KR100811018B1 - Method for making or adding structures to an article - Google Patents

Abstract

The present invention includes applying a multiphoton curable composition comprising a curable species and a multiphoton photoinitiator system to a molded article and at least partially curing the multiphoton curable composition to form a structure on the article. It relates to a method of forming.

Description

How to form or add structure to an article {METHOD FOR MAKING OR ADDING STRUCTURES TO AN ARTICLE}

Priority claim

This application claims the priority of US Provisional Application Nos. 60 / 211,588 and 60 / 211,706, filed June 15, 2000, the contents of which are incorporated herein by reference.

The present invention relates to a method of forming or adding a structure to an article using a multiphoton curing process.

Molding techniques, such as injection molding, compression molding, embossing, extrusion molding, and polymerization in a mold, can be used to make the polymeric article. Techniques such as stamping, casting, and machining may be used to manufacture metal articles, and etching, sintering, and grinding are appropriate for forming ceramic articles. Such macroscopic manufacturing techniques can be used to form an article or add structure to the surface of the article. While relatively large three-dimensional parts can be manufactured and assembled in separate molding steps and attached to the surface of the article, this technique is not useful for the fabrication and assembly of microscopic parts. Certain types of microstructures, such as for example undercuts, generally cannot be molded on the surface of the article. In addition, it may be difficult and impossible to mold the microstructure on the surface of the article if subsequent conventional microstructure processing could damage the article.

In certain applications it may be desirable to control the stresses (amount and direction) in the cured composition by the manner in which the curing process takes place. For example, if the surface of the molded article includes features such as depressions or grooves, it may be necessary to form a structure within or along the sidewalls of the molding. Some structures may be added to the molding by placing the curable composition on the molding and curing it with light. In a conventional photocuring process, the curable composition absorbs a substantial portion of the cured radiation such that the surface receives the maximum light intensity. As a result, the surface of the curable composition first cures, and then the remainder of the composition slowly cures from the surface of the curable composition to the full depth of the molding. This makes the hardening of thick layers very difficult. In some cases, it may be desirable to first cure the bottom layer of the curable composition to reduce the stress applied to or on the surface of the molded article. To cure from the bottom up, a number of layers of the curable composition must be applied to the molding, and each layer must be cured before the next layer is applied. This multi-step process is time consuming and inefficient.

Summary of the Invention

If the article is manufactured by conventional techniques, the present invention provides a method for adding one or several small major components during the multiphoton curing process. The proportional function of single photon absorption and incident radiation intensity is linear, while the proportional function of two photon absorption is second order. The larger the incident light intensity, the higher the order of the proportional function. As a result, it is possible to carry out a multiphoton curing process with three-dimensional spatial resolution. In addition, since the multiphoton process involves the simultaneous absorption of two or more photons, each photon individually has insufficient energy to excite the chromophore, but the absorbing chromophore has the total energy of the excited state of the multiphoton photoresist. Excited by multiple photons equal to Since the excitation light is not attenuated by single photon absorption in the curable matrix or material, it is possible to selectively excite molecules at deeper locations in the material than can occur through single photon excitation.

A first embodiment of the present invention includes the steps of adding a multiphoton curable composition comprising a curable species and a multiphoton photoinitiator system to a molded article; And at least partially curing the multiphoton curable composition to form a structure on the article.

A second embodiment of the present invention is a method of adding a structure to an article having a surface having one or more microscopic shaped portions, the method comprising a multiphoton photoinitiator system comprising a curable species, a multiphoton photosensitive agent and an electron acceptor. Adding the multiphoton curable composition to the molding; And at least partially curing the multiphoton curable composition to form a structure.

A third embodiment of the present invention is a method of adding a structure to an optical fiber, the method comprising: applying a multiphoton curable composition to a optical fiber comprising a curable species and a multiphoton photoinitiator system comprising a multiphoton photosensitizer and an electron acceptor ; And at least partially curing the multiphoton curable composition to form a structure.

A fourth embodiment of the present invention is a method of forming a diffraction grating on a substrate, which method applies a surface of a multiphoton curable composition comprising a curable species and a multiphoton photoinitiator system comprising a multiphoton photosensitizer and an electron acceptor. step; And at least partially curing the multiphoton curable composition to form a diffraction grating on the surface.

A fifth embodiment of the present invention is a method of filling a multiphoton cured material into a cavity, the method comprising a multiphoton curable composition comprising a curable species and a multiphoton photoinitiator system comprising a multiphoton photosensitive agent and an electron acceptor. Providing; Providing a cavity in the substrate; And exposing the multiphoton curable composition to a light source sufficient to cause multiphoton absorption.

A sixth embodiment of the present invention comprises the steps of: applying to a tooth a multiphoton curable composition comprising a curable species and a multiphoton photoinitiator system comprising a multiphoton photosensitizer and an electron acceptor; And at least partially curing the multiphoton curable composition.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.

1 is a schematic of a multiphoton curing system.                 

2 is a cross-sectional view of a cavity in an article filled with a multiphoton curable material.

3A is an end view of a flow control device in a channel within an article.

3B is a top view of the flow regulating device of FIG. 3A.

3C is a cross-sectional view of a portion of the flow regulating device of FIG. 3A.

4 is a cross-sectional view of the diffraction grating.

5 is a cross-sectional view of an undercut region in a channel in an article.

6A is an end view of a flow control device in a channel within an article.

6B is a top view of the flow regulating device of FIG. 6A.

6C is a cross-sectional view of a portion of the flow regulating device of FIG. 3A.

Like reference symbols in the different drawings indicate like elements.

The present invention provides a method of forming or adding a structure to an article. The method includes coating a multiphoton curable composition on the surface of a partially finished article and curing the multiphoton curable composition to form a structure on the surface.

Exposure system and how to use it

1, an optical system 10 for use in the present invention includes a light source 12, an optical member 14, and a movable stage 16. The stage 16 is preferably movable in three dimensions. The partially finished article 18 disposed above the stage 16 includes a surface 20 and any surface molding 22. The multiphoton curable composition 24 is applied over the surface 20 or in the mold 22. The light 26 from the light source 12 is then focused at point P in the volume of the curable composition 24 to at least partially cure the composition 24 by adjusting the three-dimensional spatial distribution of light intensity in the composition.

In general, light from a pulsed laser can be passed through a focusing optical train to focus the beam within the volume of the curable composition 24. By using the stage 16 or by moving the light source 12 (e.g., by moving the laser beam using a galvanometer), the focal point P can be scanned or transformed into a three-dimensional pattern corresponding to the desired shape. The cured or partially cured portion of the curable composition 24 then forms a three dimensional phase of the desired shape.

Light source 12 in system 10 may be any light source that generates multiphoton curing radiation (radiation that may initiate a multiphoton curing process). Examples of suitable light sources include titanium sapphire vibrators near 10 ^-15 seconds infrared (e.g., sold under the trade name MIRA OPTIMA 900-F from Coherent), pumped by an argon ion laser (e.g., sold under the trade name INNOVA from Coherent). Commercially available). The laser operates at 76 MHz and has a pulse width of less than 200 x 10 ^-15 seconds, capable of tuning from 700 to 980 nm and an average power of less than 1.4 watts [eg Spectra-Physics Inc. (California, USA) 94043 Mountain View Terra Bella Avenue 1335) "Mai Tai" model, wavelength λ = 800 nm, repetition frequency 80 MHz, pulse width approximately 100 fs (1 x 10 ^-13 seconds), operating at power levels below 1 watt].

In practice, however, any light source can be used that provides sufficient strength (to produce multiphoton absorption) at a suitable wavelength for the photoresist (used in the photoreactive composition). Such wavelengths may generally range from about 300 to about 1500 nm, preferably from about 600 to about 1100 nm, more preferably from about 750 to about 850 nm. Peak intensity may generally be at least about 10 ⁶ W / cm ² . The upper limit of pulse influence is generally determined by the flux threshold of the photoreactive composition. For example, a Q-switch Nd: YAG laser (e.g., sold under the tradename QUANTA-RAY PRO from Spectra-Physics), a visible light wavelength dye laser (e.g., spectra-pumped by Quanta-Ray PRO from Spectra-Physics) Commercially available under the trade name SIRAH from Physics), and Q-switch diode pumped lasers (eg, commercially available under the trade name FCBAR from Spectra-Physics) can also be used. Preferred light sources are lasers pulsed near infrared with a pulse length of less than about 10 ⁻⁸ seconds (more preferably less than about 10 ⁻⁹ seconds, most preferably less than about 10 ⁻¹¹ seconds). Other pulse lengths may be used if the peak intensity and flux threshold criteria described above are met.

Optical members 14 useful in system 10 include refractive optical members (e.g. lenses), reflective optical members (e.g. retroreflective or focal reflectors), diffractive optical members (e.g. diffraction gratings, image masks and holograms), polarized light Optical members (eg, linear polarizers and waveplates), diffusers, pockels cells, waveguides, and the like. Such optical members are useful for focusing, beam delivery, beam / mode shaping, pulse shaping and pulse timing. In general, combinations of optical members may be used, and other suitable combinations will be appreciated by those skilled in the art. It may often be desirable to use optical members with multiple effective apertures NA to provide high focus light. However, any optical member combination can be used that provides the desired intensity profile (and its spatial arrangement). For example, the exposure system can include a scanning confocal microscope (e.g., available under the tradename MRC600 from Biorad) equipped with a 0.75 NA objective (eg, sold under the tradename 20X FLUAR by ZEISS).

