Application of compound as two-photon initiator, two-photon photoresist and patterning method thereof

Abstract

The present invention discloses the application of a compound as a two-photon initiator, a two-photon photoresist and a patterning method thereof. The present invention provides the application of one of compound g, compound h and compound i as a two-photon initiator. The two-photon photoresist comprises 0.1-5.0% quencher, 0.1-2.5% two-photon initiator and 92.5-99.8% resin monomer by mass percentage; the quencher is selected from organic matter containing nitroxide free radicals; the two-photon initiator is one of the following compounds a-i. The present invention provides a patterning method for the above-mentioned two-photon photoresist. The present invention provides the application of compound g-h as a two-photon initiator. The present invention uses femtosecond laser direct writing technology to provide a two-photon photoresist and patterning method that can efficiently drive light promotion to light inhibition, thereby achieving multi-faceted improvements in the writing speed, photolithography accuracy, resolution and three-dimensional processing capabilities of femtosecond lasers.

Description

Technical Field

[0001] The invention belongs to the field of photosensitive materials and micro-nano structure manufacturing, and specifically relates to the application of a compound as a two-photon initiator, a two-photon photoresist for femtosecond laser direct writing, and a patterning method thereof. Background Art

[0002] Photoresists are generally composed of initiators, resin monomers and solvents. The initiator is crucial to the photosensitivity of the photoresist and determines the photolithographic performance of the photoresist, namely, the photolithographic accuracy, resolution, processing speed and multi-dimensional processability. Most of the existing initiators are ultraviolet single-photon initiators, such as 1-hydroxycyclohexyl phenyl ketone (IRG184), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinylpropane-1-one (IRG907), (2,4,6-trimethylbenzoyl)-diphenylphosphine oxide (TPO), 7-diethylamino-3-thenoylcoumarin (DETC) and isopropylthioxanthone (ITX). Photoresists containing such initiators generally undergo single-photon absorption under laser irradiation, and the writing accuracy is often greater than 100 nm, and the resolution is submicron level, which is difficult to meet the requirements of existing technologies for processing accuracy and resolution.

[0003] With the rapid development of laser direct writing technology, two-photon laser direct writing technology has shown great potential, especially the two-photon femtosecond laser direct writing technology based on edge light suppression, which has pushed the accuracy and resolution of lithography to a new level. Two-photon femtosecond laser direct writing technology based on edge light suppression is a super-resolution lithography technology that uses the nonlinear optical effect and light suppression effect of photoresist to achieve direct exposure inside the photoresist. Specifically, by applying a hollow annular beam (suppression light) that has an inhibitory effect on the polymerization process at the edge of the central beam (excitation light) area, a further breakthrough in the optical diffraction limit can be achieved. At present, the writing accuracy of this technology can reach sub-50 nm. For example, CN 115793395 A discloses a high-precision femtosecond laser direct writing photoresist composition based on a dual inhibition effect. The photoresist composition disclosed in the patent, which includes a (meth)acrylate monomer and a two-photon initiator 7-diethylamino-3-thenoylcoumarin (DETC), has a light inhibition effect. After adding an inhibitor, the chemical inhibition effect of the inhibitor is used to further improve the writing accuracy of femtosecond laser direct writing, and high-quality writing lines with a sub-50 nm accuracy are obtained. However, the existing two-photon laser direct writing technology based on edge light inhibition has extremely strict requirements on initiators, and needs to respond to both excitation light and inhibition light, that is, two-color photosensitivity. Currently, most of the initiators that meet the requirements are DETC and ITX. However, the smaller absorption cross-section and higher fluorescence quantum yield of DETC and ITX seriously hinder the speed increase of two-photon lithography. The existing two-photon laser direct writing photoresist writing speed based on edge light suppression is generally 100 μm / s, and the writing is mostly concentrated in two-dimensional processing, which is difficult to meet the application requirements of large-scale manufacturing and high-precision processing. In addition, compared with the improvement of writing accuracy, the improvement of resolution, especially the improvement of three-dimensional structure resolution, is more difficult due to the influence of memory effect. The literature (Opt. Mater. Express. 2011, 614-624) reported a method of judging the resolution of three-dimensional structures, that is, judging by writing a three-dimensional match pile structure stacked layer by layer. The best three-dimensional match pile resolution reported based on the 780 femtosecond laser system can reach sub-300 nm (PhotoniX 2022, 3,1-14).

