed arrays which can be generated which can be used to measure the changes in the size of the deposit as deposition progresses. The left shows identical pens such as the pen array of Figure 3 A; the right shows varied pens such as the array of Figure 3B.

FIG. 5 shows, in some embodiments, the different designs of pens 1-4 and examples of results for pens 1-4 as deposition size varies as the deposition progresses (plot of normalized deposition diameter as deposition progresses for varying pens on a 12 pen array).

FIG. 6 shows, in some embodiments, the different designs of pens 5-8 and examples of results for pens 5-8 as deposition size varies as the deposition progresses (plot of normalized deposition diameter as deposition progresses for varying pens on a 12 pen array).

FIG. 7 shows, in some embodiments, the different designs of pens 9-12 and examples of results for pens 9-12 as deposition size varies as the deposition progresses (plot of normalized deposition diameter as deposition progresses for varying pens on a 12 pen array).

FIG. 8 shows comparative results for pens 1-6 wherein all the pens are substantially the same

(plot of normalized deposition diameter as deposition progresses for varying pens on a 12 pen array). FIG. 9 shows comparative results for pens 7-12 wherein all the pens are substantially the same (plot of normalized deposition diameter as deposition progresses for varying pens on a 12 pen array).

FIG. 10 shows summary of results against a comparative study, illustrating how the pen array can be used to discover the best design of the pen array for a particular ink-substrate combination.

FIG. 11 shows an illustration (or schematic) of printing performance including blotting, printing, and exhaustion regions.

Color features in the Figures 3-10 form part of the disclosure.

DETAILED DESCRIPTION

INTRODUCTION

All references cited herein are incorporated by reference in their entirety. References cited herein may aid the understanding and/or practicing the embodiments disclosed herein.

Priority US provisional application serial no. 61/602,493 filed February 23, 2012 is incorporated by reference in its entirety.

One reference providing examples of dip pen cantilevers is U.S. Application No. 13/064766 (PCT/US2011/032369), which is hereby incorporated in its entirety.

Examples of prior art references relating to printing, fabrication methods, and/or fluid flow include, for example, U.S. Patent Nos. 6,642,129; 6,635,311, 6,827,979, 7,034,854, and 2005/0235869 which describe fundamental dip pen printing methods and associated technology of fabrication methods and fluid flow. See also, for example, U.S. Patent Publication Nos. 2008/0105042; 2009/0023607; 2009/0133169; 2010/0071098. Other examples include U.S. Patent No. 7,610,943 and U.S. patent publications 2003/0166263; 2007/0178014; and 2009/0104709. Other examples include U.S. Patent Nos. 7,690,325 and 7,008,769. See also, U.S. Patent Nos. 7,081,624; 7,217,396; and 7,351,303. See also, U.S. Patent Publication Nos. 2003/0148539 and 2002/0094304.

Other examples include U.S. Patent Nos. 5,221,415 and 5,399,232 to Albrecht et al. and the article entitled "Microfabrication of Cantilever Styli for the AFM", J. Vac. Sci.

Technol. A8 (4) Jul/ Aug 1990 which disclose a process for making passive AFM cantilevers.

Microfabrication is generally described in M. J. Madou, Fundamentals of

Microfabrication, The Science of Miniaturization. See also, commercial printing pen and pen array products, as well as printing instruments, and other related accessories, commercially available from Nanolnk, Inc.

(Skokie, IL).

Embodiments disclosed herein relate to more efficient and streamlined method to improve ink delivery to a substrate and devices for doing the same. In some embodiments, the method relates to delivery of a specific ink and/or deposition on a specific substrate. It is understood that transport parameters such as, for example, viscosity, surface tension, and contact angle, can affect the final qualities of the final deposited ink. Therefore, in some embodiments, the method of improved ink delivery includes inspecting the deposited ink to determine which pen provided desired results.

Additional embodiments disclosed herein can relate to the pens, arrays or cantilevers used to determine optimal ink delivery conditions. In contrast to a conventional ID-array of ink delivery pens, the varied microbeam, cantilever and/or tip designs of the present embodiments allow for the efficient improvement of ink delivery to a substrate by combining, for example, a statistically wide range of structural parameters on to one ID array. The range is chosen in order to find which pen geometry provides the best or desired ink deposition for the given substrate and ink combination. The best pen design might vary with the ink, the substrate, or both. It is understood that, in the art, there are numerous inks used for a wide range of applications, and thus the optimal or best pen for ink deposition for one ink or application may not be the best or optimal pen for ink deposition in another ink or

application. In an embodiment, the pens in the array pick up ink from an inkwell, or ink is delivered through another mechanism, such as for example via a microfluidic channel, and the array is positioned to deposit the ink upon the substrate in a pre-described pattern. In some embodiments, the deposited ink patterns are then examined, in order to determine which pen in the combinatorial array delivered ink in a desired fashion. The range of pen parameters can be set by nominal values for ink liquid material parameters, and/or substrate solid material parameters. However, no embodiments described herein preclude the choice of, or inclusion of, an alternative set of parameters, and/or an alternative range for the parameters.