Exposure time is generally the type of exposure system used to induce phase formation (and additional variables such as the number of effective apertures, the shape of the light intensity spatial distribution, the peak light intensity during the laser pulse duration [larger intensity and shorter The pulse duration is largely consistent with the peak light intensity]) as well as the nature of the exposed multiphoton curable composition. In general, the higher the peak light intensity in the focal region, the shorter the exposure time and everything else is the same. Linear phase-forming or “writing” rates are about 10 ⁻⁸ to 10 ⁻¹⁵ seconds (preferably about 10 ⁻¹¹ to 10 ⁻¹⁴ seconds) and about 10 ² to 10 ⁹ pulses / second of laser pulse duration. (preferably about 10 ^{8 3-10} pulses / sec) when it can generally be from about 5-100000 microns / second using a.

Multiphoton curable radiation 26 induces a reaction of the curable composition to produce a material having a different solubility characteristic than the unexposed curable composition. The formed pattern of the cured material can then be developed by removing the exposed or unexposed areas with a suitable solvent. In this way complex and seamless three-dimensional structures can be formed.                 

The structure formed can have any suitable size and shape, but the method of the present invention is particularly suitable for adding microstructures to the microstructured surface of an article. The structure may be formed on the surface of the article, or in or on the surface of the molding. If such molding (s) are present on the surface of the article, such as a continuous or discontinuous pattern of depressions, protrusions, posts or channels, the structure may be formed within the molding (s). The shape (s) may be microscopic, where the term “microscopic” refers to a shape small enough to require an optical aid to the naked eye upon observation at any point in time to determine shape. One criterion is described in Modem Optic Engineering by W.J. Smith, McGraw-Hill, pp. 1966, 104-105, where vision is "defined, measured for each size of the minimum recognizable character". Normal visual acuity is considered when the smallest cognitive character is 5 minutes of each height on the retina. This yields 0.36 mm (0.0145 inches) of lateral dimension for the object at a typical effective length of 250 mm (10 inches). As used herein, "microstructure" refers to the shape of a molding in which at least two dimensions of the molding are microscopic.

In FIG. 2, as a preferred embodiment, the multiphoton curable material 124 can be disposed within the mold 122 at the surface 120 of the article 118. This shape may be a cavity such as a cavity, depression or groove. Multiphoton curable radiation 126 may focus at any point P in the volume of material to cure the material. If depth control is possible in multiphoton cure, the curable composition can be easily cured from the bottom 123 of the molding 124, from the center to the outside, from the sidewall 125 to the inside, or any pattern can be used for a particular application. Is optimal. For example, when a multiphoton curable material is inserted into a dental cavity, the curable material can be cured and reinforced to form a dental filler. In such dental fillers, hardening first on all surfaces and then towards the top center can provide a strong, stress free filler.

3A-3C, the curable material 224 may be cured in a specific pattern to form a check valve type flow control structure in the channel 222 of the surface 220 of the article 218. The valve 230 includes a plurality of flexible extension regions 232 extending upward from the bottom 231 of the channel 222. This region 232 is bent to allow fluid to flow in the first direction indicated by arrow F. FIG. Side support 234 supports any cover 240 (not shown in FIG. 3B). If fluid flows in the F 'direction, the stop bar 241 in the cover 240 restricts the extension region 232 from bending to limit and / or stop the flow in the F' direction.

4, a multiphoton curable composition may be applied over a reflector layer 312 mirrored by aluminum treatment on a silicon wafer 314. The multiphoton curable composition can then be cured in a striped pattern to form a series of narrowly spaced lines 316. The line of cured material divides the surface of the mirrored layer 312 into a reflective strip through which lines 316 intervene to form a diffraction grating 310. In this way, a diffraction grating can be added to a previously prepared reflector with little additional processing. Aluminum etching is not necessary and the curing process does not damage or oxidize the mirrored surface. The grating structure can be used as a vibrating MEMS reflector grating, for example in a spectrophotometer.                 

Referring to FIG. 5, a multiphoton curable composition may be applied to the channel 362 at the surface 360 of the article 358. The curable composition may be cured to form a beam 364 in the channel 362, leaving undercut regions 366 for fluid flow.

Referring to Figures 6A-6C, the method of the present invention can be used to make movable parts on molded articles. 6A-6C, multiphoton curable material may be applied to channel 422 at surface 420 of article 418. This material may be cured to form flapper flow control valve 430, which includes a central rotating bar 432 and a flap 434. Valve 430 rotates about the longitudinal axis of bar 432 while maintaining structure 436. If the fluid flow in the channel 422 proceeds in the F direction, the flap 434 allows for substantially free fluid flow. However, if flow proceeds in direction F ', stop bar 438 comes in contact with cover 440 (not shown in Figure 6B) and moves flap 434 to a position that restricts fluid flow.

Examples of other components that may be manufactured by the method of the present invention include micropumps (which may add one or more valves in a multiphoton curing process), accelerometers (which may add cantilever beams) and channel devices (channel tops). Can be added). Examples of parts that may be attached to the body of a partially completed molded article include flapper valves, membranes, springs, bridges, cantilever beams, bends, covers, and caps. Examples of parts that can be completely separated from the body of a partially finished article include balls, balls, gears, hinges, and spinners for ball valves. Therefore, it is often desirable for a part made according to the method of the invention to adhere well to the body, and it is often desirable for the part to be separated from the body.

In a preferred embodiment of the invention, the method of adding a structure can be carried out on an optical fiber to add an optical device such as a lens, prism, diffuser or diffractive member.

Multiphoton curable compositions that can be used to form such structures include curable or non-curable species and multiphoton photoinitiator systems. Multiphoton photoinitiator systems include multiphoton photosensitizers, electron acceptors, and any electron donor.

Compositions of the present invention may comprise curable species and optionally non-curable species.

Curable species include addition polymerizable monomers and oligomers and addition crosslinkable polymers (eg, free radically polymerizable or crosslinkable ethylenically unsaturated species such as certain vinyl compounds such as acrylates, methacrylates and styrenes). , Cationically polymerizable monomers and oligomers and cationic crosslinkable polymers (including epoxies, vinylethers, cyanate esters, etc.) and mixtures thereof.

Suitable ethylenically unsaturated species are described, for example, in US Pat. No. 5,545,676 and include mono-, di-, poly-acrylates and methacrylates (eg, methyl acrylate, methyl methacrylate, ethyl acrylate). , Isopropyl methacrylate, n-hexyl acrylate, stearyl acrylate, allyl acrylate, glycerol diacrylate, glycerol triacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol dimetha Acrylate, 1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, trimethylolpropane triacrylate, 1,2,4-butanetriol trimethacrylate, 1,4-cyclo Hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacryl , Sorbitol hexaacrylate, bis [1- (2-acryloxy)]-p-ethoxyphenyldimethylmethane, bis [1- (3-acryloxy-2-hydroxy)]-p-propoxyphenyldimethyl Acrylated monomers such as methane, trishydroxyethyl-isocyanurate trimethacrylate, bis-acrylates and bis-methacrylates of polyethylene glycols having molecular weights of about 200 to 500, those disclosed in US Pat. No. 4,652,274. Copolymerizable mixtures of, acrylated oligomers such as those disclosed in US Pat. No. 4,642,126); Unsaturated amides (eg methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, diethylene triamine tris-acrylamide and beta-methacrylaminoethyl methacrylate); Vinyl compounds (eg styrene, diallyl phthalate, divinyl succinate, divinyl adipate and divinyl phthalate) and the like and mixtures thereof.

Suitable reactive polymers include pendant (meth) acrylate groups, for example polymers having from 1 to about 50 (meth) acrylate groups per polymer chain. Examples of such polymers include aromatic acid (meth) acrylate 1/2 ester resins such as Sarbox ^™ resins (eg, Sarbox ^™ 400, 401, 402, 404 and 405) commercially available from Sartomer. Other useful reactive polymers that can be cured by free radical chemistry include polymers having a hydrocarbyl backbone and pendant peptide groups having free radical polymerization functionality bound thereto, such as in US Pat. No. 5,235,015 It is described. If desired, mixtures of two or more monomers, oligomers and / or reactive polymers may be used. Preferred ethylenically unsaturated species include acrylates, aromatic acid (meth) acrylate 1/2 ester resins, and polymers having pendant peptide groups with free radical polymerization functionality bound to the hydrocarbyl backbone.

Suitable cationic reactive species are described, for example, in US Pat. Nos. 5,998,495 and 6,025,406 and include epoxy resins. Such materials are broadly called epoxides, which include monomeric epoxy compounds and epoxides in polymer form and may be aliphatic, cycloaliphatic, aromatic or heterocycles. These materials usually have an average of at least one polymerizable epoxy group per molecule (preferably at least about 1.5, more preferably at least about 2). Polymer epoxides are linear polymers with terminal epoxy groups (e.g. diglycidyl ethers of polyoxyalkylene glycols), polymers with oxirane monomer backbones (e.g. polybutadiene polyepoxides) and polymers with pendant epoxy groups (e.g. Glycidyl methacrylate polymer or copolymer). The epoxide may be a pure compound or a mixture of compounds containing one, two or more epoxy groups per molecule. These epoxy containing materials can vary widely depending on the nature of their backbones and substituents. For example, the backbone may be in any form and the substituents thereon may be any group that does not substantially interfere with cationic cure at room temperature. Examples of acceptable substituents include halogens, ester groups, ether groups, sulfonate groups, siloxane groups, nitro groups, phosphate groups and the like. The molecular weight of the epoxy containing material may vary from about 58 to about 100,000 or more.