[0004] The document (Appl. Polym. Mater. 2023, 5, 2956-2963) discloses a series of DETC derivatives, which have higher molar extinction coefficients, lower fluorescence quantum yields, higher two-photon absorption cross sections and higher two-photon sensitivity than DETC. DETC derivatives are dissolved in pentaerythritol triacrylate (PETA) to form a photoresist, among which the best photoresist can work well at a writing speed of 60 mm / s and can produce complex patterns on a laser direct writing system. However, the inventors found in subsequent studies that after superimposing the suppression light, the photoresist of the above formula has an obvious light-promoting effect, the resolution of the engraving is poor, and it is not suitable for three-dimensional processing.

[0005] The literature (Org. Lett. 2023, 25, 6352-6356) proposed a visible light-promoted and transition metal-free photoredox catalytic strategy for the synthesis of thioxanthone derivatives (TXs), but the literature did not further study the performance of these thioxanthone derivatives (TXs).

[0006] Therefore, there is an urgent need to develop a new type of photoresist to improve the writing speed, lithography accuracy, resolution and multi-dimensional patterning processing capabilities of laser direct writing. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies of the prior art, provide an application of a compound as a two-photon initiator, and utilize femtosecond laser direct writing technology to provide a two-photon photoresist and patterning method that can efficiently drive light promotion to light inhibition, so as to achieve multi-faceted improvements in the writing speed, lithography accuracy, resolution and three-dimensional processing capabilities of femtosecond lasers, and promote the development of the field of micro-nano processing.

[0008] The technical solution of the present invention is as follows:

[0009] In a first aspect, the present invention provides a use of a compound as a two-photon initiator, wherein the compound is selected from one of the following compounds g, h, and i;

[0010] .

[0011] In a second aspect, the present invention provides a two-photon photoresist for femtosecond laser direct writing, which comprises, by mass percentage, 0.1-5.0% of a quencher, 0.1-2.5% of a two-photon initiator, and 92.5-99.8% of a resin monomer;

[0012] The resin monomer is an organic acrylate that can be photopolymerized;

[0013] The quencher is selected from one or more of the following organic substances containing nitroxide free radicals: pentamethylpiperidinol, tetramethylpiperidinyl nitroxide free radical phosphite triester, N,N-diethylhydroxylamine, sebacate bis(2,2,6,6-tetramethyl-4-piperidinyl-1-oxy) ester, 2-methyl-2-acrylic acid-2,2,6,6-tetramethyl-4-piperidinyl ester, 2,2,6,6-tetramethylpiperidinyl oxide, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyl 1-oxy free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidinyl 1-oxy free radical;

[0014] The two-photon initiator is one of the following compounds ai:

[0015] .

[0016] Preferably, the resin monomer is selected from the following one or a combination of several in any proportion: pentaerythritol triacrylate, dipentaerythritol pentaacrylate, n-butyl methacrylate, tricyclodecane dimethanol diacrylate, bisphenol A di(meth)acrylate and ethoxylated bisphenol A (meth) diacrylate.

[0017] Preferably, the two-photon photoresist for femtosecond laser direct writing is composed, by mass percentage, of 0.1-5.0% quencher, 0.1-2.5% two-photon initiator and 92.5-99.8% resin monomer.

[0018] The two-photon photoresist described in the present invention introduces a new two-photon initiator and a quencher, wherein the use of the new two-photon initiator can significantly improve the photosensitivity of the photoresist and thus increase its writing speed, and the quencher acts on the new two-photon initiator to inhibit the photoresist from absorbing single photons of a 532 nm continuous laser, thereby converting the photoresist from light promotion to light inhibition, thereby achieving high-precision and high-resolution micro-nano processing.

[0019] The specific preparation method of the two-photon photoresist described in the present invention is as follows: first add the quencher into a brown bottle in a yellow light room, then add the resin monomer, ultrasonicate for 10-20 minutes, add the two-photon initiator after complete dissolution, continue ultrasonicate for 30-40 minutes, and finally shake well on a homogenizer overnight to obtain a viscous two-photon photoresist for femtosecond laser direct writing.