PROVIDING AT LEAST ONE ARRAY OF A PLURALITY OF MICROCANTILEVERS

INCLUDING A PASSIVE ARRAY

Typical microscopic or nanoscopic printing apparatuses or systems can deposit, for example, fluid using one or more elongated members reminiscent of a conventional dip pen. The elongated members can be in the form of microbeams, such as cantilevers or microcantilevers. Cantilevers usually have an end fixed to a handle, and another end that is free. The cantilevers can be fabricated using known technologies, such as MEMS

microfabrication technologies.

Cantilevers and microbeams are known in the art including use for printing inks and imaging and manipulating surfaces. For example, "diving board" cantilevers and "A-frame" cantilevers are known. The elongated sides of the cantilever can be parallel or tapered. The cantilever can comprise a gap portion disposed at the bound end of the cantilever. The cantilevers can optionally comprise one or more tips at the free end.

Cantilevers can be adapted for active or passive printing. Actuation methods include thermal and electrostatic. Passive arrays are known.

Cantilevers can form parts of arrays of cantilevers including one-dimensional and two-dimensional arrays.

Cantilevers may be in any form suitable for printing inks on a micro or nano scale.

In some embodiments the cantilever may comprise a cantilever disclosed in

PCT/US2011/032369 (U.S. Application No. 13/064,766) wherein the cantilever comprises, for example, a front surface, a first side edge, a second side edge, and a first end which is a free end, and a second end which is a non-free end, wherein the front surface comprises at least one first sidewall disposed at the first cantilever side edge and at least one second sidewall disposed at the second cantilever side edge opposing the first cantilever side edge; at least one channel, adapted to hold and control delivery of a fluid, disposed between the first and second sidewalls, wherein the channel, the first sidewall, and the second sidewall extend toward the cantilever free end but do not reach the free end, and a base region having a boundary defined by the first edge, the second edge, and the cantilever free end and also the first sidewall, second sidewall, and the channel, wherein the base region comprises a tip extending away from the cantilever front surface. See, for example, Figure 2C in

PCT/US2011/032369.

FIGS. 1, 2, and 3B show exemplary cantilevers of this embodiment. In other embodiments, the first sidewall, and the second sidewall extend toward the cantilever free end and reach the free end. In other embodiments, the cantilevers comprise one or zero sidewalls. In some embodiments, the cantilever does not contain a channel.

The cantilevers of an array can be different from one another. In some embodiments, two or more different cantilevers are structurally different. The structural difference may be any aspect of the cantilever that may affect ink delivery or deposition. In some embodiments, for example, the structural difference of the cantilevers may comprise different dimensions of the cantilever and/or tip. In embodiments wherein the cantilever comprises a channel, the dimensions of the channel may be different from the dimensions of other cantilever channels in the array. By way of non-limiting example, the channel dimensions may vary in the dimensions of a terminus of the channel or distance from a terminus of the channel to a tip located on the same cantilever. Other embodiments may be more easily defined as having one or more sidewalls extend in the direction from the base or affixed end of a cantilever to the tip or free end of the cantilever. The cantilever or pen is attached to a handle by the base portion.

By way of non-limiting example, some embodiments include structural differences related to tail width, throat width, throat-to-tip distance, base-to-tip distance, length of cantilever, width of cantilever and so on. For example, tail width refers to the distance between the interior walls of two sidewalls at the base or affixed end of a cantilever. Further, throat width refers to the distance between interior walls of two sidewalls at the point where the end point of the sidewalls closest to the tip. Finally, throat-to-tip distance refers to the distance from the throat, as previously described, to the tip attached to the cantilever (edge of tip can be used rather than center of tip). Differences in shape can be present also.

In other embodiments, the structural difference of the cantilevers may comprise different compositions used to construct the cantilever and/or tip. In addition, surface energies can be different.

In further embodiments, the cantilevers contain structural differences related to their composition. The cantilevers, and the tips, can comprise, for example, silicon nitride, silicon dioxide, or any other suitable semiconductor processing materials. Cantilevers, and the tips, can also comprise softer materials like polymers and elastomers such as silicone polymers. In one embodiment, the cantilever front surface is hydrophilic. Water droplets can form a contact angle of less than 50 degrees, or less than 40 degrees, or less than 30 degrees. After the cantilever is fabricated, the cantilever can be used directly without further treatment to adjust surface hydrophilicity. Hence, in one embodiment, the cantilever front surface is not treated to change the hydrophilicity or hydrophobicity. Alternatively, the cantilever could be treated, either the whole cantilever front surface or selected parts of the front surface. The previously mentioned structural differences are not meant to be limiting, but rather to be illustrative of various parameters that may affect the deposition of ink on a substrate. It is to be understood that not all listed parameters are present in each embodiment. If desired, the tips can be surface modified to improve printing. For example, the surface of the tip can be made more hydrophilic. Tips can be sharpened. Surfaces can be treated with ethyleneoxy units.

In some embodiments, DPN applications provide a cantilever surface that works as a pool that stores and delivers inks to the probe. The process of inking can involve dipping cantilever into a micro fluidic channel or reservoirs with inks (e.g., inkwells). See, for example, US Patent No. 7,034,854. Typically, inks spread over the cantilever surface in a form of a thin liquid film. The inks can form droplets (which are thermo dynamically more stable than a thin film of liquid) in the center of the cantilever with no connectivity to the probe. Unsatisfactory printing patterns can result, in some cases, from these cantilevers. In other embodiments, the process of inking can involve delivering ink to the cantilever via a channel such as a microfluidic channel. In other embodiments, the process of inking can involve applying the ink directly to a cantilever or tip.

