Small scale manufacturing is an important aspect of the modem economy. For example, methods such as microcontact printing, nanoimprint lithography, and Dip-Pen Nanolithography® (DPN®) printing can be used to make microscale and nanoscale structures and patterns. For microcontact printing and nanoimprint lithography, see, e.g., C. M. Sotomayor Tones, Alternative Lithography: Unleashing the Potentials of Nanotechnology (Nanostructure Science and Technology), 2003. See also, for example, U.S. Pat. Nos. 6,380,101; 6,518,189; 6,818,959; 7,442,316; and 7,665,983. For DPN® printing, see, e.g., U.S. Pat. Nos. 6,635,311 to Mirkin et al. and 6,827,979 to Mirkin et al. Direct write methods, including DPN® printing, are useful as a pattern can be directly drawn or embedded into a substrate surface. In one embodiment of DPN®, material is transferred from a tip (or an array of tips) to a substrate using, for example, one or more nanoscopic, scanning probe, or atomic force microscope tips. DPN® can be used with multiple tips, including one- and two-dimensional arrays of tips, operating in parallel on a single instrument. See, e.g., U.S. Pat. Pub. No. 2008/0105042 to Mirkin et al. In all of the small scale manufacturing methods described above, patterning can be carried out to make a variety of structures on substrate surfaces including soft and hard structures, organic and inorganic structures, and biological structures, in a variety of regular or irregular patterns.
Despite important advances, a need exists to provide devices and patterning apparatuses which provide higher quality patterns and ease of use. For example, poor patterning can result if stamps (in the case of microcontact printing), molds (in the case of nanoimprint lithography), or tips (in the case of DPN) are not aligned in a parallel orientation with respect to the surface of the substrate to be patterned. However, leveling and alignment of large numbers of stamp/mold protrusions or tips is an engineering challenge. Other challenges include viewing of the stamp, mold, or tips during the leveling process, providing user feedback that indicates that leveling has been achieved, and maintaining a parallel orientation during patterning and/or after patterning, i.e., after contact with the surface has been broken.
Provided herein are devices for leveling, apparatuses incorporating such devices, kits, methods of using and making the devices.
One embodiment provides a device comprising a support structure adapted to mount an object, the object comprising a plurality of protrusions adapted to form a pattern on a surface of a substrate upon contact of the object to the surface; and at least one flexible joint assembly mounted to the support structure and adapted to allow the object to achieve a parallel orientation with respect to the surface upon contact of the object to the surface.
Another embodiment provides a device comprising a support structure adapted to mount an array of nanoscopic tips, the array adapted to form a pattern on a surface of a substrate upon contact of the array to the surface; and at least one magnetic flexible joint assembly mounted to the support structure comprising a ball, and a magnetic joint member, the joint member comprising a depression shaped to accommodate the ball, wherein the magnetic flexible joint assembly is adapted to allow the array to achieve a parallel orientation with respect to the surface upon contact of the object to the surface.
Another embodiment provides a device comprising a support structure adapted to mount an object, the object comprising a plurality of protrusions adapted to form a pattern on a surface of a substrate upon contact of the object to the surface; and a plurality of flexible joint assemblies mounted to the support structure, the plurality of joint assemblies comprising a first flexible joint assembly positioned along a first axis parallel to the support structure, a second flexible joint assembly positioned along the first axis and opposite to the first flexible joint assembly, a third flexible joint assembly positioned along a second axis parallel to the support structure and perpendicular to the first axis, and a fourth flexible joint assembly positioned along the second axis and opposite to the third flexible joint assembly; wherein the plurality of flexible joint assemblies is adapted to allow the object to achieve a parallel orientation with respect to the surface upon contact of the object to the surface.