[0020] In a third aspect, the present invention provides a patterning method of a two-photon photoresist for femtosecond laser direct writing according to the second aspect, the specific steps of which are as follows:

[0021] (1) Dropping two-photon photoresist for femtosecond laser direct writing onto a glass or silicon wafer substrate;

[0022] (2) Call the patterning program on the laser direct writing software;

[0023] (3) Simultaneously turn on the 780 nm femtosecond laser and the 532 nm continuous laser to expose the two-photon photoresist and then let it stand, wherein the 532 nm continuous laser is controlled according to the design pattern setting program, that is, it is turned on or off at a certain time according to the pattern design setting;

[0024] (4) The photoresist pattern can be obtained after development in the primary developer and the secondary developer respectively.

[0025] Preferably, the primary developer is one or a mixture of propylene glycol methyl ether acetate, propylene glycol monomethyl ether or propylene glycol monoethyl ether, and the secondary developer is isopropanol or ethanol; the primary development time is 6-10 min, and the secondary development time is 2-5 min.

[0026] Preferably, the laser scanning speed is 150-50000 μm / s, more preferably 200-30000 μm / s.

[0027] Preferably, the excitation light power is 5-70 mW, more preferably 5-40 mW.

[0028] Preferably, the suppression optical power is 5-70 mW, more preferably 30-60 mW.

[0029] Preferably, the pattern is a three-dimensional pattern.

[0030] The beneficial effects of the present invention are:

[0031] (1) The present invention provides a novel two-photon initiator that can significantly increase the writing speed of photoresist.

[0032] (2) The present invention, by introducing a new type of two-photon initiator and quencher, proposes for the first time a photoresist formula that can achieve the transformation from photopromotion to photoinhibition. The appropriate chemical response in the formula is conducive to regulating the efficiency of excitation and inhibition of the initiator in the optical response, greatly improving the processing accuracy and processing resolution of femtosecond laser, especially the processing resolution of three-dimensional structures; at the same time, it also significantly improves the writing speed.

[0033] (3) The present invention can process and manufacture any multi-dimensional pattern without a mask, and the process is simple, which promotes the rapid development of the field of micro-nano processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a schematic diagram of the main optical components of the femtosecond laser direct writing device used in the present invention, wherein 1-substrate, 2-objective lens, 3-refractive index oil, 4-photoresist, 5-femtosecond laser spot, 6-continuous laser spot;

[0035] Figure 2 is a two-dimensional line graph of the photoresist based on edge light suppression in Example 1 and Comparative Example 1;

[0036] Figure 3 is a three-dimensional match pile image of the photoresist based on edge light suppression in Example 2 and Comparative Example 2;

[0037] Figure 4 is a two-dimensional line graph of the photoresist based on edge light suppression in Example 3 and Comparative Example 3;

[0038] Figure 5 is a three-dimensional match pile image of the photoresist based on edge light suppression in Example 4;

[0039] Figure 6 is a three-dimensional magician diagram of the photoresist based on edge light suppression in Example 5 and Comparative Example 4;

[0040] Figure 7 is a two-dimensional line graph based on edge light suppression of the photoresist in Example 6 and Comparative Example 5;

[0041] Figure 8 is a standard pattern diagram of the photoresist based on edge light suppression in Example 7 and Comparative Example 6;

[0042] Fig. 9 It is a three-dimensional hollow five-pointed star pattern based on edge light suppression of the photoresist in Example 8 and Comparative Example 7. DETAILED DESCRIPTION

[0043] The contents of the present invention will be further explained below with reference to examples, but these examples do not limit the protection scope of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the protection scope of the present invention.

[0044] If no specific conditions are specified in the examples of the present invention, the experiments were carried out according to conventional conditions or the conditions recommended by the manufacturer or the procedures provided by the device. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be obtained by conventional technical means or purchased commercially.

[0045] The main optical components of the femtosecond laser direct writing device used in the embodiment of the present invention are as follows: Figure 1 shown.

[0046] Embodiment 1:

[0047] (1) Weigh 0.024 g of 2-methyl-2-acrylic acid-2,2,6,6-tetramethyl-4-piperidinyl ester and place it in a 10 mL brown bottle. Then add 6 g of pentaerythritol triacrylate and ultrasonicate for 20 min to completely dissolve it. Then weigh 0.012 g of two-photon initiator a and place it in the above solution. Continue ultrasonicating for 30 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0048] (2) Place 1-2 drops of the above-mentioned photoresist on a glass substrate, call a specific program on the femtosecond laser system software for testing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is turned off first and then on during writing. The scanning speed is 1000 μm / s, the excitation light power is fixed at 19.4 mW, and the suppression light power is gradually stepped from 0.0 mW to 60.0 mW.