In some embodiments, the fluid activity on the cantilever can lead to inconsistent printing.

If desired, more than one tip can be disposed on each cantilever.

Arrays embodied herein comprise a plurality of cantilevers and/or microbeams wherein the cantilevers and/or microbeams are structurally different. The structural difference may be any aspect of the cantilever that may affect ink delivery or deposition. In an embodiment, for example, the structural difference of the cantilevers may comprise different dimensions of the cantilever and/or tip. In another embodiment, the structural difference of the cantilevers may comprise different compositions used to construct the cantilever and/or tip. In yet another embodiment, the structural difference of the cantilevers may comprise both different compositions used to construct the cantilever and/or tip and different dimensions of the cantilever and/or tip. In one embodiment, at least two of the cantilevers and/or microbeams have identical structural parameters. In another embodiment, the array comprises at least 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, or more cantilevers and/or microbeams where in at least a majority of the cantilevers and/or microbeams are structurally different from the other appended cantilevers and/or microbeams. In another embodiment, the array comprises 5 to 15 cantilevers and/or microbeams where in at least a majority of the cantilevers and/or microbeams is structurally different from the other appended cantilevers and/or microbeams. In yet another embodiment, the array comprises 9 to 1 1 cantilevers and/or microbeams of varying parameters. In a preferred embodiment, the array comprises a plurality of passive ink delivery pens wherein the structural difference of the cantilevers comprises different dimensions of each cantilever.

Any structural parameter of the cantilevers and/or microbeams may be varied. For example in an embodiment, the tail width, throat width, and throat-to-tip distance of cantilevers, such as cantilevers containing two sidewalls described herein may be altered. In an embodiment, the parameters are varied by standard means of combinatorial design, or statistical design of experiments. In another embodiment, the range of parameters may be set by nominal values for ink liquid material parameters, and substrate solid material parameters, such as the parameters embodied in the working examples. However, nothing precludes the choice of or inclusion of an alternative set of parameters, and/or an alternative range for the parameters.

When considering the parameters to be altered, one may also consider the write protocol values of the system, such as for example dwell time, pull-away time, write speed/velocity, as well as transport parameters of the ink, such as for example, viscosity, surface tension, and contact angle.

Individual cantilevers or microbeams can comprise a plurality of different dimensions depending on the application. Dimensions can be adapted, for example, depending on if the cantilever is A-frame type or diving board type. In addition, the type of ink can be considered. For example, viscosity of the ink can be considered. For example, DNA inks can be very viscous.

In an embodiment, the ID array comprises cantilevers of the type embodied in U.S. Application No. 13/064766 (US Patent Publication 2011/0274839). Cantilevers of this type can comprise a front surface, a first side edge, a second side edge, and a first end, which is a free end, and a second end, which is a non-free end. The front surface can include at least one first sidewall disposed at the first cantilever side edge and at least one second sidewall disposed at the second cantilever side edge opposing the first cantilever side edge, at least one channel, adapted to hold and control delivery of a fluid, disposed between the first and second sidewalls, wherein the channel, the first sidewall, and the second sidewall extend toward the cantilever free end but do not reach the free end, and a base region having a boundary defined by the first edge, the second edge, and the cantilever free end and also the first sidewall, second sidewall, and the channel. The base region can comprise a tip extending away from the cantilever front surface.

In one embodiment, for example, the area of the cantilever front surface can be less than about 10,000 square microns, or less than 5,000 square microns. In another embodiment, the area of the cantilever front surface can be less than about 2,700 square microns.

In one embodiment, the sidewalls (both first and second) can have a height, which is at least about 200 nm. In another embodiment, the sidewalls (both first and second) can have a height, which is at least about 400 nm, or at least 800 nm, or at least 1,200 nm. The height of the first and second sidewalls can be the same. Height can be, for example, 100 nm to 1,500 nm, or 200 nm to 1,200 nm.

In one embodiment, the channels can have a maximum width and a minimum width, and the maximum width can be larger than the minimum width, so that the channels are tapered. For example, the channel can have a maximum width of about three microns to about 20 microns, or about five microns to about 15 microns. The channel can have a minimum width of about one micron to about ten microns, or about two microns to about eight microns. The difference in maximum and minimum channel width can be, for example, about three microns to about ten microns.

Additionally, cantilevers comprising the same structural parameters as one or more cantilevers in the array embodied herein may be included on the pen or handle. For example, in FIG. 1, pens 1 and 12 have identical structural parameters. In some embodiments, the cantilevers comprising the same structural parameters may both be considered part of the array or the additional cantilever may be considered separate from the array.

Examples of tail width include 10 microns to 100 microns, or 20 microns to 70 microns, or 25 microns to 50 microns, or 29 microns to 49 microns.

Examples of throat-to-tip distance include, for example, 1 micron to 20 microns, or 2 microns to 15 microns, or 2 microns to 11 microns.