Another embodiment provides a device comprising: a support structure adapted to mount an array of nanoscopic tips, the array adapted to form a pattern on a surface of a substrate upon contact of the array to the surface; a first magnetic flexible joint assembly mounted to the support structure and positioned along a first axis parallel to the support structure; a second magnetic flexible joint assembly mounted to the support structure and positioned along the first axis and opposite to the first magnetic flexible joint assembly; a middle structure positioned above the support structure and mounted to the first magnetic flexible joint assembly and the second magnetic flexible joint assembly; a third magnetic flexible joint assembly mounted to the middle structure and positioned along a second axis parallel to the support structure and perpendicular to the first axis; a fourth magnetic flexible joint assembly mounted to the middle structure and positioned along the second axis and opposite to the third magnetic flexible joint assembly; and an upper structure positioned above the middle structure and mounted to the third magnetic flexible joint assembly and the fourth magnetic flexible joint assembly, wherein each magnetic flexible joint assembly comprises: a ball; and a joint member, the joint member comprising a depression shaped to accommodate the ball, wherein the ball or the joint member is magnetic, and further wherein the magnetic flexible joint assemblies are adapted to allow the array to achieve a parallel orientation with respect to the surface upon contact of the array to the surface.
Another embodiment provides an apparatus comprising a patterning instrument and a device, wherein the device is mounted to the patterning instrument, and further wherein the device comprises a support structure adapted to mount an object, the object comprising a plurality of protrusions adapted to form a pattern on a surface of a substrate upon contact of the object to the surface, and at least one flexible joint assembly mounted to the support structure and adapted to allow the object to achieve a parallel orientation with respect to the surface upon contact of the object to the surface.
Another embodiment provides a method comprising providing a device comprising a support structure adapted to mount an object, the object comprising a plurality of protrusions adapted to form a pattern on a surface of a substrate upon contact of the object to the surface, and at least one flexible joint assembly mounted to the support structure and adapted to allow the object to achieve a parallel orientation with respect to the surface upon contact of the object to the surface; mounting the object to the support structure; contacting the mounted object to the substrate; and allowing the object to achieve a parallel orientation with respect to the surface.
Another embodiment provides a method comprising providing a device comprising a support structure adapted to mount an object, the object comprising a plurality of protrusions adapted to form a pattern on a surface of a substrate upon contact of the object to the surface; and at least one flexible joint assembly mounted to the support structure and adapted to allow the object to achieve a parallel orientation with respect to the surface upon contact of the object to the surface; mounting the object to the support structure; providing at least some of the protrusions with an ink composition; and transferring the ink composition from the protrusions to the surface.
Another embodiment provides a mounting fixture adapted to facilitate the mounting of an object to a support structure, the object comprising a plurality of protrusions adapted to form a pattern on a surface of a substrate upon contact of the object to the surface.
Another embodiment provides a method including contacting a plurality of protrusions to a substrate surface, wherein the plurality of protrusions are disposed over a plurality of cantilevers; deflecting the plurality of cantilevers; observing an optical change indicative of surface contact between the plurality of protrusions and the substrate surface; and further leveling the plurality of protrusions using at least one flexible joint assembly mounted to a support structure.
At least one advantage for at least one embodiment is the ability to level an object for patterning a substrate surface, including an object having a large number of patterning protrusions, with minimal effort and in minimal time.
At least one advantage for at least one embodiment is the ability to achieve better patterning results with a leveled object for patterning a substrate surface.
At least one advantage for at least one embodiment is the ability to view an object for patterning a substrate surface during the leveling process.
At least one advantage for at least one embodiment is the ability to provide feedback that leveling has been achieved.
At least one advantage for at least one embodiment is the ability to maintain the level orientation of an object for patterning a substrate surface after contact with the surface is broken.
At least one additional advantage for at least one embodiment, due to the self-leveling aspect of the device, is that the some of process, or the entire process, can be automated, since there is reduced need for human measurement/interference. Reducing the impact of the human-element of error and subjectivity can lead to a more accurate and precise leveling process. Because the process can be automated, throughput, ease of use, and overall speed of operation can be dramatically improved.
The Figures provide exemplary embodiments.
All references cited in the present application are incorporated by reference in their entirety.
Priority U.S. provisional application Ser. No. 61/226,579 filed Jul. 17, 2009 is hereby incorporated by reference in its entirety. The article Haaheim et al., “Self-Leveling Two-Dimensional Probe Arrays for Dip Pen Nanolithography,” Scanning, 32, 49-59 (2010) is also hereby incorporated by reference in its entirety.
The term “mount” can include, for example, join, unite, connect, associate, insert, hang, hold, affix, attach, fasten, bind, paste, secure, bolt, screw, rivet, solder, weld, press against, and other like terms. Moreover, “mount” can encompass objects that are directly mounted together and objects that are indirectly mounted to one another, e.g., through a separate component.