[0049] (3) After the writing is completed, the image is first developed with propylene glycol methyl ether acetate for 8 minutes, and then placed in isopropanol developer for further development for 3 minutes. Finally, the patterned two-dimensional lithography lines are obtained. Figure 2 As shown, compared with the following control example 1, the photoresist formulation achieves a significant transition from light promotion to light inhibition, greatly improving line accuracy, and the finest line accuracy can reach 75 nm.

[0050] Comparative Example 1:

[0051] (1) Weigh 0.012 g of two-photon initiator a into a 10 mL brown bottle, then add 6 g of pentaerythritol triacrylate and dissolve it completely after ultrasonic treatment for 30 min. Then, perform homogenization on a yellow light zone homogenizer for 24 h.

[0052] (2) Take 1-2 drops of the above photoresist and drip them on a glass substrate. Perform femtosecond laser direct writing on a laser system. The writing conditions are basically the same as those in Example 1. The scanning speed is 1000 μm / s, the excitation light power is fixed at 6.5 mW, and the suppression light power is gradually stepped from 0.0 mW to 60.0 mW.

[0053] (3) After the writing is completed, the development is performed, and the development conditions are consistent with those in Example 1. Figure 2 As shown, the photoresist formulation exhibits a significant photopromotion effect and poor lithography performance.

[0054] Embodiment 2:

[0055] (1) Weigh 0.03 g of tetramethylpiperidinium nitroxide phosphite triester and place it in a 3 mL brown bottle. Then add 2 g of n-butyl methacrylate and sonicate for 20 min to completely dissolve it. Then weigh 0.05 g of two-photon initiator b and place it in the above solution. Continue sonicating for 30 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0056] (2) Place 1-2 drops of the above-mentioned photoresist on a glass substrate, call a specific program on the femtosecond laser system software for 3D processing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is always on during writing, with a scanning speed of 1000 μm / s, the excitation light power is fixed at 13.4 mW, the suppression light power is fixed at 39.3 mW, the match pile plane line spacing is set to 300 nm, and the layer spacing is set to √2 times the line spacing.

[0057] (3) After writing is completed, the image is first developed with propylene glycol methyl ether acetate for 8 min, and then placed in ethanol developer for further development for 3 min. Finally, a patterned three-dimensional match pile structure is obtained. Figure 3 As shown, the three-dimensional match pile is formed by stacking two-dimensional written lines layer by layer. Compared with the following control example 2, this photoresist formula achieves better light inhibition effect, not only showing good three-dimensional processing capability, but also significantly improving the lithography resolution, and the best resolution can reach 300 nm.

[0058] Comparative Example 2:

[0059] (1) Weigh 0.05 g of two-photon initiator b into a 2 mL brown bottle, then add 2 g of n-butyl methacrylate and dissolve it completely after ultrasonic treatment for 20 min. Then, perform homogenization on a yellow light zone homogenizer for 24 h.

[0060] (2) Take 1-2 drops of the above-mentioned photoresist and drip them on a glass substrate. Perform femtosecond laser direct writing on a laser system. The writing conditions are basically the same as those in Example 2. The scanning speed is 1000 μm / s, the excitation light power is fixed at 6.2 mW, the suppression light power is fixed at 39.3 mW, the match pile plane line spacing is set to 300 nm, and the layer spacing is set to √2 times the line spacing.

[0061] (3) After writing is completed, development is performed, and the development conditions are consistent with those in Example 2. Figure 3 As shown, the photoresist formulation exhibits a significant photo-promotion effect and the lithography resolution is poor.

[0062] Embodiment 3:

[0063] (1) Weigh 0.04 g of bis(2,2,6,6-tetramethyl-4-piperidinyl-1-oxy) sebacate and place it in a 2 mL brown bottle. Then add 1 g of pentaerythritol triacrylate and sonicate for 20 min to completely dissolve it. Then weigh 0.02 g of two-photon initiator c and place it in the above solution. Continue sonicating for 35 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0064] (2) Place 1-2 drops of the above-mentioned photoresist on a glass substrate, call a specific program on the femtosecond laser system software for testing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is turned off first and then on during writing. The scanning speed is 2000 μm / s, the excitation light power is fixed at 8.7 mW, and the suppression light power is gradually stepped from 0.0 mW to 60.0 mW.