Examples of throat width include, for example, 1 micron to 20 microns, or 2 microns to 15 microns, or 3 microns to 10 microns, or 3 microns to 9 microns.

Various ID arrays known in the art and typically combine several cantilevers and microbeams of the same dimensions and are used for use for printing inks and imaging and manipulating surfaces. Often the array may contain at least one cantilever or microbeam of a different dimension known as a reader pen, which is used in the alignment the array. Other arrays known in the art may include thermal actuators and/or varying tip materials that allow the user to selectively engage or disengage individual pens from depositing ink when the array is contacted with the substrate. These arrays are disclosed in, for example, the abstract entitled "MEMS Arrayed Scanning Probes for Soft Nanolithography", ECS 210^th Meeting,

Abstract 2157. See, also, Li et al, ECS Transactions, 3 (10) 463-472 (2006). The purpose of these methods is to include several different printing functionalities or tools onto one printing array. Other known devices contain two or more arrays fixed to a single handle. Generally, these two or more arrays are not designed to be used simultaneously. In one embodiment, the microcantilever arrays are free of polymer tips and polymer microcantilevers. In one embodiment, the microcantilevers are not scanning probe contact printing cantilevers.

TIPS

Cantilevers comprising tips are known, including tips that extend orthogonally from the plane of the cantilever. The tips can be nanoscopic tips, scanning probe microscope tips, atomic force microscope tips, NSOM tips, and the like. The tips can have, for example, a tip radius of 100 nm or less, or 50 nm or less, or 25 nm or less. The tips can be solid tips and be free of holes or apertures.

Another embodiment for tips including the octahedral and pyramid-on-post tips as described in US Provisional Application Serial No. 61/550,305 filed October 21, 2011, "OCTAHEDRAL AND PYRAMID-ON-POST TIPS FOR MICROSCOPY AND

LITHOGRAPHY" (see also PCT/US2012/061132).

DISPOSING ON THE MICROCANTILEVERS A SINGLE INK COMPOSITION COMPRISING A PATTERNING MATERIAL

A particular advantage of the present embodiments is that ink formulation need not always be altered to achieve optimal deposition; rather the design of the cantilever or microbeam is altered for each pen of a ID array to deduce rapidly the optimal parameters for the desired ink. The inks, however, can be adapted for loading, flow, deposition, and use with the cantilevers and microbeams described herein. For example, ink viscosity can be adapted. The concentration of solids and liquids can be adapted. Surface tension can be adapted. Surfactants can be used if needed. Additives and drying agents can be used.

Aqueous and non-aqueous inks can be used and solvent proportions can be adapted for mixed solvent systems.

Inks comprising one or more biological moieties are particularly of interest. For example, proteins, nucleic acids, lipids, and the like can be used.

Inks can be also adapted for introduction of the ink onto the cantilever and use with inkwells to guide the ink to desired locations for loading. Alternatively, inks can be loaded onto on-chip reservoirs, which can deliver the desired ink through microfluidic channels or other capillary processes to the desired pen. DEPOSITING THE PATTERNING MATERIALS ONTO A SUBSTRATE TO PROVIDE A SUBSTRATE COMPRISING A PLURALITY OF DEPOSITS

Printing methods are described in various references cited in the Introduction.

The embodiments disclosed herein improve optimization of ink delivery of the DPN. Using an array of cantilevers wherein the cantilevers are structurally different can reduce the time and cost of finding a cantilever with optimal parameters for the intended application.

Kits can be provided which comprise the devices described herein. The kits can also comprise at least one ink, at least one substrate, at least one inkwell, one or more other accessories, and/or at least one instruction sheet to use the kit.

Instruments can be also made to use the devices described herein. For example, printing instruments can be obtained from Nanolnk, Inc. (Skokie, IL) including the DPN 5000 or NLP 2000 instruments. See, for example, US Patent Publication No. 2009/0023607 for a deposition instrument.

INSPECTING THE DEPOSITS TO DETERMINE WHICH OF THE CANTILEVERS PROVIDES A PREFERRED DEPOSITION

Methods of evaluating the deposited ink will vary depending on the application. In some embodiments, for example, the deposition may be examined to determine the physical differences between the depositions such as, for example, the size of each ink deposit or consistency of repeated deposits or shape of deposit. ANOVA and other statistical methods can be used. Methods for evaluating the deposition are not limited by the disclosure herein.

The working examples and figures show graphs wherein dot size varies over time as deposition progresses on the substrate. One can look for a straight line, or a line with low or zero negative slope, or a line with a low amount of noise.

One can, for example, calculate a delta S parameter. This is:

Delta S = (first dot size - last dot size)/number of dots.

For example, if the dot size changes by 10 nm over 10 dots, the delta S parameter is 1 nm/spot.

METHOD OF FABRICATION Microfabrication methods are described in various references cited in the Introduction, each of which is incorporated by reference.