Useful epoxy containing materials include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-2-methylcyclohexylmethyl-3,4-epoxy-2-methylcyclohexanecarbox And those containing cyclohexene oxide groups such as epoxycyclohexanecarboxylates exemplified by bixyl and bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate. A more detailed list of useful epoxides of this nature is described in US Pat. No. 3,117,099.

Other epoxy containing materials useful include glycidyl ether monomers of the formula:

Wherein R 'is alkyl or aryl and n is an integer from 1 to 6. Examples are polyhydric phenols obtained by reacting polyhydric phenols with chlorohydrins such as excess epichlorohydrin (e.g., diglycidyl ether of 2,2-bis- (2,3-epoxypropoxyphenol) -propane). The glycidyl ether of the is mentioned. Additional examples of epoxides of this type are described in US Pat. No. 3,018,262 and Handbook of Epoxy Resins, Lee and Neville, McGraw-Hill Book Co., New York (1967).

Various commercially available epoxy resins may be used. Specifically, readily available epoxides are octadecylene oxide, epichlorohydrin, styrene oxide, vinyl cyclohexene oxide, glycidol, glycidyl methacrylate, diglycidyl ether of bisphenol A. (e. g., the body is a shell Chemical Company, resolution performance Products ^{Epon TM 828, Epon TM 825,} Epon TM 1004, Epon TM 1010 DER TM -331, DER TM -332 and -334 of the DER ^TM, as well as the Dow Chemical Company) , Vinylcyclohexene dioxide (e.g., ERL ^TM- 4206 from Union Carbide Corporation), 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexene carboxylate (e.g. ERL ^TM -4221 from Union Carbide Corporation, or Cyracure ^™ UVR 6110 or UVR 6105), 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methyl-cyclohexene carboxylate (e.g., ERL ^™ -4201 from Union Carbide Corporation), Bis (3,4-epoxy-6-methylcyclohexylmethyl) adi Pate (e.g. ERL ^TM -4289 from Union Carbide Corporation), Bis (2,3-epoxycyclopentyl) ether (e.g. ERL ^TM -0400 from Union Carbide Corporation), Aliphatic epoxy modified from polypropylene glycol (e.g. Union ERL ^TM -4050 and ERL ^TM -4052 from carbide corporations, dipentene dioxide (e.g. ERL ^TM -4269 from Union Carbide Corporation), epoxidized polybutadiene (e.g. Oxiron ^TM 2001 from FMC Corporation), epoxy functional groups Silicone resins having, flame resistant epoxy resins (e.g. brominated bisphenol type epoxy resins available from Dow Chemical Company, DER ^TM -580), 1,4-butanediol diglycidyl ethers of phenolformaldehyde novolacs (e.g. Dow Chemical DEN DEN ^TM -431 and -438 ^TM), available from CO, resorcinol diglycidyl ether (e.g., Kopoxite corpus ^TM) of Company, Inc., bis (3,4-epoxycyclohexyl) adipate ( , ERL ^{TM TM} -6128 -4299 or UVR of Union Carbide Corp.), 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) cyclohexane-meta-dioxane (for example, Union Carbide Corporation's ERL ^TM- 4234), Vinylcyclohexene Monooxide 1,2-Epoxyhexadecane (e.g. UVR ^TM -6216 from Union Carbide Corporation), Alkyl C ₈ -C ₁₀ Glycidyl Ether (e.g., Resolution Performance Products) Heloxy ^TM Modifier 7), alkyl C ₁₂ -C ₁₄ glycidyl ether (e.g. Heloxy ^TM Modifier 8 from Resolution Performance Products), butyl glycidyl ether (e.g. Heloxy ^TM Modifier 61 from Resolution Performance Products), cresyl Alkyl glycidyl ethers such as glycidyl ether (e.g. Heloxy ^TM Modifier 62 from Resolution Performance Products), p-tert-butylphenyl glycidyl ether (e.g. Heloxy ^TM Modifier 65 from Resolution Performance Products), 1,4 Diglycidyl ethers of butanediol (e.g. rezolu) Multi-functional, such as Heloxy ^TM Modifier 67) of Performance Products diglycidyl ether, neopentyl glycol diglycidyl ether (for example, re sol-Pollution Heloxy ^TM Modifier 68) of Performance Products, cyclohexane dimethanol diglycidyl Ethers (e.g. Heloxy ^TM Modifier 107 from Resolution Performance Products), trimethylol ethane triglycidyl ether (e.g. Heloxy ^TM Modifier 44 from Resolution Performance Products), trimethylol propane triglycidyl ether (e.g. Heloxy ^{TM from} Resolution Performance Products) Modifier 48), polyglycidyl ethers of aliphatic polyols (e.g. Heloxy ^TM Modifier 84 from Resolution Performance Products), polyglycol diepoxides (e.g. Heloxy ^TM Modifier 32 from Resolution Performance Products), bisphenol F epoxides (e.g. GY-281 or Epon ^™ -1138 from Ciba-Geigy Corporation) and 9,9-bis [4- (2,3-epoxypropoxy) -phenyl] fluorenone (eg, Resolution Performance Products Epon ^™ 1079).

Other useful epoxy resins include copolymers of acrylic acid esters of glycidol (eg, glycidyl acrylate and glycidyl methacrylate) with one or more copolymerizable vinyl compounds. Examples of such copolymers include 1: 1 styrene-glycidyl methacrylate, 1: 1 methyl methacrylate-glycidyl acrylate and 62.5: 24: 13.5 methyl methacrylate-ethyl acrylate-glycidyl methacrylate. There is acrylate. Other useful epoxy resins are well known and include epichlorohydrin, alkylene oxides (eg propylene oxide), styrene oxide, alkenyl oxides (eg butadiene oxide) and glycidyl esters (eg Epoxides such as ethyl glycidate).                 

Useful epoxy functional polymers include epoxy functional silicones such as those described in US Pat. No. 4,279,717, which can be purchased from General Electric Company. These are polydimethylsiloxanes in which 1 to 20 mol% of silicon atoms are substituted with epoxyalkyl groups (preferably epoxy cyclohexylethyl as described in US Pat. No. 5,753,346).

Blends of various epoxy containing materials can also be used. Such blends include two or more weight average molecular weight distributions of the epoxy containing compound (eg, low molecular weight (200 or less), medium molecular weight (about 200-10,000) and high molecular weight (about 10,000 or more)). Alternatively or additionally, the epoxy resin may comprise a blend of epoxy containing materials having different chemical properties (eg, aliphatic and aromatic), functional (eg, polar and nonpolar). If desired, other cationic reactive polymers (eg, vinyl ethers, etc.) may additionally be incorporated.

Preferred epoxies include aromatic glycidyl epoxies (eg, Epon ^™ resin from Resolution Performance Products) and cycloaliphatic epoxies (eg ERL-4221 and ERL-4299 from Union Carbide Corporation).

Suitable cationic reactive species also include vinyl ether monomers, oligomers and reactive polymers (e.g. methyl vinyl ether, ethyl vinyl ether, tert-butyl vinyl ether, isobutyl vinyl ether, triethylene glycol divinyl ether (e.g. Rapi-Cure ^™ DVE-3, available from International Specialty Products, Wayne, NJ), trimethylolpropane trivinyl ether (e.g., TMPTVE ^™ , available from BASF Corporation, Mount Olive, NJ), Vectomer ^TM divinyl ether resin from Allied Signals Eg, Vectomer ^™ 2010, Vectomer ^™ 2020, Vectomer ^™ 4010 and Vectomer ^™ 4020 and their equivalents available from other manufacturers) and mixtures thereof .. One or more vinyl ether resins and / or one or more epoxy resins Blends (random ratios) may also be used .. Polyhydroxy functional materials (eg, US Pat. No. 5,856,373 ( And those described in Kaisaki et al.) May also be used in combination with epoxy- and / or vinyl ether-functional materials.

Non-curable species include reactive polymers, for example, in which solubility can be increased during acid- or radical-induced reactions. Such reactive polymers include, for example, ester group-containing water-insoluble polymers (eg, poly (4-tert-butoxycarbonyloxystyrene)) which can be converted to water-soluble acid groups by acids generated by light. Non-curable species also include chemically amplified photoresists (RD Allen, GM Wallraff, WD Hinsberg and LL Simpson, "High Performance Acrylic Polymers for Chemically Amplified Photoresist Applications", J. Vac. Sci. Technol. B. 9, 3357 (Described in 1991). The chemically amplified photoresist concept is now widely used in microchip fabrication, particularly in wiring widths of 0.5 microns or less (or 0.2 microns or less). In such a photoresist system, catalytic species (usually hydrogen ions) are generated by irradiation, which can induce a cascade of chemical reactions. When this cascade occurs, the reaction rate is increased by initiating a reaction in which hydrogen ions produce more hydrogen ions or other acidic species. Representative examples of photoresist systems chemically amplified by an acid catalyst include deprotection (e.g. t-butoxycarbonyloxystyrene resist described in US Pat. No. 4,491,628, tetrahydropyrans described in US Pat. No. 3,779,778) THP) methacrylate-based materials, THP-phenolic materials such as t-butyl methacrylate-based materials such as those described in RD Allen et al., Proc. SPIE 2438, 474 (1995); Depolymerization (eg, polyphthalaldehyde based materials); And rearrangements (eg, materials based on pinacol rearrangements).