Herein, a self-leveling fixture for printing devices, such as the 2D nano PrintArray for example, is described and demonstrated. When mounted on, for example, NanoInk's NLP 2000 instrument for nanopatterning, for example, a 55,000 tip array can achieve a planarity of, for example, less than 0.1° with respect to a substrate in a matter of seconds, with little or no user manipulation required. Additional fine-leveling routines can improve this planarity to, for example, less than 0.002° with respect to the substrate—a Z-difference of, for example, less than 600 nm across 1 cm2 of surface area. A highly homogeneous etch-resist nanostructure can be made from a self-leveled array of tips, e.g., DPN pens.
The self-leveling process, it is believed, can be generally faster, easier, and more precise than previous methods. This brings the process towards automated nanomanufacturing. The planar misalignment can be less than, for example, 0.002° in accordance with the representative embodiments, which is believed to be better than previous results. The excellent planarity correlates to uniform patterning results, resulting in homogeneous nanostructures across 1 cm2. This is also believed to be better than previous results, which were quantified by a feature size standard deviation of 6% which is believed the best previously reported.
In the representative embodiments disclosed herein, the self-leveling gimbal device can achieve homogeneous results through (1) precise Z-positioning through accurate touch-down detection; and (2) low variance in cantilever deflection through very precise leveling.
A device for leveling can include a support structure and at least one flexible joint assembly mounted to the support structure.
Support structures can be adapted to mount an object having a plurality of protrusions for forming a pattern on a substrate. Support structures can be further adapted to be mounted to an apparatus for disposing an ink composition on the plurality of protrusions. Support structures can include one or more apertures for viewing an object mounted to the support structure. The shape and dimensions of the support structures may vary. Non-limiting examples of support structures are described below and illustrated in the figures. Similarly, the materials used to form the support structures may vary. In fact, any rigid material may be used. Suitable materials include, but are not limited to, stainless steel, aluminum, plastics, and ceramics.
The support structure and the object can be mounted together so that they function as a single piece, moving in space as one piece or an integral unit. The mount can be a rigid mount rather than a flexible mount.
Flexible joint assemblies can be adapted to allow an object mounted to the support structure to achieve a parallel orientation with respect to a surface upon contact of the object to the surface. By “flexible joint assembly,” it is meant an assembly of components which form a joint that is capable of flexing in one or more directions. By way of example only, flexible joint assemblies include rotary joint assemblies or pivot joint assemblies. Such flexible joint assemblies are capable of flexing in multiple directions via a rotating motion. The flexible joint assemblies may be further adapted to allow an object mounted to the support structure to maintain a parallel orientation with respect to a surface after contact with the surface is broken.
The ability of the flexible joint assemblies to allow objects mounted thereon to achieve and maintain a parallel orientation with respect to a surface is affected, at least in part, by the coefficient of kinetic friction and the coefficient of static friction of the flexible joint assembly. The disclosed flexible joint assemblies may be characterized by a coefficient of kinetic friction that is sufficiently low to allow a mounted object to freely move and achieve a parallel orientation upon contact of the object to a surface. The flexible joint assemblies may be further characterized by a coefficient of static friction that is sufficiently high to resist motion and allow the object to maintain the parallel orientation after contact with the surface is broken. Coefficients of kinetic and static friction can depend upon the choice of materials used for the components of the flexible joint assemblies as well as the surface characteristics (e.g., surface roughness) of those materials. Regarding surface roughness, a “rough” material has surface features that, at the microscale and nanoscale, can be thought of like the teeth of a gear. During the leveling process, the object mounted to the support structure can assume discrete planar positions that correspond to the flexible joint assembly slipping to various “gear” positions. Any rigid material may be used for the components of the flexible joint assemblies. Suitable materials include, but are not limited to, stainless steel, aluminum, plastics, and ceramics.
The flexible joint assemblies can be formed from a variety of components. By way of example only, the flexible joint assembly can include a ball and a joint member mounted to the ball, wherein the joint member has a depression shaped to accommodate the ball as the ball rests against the joint member. A variety of joint members may be used. As one example, a joint member may include a pair of rods separated by a sufficient distance to accommodate a ball set atop the pair of rods. As another example, a joint member may include a socket having a hollow to accommodate a ball resting within the hollow. The hollow of the socket can take on a variety of shapes, including but not limited to a concave shape, a linear grooved shape, and a triangular grooved shape. As yet another example, a joint member may include a triangular arrangement of three balls separated by a sufficient distance to accommodate a ball set atop the center of the triangle. In all the examples, the flexible joint assembly provides a range of motion for an object mounted to the flexible joint assembly as the ball rotates within the depression of the joint member.
