WO2019089409A1

WO2019089409A1 - Systems and methods for forming dimensionally sensitive structures

Info

Publication number: WO2019089409A1
Application number: PCT/US2018/057913
Authority: WO
Inventors: Michael Lesley Sorensen
Original assignee: Corning Incorporated
Priority date: 2017-10-30
Filing date: 2018-10-29
Publication date: 2019-05-09
Also published as: TW201933433A

Abstract

Embodiments are related to forming structures, and more particularly to systems and methods for forming structures using a two step sol-gel based process.

Description

SYSTEMS AND METHODS FOR FORMING DIMENSIONALLY

SENSITIVE STRUCTURES

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S.

Provisional Application Serial No. 62/578,887 filed on October 30, 2017, the content of which is relied upon and incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] Embodiments are related to forming structures, and more particularly to systems and methods for forming structures using a two step sol-gel based process.

BACKGROUND

[0003] LED displays, LED display components, and arrayed LED devices include a large number of diodes placed at defined locations across the surface of the display or device. Fluidic assembly may be used for assembling diodes in relation to a substrate. Such assembly is often a stochastic process whereby LED devices are deposited into wells on a substrate. Forming such wells into the surface of a substrate using traditional pattern and etch processes can result in irregular well shapes including, for example, concave down well bottoms that make fluidic assembly less controllable.

[0004] Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for manufacturing dimensionally sensitive structures.

SUMMARY

[0005] Embodiments are related to forming structures, and more particularly to systems and methods for forming structures using a two step sol-gel based process.

[0006] This summary provides only a general outline of some embodiments of the invention. The phrases "in one embodiment," "according to one embodiment," "in various embodiments", "in one or more embodiments", "in particular embodiments" and the like generally mean the particular feature, structure, or characteristic following the phrase is included in at least one embodiment of the present invention, and may be included in more than one embodiment of the present invention. Importantly, such phrases do not necessarily refer to the same embodiment. Many other embodiments of the invention will become more fully apparent from the following detailed description, the appended claims and the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

[0007] A further understanding of the various embodiments of the present invention may be realized by reference to the figures which are described in remaining portions of the specification. In the figures, like reference numerals are used throughout several figures to refer to similar components. In some instances, a sub-label consisting of a lower case letter is associated with a reference numeral to denote one of multiple similar components. When reference is made to a reference numeral without specification to an existing sub-label, it is intended to refer to all such multiple similar components.

[0008] Figs, la-lb depicts an example fluidic assembly system used to deposit physical objects into a plurality of dimensionally sensitive wells;

[0009] Fig. 2a shows a device including a sol-gel based structure layer formed over a base where the sol-gel based structure layer includes one or more vertical wells formed using a dimensionally sensitive process in accordance with various embodiments of the present inventions;

[0010] Fig. 2b is similar to Fig. 2a except that the one or more vertical wells exhibit slumping that can occur where the dimensionally sensitive process is not utilized;

[0011] Fig. 3a shows a device including a sol-gel based structure layer formed over a base where the sol-gel based structure layer includes one or more tapered wells formed using a dimensionally sensitive process in accordance with various embodiments of the present inventions;

[0012] Fig. 3b is similar to Fig. 3a except that the one or more tapered wells exhibit slumping that can occur where the dimensionally sensitive process is not utilized; [0013] Fig. 4 graphically depicts an example photonic curing process that may be used to cure a sol-gel material in accordance with one or more embodiments of the present inventions;

[0014] Fig. 5 graphically depicts an example thermal curing process that may be used to cure a sol-gel material in accordance with one or more embodiments of the present inventions; and

[0015] Fig. 6 is a flow diagram depicting a method in accordance with some embodiments of the present inventions for partially curing a sol-gel material using a first cure process followed by a curing of the sol-gel material using a second cure process; and

[0016] Fig. 7 is a flow diagram showing a method in accordance with various embodiments of the present inventions for manufacturing a sol-gel material susceptible to the first and second cure processes used to form dimensionally sensitive structures.

DETAILED DESCRIPTION OF SOME EMBODFMENTS

[0017] Embodiments are related to forming structures, and more particularly to systems and methods for forming structures using a two step sol-gel based process.