Multiphoton Photoinitiator System

(1) multiphoton photosensitizer

Multiphoton photosensitizers suitable for use in multiphoton curable compositions are those that can simultaneously absorb two or more photons when exposed to radiation from a suitable light source in an exposure system. Preferred multiphoton photosensitizers have a two photon absorption cross section greater than fluorescein (ie, 3 ', 6'-dihydroxyspiro [isobenzofuran-1 (3H), 9'-[9H] xanthene] 3-one Greater than). Typically, two-photon absorption cross sections are described in C. Xu and WW Webb [J. Opt. Soc. Am. B, 13, 481 (1996) and WO 98/21521, which may be at least about 50 × 10 ⁻⁵⁰ cm ⁴ seconds / photon as measured.

This method involves comparing the two-photon fluorescence intensity of the photosensitizer with the reference compound (under the same excitation intensity and photosensitizer concentration conditions). The reference compound may be chosen to match as closely as possible the spectral range covered by photosensitizer absorption and fluorescence. In one possible experimental setting, the excitation beam can be divided into two arms such that 50% of the excitation intensity goes to the photosensitizer and 50% to the reference compound. The relative fluorescence intensity of the photosensitizer relative to the reference compound can then be measured using two photomultipliers or other aperture detectors. Finally, the fluorescence quantum efficiency of both compounds can be measured under one photon excitation.

Methods of measuring fluorescence and phosphorescent quantum yields are known in the art. Usually, the area under the fluorescence (or phosphorescence) spectrum of the target compound is compared with the area under the fluorescence (or phosphorescence) spectrum of the standard luminescent compound having a known fluorescence (or phosphorescence) quantum yield and appropriate correction is made (e.g., here Taking into account the absorbance of the composition at wavelength, the structure of the fluorescence detection device, the difference in emission wavelength and the response of the detector to different wavelengths). Standard methods are for example I.B. Berlman, Handbook of Fluorescence Spectra of Aromatic Molecules, 2nd Edition, p. 24-27, Academic Press, New York (1971); J.N. Demas and G.A. Crosby, J. Phys. Chem. 75, 991-1024 (1971); J.V. Morris, M.A. Mahoney and J.R. Huber, J. Phys. Chem. 80, 969-974 (1976).

Assuming that the emission states are the same under one- and two-photon excitation (normal assumption), the two-photon absorption cross-sectional area (δ _sam ) of the photosensitive agent is δ _ref K (I _sam / I _ref ) (φ _sam / φ _ref ), Where δ _ref is the two-photon absorption cross-section of the reference compound, I _sam is the fluorescence intensity of the photosensitizer, I _ref is the fluorescence intensity of the reference compound, φ _sam is the fluorescence quantum efficiency of the photosensitizer, and φ _ref is the fluorescence quantum of the reference compound Efficiency, K is a correction factor that accounts for the slight difference in the light path and the response of the two detectors. K can be determined by measuring the response to the same photosensitizer in both the sample and the reference arm. To confirm that it is an effective measurement, one can confirm the apparent second order functional dependence of the two-photon fluorescence intensity on the excitation force (to avoid fluorescence reabsorption and sensitizer aggregation effects), and relatively low concentrations of sensitizers and reference compounds can be used. have.

If the photosensitizer is not fluorescent, the yield of the electron excited state can be measured and compared with known standards. In addition to the above-described methods for measuring fluorescence yield, various methods for measuring excited state yield are known (eg, transient absorption, phosphorescence yield, photoproduct formation (from photoreaction), or extinction of a photosensitizer).

Preferably, the two-photon absorption cross-sectional area of the photosensitizer is at least about 1.5 times greater than fluorescein (or alternatively at least about 75 x 10 ^-50 cm ⁴ seconds / photons as measured by the methods described above), More preferably, at least two times (or alternatively about 100 x 10 ^-50 cm ⁴ seconds / photon or more), and at least about three times (or alternatively about 150 x 10 ^-50 cm ⁴ ) of fluorescein Most preferably at least about 4 times per photon, or at least about 4 times (or alternatively about 200 × 10 ⁻⁵⁰ cm ⁴ seconds per photon) of fluorescein.

The photosensitizer is preferably soluble in the reactive species (if the reactive species is a liquid) or compatible with the reactive species and other binders included in the compositions (described below). Most preferably, when the photosensitizer is continuously irradiated in a wavelength range overlapping with the photon absorption spectrum of the photosensitive agent using the test method described in US Pat. No. 3,729,313 (monophoton absorption conditions), 2-methyl-4,6-bis (Trichloromethyl) -s-triazine can be exposed. Using currently commercially available materials, the test can be conducted as follows.

Standard test solutions can be prepared with the following composition: 5% (w / v) solution in methanol of hydroxyl content polyvinyl butyral (e.g., Butvar ^™ B76, Monsanto) of molecular weight 45,000-55,000, 9.0-13.0% 5.0 parts; 0.3 parts trimethylolpropane trimethacrylate and 2-methyl-4,6-bis (trichloromethyl) -s-triazine (see Bull. Chem. Soc. Japan, 42, 2924-2930 (1969)) 0.03 parts . To this solution can be added 0.01 part of the compound to be tested as a photosensitizer. The resulting solution is then knife coated using a 0.05 mm knife orifice on a 0.05 mm transparent polyester film, and the coating can be air dried for about 30 minutes. The 0.05 mm of transparent polyester cover film can be carefully placed on the dried but soft, sticky coating so that the amount of air trapping is minimal. The resulting sandwich structure can then be exposed for 3 minutes to 161,000 lux incident light (eg, light generated from an FCH ^™ 650 watt quartz-iodine lamp, General Electric) from a tungsten light source providing light in the visible and ultraviolet ranges. Exposure may be effected through a stencil such that exposed and unexposed areas are provided within the structure. The cover film may be removed after exposure, and the coating may be treated with finely divided colored powder (eg, color toner powder of the type commonly used in dry printing). If the compound tested is a photosensitizer, the trimethylolpropane trimethacrylate monomer is a region exposed to light by free radicals produced by light from 2-methyl-4,6-bis (trichloromethyl) -s-triazine. Will be polymerized at Since the polymerized regions will be virtually tacky, the colored powders are almost selectively attached only to the unexposed tacky regions of the coating and provide a corresponding visual phase in the stencil.

Preferably the photosensitizer may be selected in part in view of storage stability. Thus, the choice of particular photosensitizer may vary to some extent depending on the particular reactive species used (as well as the choice of electron donor compound and / or electron acceptor compound).

Particularly preferred multiphoton photosensitizers are those having a large multiphoton absorption cross-sectional area, for example rhodamine B (ie N- [9- (2-carboxyphenyl) -6- (diethylamino) -3H-xanthene-3- Iridene] -N-ethylethanealuminum chloride or hexafluoroantimonate) and four photosensitizers described in, for example, International Patent Publications WO 98/21521 and WO 99/53242, such as Marder and Perry. The four types can be described as follows: (a) two donors are linked to conjugated π-electron bridges, and (b) two donors are linked to conjugated π-electron bridges substituted with one or more electron acceptors. Molecule, (c) a molecule in which two receptors are linked to a conjugated π-electron bridge, and (d) a molecule in which two receptors are linked to a conjugated π-electron bridge substituted with one or more electron donors, wherein "legs" are 2 By molecular fragments connecting more than one chemical group, "donor" means an atom or group of atoms with a low ionization potential that can be bound to a conjugated π-electron bridge, and a "receptor" to a conjugated π-electron bridge Means an atom or group of atoms with a high electron affinity).

Representative examples of such preferred photosensitizers include:

The four types of photosensitizers described above can be prepared by reacting aldehydes and illi under standard Wittig conditions, or using the McMurray reaction (see International Patent Publication WO 98/21521).

US Pat. Nos. 6,100,405, 5,859,251 and 5,770,737 disclose other compounds with large multiphoton absorption cross sections, but the cross-sectional areas of these compounds were measured by methods other than those described above. Representative examples of such compounds include the following:

(2) electron acceptor

Suitable electron acceptor compounds for the multiphoton curable composition are those which can accept and photo electrons from the electron excited state of the multiphoton photosensitizer to form one or more free radicals and / or acids. Such electron acceptor compounds include iodonium salts (eg, diaryliodonium salts), chloromethylated triazines (eg, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2,4, 6-tris (trichloromethyl) -s-triazine and 2-aryl-4,6-bis (trichloromethyl) -s-triazine), diazonium salts (e.g. alkyl, alkoxy, halo or nitro, etc.) Phenyldiazonium salts optionally substituted with groups, sulfonium salts (e.g. triarylsulfonium salts optionally substituted with alkyl or alkoxy groups and optionally having a 2,2'oxy group crosslinking near the aryl moiety), azinium salts (e.g., N-alkoxy Pyridinium salts) and triarylimidazolyl dimers (preferably 2,4,5-triphenylimidazolyl dimers, such as 2,2 ', 4,4', 5,5'-tetraphenyl-1) , 1'-biimidazole, which may optionally be substituted with a group such as alkyl, alkoxy or halo) and the like, and mixtures thereof.

The electron acceptor is preferably soluble in the reactive species and is preferably storage stable (ie, does not spontaneously promote the reaction of the reactive species when dissolved in the presence of a photosensitizer and an electron donor compound). Thus, the choice of a particular electron acceptor may vary to some extent depending upon the particular reactive species, photosensitizer and electron donor compound selected as described above.

Suitable iodonium salts include those disclosed in US Pat. Nos. 5,545,676, 3,729,313, 3,741,769, 3,808,006, 4,250,053 and 4,394,403. Iodonium salt is a simple salt (for ^{example, Cl -, Br -, I} - or C ₄ H ₅ SO ₃ ^- salt containing the same anion as) or a metal complex salt (for _{^{example, SbF 6 -, PF 6 -}} , BF 4 - It may be a salt containing a) ^-, tetrakis (perfluoro phenyl) borate, SbF ₅ OH ^- or AsF _6. If necessary, a mixture of iodonium salts can be used.