Silicon nitride cantilevers with integrated pyramidal tips can be fabricated by a method similar to that described by Albrecht et al. (Albrecht TR, Akamine S, Carver TE, et al. Microfabrication of cantilever styli for the atomic force microscope. Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films 1990; 8:3386-3396). Subsequent to crystallographic etching of the pyramidal pits and removal of the masking layer from the silicon wafer, an oxide layer is formed. This oxide is then patterned to form a region that includes the pyramidal pits and an adjoining triangular area. This oxide layer can serve the role of sharpening the tip, and/or otherwise controlling the apex radius and shape of the pit (Akamine S., Quate C.F.) Low temperature thermal oxidation sharpening of microcast tips. J Vac Sci Technol B 1992; 10:2307-2310). While not limited by theory, compressive stress in the oxide layer can cause the oxide to expand in the direction normal to the surface. Near the bottom of the pyramidal pit, this expansion can be frustrated by the proximity of the opposite face. This can result in a change of the cross sectional profile from v-shaped to cusped, and a reduction in the radius of curvature at the apex.

The oxide layer can also serve the role of forming a mold for a channel in the subsequently- formed silicon nitride cantilever. A step that is already performed to make sharp tips can thus be modified to make an open channel on the cantilever. Open channels for fluid transport are used for the inkwell products developed and sold by Nanolnk, Inc. (Skokie, IL).

In some alternative embodiments, the recessed base portion can have a sidewall on one, two, or three sides. The sidewalls can be lower than the sidewall regions of the channel.

For fabrication methods, see also US Patent Publication 2011/0274839 (Nanolnk,

Inc.).

EMBODIMENTS FROM PCT/US2011/032369 (ASSIGNEE: NANOINK, INC.)

Additional embodiments for microcantilever design are described in

PCT/US2011/032369 which are also expressly described herein and incorporated by reference including Figures, claims, and working examples. These embodiments, including microcantilevers, can be used as further described herein. For example, arrays can be prepared wherein different types of cantilevers are disposed onto the same array and used as described herein including the working examples below. For example, one embodiment provides a device comprising: at least one cantilever comprising a front surface, a first side edge, a second side edge, and a first end which is a free end, and a second end which is a non-free end, wherein the front surface comprises: at least one first sidewall disposed at the first cantilever side edge and at least one second sidewall disposed at the second cantilever side edge opposing the first cantilever side edge; at least one channel, adapted to hold a fluid, disposed between the first and second sidewalls, wherein the channel, the first sidewall, and the second sidewall extend toward the cantilever free end but do not reach the free end, and a base region having a boundary defined by the first edge, the second edge, and the cantilever free end and also the first sidewall, second sidewall, and the channel, wherein the base region comprises a tip extending away from the cantilever front surface.

In another embodiment, the channel is tapered and has a gradually narrowing width as the channel extends toward the base region. In another embodiment, the first and second sidewalls are tapered and have a gradually narrowing width as they extend towards the base region. In another embodiment, the base region is substantially flush with the bottom surface of the channel. In another embodiment, the first side edge and the second side edge are not parallel, and the cantilever narrows with approach to the free end.

In another embodiment, the area of the cantilever front surface is less than about 10,000 square microns. In another embodiment, the area of the cantilever front surface is less than about 2,700 square microns.

In another embodiment, the sidewalls have a height which is at least about 200 nm. In another embodiment, the sidewalls have a height which is at least about 400 nm.

In another embodiment, the channel has a length of about 10 microns to about 200 microns. In another embodiment, the channel has a maximum width of about 50 microns or less.

In another embodiment, the cantilever front surface is hydrophilic. In another embodiment, the cantilever front surface is not treated to change the hydrophilicity or hydrophobicity.

In another embodiment, the tip is nanoscopic tip. In another embodiment, the tip is a solid tip without a hole or aperture. In another embodiment, the tip is characterized by a tip radius of less than about 20 microns. In another embodiment, the tip has a tip height of at least about 3 microns.

In another embodiment, the first sidewall, the second sidewall, and the channel are all tapered to become more narrow when moving toward the free end. In another embodiment, the first sidewall, the second sidewall, and the channel are all tapered to become more narrow when moving toward the free end, and the first and second sidewalls narrow by at least four microns, and the channel narrows by at least 15 microns.

In another embodiment, the cantilever is an A-frame cantilever or a diving board cantilever.

Another embodiment provides a system configured to deliver fluid to form

microscopic or nanoscopic patterns, the system comprising: at least one array of

microbeams; and a control device configured to control a motion of the array of microbeams; wherein each microbeam comprises: an end portion; a tip protruding from a base region of the end portion; a channel along the micro beam and in fluidic connection with the base region, wherein the channel has a side wall; and wherein the base region is recessed from an outer surface of the side wall and extends to at least one side of the end portion.

In another embodiment, the base extends to three sides of the end portion. In another embodiment, the base extends to three sides of the end portion, and wherein the base is formed by masking the end portion completely. In another embodiment, the channel is tapered and has a gradually narrowing width toward the base region. In another embodiment, the base is configured to draw the fluid from the channel by a surface tension difference between the fiuid over the base and the fiuid in the channel. In another embodiment, the base region comprises an enlarged portion of the channel, and wherein the enlarged portion has at least one side without a sidewall. In another embodiment, the base region has a lateral surface substantially flush with the bottom surface of the channel.

In another embodiment, the tip is integrally formed with the base region. In another embodiment, the tip has a height of about at least about 3 microns from the base region.

In another embodiment, the array includes at least ten microbeams.