[0018] Various embodiments provide methods for manufacturing a sol-gel based structure layer. The methods include: forming patterned sol-gel material layer from a sol-gel material, where the patterned sol-gel material layer includes one or more features; applying a first cure to the patterned sol-gel material layer to yield a partially cured sol-gel material layer, where the sol-gel material of the patterned sol-gel material layer is hardened such that a possibility of a loss of resolution of the one or more features is reduced; and applying a second cure to the partially cured sol-gel material layer to further harden the sol -gel material of the partially cured sol-gel material layer.

[0019] In some instances of the aforementioned embodiments, the partially cured sol -gel material layer exhibits tack. In various instances, the partially cured sol -gel material layer exhibits a modulus below 0.33 mega Pascals at 25 degrees Celsius and 1 Hertz. In some such instances, the cured sol-gel material layer exhibits a modulus above 0.33 mega Pascals at 25 degrees Celsius and 1 Hertz. In one or more instances of the aforementioned embodiments, the partially cured sol-gel material layer is flexible. In some instances of the aforementioned embodiments, the first cure is a photonic cure. In some such instances, the photonic cure includes exposing the patterned sol-gel material layer to light of a wavelength between two hundred and seven hundred nanometers. In various instances of the aforementioned embodiments, the second cure is a thermal cure. In some such instances, the thermal cure includes heating the partially cured sol-gel material layer to a defined temperature for a defined time.

[0020] Other embodiments provide a sol-gel material that is: transitional from a liquid to a solid at a first hardness where the sol-gel material has tack using a first cure process; and transitional to a solid at a second hardness where the sol-gel material does not have tack using a second cure process. In some instances of the aforementioned embodiments, the first cure process is a photonic cure process. In some cases, the such a photonic cure process includes exposing the sol-gel material layer to light of a wavelength between two hundred and seven hundred nanometers. In various instances of the aforementioned embodiments, the second cure process is a thermal cure process. In some cases, the thermal cure process includes heating the partially cured sol-gel material layer to a defined temperature for a defined time. In one or more instances of the aforementioned embodiments, the sol-gel material is a thio- ene crosslinked sol-gel material that contains between ten percent and forty percent by weight of thiol-ene functional materials. In particular instances of the aforementioned embodiments, the sol-gel material contains a thiol containing sol-gel and a vinyl containing sol -gel. In some such instances, the sol-gel material further contains a free radical initiator. In various of the aforementioned instances, the sol-gel material further contains a stabilizer.

[0021] Yet other embodiments provide methods for manufacturing a dual cure sol-gel material. The methods include: forming a liquid sol-gel material by combining a thiol containing sol-gel, a vinyl containing sol-gel, and a stabilizer. The liquid sol-gel material is curable using: a first cure process to yield a partially cured sol -gel that is in solid form and exhibits tack; and a second cure process to yield a cured sol -gel that is in solid form and does not exhibit tack. In some instances of the aforementioned embodiments, the first cure process is a photonic cure process, and the second cure process is a thermal cure process.

[0022] Turning to Fig. la, a fluidic assembly system 100 is shown that is used to deposit physical objects 130 into a plurality of dimensionally sensitive wells 142 formed in a sol-gel based structural alignment layer 190 atop a surface of a substrate 140. In some cases, physical objects 130 may be micro-diodes, however, in other cases the physical objects may be other electronic devices or even non-electronic devices. Turning to Fig. lb, an example top view 199 of the surface of substrate 140 is shown with an array of wells (shown as circles) extending into sol-gel based structural alignment layer 190. It should be noted that while wells 142 are shown as circular in cross-section that other shapes may be used in relation to different embodiments. In some embodiments, substrate 140 is a glass substrate and wells 142 are sixty (60) micrometers in diameter formed in sol-gel based structural alignment layer 190 at five hundred (500) micrometers offsets. Sol -gel based structural alignment layer 190 may be formed substrate 140 using a sol -gel material similar to that discussed below in relation to Fig. 7, and created using a two step curing process as discussed below in relation to Figs. 2-3 and 6.

[0023] A depositing device 150 deposits suspension 110 over the surface of substrate 140 with suspension 110 held on top of substrate 140 by sides 120 of a dam structure. In some cases, depositing device 150 is a pump with access to a reservoir of suspension 110. A suspension movement device 160 agitates suspension 110 deposited on substrate 140 such that physical objects 130 move relative to the surface of substrate 140. As physical objects 130 move relative to the surface of substrate 140 they deposit into wells 142. In some embodiments, suspension movement device 160 is a brush that moves in three dimensions. A capture device 170 includes an inlet extending into suspension 110 and capable of recovering a portion of suspension 1 10 including a portion of carrier liquid 115 and non-deposited physical objects 130, and returning the recovered material for reuse. In some cases, capture device 170 is a pump.