Examples of useful aromatic iodonium complex salt electron acceptor compounds include diphenyliodonium tetrafluoroborate; Di (4-methylphenyl) iodonium tetrafluoroborate; Phenyl-4-methylphenyliodonium tetrafluoroborate; Di (4-heptylphenyl) iodonium tetrafluoroborate; Di (3-nitrophenyl) iodonium hexafluorophosphate; Di (4-chlorophenyl) iodonium hexafluorophosphate; Di (naphthyl) iodonium tetrafluoroborate; Di (4-trifluoromethylphenyl) iodonium tetrafluoroborate; Diphenyliodonium hexafluorophosphate; Di (4-methylphenyl) iodonium hexafluorophosphate; Diphenyliodonium hexafluoroarsenate; Di (4-phenoxyphenyl) iodonium tetrafluoroborate; Phenyl-2-thienyliodonium hexafluorophosphate; 3,5-dimethylpyrazolyl-4-phenyliodonium hexafluorophosphate; Diphenyliodonium hexafluoroantimonate; 2,2'-diphenyliodonium tetrafluoroborate; Di (2,4-dichlorophenyl) iodonium hexafluorophosphate; Di (4-bromophenyl) iodonium hexafluorophosphate; Di (4-methoxyphenyl) iodonium hexafluorophosphate; Di (3-carboxyphenyl) iodonium hexafluorophosphate; Di (3-methoxycarbonylphenyl) iodonium hexafluorophosphate; Di (3-methoxysulfonylphenyl) iodonium hexafluorophosphate; Di (4-acetamidophenyl) iodonium hexafluorophosphate; Di (2-benzothienyl) iodonium hexafluorophosphate; And diphenyl iodonium hexafluoroantimonate; and mixtures thereof. Aromatic iodonium complex salts are described in Beringer et al. Am. Chem. Soc. 81, 342 (1959)] can be prepared by metathesis of the corresponding aromatic iodonium simple salt (e.g. diphenyliodonium bisulfate, etc.).

Preferred iodonium salts include diphenyl iodonium salts (e.g. diphenyl iodonium chloride, diphenyl iodonium hexafluorophosphate and diphenyl iodonium tetrafluoroborate), diaryl iodonium hexafluoro Antimonates (eg, SARCAT ^™ SR 1012 available from Sartomer Company) and mixtures thereof.

Anions X ⁻ suitable for sulfonium salts (and any other type of electron acceptor compound) include various anion types such as imides, metades, boron centers, phosphorus centers, antimony centers, arsenic centers and aluminum center anions.

Non-limiting examples of suitable imide and metaide anions include the following.

Preferred anions of this type has the formula _{(R f SO 2) 3 C} - include compounds represented by [R _f is a perfluoroalkyl alkyl radical of 1 to about 4 carbon atoms being.

Non-limiting examples of suitable boron central anions include the following.

Preferred boron central anions generally comprise aromatic hydrocarbon radicals substituted with at least three halogens bonded to boron, with fluorine being the most preferred halogen. Non-limiting examples of the preferred anions include (3,5-bis _{(CF 3) C 6 H 3} ) 4 B -, (C 6 F 5) 4 B -, (C 6 F 5) 3 (nC 4 H 9) ^{_{B -, (C 6 F 5}} ) 3 FB - and the like ^- and _{(C 6 F 5) 3 (} CH 3) B.

Examples of suitable anions include other metal or metalloid center are (3,5-bis _{(CF 3) C 6 H 3} ) 4 Al -, (C 6 F 5) 4 Al -, (C 6 F 5) ^{_{2 F 4 P -, (C}} 6 F 5) F 5 P -, F 6 P -, (C 6 F 5) F 5 Sb -, F 6 Sb -, (HO) F 5 SB - , and F ₆ As ^- Etc. Anion X ⁻ is used with tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate and hydroxypentafluoroantimonate (e.g. cationic reactive species such as epoxy resins) Is selected).

Examples of suitable sulfonium salt electron acceptors include

Triphenylsulfonium tetrafluoroborate,

Methyldiphenylsulfonium tetrafluoroborate,

Dimethylphenylsulfonium hexafluorophosphate,

Triphenylsulfonium hexafluorophosphate,

Triphenylsulfonium hexafluoroantimonate,

Diphenylnaphthylsulfonium hexafluoroarsenate,

Tritolylsulfonium hexafluorophosphate,

Anylsildiphenylsulfonium hexafluoroantimonate,

4-butoxyphenyldiphenylsulfonium tetrafluoroborate,

4-chlorophenyldiphenylsulfonium hexafluorophosphate,

Tri (4-phenoxyphenyl) sulfonium hexafluorophosphate,

Di (4-ethoxyphenyl) methylsulfonium hexafluoroarsenate,

4-acetonylphenyldiphenylsulfonium tetrafluoroborate,

4-thiomethoxyphenyldiphenylsulfonium hexafluorophosphate,                 

Di (methoxysulfonylphenyl) methylsulfonium hexafluoroantimonate,

Di (nitrophenyl) phenylsulfonium hexafluoroantimonate,

Di (carbomethoxyphenyl) methylsulfonium hexafluorophosphate,

4-acetamidophenyldiphenylsulfonium tetrafluoroborate,

Dimethylnaphthylsulfonium hexafluorophosphate,

Trifluoromethyldiphenylsulfonium tetrafluoroborate,

p- (phenylthiophenyl) diphenylsulfonium hexafluoroantimonate,

10-methylphenoxane hexafluorophosphate,

5-methylthianthrenium hexafluorophosphate,

10-phenyl-9,9-dimethylthioxanthium hexafluorophosphate,

10-phenyl-9-oxothioxanthium tetrafluoroborate,

5-methyl-10-oxotianthrenium tetrafluoroborate,

5-methyl-10,10-dioxothioanthrenium hexafluorophosphate is mentioned.

Preferred sulfonium salts include triaryl substituted salts such as triarylsulfonium hexafluoroantimonate (e.g. SARCAT ^TM SR1010 available from Sartomer Company), triarylsulfonium hexafluorophosphate (e.g. Satomer Company). Commercially available SARCAT ^TM SR1011), and triarylsulfonium hexafluorophosphate (e.g., SARCAT ^™ KI85 available from Sartomer Company).

Useful azinium salts include those described in US Pat. No. 4,859,572, which includes azinium moieties such as pyridinium, diazinium, or triazinium moieties. The azinium moiety may comprise one or more aromatic rings, typically carbocyclic aromatic rings (eg, quinolinium, isoquinolinium, benzodiazinium and naphthodiazonium moieties) fused with an azinium ring. The quaternized substituents of nitrogen atoms in the azinium ring can be dissociated as free radicals when electrons are transferred from the electron excited state of the photosensitizer to the azinium electron acceptor compound. In a preferable embodiment, the quaternized substituent is an oxy substituent. The oxy substituent -OT which quaternizes the ring nitrogen atom of an azinium part can be selected from the various oxy substituents which are easy to synthesize | combine. The T moiety can be, for example, an alkyl radical such as methyl, ethyl, butyl and the like. Alkyl radicals may be substituted. Aralkyl (eg benzyl and phenethyl) and sulfoalkyl (eg sulfomethyl) radicals may be useful. In another form T may be an acyl radical, such as an —OC (O) —T ¹ radical, where T ¹ may be any of the various alkyl and aralkyl radicals described above. In addition, T ¹ may be an aryl radical such as phenyl or naphthyl. Aryl radicals may also be substituted. For example T ¹ may be a tolyl or xylyl radical. T generally contains 1 to 18 carbon atoms, preferably in each case the alkyl moiety is a lower alkyl moiety, and in each case the aryl moiety preferably contains about 6 to about 10 carbon atoms. The highest activity was realized when the oxy substituent -OT- contained one or two carbon atoms. The azinium nucleus need not contain substituents other than quaternized substituents. However, the presence of other substituents does not adversely affect the activity of these electron acceptor compounds.

Useful triarylimidazolyl dimers include those described in US Pat. No. 4,963,471. Examples of such dimers include 2- (o-chlorophenyl) -4,5-bis (m-methoxyphenyl) -1,1'-biimidazole; 2,2'-bis (o-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,1'-biimidazole; And 2,5-bis (o-chlorophenyl) -4- [3,4-dimethoxyphenyl] -1,1'-biimidazole.

Preferred electron acceptors include photoacid generators such as iodonium salts (more preferably aryliodonium salts), chloromethylated triazines, sulfonium salts and diazonium salts. More preferred are aryliodonium salts and chloromethylated triazines.

(3) electron donor compound

Electron donor compounds useful in multiphoton photoresist systems of multiphoton curable compositions are compounds (except the photoresist itself) that can donate electrons to the electron excited state of the photosensitizer. The electron donor compound preferably has an oxidation potential of zero or more and is equal to or smaller than the oxidation potential of p-dimethoxybenzene. It is preferable that the oxidation potential is about 0.3 to 1 volt with respect to the standard saturated magenta electrode ("S.C.E").

The electron donor compound is also preferably soluble in the reactive species and is selected in part in view of storage stability (as described above). Suitable donors generally can increase the phase density or cure rate of the photoreactive composition upon exposure to light of the desired wavelength.

Those skilled in the art will appreciate that when using cationic reactive species, the electron donor compound (if significantly basic) can adversely affect the cationic reaction (see, for example, discussion of US Pat. No. 6,025,406).