Another embodiment provides for printing a microscopic or nanoscopic pattern on a surface, the method comprising: depositing a fiuid from a channel in a cantilever to the surface at an end portion of the cantilever; wherein the end portion comprises a base region having a tip thereon, and wherein the base region has no boundary at least at one side or has a side wall substantially lower than a side wall of the channel.

In another embodiment, said depositing comprises drawing the fluid from the channel toward the base region through a surface tension difference between the fluid in the base region and the fluid in the channel. In another embodiment, the method further comprises moving the cantilever end portion relative to the surface so that the fluid is delivered from the cantilever end portion to the surface.

In another embodiment, the fluid forms a feature on the surface with a width of about one micron to about 100 microns. In another embodiment, the fluid forms a feature on the surface with a width of about one micron to about 15 microns.

In another embodiment, said depositing comprises contacting the cantilever and the surface. In another embodiment, the fluid is an aqueous fluid. In another embodiment, the fluid comprises at least one biomolecule. In another embodiment, the fluid comprises at least one protein. In another embodiment, the cantilever is part of an array of cantilevers.

In another embodiment, a method is provided for manufacturing a micro cantilever, the method comprising: providing an elongated beam having an end portion; forming a tip at the end portion; apply a mask having a tapered channel region along the beam, wherein the mask portion for the channel has an expanded portion that substantially encloses the end portion; and

etching the elongated beam to form the tapered region and to a base region corresponding the expanded portion, wherein the base region extends completely through at least one side of the end portion.

Another embodiment provides a device comprising: a cantilever including: a channel; two side wall areas sandwiching the channel; an optional tip disposed at a free end portion of the cantilever; and a broadened channel area surrounding the tip; wherein the broadened channel area extends completely through at least one side of the free end portion.

Another embodiment provides a method comprising: providing a device according to embodiments described herein, disposing an ink in the channel and on the tip, and depositing the ink from the tip to a substrate.

Another embodiment provides an instrument adapted for printing an ink onto a substrate and comprising the device as described herein.

Another embodiment provides for a kit comprising the device as described herein. In another embodiment, the kit further comprises instructions for use of the device. In another embodiment, the kit further comprises an ink for use with the device.

Another embodiment provides for a method comprising: loading at least one ink onto a device comprising a plurality of cantilevers comprising at least one tip on each cantilever, depositing the ink from the plurality of cantilevers and tips to a substrate, wherein at least

80% of the tips show successful deposition of the ink onto the substrate. In another embodiment, at least 90% of the tips show successful deposition of the ink onto the substrate. In another embodiment, the cantilever is a cantilever is as described herein.

In another embodiment, the method is used to pattern over 1,000 features, and over 80%) of the features are successfully patterned. In another embodiment, the method is used to pattern over 1 ,000 features, and over 90%> of the features are successfully patterned. In another embodiment, the method is used to pattern over 1,000 features, and over 95% of the features are successfully patterned.

In another embodiment, a device is provided comprising: an elongated cantilever having a first surface and a second surface, wherein the cantilever comprises: at least one tip disposed at an end portion of the cantilever; a recessed area on the first surface, wherein the recessed area comprises: a first elongated portion along the length direction of the cantilever; and a second expanded portion around the tip.

In another embodiment, surface tension drives fluid from the channel toward the base region.

WORKING EXAMPLES

Additional embodiments are provided in the following, non-limiting working examples.

Figure 1 illustrates an embodiment of the microfabrication mask design which implements the pens specified in Table 1 (hereinbelow). The embodiment contains a 12-pen, ID array wherein pens 1 and 12 have the same parameters, and the 10 pens located between pen 1 and pen 12 have various parameters for tail width, throat width, and throat-to-tip distance. Table 1 includes parameters for variations in cantilever characteristics that may alter the print results. Figure 2 shows a close-up of the 12 pens in the ID array of Figure 1. Pens 1 and 12 are the same to provide a control in case there is variation as one moves across the ID array. The variation in the structural parameters is particularly evident in the mask defining the channel walls, which provides a cut in a silicon oxide layer. This cut then constrains the flow of the liquid ink, depending upon the contact angle between the pen materials and the ink, the contact angle between the ink and the substrate, and the surface tension and viscosity of the ink.

Figures 3 A and 3B show embodiments of a pen array with 12 identically designed (or substantially similar in practice) pens and a 12 pen array of Figure 1, respectively. Patterning experiments were carried out using both pen arrays to compare the results. Prior to printing, the tested pens were plasma cleaned for 40 sec at low power before use. Nanolnk, Inc. inks with cytokine IL-5 capture Ab and Alexa 555 tracking dye were used for printing. Arrays of 100 dots were printed on Schott Slide E (epoxy substrate) with the pen arrays of Figures 3 A and 3B. The printing parameters used were: Dwell time: 0.2 sec; Z- Clearance: 200 μιη; Inking pause: 1 sec; Dot spacing: 30 μιη; and Humidity: 30%. The slides were scanned with Innopsys scanner and data were processed using Mapix software.