[0024] It has been determined that use of sol-gel material to form structural alignment layers for capturing micro devices during fluidic assembly is superior to organic coating as it allows for improved hermeticity, higher temperature processing, greater optical transmission, desirable mechanical stability, compatibility with various solder processes, and a more chemically tunable surface onto which fluidic assembly is performed. As an example, use of the sol-gel based structural material enables thermal processing with temperature excursions in some cases greater than two hundred degrees Celsius (>200C) depending upon the particular sol-gel material and a desired optical transmission (e.g., >70%, >80%, or >90 in a wavelength range of 400-800nm). In other cases, temperature excursions greater than three hundred degrees Celsius (>300C) are possible depending upon the particular sol-gel material and a desired optical transmission (e.g., >70%, >80%, or >90 in a wavelength range of 400- 800nm). In yet other cases, temperature excursions greater than three hundred, fifty degrees Celsius (>350C) are possible depending upon the particular sol-gel material and a desired optical transmission (e.g., >70%, >80%, or >90 in a wavelength range of 400-800nm). In particular cases, temperature excursions greater than four hundred degrees Celsius (>400C) are possible depending upon the particular sol-gel material and a desired optical transmission (e.g., >70%, >80%, or >90 in a wavelength range of 400-800nm). The aforementioned temperature excursions and characteristics can be achieved while forming structural alignment layer 190 with relatively large thicknesses (e.g., from less than one micron (lum) to more than ten microns (lOum) in thickness.

[0025] Further, such use of sol-gel materials offer easier tuning of viscosity to facilitate processing without significantly altering the final film properties when compared with organic coating, and/or greater tuning ability of optical and electrical properties of sol-gel process to form sol-gel based structural alignment layer 190. Additionally, or alternatively, use of a sol-gel process to form sol -gel based structural alignment layer 190 allows for printing to a known thickness in a single step while a traditional pattern and etch of an organic coating to a consistent depth requires constant maintenance of an etch bath. It should be noted that the aforementioned are just example advantages that may be achieved, and that based upon the disclosure provided herein, one of ordinary skill in the art will recognize additional or alternative advantages that may be achievable in accordance with different embodiments.

[0026] Turning to Fig. 2a, a device 200 is shown that includes a sol-gel based structure layer 210 formed over a base 202 where sol -gel based structure layer 210 includes one or more vertical wells 242 formed using a dimensionally sensitive process in accordance with various embodiments of the present inventions. Such a dimensionally sensitive process is more fully described below in relation to Fig. 6. Vertical wells 242 are defined by a wall 225 that extends at ninety (90) degrees from base 202 as shown by an angular mark 230. Sol-gel based structure layer 210 exhibits a thickness 232.

[0027] Device 200 is manufactured by forming a sol-gel material on base 202 at a selected thickness (i.e., a thickness that will result in thickness 232 after condensing the sol-gel material during a thermal cure process). The sol-gel material is patterned to include one or more patterns of structures corresponding to those in sol -gel based structure layer 210. In one particular embodiment, the patterns of structures are formed by micro-replication that includes: spin coating a layer of sol-gel onto a glass base to a desired thickness (e.g., ten (10) micrometers), and embossing with a polydimethylsiloxane (PDMS) mold. As just some of many other examples, the sol-gel material may be patterned using one or more of the following processes: screen printing, flexo printing, micro-replication, gravure printing, ink jet printing, offset printing, or stamping.