In general, electron donor compounds suitable for use with certain photosensitizers and electron donor compounds can be selected by comparing the oxidation and reduction potentials of the three components (see, eg, US Pat. No. 4,859,572). This potential can be measured experimentally [eg, in R.J. Cox, Photographic Sensitivity, Chapter 15, by the method described in Academic Press (1973), or by N.L Weinburg, Technique of Electroorganic Synthesis Part II Techniques of Chemistry, Vol. V (1975) and C.K. Mann and K.K. Barnes et al., Electrochemical Reactions in Nonaqueous Systems (1970). The potentials represent relative energy relationships and can be used in the following manner to assist in the electron donor compound selection.

When the photosensitizer is in an electron excited state, the highest occupied molecular orbital (HOMO) of the photosensitizer is raised to a higher energy level (i.e., the lowest unoccupied molecular orbital (LUBO) of the photosensitizer), and the vacancy is occupied by the first occupied molecular orbital. Left. The electron acceptor compound can accept electrons from higher energy orbitals and the electron donor compound can donate electrons to fill the voids of the initially occupied orbitals if certain relative energy relationships are satisfied.

If the reduction potential of the electron acceptor compound is less negative (or a larger positive value) than the reduction potential of the photosensitizer, electrons in the higher energy orbital of the photosensitizer are easily transferred from the photosensitizer to the lowest unoccupied molecular orbital (LUMO) of the electron acceptor compound. This is because it represents an exothermic process. Although this process is rather endothermic (ie, the reduction potential of the photosensitizer is a negative value up to 0.1 volts higher than the reduction potential of the electron acceptor compound) ambient thermal activation can easily overcome this small barrier.

In a similar manner, electrons that move from the HOMO of the electron donor compound to the orbital vacancies of the photoconductor when the oxidation potential of the electron donor compound is less positive (or greater negative) than the oxidation potential of the photosensitizer It moves to a low potential, which also represents an exothermic process. Even if this process is a weak endothermic reaction (ie, the oxidation potential of the photosensitizer is a positive value up to 0.1 volts greater than the oxidation potential of the electron donor compound), ambient thermal activation can easily overcome this small barrier.

Weak endothermic reactions where the reduction potential of the photosensitizer is a negative value that is up to 0.1 volts greater than the reduction potential of the electron acceptor compound, or where the oxidation potential of the photosensitizer is a positive value that is up to 0.1 volts greater than the oxidation potential of the electron donor compound. Or in all cases regardless of whether the electron donor compound first reacts with the photosensitizer in an excited state. When the electron acceptor compound or electron donor compound reacts with the photosensitizer in an excited state, the reaction is preferably exothermic or only a weak endothermic reaction. If the electron acceptor compound or electron donor compound reacts with the photosensitizer ion radical, an exothermic reaction is still preferred, but in many cases more endothermic reactions can be expected to occur. Thus, the reduction potential of the photosensitizer may be a negative value up to 0.2 volts (or more) than the reduction potential of the second-to-react electron acceptor compound, or the oxidation potential of the photosensitizer is second- It can be a positive value up to 0.2 volts (or more) than the oxidation potential of the two-react electron donor compound.

Examples of suitable electron donor compounds are described in DF Eaton, Advances in Photochemistry, B. Voman et al., Volume 13, pp. 427-488, John Wiley and Sons, New York (1986); US Patent No. 6,025,406; And those described in US Pat. No. 5,545,676. Such electron donor compounds include amines such as triethanolamine, hydrazine, 1,4-diazabicyclo [2.2.2] octane, triphenylamine [and triphenylphosphine and triphenylarcin analogs thereof], aminoaldehydes and amino Silanes), amides (e.g. phosphoamides), ethers (e.g. thioethers), urea (e.g. thioureas), sulfinic acid and salts thereof, salts of ferrocyanide, ascorbic acid and salts thereof, dithiocarbamic acid And salts thereof, salts of xanthic acid, salts of ethylene diamine tetraacetic acid, salts of (alkyl) _n (aryl) _m borate (n + m = 4), preferably tetraalkylammonium salts, various organometallic compounds such as SnR ₄ compound, wherein each R is independently selected from alkyl, aralkyl (especially benzyl), aryl and alkaryl groups (e.g. nC ₃ H ₇ Sn (CH ₃ ) ₃ , (allyl) Sn (CH ₃ ) ₃ And (benzyl) Sn (compounds such as nC ₃ H ₇ ) ₃ ), ferrocene and the like and mixtures thereof. The electron donor compound may be unsubstituted or substituted with one or more noninterfering substituents. Particularly preferred electron donor compounds include electron donor atoms (eg, nitrogen, oxygen, phosphorus or sulfur atoms) and removable hydrogen atoms bonded to carbon or silicon atoms at the alpha position of the electron donor atom.

Preferred amine electron donor compounds include alkyl-, aryl-, alkaryl- and aralkyl-amines (e.g. methylamine, ethylamine, propylamine, butylamine, triethanolamine, amylamine, hexylamine, 2,4-dimethylaniline , 2,3-dimethylaniline, o-, m- and p-toluidine, benzylamine, aminopyridine, N, N'-dimethylethylenediamine, N, N'-diethylethylenediamine, N, N'-dibenzyl Ethylenediamine, N, N'-diethyl-1,3-propanediamine, N, N'-diethyl-2-butene-1,4-diamine, N, N'-dimethyl-1,6-hexanediamine, Piperazine, 4,4'-trimethylenedipiperidine, 4,4'-ethylenedipiperidine, pN, N-dimethyl-aminophenethanol and pN-dimethylaminobenzonitrile); Aminoaldehydes (eg, p-N, N-dimethylaminobenzaldehyde, p-N, N-diethylaminobenzaldehyde, 9-julolidine carboxaldehyde and 4-morpholinobenzaldehyde); And aminosilanes (eg trimethylsilylmorpholine, trimethylsilylpiperidine, bis (dimethylamino) diphenylsilane, tris (dimethylamino) methylsilane, N, N-diethylaminotrimethylsilane, tris (dimethylamino) phenyl Silane, tris (methylsilyl) amine, tris (dimethylsilyl) amine, bis (dimethylsilyl) amine, N, N-bis (dimethylsilyl) aniline, N-phenyl-N-dimethylsilylaniline and N, N-dimethyl- N-dimethylsilylamine); And mixtures thereof. Tertiary aromatic alkylamines, especially compounds with one or more electron-withdrawing groups on aromatic rings, have been found to provide particularly good storage stability. Excellent storage stability was also obtained using amines that were solid at room temperature. The use of amines containing one or more zoloridinyl moieties resulted in good photography speeds.

Preferred amide electron donor compounds include N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-N-phenylacetamide, hexamethylphosphoamide, hexaethylphosphoamide, hexapropylphospho Amide, trimorpholinophosphine oxide, tripiperidinophosphine oxide and mixtures thereof.                 

Preferred alkylarylborate salts are

Where Ar is phenyl, naphthyl, substituted (preferably fluorine substituted) phenyl, substituted naphthyl, and a group having a greater number of fused aromatic rings), as well as tetramethylammonium n-butyltri Phenylborate and tetrabutylammonium n-hexyl-tris (3-fluorophenyl) borate (commercially available as CGI 437 and CGI 746 from Ciba Specialty Chemicals Corporation) and mixtures thereof.

Suitable ether electron donor compounds include 4,4'-dimethoxybiphenyl, 1,2,4-trimethoxybenzene, 1,2,4,5-tetramethoxybenzene and mixtures thereof. Suitable urea electron donor compounds include N, N'-dimethylurea, N, N-dimethylurea, N, N'-diphenyl urea, tetramethylthiourea, tetraethylthiourea, tetra-n-butylthiourea, N , N-di-n-butylthiourea, N, N'-di-n-butylthiourea, N, N-diphenylthiourea, N, N'-diphenyl-N, N'-diethylthiourea And mixtures thereof.

Preferred electron donor compounds for free radical induction reactions include amines, alkylarylborate salts and salts of aromatic sulfinic acids comprising one or more zoloridinyl moieties. However, the electron donor compound may be excluded for this reaction as needed (eg to improve the storage stability of the photoreactive composition or to change the resolution, contrast and interrelationship). Preferred electron donor compounds for the acid induction reaction are 4-dimethylaminobenzoic acid, ethyl 4-dimethylaminobenzoate, 3-dimethylaminobenzoic acid, 4-dimethylaminobenzoin, 4-dimethylaminobenzaldehyde, 4-dimethylaminobenzonitrile, 4-dimethylaminophenethyl alcohol and 1,2,4-trimethoxybenzene.

Preparation of Multiphoton Curable Compositions

Curable and optionally non-curable species, multiphoton photosensitizers, electron donor compounds and electron acceptor compounds can be prepared by the methods described above or by other methods known in the art, many of which are commercially available. These components are formulated under "safe light" conditions (optionally stirring or shaking) using any combination order and manner, but often end up with the electron acceptor compound (in terms of shelf life and thermal stability). Preference is given to adding (and then optionally using any heating step to promote dissolution of the other components). Solvents may be used as needed, provided that the solvents are selected so as not to react significantly with the components of the composition. Examples of suitable solvents include acetone, dichloromethane and acetonitrile. The reactive species itself may often act as a solvent for other components.