The flexible joint assemblies can be magnetic joint assemblies such that at least one of the components of the assembly is magnetic. For those embodiments in which the flexible joint assembly includes a ball and a joint member, the ball, the joint member, or both may be magnetic. A variety of materials may be used, provided that the material is a magnet. Suitable materials include ultra-high pull, neodymium, and nickel-plated magnets. Such magnets are commercially available. When one component of the flexible joint assembly is a magnet, the other component can be composed of a material that is capable of being attracted to a magnet, including, but not limited to, steel.
The disclosed devices may include one flexible joint assembly or a plurality of flexible joint assemblies. Flexible joint assemblies may be mounted to the support structure by a variety of known means, including, but not limited to, adhesives, glues, or magnets.
Exemplary flexible joint assemblies are further described below and illustrated in the figures.
The objects to be mounted to the support structure include a plurality of protrusions, the protrusions adapted to form a pattern on a surface of a substrate upon contact of the object to the surface. The pattern can be a microscale or a nanoscale pattern. By “microscale” it is meant that the pattern includes, for example, a feature having a dimension on the order of microns, e.g., 1, 10, 100 μm, etc. By “nanoscale” it is meant that the pattern includes, for example, a feature having a dimension on the order of nanometers, e.g., 1, 10, 100 nm, etc. The pattern can include dots, lines, and circles having arranged in various irregular or regular orientations. Exemplary objects include stamps, including polymeric stamps, used in microcontact printing and molds used in nanoimprint lithography. Such stamps and molds are known in the art. The object may be an elastomeric tip array such as those described in Hong et al., “A micromachined elastomeric tip array for contact printing with variable dot size and density,” J. Micromech. Microeng. 18 (2008).
Another non-limiting exemplary object is an array of nanoscopic and/or scanning probe tips. The array may be a one-dimensional array of tips or a two-dimensional array of tips, including high density arrays of tips. See, e.g., U.S. Pat. Nos. 6,635,311 and 6,827,979 to Mirkin et al; U.S. Patent Application Pub. No. 2008/0105042 to Mirkin et al; and U.S. Patent Application Pub. No. 2008/0309688 to Haaheim et al. See also DPN 5000, NLP 2000, NSCRIPTOR™ and other nanolithography instrumentation sold by NanoInk (Skokie, Ill.). The tips can be solid or hollow, and can have a tip radius of, for example, less than 100 nm. Tips can be, but need not be, formed at the end of a cantilever structure. The cantilever can be mounted to a holder. The holder may include one or more viewports adapted for viewing the tips. The viewports may have a variety of shapes, sizes, and configurations as described in, e.g., U.S. Pat. Pub. No. 2008/0309688 to Haaheim et al. This reference also describes methods of making the viewports. The holder may also include one or more edge standoff spacers which help prevent crushing tips against the underside of the holder. Again, see, e.g., U.S. Patent Application Pub. No. 2008/0309688 to Haaheim et al.
Polymer pen arrays of tips are described in, for example, WO 2009/132,321 (PCT/US2009/041738) to Mirkin et al.
Objects, and support structure and other devices mounted to the object, as well as substrates, can be adapted to move with nanopositioners such as piezoresistor nanopositioners. Motion can be in x, y, and z directions, as well as rotational motions. See, e.g., U.S. Patent Application Pub. No. 2009/0023607, and The Nanopositioning Book. Moving and Measuring to Better than a Nanometre, T. R. Hicks et al, 2000.
The objects may be mounted to the support structure via a variety of known mounting means. By way of example only, adhesives, glues, or magnets may be used to mount the object to the support structure.