[0028] The patterned, uncured sol-gel material is exposed to a first cure process to yield a partially cured sol-gel material (also corresponding to sol -gel based structure layer 210). The first cure process may be a photonic cure where the patterned, uncured sol-gel material is exposed to photonic radiation (e.g., ultraviolet or other light) which results in a transition of the sol-gel material from a liquid to a solid. The photonic cure results in fixing the structures by hardening the sol-gel material and thus reducing the possibility of slumping or other dimensional changes due to flow characteristics of the liquid sol-gel material. In one particular embodiment, the first cure process includes exposing the patterned, uncured sol-gel material to light from either a mercury source or an LED in the range of two hundred (200) nanometers to seven hundred (700) nanometers. In one embodiment, the first cure process includes exposing the patterned, uncured sol-gel material to three hundred, ninety five (395) nanometers which provides a relatively slow cure compared with another embodiment where the patterned, uncured sol-gel material is exposed to lower wavelength light sources (e.g., three hundred, sixty five (365) nanometers; three hundred, seventy five (375) nanometers, or three hundred, eighty five (385) nanometers). Such a slow cure results in an increase in flexibility and tack of the partially cured so-gel material. It should be noted that the intensity of light impacts the cure rate, and thus, the light intensity may be adjustable to offer further control of the cure rate. In another embodiment, the first cure process includes exposing the patterned, uncured sol-gel material to relatively low wavelength light which provides a relatively fast cure. Such a fast cure may be desirable in, for example, roll-to-roll processing systems with high line speeds. In any case, the first cure results in the sol -gel material transitioning to a solid phase (i.e., the storage modulus exceeds the loss modulus as discussed below in relation to Fig. 4). Further, in some cases, the first cure results in the sol-gel material transitioning to a partially cured so-gel material with a shear storage modulus below 0.33MPa at 25°C and lHz.

[0029] The partially cured sol-gel material is later exposed to a second cure process to yield sol-gel based structure layer 210. This second cure process results in a sol -gel based structure layer 210 that loses tack as it has a shear storage modulus below 0.33MPa at 25°C and lHz. The second cure process may be a thermal cure where the partially cured sol -gel structure layer is exposed to a heating process which results in further hardening of the sol-gel material. This thermal cure process may be done at a relatively high temperature for a short period, or at a relatively low temperature for a shorter period. In one particular embodiment, the second cure process involves exposing the partially cured sol -gel material to a

temperature of two hundred, thirty (230) degrees Celsius for one hour. Such a thermal cure condenses the partially cured sol-gel material causing weight loss as discussed below in relation to Fig. 5, and achieving thickness 232.

[0030] Turning to Fig. 2b, a device 250 that is similar to device 200 except that the one or more vertical wells exhibit slumping that can occur where the first cure process is skipped and only the second cure process is utilized. As shown, the flow characteristics of the utilized sol-gel material result in the walls of vertical wells 242 slumping such that a wall 275 extends at an unselected angle from base 202 as shown by an angular mark 280. Such a lack of control of a dimensionally sensitive structure may not be acceptable in some applications.

[0031] Turning to Fig. 3a, a device 300 is shown that includes a sol-gel based structure layer 310 formed over a base 302 where sol-gel based structure layer 310 includes one or more tapered wells 342 formed using a dimensionally sensitive process in accordance with various embodiments of the present inventions. Such a dimensionally sensitive process is more fully described below in relation to Fig. 6. Tapered wells 342 are defined by a wall 325 that extends at a desired angle from base 302 as shown by an angular mark 330. Sol-gel based structure layer 310 exhibits a thickness 332.

[0032] Device 300 is manufactured by forming a sol-gel material on base 302 at a selected thickness (i.e., a thickness that will result in thickness 332 after condensing the sol-gel material during a thermal cure process). The sol-gel material is patterned to include one or more patterns of structures corresponding to those in sol-gel based structure layer 310. In one particular embodiment, the patterns of structures are formed by screen printing that includes screen printing a pattern of sol-gel onto a glass base to a desired thickness (e.g., ten (10) micrometers). As just some of many other examples, the sol-gel material may be patterned using one or more of the following processes: screen printing, flexo printing, micro- replication, gravure printing, ink jet printing, offset printing, or stamping.