The components of the multiphoton photoinitiator system are present in photochemically effective amounts (as described above). Generally, multiphoton curable compositions contain from about 5 to about 99.79 weight percent (preferably from about 10 to about 1) at least one reactive species based on the total weight of solids in the composition (ie, the total weight of components other than solvents). 95 weight percent, more preferably about 20 to about 80 weight percent); From about 0.01 to about 10 weight percent of one or more photosensitizers (preferably about 0.1 to about 5 weight percent, more preferably about 0.2 to about 2 weight percent); About 10% or less (preferably about 0.1 to 10% by weight, more preferably about 0.1 to about 5% by weight) of one or more electron donor compounds; And about 0.1 to about 10 weight percent (preferably about 0.1 to about 5 weight percent) of one or more electron acceptor compounds.

Various adjuvants may be included in the multiphoton curable composition, depending on the desired end use. Suitable auxiliaries include solvents, diluents, resins, binders, plasticizers, pigments, dyes, inorganic or organic reinforcing or extending fillers (preferred amounts of from about 10 to 90% by weight, based on the total weight of the composition), thixotropic agents, reaction indicators, inhibitors , Stabilizers, ultraviolet absorbers, pharmaceuticals (eg, porous fluorides), and the like. The amount and type of such adjuvants and the manner in which they are added to the composition are well known to those skilled in the art.

It is within the scope of the present invention to include non-reactive polymer binders in the composition, such as to control viscosity and provide film forming properties. Such polymeric binders may generally be selected to be compatible with the reactive species. For example, a polymeric binder may be used that is soluble in the same solvent as used for the reactive species and free of functional groups that may adversely affect the reaction process of the reactive species. The binder may have a molecular weight suitable for obtaining the desired film forming properties and solution flowability (eg, about 5,000 to 1,000,000 Daltons, preferably about 10,000 to 500,000 Daltons, more preferably about 15,000 to 250,000 Daltons). Examples of suitable polymeric binders include polystyrene, poly (methyl methacrylate), poly (styrene) -co- (acrylonitrile), cellulose acetate butyrate, and the like. Suitable non-reactive polymer binders (if present) may be included in the composition at 90% or less, preferably 75% or less, more preferably 60% or less by weight of the total weight of the composition.

Prior to exposure, the formed photoreactive composition can be applied onto the substrate by any of a variety of application methods as desired. The composition may be applied by a coating method such as knife coating, bar coating, reverse roll coating and knurled roll coating, or by an application method such as dipping, dipping, spraying, brushing, curtain coating or the like. Alternatively, the composition can be applied in a dropwise manner. Substrates can be selected from a variety of films, sheets and substrate surfaces depending on the specific application and the exposure method to be used.

Preparation Example 1 Synthesis of Multiphoton Photosensitive Agent (MPS 1)

Reaction of 1,4-bis (bromomethyl) -2,5-dimethoxybenzene with triethyl phosphite:

1,4-bis (bromomethyl) -2,5-dimethoxybenzene was prepared according to the procedure disclosed in Syper et al., Tetrahedron, 39, 781-792, 1983. Into a 1000 mL round bottom flask was placed 1,4-bis (bromomethyl) -2,5-dimethoxybenzene (253 g, 0.78 mol). Triethyl phosphite (300 g, 2.10 mol) was added and the reaction heated to vigorously reflux with stirring for 48 h under a nitrogen atmosphere. The reaction mixture was cooled down and excess triethyl phosphite was removed under vacuum using a Kugelrohr apparatus. A clear oil was formed upon heating to 100 ° C. at 0.1 mmHg. Upon cooling the desired product solidified, which was suitable for direct use in the next step. ¹ H NMR spectra of the product were consistent with the desired product. Recrystallization from toluene gave a colorless needle.

Synthesis of 1,4-bis- [4- (diphenylamino) styryl] -2,5- (dimethoxy) benzene:

A graduated dropping funnel and magnetic stirrer were installed in a 1000 ml round bottom flask. Into the flask, the product prepared from the above reaction (19.8 g, 45.2 mmol) and N, N-diphenylamino-p-benzaldehyde (25 g, 91.5 mmol; sold by Fluka Chemical Corporation, Milwaukee, WI) were charged. It was. The flask was flushed with nitrogen and sealed with a septum. Anhydrous tetrahydrofuran (750 mL) was placed in the flask through the conduit to dissolve all solids. Potassium t-butoxide (125 mL, 1.0 M in THF) was added to the dropping funnel. The solution in the flask was stirred and potassium t-butoxide solution was added to the contents of the flask for 30 minutes. The solution was stirred overnight at room temperature. Water (500 mL) was then added to terminate the reaction. Stirring continued, and after about 30 minutes a highly fluorescent yellow solid formed in the flask. The solid was isolated by filtration, air dried and then recrystallized from toluene (450 mL). The desired product was obtained as a fluorescent needle (24.7 g, 81% yield). ¹ H NMR spectrum results of the product were consistent with the proposed structure.

Example 2-Reflective Diffraction Grating

The multiphoton curable composition was prepared as follows. 30 g of PMMA (Aldrich) was added to 120 g of dioxane and mixed overnight in a roller to prepare a mother liquor. 1 g of MPS I was added to 35 g of Sartomer SR9008 and then heated and stirred to partially dissolve the photosensitizer to prepare a second solution. The second solution was added to the mother liquor and mixed overnight on a roller. To this solution was added 35 g of Sartomer SR368 and the solution was mixed overnight on a roller to prepare Masterbatch B. 0.1 g of diaryliodonium hexafluoroantimonate (SR1012, Sartomer) and 0.1 g of alkyltriaryl borate salt (CGI 7460, Ciba Specialty) are dissolved in 1 ml of acetonitrile and contain 11 g of masterbatch B. It was added to the fourth vial and stirred to mix the solution.

The multiphoton curable composition diluted to about 4 weight percent solids was coated onto the aluminum treated silicon reflector using droplets from the syringe to form discrete islands. These islands were then dried for 10 minutes in an air oven at 80 ° C. to form a film that extended over an area of several mm in diameter.

Spectra-Physics Inc. (94043 Mountain View Terra Bella Avenue, 1335, California, USA). The laser of the "Mai Tai" model is wavelength λ = 800 nm, repetition frequency 80 MHz, and pulse width of about 100 fs (1 × 10 ^-13). Second). The laser beam was focused on an aluminum treated reflector surface after passing through the dried resin film using a 40 × microscope objective with a focal length of 4.48 mm and an effective aperture of 0.65. Under a fixed laser beam, the completed aluminum treated reflector was moved to draw a series of equally spaced lines to form a grid pattern. New England Applied Technologies (NEAT) Inc. (Low-Lens, Mass.) Type 310 translations were installed in a cross-section arrangement and scanned in two orthogonal directions, each with respect to the laser beam. It was right angle. The reflectors were placed in the translation assembly and scanned under a laser beam to polymerize the resin in two-photon interaction to form a series of parallel lines of polymerized resin at about 19.1 μm intervals.

The resin pattern was developed by first washing in dimethylformamide (DMF) to remove the unexposed resin, followed by washing in isopropyl alcohol to remove the remaining residues. The reflector was then dried over nitrogen. The polymerized resin lines interfere with the continuous reflector surface to form a reflective diffraction grating. Thus, a diffraction grating can be added to a prefabricated reflector with almost no further processing.

The grating area may be any size and may be the maximum total reflector size, and may be applied to the grating area at any position or orientation depending on the choice of installation location and the translational control program content. Since the organic solvent used to develop the polymerized pattern is not corrosive, there is no possibility of chemically damaging the exposed aluminum thin film used for the reflective surface. Aluminum etching is not necessary. The drying temperature is too low to cause significant oxidation and, if necessary, the drying time can be extended to significantly lower the drying temperature.

The width of the resin line depends on the laser beam intensity, the speed of movement of the focal point relative to the reflector surface and the position of the focal point relative to the reflector surface. In these examples, reflectors were installed in a pair of NEAT Incorporated Type 310 translations operated in an x-y arrangement in a plane perpendicular to the beam. These translations were used to move the reflector at about 5.08 mm / sec under a stationary laser beam. A neutral density filter was used to adjust the average beam power to about 13 mW or 50 mW. When scanning at 50 mW, the line width was 4.5 to 5.2 µm, and when scanning at 13 mW, the line width was about 3.7 µm.

As noted above, the recorded pattern visually exhibits an iridescent appearance associated with the lattice, which is more curved at longer wavelengths than at short wavelengths so that white light spreads into the spectrum. At a given wavelength of light, each separation between the optical axis of the beam and the different diffraction orders is given by d sin θ = mλ (Jenkins and White, Fundamentals of Optics, 3rd Edition, McGraw-Hill, New York, 1957, p 331.) Where d is the lattice spacing, θ is the angle between the optical axis and the maximum diffraction of a given order, m is an integer representing the diffraction order, and λ is the wavelength of light used.

The above grating can be illuminated at a nearly vertical angle of incidence using a 5 mW, helium-neon laser of Melus-Greech Incorporated (Rochester Science Parkway 55, NY) using a wavelength of λ = 632 nm. The reflection of the first beam and the first few diffraction orders were projected on a white screen located about 71.8 cm from the reflector. When the lattice spacing was 19.1 μm, the above equation was applied to obtain an angle of 1.90 ° for the first order maximum diffraction and a 3.79 ° angle for the second order maximum diffraction. The angles were the same as 1.90 ° and 3.79 °, respectively, when measured on the screen, demonstrating that a well-acting diffraction grating was produced.