Figure 4 shows the process results. Tables 2 and 3 (hereinbelow) show the dot size at the beginning and at the end of the deposition. The left printed array shows use of a 12-pen array wherein all the pens are substantially the same. The right printed array shows the use of a 12 pen array wherein eleven of the pens are different from each other. Furthermore, Figures 5-9 show a visualization of the results of the test wherein the deposited dots were plotted against the normalized dot size of the deposition. This data demonstrated that several pens perform with a flatter more consistent slope over the deposition of the 100 dots, which was desirable for the intended application of the embodied pens.

In Figure 10, the number of the dot deposited was plotted against the actual dot size in microns. The data was quantified by calculating AS, which was determined by dividing the change in dot size by the number of dots. The data showed marked improvement for pens 3, 5, 9, and 11 compared to a standard.

Figure 1 1 illustrates an exemplary situation for which experiments can be interpreted by. Figure 11 shows three regions of deposition, as measured with dot size versus dot number. The first region is a blotting region; a second region is the core-printing region; the third region is then the exhaustion region as ink is depleted. Pen arrays as described herein can be used to find the best printing region performance and minimize blotting and exhaustion.

The cantilevers were produced using CAD software. Parameters such as throat-to-tip distance can be taken from the design software (e.g., CAD) or taken from the actual produced device. If there is a difference, the design software can be used for the parameter. The edge of the tip, not the center of the tip, is used for the distance measurements such as throat-to-tip distance. Table 1. Structural Design Parameters Embodied in FIGS. 1 and 2 (all values in μιη)

Table 2 Ink Dot Diameter (in μιη) for 100 Printed Dots (From the Array Disclosed in Table 1)

Row Diai neier

Pen 1 Pen 2 1 »en 3 Pen 4 Pen 5 1 'en 6 Pen 7 Pen 8 Pen 9 Pen 10 Pen 1 1 Pen 12

100 8.5 6.6 9.1 8.4 9.9 10 10.5 6.8 10.4 8.1 10.1 10

99 7.2 6.5 8.8 7.1 8.8 10.1 9.9 6.7 10.1 7.1 9.7 8.9

98 8.8 7.1 9.2 9.4 10.3 10.3 10.8 8 10.5 9.2 10.3 10.3

... ... ... ... ... ...

3 15.8 19.5 14.2 18.' 7 13.7 15.4 14.5 18 14.2 18 132. 15.2

2 15.9 19.6 14.4 18.< * 13.6 15.3 14.5 17.8 14.2 17.7 13.4 15.2

1 16.6 10 14.5 19.( S 13.9 15.9 14.9 18.9 14.8 18.7 13.9 15.9

AD sum -7.4 -13 -5.3 -10 -3.7 -5.3 -4 -11 -3.8 -9.6 -3.3 -5.2

Table 3. Ink Dot Diameter (in μιη) for 100 Printed Dots (All 12 Pens Identical as in FIG.

Row Dian icier

Pen 1 Pen 2 1 »en 3 Pen 4 Pen 5 Pen 6 »en 7 Pen 8 Pen 9 Pen 1 0 Pen 1 1 Pen 12

100 6.2 6.0 6.3 6.6 6.2 6.6 6.8 6.6 6.2 6.3 6.0 6.1

99 6.4 6.3 6.3 6.8 6.3 6.6 6.8 6.3 6.2 6.5 6.0 6.2

98 6.4 6.4 6.4 7.1 6.6 6.9 7.1 6.7 6.4 6.7 6.3 6.5

... ... ... ··· ··· ··· ···

3 16.8 16.0 16.0 16.! 5 16.1 15.9 16.7 15.9 15.9 16.4 15.7 15.8

2 17.6 16.6 16.5 17.. 5 16.8 16.4 17.5 16.7 16.6 17.5 16.3 16.4

1 17.8 16.7 16.7 17.1 S 16.8 16.3 17.4 16.4 16.7 17.5 16.3 16.5

AD

Sum -11.6 -10.7 - 10.4 -11. 0 -10.6 -9.7 -10.6 -9.8 -10.5 -11.: J -10.3 -10.5

Claims

CLAIMS:

1. A method comprising:

providing at least one passive array of a plurality of microcantilevers wherein each microcantilever has at least one nanoscopic tip thereon;

disposing on the microcantilevers a single ink composition comprising a patterning material;

depositing the patterning materials onto a substrate to provide a substrate comprising a plurality of deposits;

inspecting the deposits to determine which of the cantilevers provides a preferred deposition.

2. The method of claim 1, wherein the array of microcantilevers comprises at least two different microcantilevers which are structurally different.

3. The method of claim 1, wherein the array of microcantilevers comprises at least three different microcantilevers which are structurally different.

4. The method of claim 1, wherein the array of cantilevers comprises eleven different cantilevers which are structurally different.

5. The method of claim 1, wherein the at least one tip is a solid tip without a hole or aperture.

6. The method of claim 1, wherein the cantilevers are A-frame cantilevers or diving board cantilevers.

7. The method of claim 1, wherein the array of cantilevers comprises at least two different cantilevers which contain different dimensions in at least one of the following parameters: tail width, throat width, throat-to-tip distance, channel depth, and tip radius.

8. The method of claim 1, wherein the array of cantilevers comprises at least five different cantilevers which contain different dimensions in at least one of the following parameters: tail width, throat width, throat-to-tip distance, channel depth, and tip radius.