A separate mounting fixture adapted to facilitate the mounting of the object to the support structure can also be used. The mounting fixture can be useful when adhesives, glues, or similar mounting means are used to mount the object to the support structure. The mounting fixture can include a cavity adapted to hold the object in a fixed position while leaving a mounting surface of the object exposed during the mounting process. The mounting fixture can further include a channel adapted to accommodate a support structure placed onto the mounting surface of the object. The mounting fixture can further include a clipping member adapted to hold the support structure in a fixed position atop the mounting surface of the object during the mounting process. The overall shape and dimensions of the mounting fixture are not limited and can vary depending upon the shapes and dimensions of the object and the support structure to be mounted together using the mounting fixture. Similarly, the materials used to form the mounting fixture may vary. Any of the metals and plastics described herein may be used, although other similar materials are possible. Non-limiting examples of mounting fixtures are described below and illustrated in the figures.
The devices can include a variety of other components. By way of example only, the devices can include a mounting structure mounted to the at least one flexible joint assembly. The mounting structure can be adapted to be mounted to a patterning instrument. The shapes and dimensions of the mounting structure may vary. Non-limiting examples of mounting structures are described below and illustrated in the figures. Similarly, the materials used to form the support structures may vary. Suitable materials include, but are not limited to copper and the like. The mounting structure may be mounted to the flexible joint assembly and the patterning instrument in a variety of ways, including, but not limited to adhesives, glues, and screws.
The devices can further include a signaling system for signaling the orientation of the mounted object with respect to a surface. For example, the signaling system may be adapted to signal when a parallel orientation of the mounted object to a surface has been achieved. Non-limiting examples of signaling systems are described below and illustrated in the figures.
An embodiment of a device for leveling is illustrated in
Other signaling systems for signaling when a parallel orientation has been achieved and for providing associated quantitative information are possible. Such signaling systems can be integrated with any of the devices disclosed herein. As one example, a signaling system can include means for a deflection measurement. A device integrated with such a signaling system can include a rigid arm coupled to the device. The arm can be adapted to protrude outwardly from the device. The arm can be further adapted to measure the movement of the device when the device comes under load. For example, the arm can be coupled to a deflection measurement device such as a digital encoder or a capacitive sensor for measuring movement. When the device makes contact with the surface of the substrate and the protrusions on an object mounted to the device begin to deflect and apply force upward on the arm, very small deflections of the arm can be measured.
As another example, a signaling system can include means for a strain gauge measurement. A device integrated with such a signaling system can include a strain gauge coupled to the device, the strain gauge adapted to measure the applied force and quantify the touch down point when the device and substrate make contact. Alternatively, the device can include pressure sensors coupled to a substrate to be contacted by the device. The pressure sensors can be adapted to provide information about when and where protrusions on an object mounted to the device begin applying a force on the substrate.
The leveling process will now be described, with reference to
The signaling process will now be described, also with reference to
Another embodiment of a device for leveling is shown in
The flexible joint assemblies in
As shown in
As shown in
As described above, the support structure 302 can be further adapted to be mounted to an apparatus for disposing an ink composition on the plurality of protrusions. As shown in
As described above, the leveling devices can include a mounting structure adapted to be mounted to a patterning instrument. Such a device 500 is shown in
In some representative embodiments, the gimbal design only occludes the outer circumference of the object, such as an array of tips, such as for example a 2D nano PrintArray, leaving the internal viewing area free to be observed. Advantageously, this allows viewport deflection measurements to provide a useful form of corroboration for planarity. This design is different from the two-axis design or single-ball designs.
The leveling process will now be described, with reference to
The leveling devices can also be integrated with a signaling system for signaling when a parallel orientation of an object mounted to the device has been achieved. As described above, the device can include one or more apertures and an object mounted to the device can include one or more viewports, the apertures and viewports adapted to view one or more protrusions on the object.
An exemplary signaling process will now be described for a mounted array of scanning probe tips disposed on cantilevers using the signaling system described above. However, it is to be emphasized that the description below is not limited to an array of scanning probe tips disposed on cantilevers, but rather applies to any of the objects to be mounted to a support structure described herein and similar objects. Before the mounted array achieves a parallel orientation, the array of cantilevers and scanning probe tips as viewed through the viewports can appear out of focus. In addition, light reaching the cantilevers through the viewports can reflect off the cantilevers. The reflected light can have a particular color and intensity, providing an indication of the deflection state of the cantilevers. As the mounted array makes contact with the substrate and the array moves into a parallel orientation with respect to the substrate, the tips make contact with the substrate, and the cantilevers are deflected upwards. As the tips make contact with the substrate and the cantilevers deflect, the tips are brought into focus and the reflection of light off of the cantilever beams changes, resulting in a corresponding change in color and/or intensity. Any further perpendicular motion of the substrate and object against each other can cause further changes in light reflection and the tips to move out of focus. Thus, the imaging of the tips and/or cantilevers (at three different XY locations) provides a signal that the parallel orientation of the object with respect to the substrate has been achieved.