[0065] (3) After the writing is completed, the image is first developed with propylene glycol methyl ether acetate for 8 minutes, and then placed in isopropanol developer for further development for 3 minutes. Finally, the patterned two-dimensional lithography lines are obtained. Figure 4 As shown, compared with the control example 3 without adding quencher, the photoresist formulation realizes the performance transformation from light promotion to light inhibition, the finest line accuracy can reach 38 nm, and the photolithography accuracy is improved by 54%.

[0066] Comparative Example 3:

[0067] (1) Weigh 0.02 g of two-photon initiator c into a 2 mL brown bottle, then add 1 g of pentaerythritol triacrylate and dissolve it completely after ultrasonic treatment for 35 min. Then, perform homogenization on a yellow light zone homogenizer for 24 h.

[0068] (2) Take 1-2 drops of the above photoresist and drip them on a glass substrate. Perform femtosecond laser direct writing on a laser system. The writing conditions are basically the same as those in Example 3. The scanning speed is 2000 μm / s, the excitation light power is fixed at 5.6 mW, and the suppression light power is gradually stepped from 0.0 mW to 60.0 mW.

[0069] (3) After the writing is completed, the development is performed, and the development conditions are consistent with those in Example 3. Figure 4 As shown, the photoresist formulation exhibits a significant photopromotion effect and poor lithography performance.

[0070] Embodiment 4:

[0071] (1) Weigh 0.02 g of N,N-diethylhydroxylamine and place it in a 10 mL brown bottle. Then add 6 g of bisphenol A di(meth)acrylate and sonicate for 15 min to completely dissolve it. Then weigh 0.04 g of two-photon initiator e and place it in the above solution. Continue sonicating for 40 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0072] (2) Place 1-2 drops of the above-mentioned photoresist on a glass substrate, call a specific program on the femtosecond laser system software for 3D processing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is always on during writing, with a scanning speed of 1000 μm / s, an excitation light power fixed at 22.5 mW, a suppression light power fixed at 40.5 mW, a match pile plane line spacing of 400 nm, and a layer spacing of √2 times the line spacing.

[0073] (3) After writing, the image was first developed with propylene glycol monoethyl ether for 7 min, and then placed in isopropanol for further development for 2 min. Finally, a patterned three-dimensional matchstick structure was obtained. Figure 5 As shown, compared with the photoresist formulation without quencher, the photoresist formulation achieves a performance transition from photopromotion to photoinhibition, and has good three-dimensional processing capabilities, with the finest line accuracy reaching 100 nm and a processing resolution of 400 nm.

[0074] Embodiment 5:

[0075] (1) Weigh 0.04 g of 2-methyl-2-acrylic acid-2,2,6,6-tetramethyl-4-piperidinyl ester and place it in a 6 mL brown bottle. Then add 4 g of tricyclodecane dimethanol diacrylate and sonicate for 20 min to completely dissolve it. Then weigh 0.04 g of two-photon initiator f and place it in the above solution. Continue sonicating for 35 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0076] (2) Place 1-2 drops of the above-mentioned photoresist on a silicon wafer substrate, call a specific program on the femtosecond laser system software for 3D processing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is kept on during writing, with a scanning speed of 10,000 μm / s, the excitation light power fixed at 16.3 mW, and the suppression light power fixed at 36.3 mW.

[0077] (3) After writing is completed, the image is first developed with propylene glycol methyl ether acetate for 10 min, and then placed in ethanol for further development for 3 min. Finally, a patterned three-dimensional magician structure is obtained. Figure 6As shown, compared with the following control example 4, the photoresist formulation not only achieves a performance transition from photopromotion to photoinhibition, but also significantly improves the accuracy and resolution of the three-dimensional processing pattern.

[0078] Comparative Example 4:

[0079] (1) Weigh 0.04 g of two-photon initiator f into a 6 mL brown bottle, then add 4 g of tricyclodecane dimethanol diacrylate and dissolve it completely after ultrasonic treatment for 35 min. Then, homogenize it on a yellow light zone homogenizer for 24 h.

[0080] (2) Take 1-2 drops of the above photoresist and drip them on a silicon wafer substrate. Perform femtosecond laser direct writing on a laser system. The writing conditions are basically the same as those in Example 5. The scanning speed is 10000 μm / s, the excitation light power is fixed at 10.7 mW, and the suppression light power is fixed at 15.3 mW.

[0081] (3) After writing is completed, development is performed, and the development conditions are consistent with those in Example 5. Figure 6 As shown, the photoresist formulation exhibits a significant photo-promotion effect, and the accuracy and resolution of the three-dimensional processing pattern are poor.

