EMBOSSING LACQUER AND METHOD FOR EMBOSSING, AND SUBSTRATE SURFACE COATED WITH THE EMBOSSING LACQUER

Abstract

In the case of an embossing lacquer based on a UV-polymerizable prepolymer composition containing at least one acrylate monomer, the prepolymer composition—in addition to the acrylate monomer—contains at least one thiol selected from the group: 3-Mercaptopropianates, mercaptoacetates, thioglycolates, and alkylthiols as well as potentially a surface-active anti-adhesive additive selected from the group of anionic surfactants, such as polyether siloxanes, fatty alcohol ethoxylates, such as polyoxyethylene (9) lauryl ethers, monofunctional alkyl (meth)acrylates, polysiloxane (meth)acrylates, perfluoroalkyl (meth)acrylates, and perfluoropolyether (meth)acrylates as well as a photoinitiator, as well as a method for imprinting substrate surfaces coated with an embossing lacquer.

Claims

1. An embossing lacquer based on a UV-polymerizable prepolymer composition containing at least one acrylate monomer, wherein the prepolymer composition contains a thiol, selected from the group: 3-Mercaptopropionates, mercaptoacetates, thioglycolates, and alkyl thiols, as well as a surface-active anti-adhesive additive selected from the group consisting of anionic surfactants, such as polyether siloxanes, fatty alcohol ethoxylates, such as polyoxyethylene (9)-lauryl ethers, monofunctional alkyl (meth) acrylates, polysiloxane (meth) acrylate, perfluoroalkyl (meth) acrylates, and perfluoropolyether (meth) acrylate, as well as a photoinitiator.

2. Embossing lacquer according to claim 1, wherein the acrylate monomer is selected from the group consisting of acryloylmorpholine (ACMO) or isobornyl acrylate (IBOA).

3. Embossing lacquer according to claim 1, wherein the thiol is contained in the prepolymer composition in a quantity between 0.5 and 20 wt %.

4. Embossing lacquer according to claim 1, wherein the surface-active anti-adhesive additive is an additive containing silicone or fluoride selected from the group consisting of anionic surfactants, such as polyether siloxanes, fatty alcohol ethoxylates, such as polyoxyethylene (9) lauryl ethers, mono-functional polydimethylsiloxane (meth) acrylates, perfluoro-n-alkyl (meth) acrylates or perfluoropolyether (meth) acrylates.

5. Embossing lacquer according to claim 4, wherein the surface-active anti-adhesive additive is contained in a quantity of 0.1 wt % to 3 wt %.

6. Embossing lacquer according to claims 1, wherein the photoinitiator is selected from the group consisting of thioxanthones, ketosulfones, (alkyl) benzoyl phenyl phosphine oxides, 1-Hydroxy alkyl phenyl ketones or 2,2-Dimethoxy-1,2-diphenylethane-1-one.

7. Embossing lacquer according to claim 6, wherein the photoinitiator is contained in a quantity of 0.1 to 10 wt %, particularly 0.5 to 5 wt %.

8. Embossing lacquer according to claim 1, wherein the thiol is selected from the group consisting of a mono or dithiol of the group: octanethiol, 1,8-Octanedithiol, decanethiol, 1,10-Decanedithiol, dodecanethiol, 1,12-Dodecanedithiol, 2-Ethylhexyl mercaptoacetate, 2-Ethyl-hexyl-3-mercaptopropionate, 2-Ethylhexyl thioglycolate, glycol di-(3-mercaptoproprionate), glycol di(mercaptoacetates), glyceryl dimercaptoacetate or glyceryl di-(3-mercaptopropionate).