[0033] The patterned, uncured sol -gel material is exposed to a first cure process to yield a partially cured sol-gel material (also corresponding to sol-gel based structure layer 310). The first cure process may be a photonic cure where the patterned, uncured sol -gel material is exposed to photonic radiation (e.g., ultraviolet or other light) which results in a transition of the sol-gel material from a liquid to a solid. The photonic cure results in fixing the structures by hardening the sol-gel material and thus reducing the possibility of slumping or other dimensional changes due to flow characteristics of the liquid sol-gel material. In one particular embodiment, the first cure process includes exposing the patterned, uncured sol-gel material to light from either a mercury source or an LED in the range of two hundred (200) nanometers to seven hundred (700) nanometers. In one embodiment, the first cure process includes exposing the patterned, uncured sol-gel material to three hundred, ninety five (395) nanometers which provides a relatively slow cure compared with another embodiment where the patterned, uncured sol-gel material is exposed to lower wavelength light sources (e.g., three hundred, sixty five (365) nanometers; three hundred, seventy five (375) nanometers, or three hundred, eighty five (385) nanometers). Such a slow cure results in an increase in flexibility and tack of the partially cured so-gel material. In another embodiment, the first cure process includes exposing the patterned, uncured sol-gel material to relatively low wavelength light which provides a relatively fast cure. Such a fast cure may be desirable in, for example, roll-to-roll processing systems with high line speeds. In any case, the first cure results in the sol-gel material transitioning to a solid phase (i.e., the storage modulus exceeds the loss modulus as discussed below in relation to Fig. 4). Further, in some cases, the first cure results in the sol-gel material transitioning to a partially cured so-gel material with a shear storage modulus less than 0.33MPa at 25°C and 1 Hz.

[0034] The partially cured sol-gel material is later exposed to a second cure process to yield sol-gel based structure layer 310. This second cure process results in a sol -gel based structure layer 310 that has no tack as it has exceeded a shear storage modulus of 0.33MPa at 25°C and 1 Hz. The second cure process may be a thermal cure where the partially cured sol -gel structure layer is exposed to a heating process which results in further hardening of the sol- gel material. This thermal cure process may be done at a relatively high temperature for a short period, or at a relatively low temperature for a shorter period. In one particular embodiment, the second cure process involves exposing the partially cured sol-gel material to a temperature of two hundred, thirty (230) degrees Celsius for one hour. Such a thermal cure condenses the partially cured sol-gel material causing weight loss as discussed below in relation to Fig. 5, and achieving thickness 332.

[0035] Turning to Fig. 3b, a device 350 that is similar to device 300 except that the one or more tapered wells exhibit slumping that can occur where the first cure process is skipped and only the second cure process is utilized. As shown, the flow characteristics of the utilized sol-gel material result in the walls of tapered wells 342 slumping such that a wall 375 extends at an unselected angle from base 302 as shown by an angular mark 330. Such a lack of control of a dimensionally sensitive structure may not be acceptable in some applications.

[0036] Turning to Fig. 4, an example photonic curing process 400 is graphically depicted. The depicted photonic curing process 400 may be used to cure a sol-gel material in accordance with one or more embodiments. The graph includes a modulus axis 402 and a time axis 401. A storage modulus curve 410 is shown as a solid line, and a loss modulus curve 420 is shown as a dotted line. At a time 460 shortly before t=x (e.g., about one (1) to three (3) seconds before t=x depending upon the particular material), the sol-gel material represented by storage modulus curve 410 and loss modulus curve 420 is exposed to photonic radiation. Exposure to the photonic radiation causes the sol-gel material to start a hardening process. As shown, during the photonic curing process storage modulus curve 410 rises more quickly than loss modulus curve 420 resulting in a cross-over point 450 at time t=x. Prior to the time (i.e., t=x) corresponding to cross-over point 450 the sol-gel material is a liquid, and after the time (i.e., t=x) corresponding to cross-over point 450 the sol-gel material becomes a solid.

[0037] Turning to Fig. 5, an example thermal curing process 500 is graphically depicted. The depicted thermal curing process 500 may be used to cure a sol-gel material in accordance with one or more embodiments. The graph includes a weight and temperature axis 502 and a time axis 501. A temperature curve 510 is shown as a solid line representing the weight of the sol-gel material, and a weight curve 520 is shown as a dotted line representing the weight of the sol-gel material. As temperature curve 510 increases and is maintained, weight curve 520 decreases as a condensing process of the sol -gel material continues. At some point (e.g., time t=x), the condensing process slows and the sol -gel material is considered fully cured.