The objects, devices, and assemblies described herein can function as a gimbal.
Any of the devices described above can be assembled into apparatuses and kits. Use of the devices can be controlled by instruments, software, computers, and external hardware.
As described above, also provided are separate mounting fixtures adapted to facilitate the mounting of any of the disclosed objects to any of the disclosed support structures. An exemplary embodiment of a mounting fixture 600 is shown in
An exemplary mounting process will now be described, with reference to
As noted throughout, the dimensions of the devices and components provided herein may vary. In some cases, the dimensions of the devices (e.g., the leveling devices, the mounting fixtures, etc.) and components of those devices (e.g., the object, the support structure, the middle structure, the upper structure, the flexible joint assembly, the joint member, the mounting structure, etc.) can be quite small, on the order of centimeters, millimeters, or even smaller. The small-scale manufacturing of devices and components having the ability to flex and move can be particularly challenging. By way of example only, the largest dimension of any of the devices herein can be about 10 cm or less. This includes embodiments in which the largest dimension is about 5 cm, 2 cm, 1 cm, or 0.5 cm. However, larger and smaller dimensions are also possible. As another non-limiting example, the largest dimension of any of the components herein can be about 5 cm or less. This includes embodiments in which the largest dimension is about 5 cm, 2 cm, 1 cm, 0.5 cm, or 1 mm. However, larger and smaller dimensions are also possible.
In another aspect, apparatuses incorporating the disclosed devices are provided. In some embodiments, the apparatus can include a patterning instrument and any of the devices described above, wherein the device is mounted to the patterning instrument. A variety of patterning instruments may be used, including, but not limited to, commercially available instruments for microcontact printing and nanoimprint lithography. Patterning instruments can also include scanning probe instruments adapted for patterning. Such scanning probe instruments include, but are not limited to, scanning tunneling microscopes, atomic force microscopes, and near-field optical scanning microscopes, all of which are commercially available. Other scanning probe instruments include the DPN 5000, NLP 2000, and the NSCRIPTOR systems commercially available from NanoInk, Inc., Skokie, Ill.
Another possible patterning instrument is described in U.S. Patent Application Pub. No. 2009/0023607 to Rozhok et al. Such an instrument can include at least one multi-axis assembly having at least five nanopositioning stages; at least one scanning probe tip assembly, wherein the scanning probe tip assembly and the multi-axis assembly are adapted for delivery of a material from the scanning probe tip assembly to the substrate, the substrate positioned by the multi-axis assembly; at least one viewing assembly; and at least one controller. Nanopositioning stages, multi-axis assemblies, scanning probe tips assemblies, viewing assemblies, and controllers are described in U.S. Patent Application Pub. No. 2009/0023607 to Rozhok et al.
Environmental chambers can be included on any of the patterning instruments described above, to control, for example, temperature, humidity, and gas content.
One or more of the components and devices described herein can be combined into useful kits. The kits can further comprise one or more instructions on how to use the kit. The kit can be, for example, adapted to function with a patterning instrument such as an existing commercial patterning instrument.
In another aspect, methods for using any of the disclosed devices and apparatuses are provided, including leveling methods and patterning methods. In an embodiment of a leveling method, the method can include providing any of the devices disclosed herein, mounting any of the disclosed objects to the support structure of the device, contacting the mounted object to a substrate, and allowing the object to achieve a parallel orientation with respect to the substrate surface. The step of contacting the mounted object can be accomplished as described above, e.g., moving the device and mounted object towards the substrate or moving the substrate towards the device and mounted object. The step of allowing the object to achieve a parallel orientation is accomplished as the flexible joint assemblies flex, and thus, the mounted object moves, in response to the force exerted by the mounted object and the substrate against each other.