9. Embossing lacquer according to claim 1, wherein the prepolymer composition has a viscosity between 10 and 100 mPas.

10. A method for imprinting substrate surfaces coated with a embossing lacquer according to claim 1, distinguished by the following steps: a) Application of a layer of embossing lacquer on a carrier, b) UV structuring of the embossing lacquer, c) Potential application of at least one additional layer to be structured selected from a metal, semiconductor, and/or dielectric layer, and d) Removal of the embossing lacquer remaining after structuring with potential additives selected from the group consisting of diluted acids with pH values in the range of 1 to 6, diluted lyes with pH values in the range of 8 to 13 or water containing surfactants or propylene glycol monomethyl ether acetate (PGMEA), N-methyl-2-pyrrolidone (NMP), methyl ethyl ketone (MEK) or acetone.

11. Method according to claim 10, wherein the UV structuring of the embossing lacquer is conducted with a UV nanoimprint lithography method.

12. Method according to claim 10, wherein the additional metal, semiconductor, and/or dielectric layer to be structured is applied with a layer thickness between 5 nm and 500 nm.

13. Method according to claim 10, wherein the additional layer to be structured consisting of metals, such as nickel, aluminum, chrome or titanium, conjugated organic semiconductors, such as pentazen, C60, thiophene, DNTT; P3HT, phthalocyanine, hydrogen bridge-bonded organic semiconductors, such as indigo and indigo derivatives as well as quinacridone and anthraquinone, inorganic semiconductors, such as ZnO, SnO, InGaZnO or dielectrics, selected from polynorbornene, ormocer, cellulose, PVCi, BCB, PMMA, shellac, polyimide, Cytop, PVDF, PVDF-TrFE, polystyrenes, Al.sub.2O.sub.3, ZrO.sub.2, SiO.sub.2, SiON, Si.sub.3N.sub.4, as well as combinations thereof, is selected.

14. Method according to claim 10, wherein the removal of the embossing lacquer remaining after structuring is conducted through immersion in a solvent bath or by spraying potentially with additional mechanical means, such as brushes or ultrasound.

Description

[0032] The invention will be explained in further detail below based on examples as well as design examples depicted in the drawing. The following are shown therein:

[0033] FIG. 1 a diagram of residue-free imprinting by dewetting the UV embossing lacquer,

[0034] FIG. 2 a scanning electron depiction of residue-free UV-NIL imprinting of a PET foil, and

[0035] FIG. 3 a diagram of the lift-off principle based on a lift-off-capable embossing lacquer according to the invention as a sacrificial layer, and

[0036] FIG. 4 four scanning electron microscope images of linear or grid structures, which were produced with an embossing lacquer according to the invention.

[0037] FIG. 1 shows that a substrate 1 is coated with a UV embossing lacquer 2 based on acrylate, which also contains surface-active substances. When an embossing stamp 3 approaches, the splitting coefficient, i.e. the interfacial energy between substrate 1 and stamp 3 less the interfacial energy between substrate 1 and embossing lacquer 2 and between embossing lacquer 2 and stamp 3 becomes negative due to the wetting properties of embossing lacquer 2, through which embossing lacquer 2 retracts between the stamp surface and substrate 1 as is depicted in FIG. 1b, which shows the hardened UV embossing lacquer after removing embossing stamp 3, embossing lacquer 2 of which has a gap 4 corresponding to stamp 3.

[0038] Due to this residue-free UV NIL imprinting, the oxygen reactive-ion etching step (RIE) generally required with the nanoimplantlithography process for removing any residual embossing lacquer layers on substrate 1 as is depicted in FIG. 2 is superfluous. FIG. 2 clearly shows that no remaining embossing lacquer 2 is present on substrate foil 1, which is coated with embossing lacquer 2, where embossing stamp 3 lead for dewetting the UV embossing lacquer on the substrate.

[0039] The sequence of the process steps of a lift-off process is schematically shown in FIG. 3.

[0040] In FIG. 3a, a sacrificial layer, e.g. a photo embossing lacquer 2, is applied on substrate 1. It is evident in FIG. 3b that sacrificial layer 2 was structured; namely with a negative sidewall angle in the present case.

[0041] In FIG. 3c, the entire surface of exposed substrate 1 as well as remaining sacrificial layer 2 is covered with a target material, e.g. aluminum 5.