9. The method of claim 1, wherein each tip in the array deposits the ink containing patterning materials on the substrate at essentially the same time.

10. The method of claim 1, wherein each tip in the array is composed of the same material.

11. A method comprising:

providing at least one array of microcantilevers, wherein each microcantilever has a nanoscopic tip thereon; depositing at least one ink composition comprising at least one patterning material on at least two of the tips,

depositing the patterning material from the tip to a substrate,

wherein the array of microcantilevers comprises at least two different cantilevers that are structurally different.

12. The method of claim 11, wherein the array of cantilevers comprises at least five different cantilevers which are structurally different.

13. The method of claim 11, wherein the array of cantilevers comprises eleven different cantilevers which are structurally different.

14. The method of claim 11 , wherein each tip in the array deposits the ink containing patterning materials on the substrate at the essentially the same time.

15. The method of claim 11, wherein the tip is a solid tip without a hole or aperture.

16. The method of claim 11, wherein all of the tips are contacted with the same ink composition.

17. The method of claim 11, wherein the cantilevers are A-frame cantilevers and/or diving board cantilevers.

18. The method of claim 11, wherein the array of cantilevers comprises a passive array of cantilevers.

19. The method of claim 11, wherein each tip in the array is composed of the same material.

20. The method of claim 11, wherein the method further comprises a step comprising inspecting the deposits to determine which of the cantilevers provides a preferred deposition.

21. A device for optimizing ink deposition onto a substrate, comprising:

at least one passive array of three or more cantilevers comprising a plurality of different dimensions wherein each cantilever has tip thereon and a free end and wherein the cantilevers are affixed to a handle so as to allow the cantilever tips to contact a substrate at essentially the same time.

22. The device according to claim 21, wherein the at least one array of cantilevers comprises five or more cantilevers.

23. The device according to claim 21, wherein the at least one array of cantilevers comprises eleven or more cantilevers.

24. The device according to claim 21, wherein each of the cantilevers comprises an area adapted to hold and control delivery of a fluid.

25. The device according to claim 21, wherein each of the cantilevers comprises an area adapted to hold and control delivery of a fluid, wherein the area is a channel.

26. The device according to claim 21, wherein each of the cantilevers comprises a channel extending towards the free end adapted to hold and control delivery of a fluid, wherein the area is a channel wherein each channel comprises a plurality of different dimensions.

27. The device according to claim 26, wherein the plurality of different dimensions comprises at least one of the following dimensions:

width of the channel at the channel terminus located closest to the free end; width of the channel at the channel terminus located furthest from the free end, distance from the channel terminus located closest to the free end to the tip thereon, and distance from the channel terminus located furthest from the free end to the tip thereon.

28. The device according to claim 21, wherein at least one additional cantilever consisting of identical dimensions to at least one of the cantilevers comprising a plurality of different dimensions is affixed to the handle.

29. A device comprising:

at least one array of microcantilevers wherein the microcantilevers display different distinct deposition patterns when a single ink is loaded onto the array and the ink is deposited from the array of microcantilevers to a substrate.

30. The device according to claim 29, wherein the at least one array of microcantilevers comprises five or more microcantilevers.

31. The device according to claim 29, wherein the at least one array of microcantilevers comprises eleven or more microcantilevers.

32. The device according to claim 29, wherein the ink is deposited from each microcantilever at substantially the same time.

33. The device according to claim 29, wherein the array comprises a passive array of microcantilevers.

34. The device according to claim 29, wherein the microcantilevers comprise a plurality of different dimensions.

35. The device according to claim 29, wherein every microcantilever of the array comprises a channel.

36. The device according to claim 29, wherein every microcantilever comprises a channel of varying dimensions or of varying distance from a terminus of the channel to a tip located on the same cantilever.

37. A kit for optimizing ink deposition from a microcantilever comprising at least one device of claim 21 or 29.

38. A device comprising:

at least one cantilever comprising a front surface, a first side edge, a second side edge, and a first end which is a free end, and a second end which is a non-free end,

wherein the front surface comprises:

at least one first sidewall disposed at the first cantilever side edge and at least one second sidewall disposed at the second cantilever side edge opposing the first cantilever side edge;

at least one channel, adapted to hold a fluid, disposed between the first and second sidewalls, wherein the channel, the first sidewall, and the second sidewall extend toward the cantilever free end but do not reach the free end, and

a base region having a boundary defined by the first edge, the second edge, and the cantilever free end and also the first sidewall, second sidewall, and the channel,

wherein the base region comprises a tip extending away from the cantilever front surface,

and wherein the device has a distance between the terminus of the at least one channel and the tip extending away from the cantilever front surface which is about 2 microns to about 13 microns.

39. The device of claim 38, wherein the distance is about 9 microns to about 13 microns.

40. The device of claim 38, wherein the distance is about 11 microns.

41. A microcantilever comprising a tip and a micro f uidic channel thereon for delivery of ink to the tip, wherein the microcantilever has a tail width, a throat-to-tip distance, and a throat width adapted to provide an improved ink delivery from the tip to a substrate.

42. The microcantilever of claim 41, wherein the improved ink delivery is measured by measuring a dot size diameter change as a plurality of dots is patterned.