[0082] Embodiment 6:

[0083] (1) Weigh 0.05 g of bis(2,2,6,6-tetramethyl-4-piperidinyl-1-oxy) sebacate and place it in a 6 mL brown bottle. Then add 4 g of tricyclodecane dimethanol diacrylate and sonicate for 20 min to completely dissolve it. Then weigh 0.04 g of two-photon initiator g and place it in the above solution. Continue sonicating for 35 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0084] (2) Place 1-2 drops of the above-mentioned photoresist on a glass substrate, call a specific program on the femtosecond laser system software for testing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is turned off first and then on during writing. The scanning speed is 1000 μm / s, the excitation light power is fixed at 21.5 mW, and the suppression light power is gradually stepped from 0.0 mW to 60.0 mW.

[0085] (3) After the writing is completed, the 2D patterned lithography lines are obtained by developing with propylene glycol methyl ether acetate for 10 min and then continuing to develop in ethanol for 3 min. Figure 7 As shown, compared with the following control example 5, the photoresist formulation achieves a performance transition from light promotion to light inhibition, the finest line accuracy can reach 60 nm, and the lithography accuracy is improved by 45%.

[0086] Comparative Example 5:

[0087] (4) Weigh 0.04 g of two-photon initiator g into a 6 mL brown bottle, then add 4 g of tricyclodecane dimethanol diacrylate and dissolve it completely after ultrasonic treatment for 35 min. Then, homogenize it on a yellow light zone homogenizer for 24 h.

[0088] (5) Take 1-2 drops of the above photoresist and drip them on a glass substrate. Perform femtosecond laser direct writing on a laser system. The writing conditions are basically the same as those in Example 5. The scanning speed is 1000 μm / s, the excitation light power is fixed at 10.7 mW, and the suppression light power is gradually stepped from 0.0 mW to 60.0 mW.

[0089] (6) After the writing is completed, the development is performed, and the development conditions are consistent with those in Example 6. Figure 7 As shown, the photoresist formulation exhibits a significant photopromotion effect and poor lithography performance.

[0090] Embodiment 7:

[0091] (1) Weigh 0.03 g of bis(2,2,6,6-tetramethyl-4-piperidinyl-1-oxy) sebacate and place it in a 3 mL brown bottle. Then add 2 g of dipentaerythritol pentaacrylate and sonicate for 20 min to completely dissolve it. Then weigh 0.02 g of two-photon initiator h and place it in the above solution. Continue sonicating for 40 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0092] (2) Place 1-2 drops of the above-mentioned photoresist on a glass substrate, call a specific program on the femtosecond laser system software for testing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is turned off first and then on during writing. The scanning speed is 10,000 μm / s, the excitation light power is fixed at 38.2 mW, and the suppression light power is fixed at 55.0 mW.

[0093] (3) After the writing is completed, the image is first developed with propylene glycol methyl ether acetate for 8 minutes, and then placed in isopropanol for further development for 3 minutes. Finally, a patterned two-dimensional lithography line is obtained. Figure 8 As shown, compared with the following Control Example 6, the photoresist formulation achieves a performance transition from photopromotion to photoinhibition.

[0094] Comparative Example 6:

[0095] (1) Weigh 0.02 g of two-photon initiator h into a 3 mL brown bottle, then add 2 g of dipentaerythritol pentaacrylate and dissolve it completely after ultrasonic treatment for 40 min. Then, perform homogenization on a yellow light zone homogenizer for 24 h.

[0096] (2) Take 1-2 drops of the above photoresist and drip them on a glass substrate. Perform femtosecond laser direct writing on a laser system. The writing conditions are basically the same as those in Example 6. The scanning speed is 10000 μm / s, the excitation light power is fixed at 27.5 mW, and the suppression light power is fixed at 55.0 mW.

[0097] (3) After writing is completed, development is performed, and the development conditions are consistent with those in Example 7. Figure 8 As shown, the photoresist formulation exhibits a significant photopromotion effect and poor lithography performance.

[0098] Embodiment 8:

[0099] (1) Weigh 0.03 g of bis(2,2,6,6-tetramethyl-4-piperidinyl-1-oxy) sebacate and place it in a 3 mL brown bottle. Then add 2 g of n-butyl methacrylate and sonicate for 20 min to completely dissolve it. Then weigh 0.05 g of two-photon initiator i and place it in the above solution. Continue sonicating for 30 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0100] (2) Place 1-2 drops of the above-mentioned photoresist on a glass substrate, call a specific program on the femtosecond laser system software for 3D processing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is kept on during writing, with a scanning speed of 20,000 μm / s, the excitation light power fixed at 23.4 mW, and the suppression light power fixed at 35.3 mW.