[0038] Turning to Fig. 6, a flow diagram 600 depicts a method in accordance with some embodiments of the present inventions for partially curing a sol -gel material using a first cure process followed by a curing of the sol-gel material using a second cure process. Following flow diagram 600, a sol-gel material is formed on a base at a selected thickness and having one or more structures of a defined dimension to yield an uncured sol-gel structure layer (block 605). The sol-gel material may be any of a number of sol-gel materials that are susceptible to two different curing processes. The photonic cure chemistries available for this include epoxy, acrylate, thiol-ene, and others compatible with the condensation cure conditions of the sol-gel. Various embodiments discussed here rely on acid catalyzed hydrolysis and condensation sol-gels. Acid catalysis was chosen because it produces high density, low-porosity gels. Working with epoxy based materials in such an acid catalyzed environment as the acidic environment kills the basic initiator for these reactions, but it is not impossible. In various embodiments, the sol-gel material is a thiol-ene crosslinked sol-gel material with a composition that contains twenty -five (25) percent by weight of thiol-ene functional materials. This material exhibits great patternability with micro-replication, can withstand the condensation and post cure temperature requirements, has a cure that is not inhibited by oxygen, and remains clear throughout the process. Some example sol-gel materials suitable for two different curing processes are discussed below in relation to Fig. 7. In one particular embodiment, the two different curing processes are a photonic curing process and a thermal curing process. While this embodiment discusses the use of photonic curing (i.e., radiation curing) to yield a partially cured sol-gel layer followed by a thermal cuing to yield a cured sol-gel layer, it should be noted that other embodiments may rely on a first thermal curing to yield the partially cured sol-gel layer followed by a second thermal curing to yield the cured sol-gel layer, or a first photonic curing to yield the partially cured sol-gel layer followed by a second photonic curing to yield the cured sol-gel layer.

[0039] The sol-gel material may be filled with additional components or additives that can include, but are not limited to, particles (e.g., silica particles), flakes, nano-particles (e.g., nanorods and/or nano-spheres), meshes, wires. Composition of these additives can include, but are not limited to, glass, ceramic, glass-ceramic, metal, and organic. The aforementioned additional components or additives may be selected to achieve various results including, but not limited to, adjusting: a coefficient of thermal expansion (CTE) of the sol-gel material, shrinkage, optical index, optical transmission and scattering, color and optical absorption, coefficient of friction, adhesion, surface energy, modulus, hardness, hermeticity, flexibility, surface roughness and/or leveling, fracture toughness, susceptibility to cracking, and/or dimensional stability. In particular cases, the sol-gel material can be pigmented to reduce transmission, the sol-gel material may be cured in a range of thicknesses extending from less than one (1) micrometer to greater than one (1) millimeter, and can have a tunable viscosity and stable shelf life with viscosities from fifty (50) centipoise (cPs) to greater than ten thousand (10,000) cPs.

[0040] In some cases, the sol-gel material exhibits a thermal capability of greater than two hundred (200) degrees Celsius. In other cases, the sol-gel material exhibits a thermal capability of greater than three hundred (300) degrees Celsius. In yet other cases, the sol-gel material exhibits a thermal capability of greater than four hundred (400) degrees Celsius. In some cases, the sol-gel material is designed to exhibit an optical transmission of greater than eighty -five (85) percent in the 350-800 nanometer wavelength range. In other cases, sol -gel material 122 is designed to exhibit an optical transmission of greater than ninety (90) percent in the 400-800 nanometer wavelength range.

[0041] Forming the one or more patterns of structures in the sol-gel material may be accomplished using a variety of processes. In one particular embodiment, the patterns of structures are formed by micro-replication that includes: spin coating a layer of sol-gel onto a glass base to a desired thickness (e.g., ten (10) micrometers), and embossing with a

Polydimethylsiloxane (PDMS) mold. As just some of many other examples, the sol-gel material may be patterned using one or more of the following processes: screen printing, flexo printing, micro-replication, gravure printing, ink jet printing, offset printing, or stamping.

[0042] The uncured sol-gel structure layer is exposed to a first cure process to yield a partially cured so-gel structure layer (block 610). The first cure process may be a photonic cure where the uncured sol-gel structure layer is exposed to photonic radiation which results in a transition of the sol-gel material from a liquid to a solid. The photonic cure results in fixing the structures by hardening the sol-gel material and thus reducing the possibility of slumping or other dimensional changes due to flow characteristics of the liquid sol-gel material. In one particular embodiment, the first cure process includes exposing the sol-gel structure layer to light from either a mercury source or an LED in the range of two hundred (200) nanometers to seven hundred (700) nanometers. In one particular embodiment, the first cure process includes exposing the sol-gel structure layer to three hundred, ninety five (395) nanometers which provides a relatively slow cure compared with another embodiment where the sol-gel structure layer is exposed to lower wavelength light sources (e.g., three hundred, sixty five (365) nanometers; three hundred, seventy five (375) nanometers, or three hundred, eighty five (385) nanometers). Such a slow cure results in an increase in flexibility and tack of the partially cured so-gel structure layer. In another particular embodiment, the first cure process includes exposing the sol-gel structure layer to relatively low wavelength light which provides a relatively fast cure. Such a fast cure may be desirable in, for example, roll-to-roll processing systems with high line speeds. In any case, the first cure results in the sol-gel material transitioning to a solid phase (i.e., the storage modulus exceeds the loss modulus as discussed above in relation to Fig. 4). Further, in some cases, first cure results in the sol-gel material transitioning to a partially cured sol-gel structure layer with a shear storage modulus below 0.33MPa at 25°C and lHz that has tack.