The leveling method can include additional steps. By way of example only, the method can include confirming that the parallel orientation has been achieved by using any of the signaling systems described above. As another example, the method can include breaking contact of the mounted object with the substrate surface, wherein the parallel orientation of the mounted object is maintained after contact is broken.
In an embodiment of a patterning method, the method can include providing any of the devices disclosed herein, mounting any of the disclosed objects to the support structure of the device, providing at least some of the protrusions of the object with an ink composition, and transferring the ink composition from the protrusions to the surface of a substrate. Ink compositions are known and include organic compounds and inorganic materials, chemicals, biological materials, non-reactive materials and reactive materials, molecular compounds and particles, nanoparticles, materials that form self assembled monolayers, soluble compounds, polymers, ceramics, metals, magnetic materials, metal oxides, main group elements, mixtures of compounds and materials, conducting polymers, biomolecules including nucleic acid materials, RNA, DNA, PNA, proteins and peptides, antibodies, enzymes, lipids, carbohydrates, and even organisms such as viruses. Sulfur-containing compounds including thiols and sulfides can be used. Any of the references listed herein describe other ink compositions that may be used. Methods for providing protrusions with ink composition are known, including, e.g., solution dipping or vacuum evaporation. See, e.g., U.S. Patent Application Pub. No. 2005/0035983 to Cruchon-Dupeyrat et al. Parameters for transferring the ink composition from the protrusions to the substrate, e.g., dwell time, rate of forming patterns, and environmental conditions, are also known. Patterns can include dots, lines, circles, or other features. See, e.g., any of the references provided herein and U.S. Patent Application Pub. Nos. 2002/0063212 and 2002/0122873 to Mirkin et al.
The leveling methods and patterning methods can be combined. In one embodiment, any of the leveling methods described above can further include providing at least some of the protrusions of the object with an ink composition. The step of providing at least some of the protrusions with an ink composition can occur before or after contacting the mounted object to the substrate and allowing the object to achieve a parallel orientation. In other words, the protrusions can be coated with an ink composition before or after leveling the mounted object. In some embodiments, the protrusions are coated before leveling the mounted object. After the protrusions are coated and the mounted object is leveled, the methods can include transferring the ink composition from the protrusions to the substrate surface.
The devices and apparatuses described herein can be used for a variety of applications, including biological applications, pharmaceutical applications, and fabrication of microscale and nanoscale structures. Fabrication applications include the formation of MEMS and NEMS. The acronym “MEMS” can encompass all microsystems, such as microelectromechanical, microelectrooptical, microelectromagnetic, and microfluidic systems. MEMS also can include nanoelectromechanical systems, NEMS. These and other applications are described in any of the references provided herein, including U.S. Patent Application Pub. No. 2008/0309688 to Haaheim et al.
For biological applications, cell growth, including stem cell growth, can be controlled with use of arrays fabricated with devices and instruments described herein. Protein arrays, nucleic acid arrays, and lipid and phospholipid arrays can be also fabricated.
Methods known in the art can be used to make and assemble the components and devices described herein. This includes adapting the components and devices with commercial instrumentation. Additional non-limiting embodiments are described in
This concept—controlled and uniform contact—is important in terms of optimizing 2D-DPN. Traditional DPN with single tips or 1D arrays can be performed in force-feedback, with a laser bouncing off the cantilever and onto a photodetector to facilitate a constant applied force (i.e., cantilever deflection) with respect to the substrate. Due to the nature of mechanical amplification on an AFM, the range of cantilever deflection achievable in force-feedback is necessarily constrained by the dimensions of the photodetector; this cantilever deflection range is usually less than 2 μm. By contrast, 2D-DPN can be performed without force-feedback, where the Z-actuator is set at a constant height with respect to the substrate. Within the range of force-feedback conditions, DPN is effectively force independent, and patterns are created nearly identically between minimum and maximum deflections. However, in situations of extreme tip deflection (e.g., more than 10 μm), we have observed anomalous patterning behavior, including skewed features and non-standard formation of self-assembled monolayers (SAMs). This implies two very important operating conditions for creating uniform and homogenous patterns with 2D-DPN: (1) the overall Z-position of the 2D array must be carefully controlled with respect to the substrate (i.e., cantilever deflection average), and (2) the variation in cantilever deflection must be minimized (i.e., cantilever deflection variance, which is directly linked to array-substrate planarity). In one embodiment, the improved optics of the NLP 2000 make #1 easier to achieve; the self-leveling fixture improves the ease of achieving #2 while simultaneously enabling unprecedented planarity.