[0101] (3) After the writing is completed, the image is first developed with propylene glycol methyl ether acetate for 8 min, and then placed in ethanol developer for further development for 3 min. Finally, a self-designed patterned three-dimensional hollow five-pointed star structure is obtained. Fig. 9 As shown, compared with the following control example 7, the photoresist formulation exhibits good three-dimensional processing capability and suitable lithography resolution.

[0102] Comparative Example 7:

[0103] (1) Weigh 0.05 g of two-photon initiator i and place it in a 3 mL brown bottle. Then add 2 g of n-butyl methacrylate and sonicate for 20 min. After it is completely dissolved, perform homogenization on a yellow light zone homogenizer for 24 h.

[0104] (2) Place 1-2 drops of the above-mentioned photoresist on a glass substrate, call a specific program on the femtosecond laser system software for 3D processing, and turn on the 780 nm femtosecond laser and 532 nm continuous laser at the same time. The suppression light is kept on during writing, with a scanning speed of 20,000 μm / s, the excitation light power fixed at 16.5 mW, and the suppression light power fixed at 35.3 mW.

[0105] After the writing is completed, the image is first developed with propylene glycol methyl ether acetate for 8 min, and then placed in ethanol developer for further development for 3 min. Finally, a patterned three-dimensional hollow five-pointed star is obtained. Fig. 9 As shown, the photoresist formulation exhibits a significant photo-promoting effect, the writing resolution is poor, and it is not suitable for three-dimensional processing.

Claims

1. A two-photon photoresist for femtosecond laser direct writing based on edge light suppression, characterized in that: The two-photon photoresist is composed of 0.1-5.0% quencher, 0.1-2.5% two-photon initiator and 92.5-99.8% resin monomer by mass percentage; The resin monomer is selected from the following one or a combination of several in any proportion: pentaerythritol triacrylate, dipentaerythritol pentaacrylate, n-butyl methacrylate, tricyclodecane dimethanol diacrylate, bisphenol A di(meth)acrylate, ethoxylated bisphenol A (meth) diacrylate; The quencher is selected from one or more of the following organic substances containing nitroxide free radicals: pentamethylpiperidinol, tetramethylpiperidinyl nitroxide free radical phosphite triester, N,N-diethylhydroxylamine, sebacate bis(2,2,6,6-tetramethyl-4-piperidinyl-1-oxy) ester, 2-methyl-2-acrylic acid-2,2,6,6-tetramethyl-4-piperidinyl ester, 2,2,6,6-tetramethylpiperidinyl oxide, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyl 1-oxy free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidinyl 1-oxy free radical; The two-photon initiator is one of the following compounds ai: 。 2. A patterning method for a two-photon photoresist for femtosecond laser direct writing based on edge light suppression as claimed in claim 1, comprising the following steps: (1) Place 1-2 drops of two-photon photoresist for femtosecond laser direct writing onto a glass or silicon wafer substrate; (2) Call the patterning program on the laser direct writing software; (3) Simultaneously turn on the 780 nm femtosecond laser and the 532 nm continuous laser to expose the two-photon photoresist and then let it stand, wherein the 532 nm continuous laser is controlled according to the design pattern setting program, that is, it is turned on or off at a certain time according to the pattern design setting; (4) The photoresist pattern can be obtained after development in the primary developer and the secondary developer respectively.

3. The patterning method according to claim 2, wherein: The primary developer is one or a mixture of propylene glycol methyl ether acetate, propylene glycol monomethyl ether or propylene glycol monoethyl ether, and the secondary developer is isopropyl alcohol or ethanol; the primary development time is 6-10 minutes, and the secondary development time is 2-5 minutes.

4. The patterning method according to claim 2, wherein: The laser scanning speed is 150-50000 μm / s.

5. The patterning method according to claim 2, wherein: The excitation light power is 5-70 mW, and the suppression light power is 5-70 mW.

6. The patterning method according to claim 5, characterized in that: The excitation light power is 5-40 mW, and the suppression light power is 30-60 mW.

7. The patterning method according to claim 2, wherein: The pattern is a three-dimensional pattern.

Images