[0043] One or more intervening processes are applied (block 615). Such intervening processes may include, but are not limited to, storage, separation from the base, application to a device surface, or the like. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of processes that may be performed after the first cure process and before a subsequent second cure process.

[0044] The partially cured sol-gel structure layer is exposed to a second cure process to yield a cured sol-gel structured layer (block 620). This second cure process results in a cured sol-gel structured layer that has lost tack as it has exceeded a shear storage modulus of 0.33MPa at 25°C and lHz. The second cure process may be a thermal cure where the partially cured sol-gel structure layer is exposed to a heating process which condenses the sol-gel material resulting in further hardening of the sol-gel material. This thermal cure process may be done at a relatively high temperature for a short period, or at a relatively low temperature for a longer period. In one particular embodiment, the second cure process involves exposing the partially cured sol-gel structure layer to a temperature of two hundred, thirty (230) degrees Celsius for one hour. Such a thermal cure condenses the sol-gel material causing weight loss as discussed above in relation to Fig. 5. [0045] After the second cure is complete, one or more subsequent processes may be performed (block 625). Such subsequent process may include, but are not limited to, deposition of physical elements into structures formed in the cured sol-gel structure layer using fluidic assembly, or other varying manufacturing processes. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize a variety of processes that may be performed after the second cure process is complete.

[0046] Turning to Fig. 7, a flow diagram 700 shows a method in accordance with various embodiments of the present inventions for manufacturing a sol-gel material susceptible to the first and second cure processes used to form dimensionally sensitive structures. Following flow diagram 700, a thiol containing sol-gel is combined with a vinyl containing sol-gel to yield a sol-gel base (block 705). A variety of different materials may be used to make the aforementioned sol-gel base material are set forth in Table 1 below.

Table 1

[0047] Example formulations of various sol -gel materials (Thiol 1, Thiol2, Vinyl 1, Vinyl2) created from the aforementioned materials are set forth in Table 2 below. Based upon the disclosure provided herein, one of ordinary skill in the art will recognize other thiol containing sol-gel materials and vinyl containing sol-gel materials that may be used in relation to different embodiments of the present inventions.

Table 2

[0048] Thiol containing sol-gels (e.g., Thioll or Thiol2) and the vinyl containing sol -gels (e.g., Vinyl 1 or Vinyl 2) can all be prepared the same way. The respective component materials are weighed, in the case of DPSD, or volumetrically measured (for all of TEMS, TEPS, TEOS, HPDMS, Water, TAMS, MPTMS, and VTMS) and added to a round bottom flask (RBF). For the purposes of volumetric measuring a pipette with disposable tips, for example, can be used. A stir bar can be added to the flask and the RBF placed in an oil bath preheated to one hundred (100) degrees Celsius and the solution stirred with, for example, a magnetic stirrer. The top of the RBF is left to allow for the evaporation of any methanol, ethanol, water, or acetic acid generated during the reaction. The reaction is allowed to continue for between two and one half (2 1/2) to four (4) hours. The reaction is deemed complete when materials no longer condense at the top of the RBF and run down the inside wall, or the desired viscosity has been obtained. The materials can then be removed from the vial with a pipette with disposable tips, and stored in Nalgene™ bottles. In various embodiments, combining the thiol containing sol-gel with the vinyl containing sol-gel to yield a sol -gel base includes combining one of Thioll or Thiol2 with one of Vinyl 1 or Vinyl 2 to yield the yield the sol-gel base.

[0049] It is determined whether the desired viscosity has been achieved (block 710).