[0042] The dissolving of the sacrificial layer or embossing lacquer 2 in a wet chemical process, in the present case, in water, is schematically shown in FIG. 3d. Sacrificial layer 2 dissolves in water 6 and all areas of substrate 1, on which a sacrificial layer 2 remained in the previous steps, are exposed by sacrificial layer 2 and target material 5 located over sacrificial layer 2 is dissolved or removed together with sacrificial layer 2, such that substrate 1 remains with separated target material 5. After substrate 1 is dried, structured target material 5 on substrate 1 is ready for further use, as is depicted in FIG. 3e.

[0043] Images of structured target materials 5 are depicted in FIG. 4, wherein this involves scanning electron microscope images, for which aluminum was used as the structured target material. The remaining line width is 400 nm. From the photographs of the scanning electron microscope, it is evident that sharp structures of the line pattern can be achieved with the embossing lacquer according to the invention or the method for imprinting and that no residues of the embossing lacquer layer are left on the surface of the structures.

EXAMPLE 1

Production of an Embossing Lacquer According to the Invention

[0044] 84% acryloylmorpholine (ACMO), 10% 2-Ethylhexyl thioglycolate, 5% 2-Hydroxy-2-methyl-1-phenyl propane-1-one as a photoinitiator as well as 1% polysiloxane surfactant are applied to a 50 μm thick PET foil by means of gravure printing, wherein the pick-up volume of the gravure printing roller is 1.6 ml/m.sup.2, which roughly corresponds to a 0.8 μm wet layer thickness and are imprinted with a nickel imprinting tool with protruding imprinting structures with a 5 μm structural width and 1 μm structural height with a speed of 10 m/min. The pneumatic pressure on the counter roller is 4 bar. UV polymerization occurred through irradiation with a medium-pressure mercury-vapor lamp with 100 W/cm.

EXAMPLE 2

Production of an Embossing Lacquer According to the Invention

[0045] 84% IOBA, 10% 2-Glycol di(3-mercaptopropionate), 5% 2-Hydroxy-2-methyl-1-phenyl propane-1-one as a photoinitiator as well as 1% 1H,1H,2H,2H-perfluoroctylacrylate are applied to a 50 μm thick PET foil by means of gravure printing, wherein the cell volume of the gravure printing roller is 1.6 ml/m.sup.2, which roughly corresponds to a 0.8 μm wet layer thickness and are imprinted with a nickel imprinting tool with protruding imprinting structures with a 5 μm structural width and 1 μm structural height with a speed of 10 m/min. The pneumatic pressure on the counter roller is 4 bar. UV polymerization occurred through irradiation with a medium-pressure mercury-vapor lamp with 100 W/cm.

EXAMPLE 3

Production of an Embossing Lacquer According to the Invention

[0046] 84% acryloylmorpholine (ACMO), 10% dodecanethiol, 5% ethyl(2,4,-trimethylbenzoyl) phenylphosphinate as a photoinitiator as well as 1% 1H,1H,2H,2H-perfluoroctylacrylate are applied to a 50 μm thick PET foil by means of gravure printing, wherein the cell volume of the gravure printing roller is 1.6 ml/m.sup.2, which roughly corresponds to a 0.8 μm wet layer thickness and are imprinted with a nickel imprinting tool with protruding imprinting structures with a 5 μm structural width and 1 μm structural height with a speed of 10 m/min. The pneumatic pressure on the counter roller is 4.2 bar. UV polymerization occurred through irradiation with a medium-pressure mercury-vapor lamp with 100 W/cm.