Example 3 Reflective Diffraction Gratings on MEMS Scanning Reflectors

Reflective diffraction gratings were fabricated on a precision electromechanical system (MEMS) reflector used as an electrically driven optical syringe using the same apparatus, materials and techniques as described in Example 2 above. This rotates the grating several degrees sharply, scanning the reflected beam back and forth through twice its angle. This may be useful for various optical techniques, particularly in the fabrication of rapidly scanned spectrophotometers in which the scanned beam is projected through slits with photocells on the back. As the reflector rotates, the spectrum sweeps through the slit. This technique allows for easy fabrication of reflectors at frequencies from hundreds of Hz up to tens of kHz, enabling fast spectral data acquisition. Typical reflectors used in this embodiment have a drive frequency of about 10 kHz to about 15 kHz.

Reflectors and their bases were etched from single crystal silicon using known wet anisotropic etching techniques. The reflector itself was etched into a thin (.003 "= .005") wafer of single crystal silicon and cut into exposed (100) crystal planes. After etching, the square or rectangular reflector was attached to the rest of the wafer only by two torsion arms. The surface of the reflector was vacuum coated with aluminum for reflectance and electrical conductivity. The reflector base was similarly etched from the thicker silicon wafer. Here, when power was applied, the bottom flat cavity was anisotropically wet etched so that the reflector rotated about the axis of rotation in the torsion arm. An aluminum electrode was formed on one side of the cavity and operated in parallel with the torsion arm. The wafer containing the reflector was centered in the cavity, aligned as specified, and then attached to the base with epoxy. Wiring was connected to the two base electrodes and the reflector electrodes to supply power. Typically, when the reflector is grounded and the base electrode is alternating between the ground and some bias voltage, the bias electrode attracts the grounded reflector. The bias potential and the ground potential were reversed back and forth between the two electrodes at the resonant frequency of the reflector-torsion arm unit to produce a useful amplitude. In this embodiment, a simple drive circuit capable of achieving this is provided externally, but an integrated circuit can be formed by almost completely integrating with silicon.

The MEMS reflector assembled and tested as described above was coated with a resin photosensitive with two photons as follows: 2% by weight of tris (methoxysilyl) methacrylate (Aldrich) (acetic acid in 95% ethyl alcohol as an adhesion promoter) Oxidized), and then dried at 80 ° C. for 60 minutes in an air oven. The multiphoton curable composition was diluted to 5% by weight solids, 1 drop per reflector was added, and then dried in an air oven at 80 ° C. for 10 minutes to form a film.

Spectra-Physics Inc. (94043 Mountain View Terra Bella Avenue, 1335, CA, USA) Lasers of the "Mai Tai" model have a wavelength of λ = 800 nm, a repetition frequency of 80 MHz, and about 100 fs (1 × 10 ^-13 seconds). It was operated at the pulse width of. The laser beam was focused on an aluminum treated reflector surface after passing the dried resin film using a 40 × microscope objective with a focal length of 4.48 mm and an effective aperture of .65. Under a fixed laser beam, the completed aluminum treated reflector was moved to draw a series of equally spaced lines to form a grid pattern. Type 310 translations of NEAT Incorporated were installed in a crossover configuration and scanned in two perpendicular directions, each perpendicular to the laser beam. The reflector was placed in the translation assembly and scanned at 5.08 mm / sec under the laser beam to polymerize the resin in two-photon interaction, forming a series of parallel lines of polymerized resin at about 19.1 μm intervals.

The resin pattern was developed by first washing in propylene-glycol-methyl-ether acetate (Aldrich) to remove the unexposed resin and then washing in isopropyl alcohol to remove the remaining residues. The developing time was successful for 30 to 60 seconds. The reflector was then dried over nitrogen. The polymerized resin lines interfere with the continuous reflector surface to form a reflective diffraction grating.

Example 4-Joint Filling

30 g of PMMA (135 K molecular weight) was taken and dissolved in 120 g of dichloromethane to prepare a resin mother liquor. Further 35 g of Sartomer SR 368 were added along with Sartomer SR-9008.

A second mother liquor of the initiator component was also prepared. Bi-photon dye bis- [4- (diphenylamino) styryl] -1,4- (dimethoxy) benzene (MPS 1,150 mg), diaryliodonium hexafluoroantimonate [SR-1012 , Satomer, (250 mg)] and organic borate [CGI-7460, Ciba Specialties (250 mg)] were dissolved in a total of 12.35 g of dichloromethane.

11.0 g of the resin mother liquor was mixed with 1.5 g of the initiator component solution to prepare a polymerizable solution. Five holes with a diameter of 1 mm and a depth of 2 mm were made and two-thirds of the holes were placed in steel and 1/3 in PTFE to make a two-piece mold of steel and PTFE. The solution to be polymerized by partially filling the cavity with an uncured resin solution using a 25 μl syringe was first charged into the cavity and the solvent was evaporated for 30 minutes. This process was then repeated until the cavity was completely filled with unpolymerized resin.

Using a diode-pumped Ti-sapphire laser operating at 100 MHz, 100 fs pulse, 800 nm, average brightness of 109 mW as a light source, one of the cavities filled with unpolymerized resin was irradiated and filled with a 10X objective Focusing was performed using an effective number of 0.25. A 1.2 mm square pattern was formed by focusing the laser beam at the interface between the unpolymerized resin and the cavity bottom and scanning the focus with 240 lines of 1.2 mm length spaced at 5 μm intervals to cure the uncured resin. The 1.2 mm square pattern was repeatedly injected until the resin cured to about 1/2 of the cavity depth (slightly smaller than 1 mm in Example A), with each successive scan being 40 μm further from the bottom of the cavity. Moved. The second cavity filled with the uncured resin was cured by focusing the laser beam at the interface between the unpolymerized resin and the air (upper part of the cavity). The 1.2 mm square pattern was repeatedly scanned with the laser focused as described above until the resin had cured all the way to the bottom of the cavity, and with each successive scan the focus was moved to about 40 μm closer to the bottom of the cavity (Example B). The article comprising the cavity filled with the partially cured resin was immersed in dimethylformamide for 2 hours to remove any unreacted resin. After washing with isopropyl alcohol and drying, the mold was disassembled and the height and width of the resulting plug (height measured along the axis of the cylindrical cavity) were measured under a microscope (see table below) and the cavity irradiated upwards from the bottom was It is confirmed that half of the bottom is cured but the top is not cured and the cavity irradiated from top to bottom is cured at the full depth of the cavity.

Examples C, D, E, F (comparative). As described above, the second mold was filled with the curable resin. For comparison, each cavity filled with curable resin was irradiated starting at 71 mJ / cm ² to 566 J / cm ² to provide twice the dose applied to the cavity filled with the curable resin of the previous example. The curable resin in the four cavities was irradiated using a He-Cd laser continuously operating at 1 m of the photon absorption agent, 2 mW, and a beam diameter of 3 mm). The formed article comprising the cavity holding the partially cured resin was immersed in dimethylformamide for 2 hours to remove any unreacted resin. After washing with isopropyl alcohol and drying, the mold was disassembled and the height and width (measured along the axis of the cylindrical cavity) of each plug was measured under a microscope (see table below). From this data, it was confirmed that the comparative example cured only from top to bottom, and that the resin at the bottom of the cavity can be cured only after the resin closer to the light source first cured.

Example Curing method Dose (mJ / cm ² ) Height (㎛) Width (㎛) A Multiphoton, from bottom to top 710 (height from bottom) 1002 B Multiphoton, from top to bottom 1403 985 C (comparative example) 1 photon 71 830 (height from the top) 1409 D (Comparative Example) 1 photon 142 906 (height from the top) 1700 E (comparative example) 1 photon 283 1568 838 F (comparative example) 1 photon 566 1620 1329

A number of embodiments of the invention have been disclosed. However, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are also included within the scope of the following claims.

Claims (44)

Forming a molded article in one or more macroscopic manufacturing processes including injection molding, compression molding, embossing, extrusion molding and polymerization in a mold; Applying a multiphoton curable composition to the molded article comprising a curable species and a multiphoton photoinitiator system; And At least partially curing the multiphoton curable composition to produce a three-dimensional image of a desired shape and forming a structure on the article Including a method of forming a structure. (a) (1) curable species, and (2) applying to the feature a multiphoton curable composition comprising a multiphoton photoinitiator system comprising a multiphoton photosensitive agent and an electron acceptor; And (b) at least partially curing the multiphoton curable composition to form a structure on the shaped portion A method of adding a structure to an article having a surface with one or more microscopic shapes, comprising: (a) (1) curable species, and (2) applying to the optical fiber a multiphoton curable composition comprising a multiphoton photoinitiator system comprising a multiphoton photosensitizer and an electron acceptor; And (b) at least partially curing the multiphoton curable composition to form a structure on the optical fiber Including, the method of adding a structure to the optical fiber. (a) (1) curable species, and (2) applying to the surface a multiphoton curable composition comprising a multiphoton photoinitiator system comprising a multiphoton photosensitizer and an electron acceptor; And (b) at least partially curing the multiphoton curable composition to form a diffraction grating on the surface Comprising a diffraction grating on the substrate. Providing a multiphoton curable composition comprising a curable species and a multiphoton photoinitiator system, wherein the multiphoton photoinitiator system comprises a multiphoton photosensitive agent and an electron acceptor; Providing a substrate having a cavity; And Exposing the multiphoton curable composition to a light source sufficient to cause multiphoton absorption to at least partially cure the multiphoton curable composition. And a cavity filled with the multiphoton cured material. Curable species, and Multiphoton photoinitiator system containing multiphoton photosensitizer and electron acceptor Comprising, multi-photon curable composition for dental restoration. The method of claim 1, further comprising removing the uncured multiphoton curable composition. 4. The method of any one of claims 1 to 3, wherein the structure is microscopic. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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