Where the desired viscosity has not yet been achieved (block 710), the viscosity of the sol-gel base may be increased by allowing the thiol containing sol -gel to mix with the vinyl containing sol-gel (e.g., by rolling on a roller) until the viscosity builds to the desired level (block 715). Alternatively, or in addition, where the desired viscosity has not yet been achieved (block 710), the viscosity of the sol -gel base can be thermally reacted to increase the viscosity with or without a cationic initator or other initiator (e.g., a free radical initiator), until the desired viscosity is achieved.

[0050] When the desired viscosity of the thiol-ene sol gel base is reached, a stabilizer is added to yield the sol-gel material that can be used as discussed above in relation to Figs. 2-3 and 6 (block 715). In one particular embodiment, the stabilizer is pyrogallol in an amount of between ten (10) and thirty (30) mM (based on thiol content of the sol-gel). If desired, DMPA and VPA can be added to the sol-gel material. DMPA is an initiator that can be used in conjunction with or in place of another initiator. VPA is a stabilizer.

[0051] In conclusion, the invention provides novel systems, devices, methods and arrangements for forming structures on a substrate. While detailed descriptions of one or more embodiments of the invention have been given above, various alternatives,

modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention. Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method for manufacturing a sol-gel based structure layer, the method including:

forming patterned sol-gel material layer from a sol-gel material, wherein the patterned sol-gel material layer includes one or more features;

applying a first cure to the patterned sol-gel material layer to yield a partially cured sol-gel material layer, wherein the sol-gel material of the patterned sol-gel material layer is hardened such that a possibility of a loss of resolution of the one or more features is reduced; and applying a second cure to the partially cured sol-gel material layer to further harden the sol-gel material of the partially cured sol-gel material layer.

2. The method of claim 1, wherein the partially cured sol -gel material layer exhibits tack.

3. The method of claim 1, wherein the partially cured sol -gel material layer exhibits a modulus below 0.33 mega Pascals at 25 degrees Celsius and 1 Hertz.

4. The method of claim 3, wherein the cured sol-gel material layer exhibits a modulus above 0.33 mega Pascals at 25 degrees Celsius and 1 Hertz.

5. The method of claim 1, wherein the partially cured sol -gel material layer is flexible.

6. The method of claim 1, wherein the first cure is a photonic cure.

7. The method of claim 6, wherein the photonic cure includes exposing the patterned sol-gel material layer to light of a wavelength between two hundred and seven hundred nanometers.

8. The method of claim 1, wherein the second cure is a thermal cure.

9. The method of claim 8, wherein the thermal cure includes heating the partially cured sol-gel material layer to a defined temperature for a defined time.

10. A sol-gel material, wherein the sol-gel material is:

transitional from a liquid to a solid at a first hardness where the sol-gel material has tack using a first cure process; and

transitional to a solid at a second hardness where the sol-gel material does not have tack using a second cure process.

11. The sol-gel material of claim 10, wherein the first cure process is a photonic cure process.

12. The sol-gel material of claim 11, wherein the photonic cure process includes exposing the sol-gel material layer to light of a wavelength between two hundred and seven hundred nanometers.

13. The sol-gel material of claim 10, wherein the second cure process is a thermal cure process.

14. The sol-gel material of claim 13, wherein the thermal cure process includes heating the partially cured sol-gel material layer to a defined temperature for a defined time.

15. The sol-gel material of claim 10, wherein the sol-gel material is a thio-ene crosslinked sol-gel material that contains between ten percent and forty percent by weight of thiol-ene functional materials.

16. The sol-gel material of claim 10, wherein the sol-gel material contains a thiol containing sol-gel and a vinyl containing sol-gel.

17. The sol-gel material of claim 16, wherein the sol-gel material further contains a free radical initiator.

18. The sol-gel material of claim 16, wherein the sol-gel material further contains a stabilizer.

19. A method for manufacturing a dual cure sol-gel material, the method comprising:

forming a liquid sol-gel material by combining a thiol containing sol-gel, a vinyl containing sol -gel, and a stabilizer; and

wherein the liquid sol-gel material is curable using:

a first cure process to yield a partially cured sol-gel that is in solid form and exhibits tack; and

a second cure process to yield a cured sol-gel that is in solid form and does not exhibit tack.

20. The method of claim 19, wherein the first cure process is a photonic cure process, and the second cure process is a thermal cure process.