EXAMPLE 4

Production of an Embossing Lacquer According to the Invention

[0047] 84% IBOA, 10% 2-Ethylhexyl thioglycolate, 5% ethyl(2,4, trimethylbenzoyl)phenylphosphinate as a photoinitiator as well as 1% siloxane-based Gemini surfactant are applied to a 50 μm thick PET foil by means of gravure printing, wherein the cell volume of the gravure printing roller is 1.6 ml/m.sup.2, which roughly corresponds to a 0.8 μm wet layer thickness and are imprinted with a nickel imprinting tool with protruding imprinting structures with a 5 μm structural width and 1 μm structural height with a speed of 10 m/min. The pneumatic pressure on the counter roller is 3.8 bar. Die UV cross-linking occurred through irradiation with a medium-pressure mercury-vapor lamp with 100 W/cm.

EXAMPLE 5

[0048] The structures manufactured according to Example 1 are metalized through vapor-depositing 30 nm of nickel and after metallization, the embossing lacquer structures are removed by introducing the metalized foil into a water bath and heating to temperatures of 40° C. and using additional measures, such as ultrasound, spraying, brushing, etc. With this treatment, the embossing lacquer, which is water-soluble, is dissolved and the metallic layer located over the embossing lacquer is simultaneously removed with the embossing lacquer, while the metallic layer areas located directly on the foil areas exposed in the previous imprinting step remain on the foil. Thus, only a negative metallic structure of the imprinted embossing lacquer structure remains after the lift-off process.

EXAMPLE 6

[0049] The structures manufactured according to Example 3 are metalized through vapor-depositing 30 nm of aluminum and after metallization, the excess embossing lacquer structures are removed by applying ultrasound in a water bath. Wth this treatment, the water-soluble embossing lacquer is dissolved and the metallic layer located over the embossing lacquer is simultaneously removed with the embossing lacquer, such that only a negative profile of the imprinted profile remains after the lift-off process, which consists exclusively of a metallic structure.

EXAMPLE 7

[0050] The structures manufactured in this way are metalized through vapor-depositing 30 nm of chromium and after metallization, the excess embossing lacquer structures are removed by introducing the metalized structure into a water bath and heating to temperatures of 60° C. by spraying and pressure through the application of ultrasound and using additional measures, vibration, brushing, etc. Wth this treatment, the embossing lacquer, which is water-soluble, is dissolved and the metallic layer located over the embossing lacquer is simultaneously removed with the embossing lacquer, such that only a negative profile of the imprinted profile remains after the lift-off process, which consists exclusively of a metallic structure.

EXAMPLE 8

[0051] The structures manufactured according to Example 2 are metalized through vapor-depositing 30 nm of aluminum and after metallization the excess embossing lacquer structures are removed by introducing the metalized structure in propylene glycol monomethyl ether acetate (PGMEA) and heating to temperatures of 50° C. using additional measures, vibration, brushing, etc. With this treatment, the embossing lacquer, which is soluble in solvent, is dissolved and the metallic layer located over the embossing lacquer is simultaneously removed with the embossing lacquer, such that only a negative profile of the imprinted profile remains after the lift-off process, which consists exclusively of a metallic structure.

EXAMPLE 9

[0052] The structures manufactured according to Example 4 are coated through vapor-depositing 30 nm of P3HT and after coating the excess embossing lacquer structures are removed by introducing the coated structure into a water bath and heating to temperatures of 50° C. or by spraying the water and through pressure. With this treatment, the embossing lacquer is dissolved and the semiconductor layer located over the embossing lacquer is simultaneously removed with the embossing lacquer, such that only a negative profile of the imprinted profile remains after the lift-off process, which consists exclusively of an organic semiconductor structure.

EXAMPLE 10

[0053] The structures manufactured according to Example 4 are coated through vapor-depositing 30 nm of ZnO and after coating the excess embossing lacquer structures are removed by introducing the coated structure in propylene glycol monomethyl ether acetate (PGMEA) and heating to temperatures of 50° C. or by spraying the solvent and through pressure. With this treatment, the embossing lacquer is dissolved and the semiconductor layer located over the embossing lacquer is simultaneously removed with the embossing lacquer, such that only a negative profile of the imprinted profile remains after the lift-off process, which consists exclusively of an inorganic semiconductor structure.