Beginning with the 2D nano PrintArray itself,
The viewport width allows viewing one row of 13 adjacent cantilevers simultaneously; this greatly aides navigating to the substrate in Z, and across it in X and Y. The silicon nitride (SiN) cantilevers appear green in front of the green-yellow backdrop of the silicon handle wafer, and the pink areas of SiN provide the anchor to the handle. This arrangement is seen explicitly in
The FOT available to the cantilevers directly defines the minimum allowable planarity to get all of the tips in contact with the substrate.
From this point, the leveling process is straightforward: one views the cantilevers through the viewports and brings the substrate upward in Z until it meets the first corner of the device, whereafter it self-levels as the cantilevers fully deflect. The cantilever deflection behavior can be seen in
There are several optical indicators that enable that degree of precision: most prominently, the red-orange refracted light “butterfly wing” formation inside the pyramidal tip (
However, this situation naturally lends itself to a “fine-leveling” step. Using the measured Z-coordinates from
With the variation in cantilever deflection minimized (i.e., the device being extremely level), it was then straightforward to observe cantilever deflection at one viewport to calibrate the array's overall Z-position with respect to the substrate. (Cantilever deflection of 2 μm past the first contact point can be optimal.) Having satisfied the two important operating conditions for homogeneous patterning, subsequent results confirmed the expected homogeneity (
The large spot in the bottom left corner of the 5×5 array was formed by dwelling on the substrate for several seconds before initiating patterning.
Trials 9-11 show the beginning of the fine-leveling steps, leading to the expected minimized ΔZ (0.5 μm).
Hence, a variety of embodiments for a self-leveling fixture for 2D-DPN patterning is demonstrated that greatly minimizes the time required to level the device, simplifies the leveling procedure, and provides much better co-planarity than was previously achievable. Fine leveling routines can result in less than 0.002° misalignment with respect to the substrate—a Z-difference of less than 600 nm across 1 cm2 of surface area. The degree of planarity directly correlates to homogeneity, which determines patterning quality across large areas. The ease and precision of this method enhances access to three categories of 2D nanopatterning applications mentioned above: (1) rapidly and flexibly generating nanostructures (e.g., Au, Si) via etch-resist techniques; (2) chemically directed assembly and patterning templates for either biological molecules (e.g., proteins, viruses, and cell adhesion complexes), or inorganics (e.g., CNTs, quantum dots); and (3) directly writing biological materials. Both phospholipids and alkanethiols have been patterned, with thiol functional groups including methyl, hydroxyl, amine, and carboxyl. One can thereby create hundreds of millions of chemically tailored nanostructures in a matter of minutes, with functional groups tailored to specific templating requirements.
To date, it is either very difficult or not possible to flexibly pattern a variety of materials at the DPN's resolution (14 nm) across centimeter square areas. Fundamentally, this enables flexible direct-writing with a variety of molecules, simultaneously generating large numbers (e.g., 55,000) duplicates at the resolution of single-pen DPN. By enhancing the speed, ease, and precision of the process, the self leveling methodology helps to enable practical nanomanufacturing.
The 2D nano PrintArray devices as commercially available (NanoInk, Inc.) were used. Before patterning, the 2D tip arrays were vapor-coated with ODT, according to three coating cycles: 60 min at 65° C. and 100 min cool down at 0.1° C./min. The patterning was performed on the NLP 2000 (NanoInk, Inc.), which was used for capturing optical images of cantilever deflection behavior. Patterning was performed in ambient conditions (22° C., 30% Rh). Post-patterning, the substrate was etched to create metallic nanostructures, according to the published methods (e.g., Salaita et al. 2006). Scanning electron microscope images are obtained with a Hitachi 54800 SEM Tokyo, Japan. Bright field and dark field optical images are obtained with a Zeiss Axio-Imager ZIM Thonrwood, N.Y.
The following references further enable practice of various embodiments described herein and are incorporated by reference in their entirety.
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This application claims priority to U.S. provisional application Ser. No. 61/226,579 filed Jul. 17, 2009, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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61226579 | Jul 2009 | US |