Self-standing-wave-resistant photoresist and preparation process thereof

Abstract

The invention discloses a self-standing-wave-resistant photoresist and a preparation process thereof, and relates to the technical field of photoresists. The colored agent is added into the photoresist, reflected light is absorbed, the interference phenomenon is reduced, and therefore the standing wave prevention effect is achieved. No extra coating is needed, and the process is simple. According to the invention, sulfhydrylated titanium dioxide is prepared, then a sodium borohydride reducing agent is added, metal silver is loaded on the sulfhydrylated titanium dioxide, nano-silver loaded titanium dioxide is added into the photoresist, and the nano-silver loaded titanium dioxide is a photocatalyst, so that the exposure efficiency of the photoresist can be improved after the nano-silver is loaded. And moreover, the contact area between the photoresist and the silicon substrate is also increased by loading the metal silver, so that the adhesive force is improved. The acid resistance of the titanium dioxide and the synergistic effect of the nano-silver can enhance the acid shedding resistance of the photoresist in the subsequent etching process.

Description

Technical Field

[0001] The invention relates to the technical field of photoresists, in particular to a self-standing wave-proof photoresist and a preparation process thereof. Background Art

[0002] In the field of semiconductor manufacturing and microelectronics processing, photolithography is the core process for achieving high-precision pattern transfer. In the photolithography process, the standing wave effect is caused by the reflection of light at the interface between the photoresist and the substrate and the interference with the incident light, resulting in ripples on the edge of the photoresist pattern. The standing wave effect will seriously affect the resolution and line width control.

[0003] In order to suppress the standing wave effect, traditional methods reduce the standing wave by adding an anti-reflection layer or optimizing the exposure conditions, but these methods increase the process complexity, and traditional photoresists have poor corrosion resistance and a short service life.

[0004] In order to solve the above problems and improve the corrosion resistance of the photoresist, the present invention provides a self-standing wave-proof photoresist and a preparation process thereof. Summary of the invention

[0005] The purpose of the present invention is to provide a self-standing wave-proof photoresist and a preparation process thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A preparation process of a self-standing wave-proof photoresist comprises the following steps:

[0008] Step 1: Take a solvent, a modified phenolic resin, a photosensitizer, titanium dioxide loaded with nano-silver, an organic silicon leveling agent, and an adhesion promoter, stir evenly to obtain a mixed solution;

[0009] Step 2: Add colorant to the mixed solution and stir evenly to obtain a photoresist with self-preventing standing waves.

[0010] More optimally, the self-standing wave-proof photoresist comprises the following components, calculated by weight: 60-65 parts of solvent, 30-33 parts of modified phenolic resin, 5-5.5 parts of photosensitizer, 2-3 parts of nanosilver-loaded titanium dioxide, 0.2-0.4 parts of silicone leveling agent, 0.3-0.6 parts of adhesion promoter, and 1-2 parts of colorant.

[0011] More optimally, the preparation method of the nano-silver-loaded titanium dioxide is: take silver nitrate and deionized water, stir evenly, add thiolated titanium dioxide, heat to 65-70°C, react for 10-12h, filter, wash, add deionized water, stir evenly, add sodium borohydride, stir for 20-30min, filter, wash, and dry to obtain nano-silver-loaded titanium dioxide.

[0012] Preferably, the preparation method of the mercapto-functionalized titanium dioxide is as follows: Take titanium dioxide and deionized water, and perform ultrasonic dispersion to obtain a titanium dioxide solution; take ethanol, deionized water, and the titanium dioxide solution, add 3-mercaptopropyltrimethoxysilane, and react for 22-24 h to obtain mercapto-functionalized titanium dioxide.

[0013] Preferably, the preparation method of the modified phenolic resin is as follows: Take 3,5-xylenol, p-cresol, m-cresol, formalin solution, and oxalic acid, pass nitrogen, heat up to 40-42 °C, react for 60-70 min, heat up to 60-65 °C, react for 2-2.5 h, add oxalic acid, heat up to 100 °C, react for 3-5 h, add an epoxy-group branched polymer, and stir for 2-3 h to obtain the modified phenolic resin.

[0014] Preferably, the preparation method of the epoxy-group branched polymer includes the following steps:

[0015] S1: Take diethanolamine and anhydrous methanol, stir evenly, pass nitrogen, dropwise add methyl acrylate, heat up to 35-40 °C, react for 4-5 h, perform rotary evaporation and extraction to obtain compound A; take trimethylolpropane and p-toluenesulfonic acid, heat up to 110-112 °C, dropwise add compound A, heat up to 120-122 °C, stir for 5-6 h, and purify to obtain a hydroxyl-group branched polymer;

[0016] S2: Take the hydroxyl-group branched polymer and N,N-dimethylformamide, stir evenly, add boron trifluoride diethyl etherate, dropwise add epichlorohydrin, heat up to 65-70 °C, react for 2-3 h, perform rotary evaporation, dropwise add an aqueous sodium hydroxide solution, heat up to 80-85 °C, react for 2-3 h, perform rotary evaporation, and filter to obtain the epoxy-group branched polymer.

[0017] Preferably, the photosensitizer is any one of 2,3,4,4'-tetrahydroxybenzophenone or 2,2',4,4'-tetrahydroxybenzophenone; the solvent is any one of ethyl acetate or n-butyl acetate; the organosilicon leveling agent is polydimethylsiloxane; the adhesion promoter is γ-glycidoxypropyltrimethylsilane.

[0018] The colorant is any one of solvent red, sudan red, solvent yellow, pigment black 32, Prussian blue soluble, 29H,31H-phthalocyanine, or phthalocyanine green.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. In the present invention, a colorant is added to the photoresist to absorb the reflected light and reduce the interference phenomenon, thereby achieving the effect of preventing standing waves. The present invention does not require an additional coating and has a simple process.

[0021] 2. The present invention prepares a mercapto-functionalized titanium dioxide, and then loads silver metal on it by adding a sodium borohydride reducing agent. Titanium dioxide loaded with silver nanoparticles is added to the photoresist. Titanium dioxide is a photocatalyst. After loading silver nanoparticles, the exposure efficiency of the photoresist can be improved. Moreover, loading silver metal also increases the contact area between the photoresist and the silicon substrate, thereby improving the adhesion. The synergistic effect of the acid resistance of titanium dioxide and silver nanoparticles can enhance the acid resistance and peeling resistance of the photoresist in the subsequent etching process.

[0022] 3. The present invention modifies phenolic resin by adding an epoxy-group branched polymer, so that the phenolic resin has epoxy groups. The epoxy groups have good compatibility with the mercapto groups on the titanium dioxide loaded with silver nanoparticles, so that the titanium dioxide loaded with silver nanoparticles has good dispersibility in the photoresist, and the acid resistance and peeling resistance and adhesion of the photoresist are improved. Detailed implementation mode

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] There are no special restrictions on the sources and models of the substances involved in the present invention. Exemplarily, they include: Solvent Red: Solvent Red 195, which can be purchased from Wuhan Mike Biotechnology Co., Ltd.; Titanium Dioxide: particle size: 40 nm, which can be purchased from Kermel.

[0025] Example 1: A preparation process of a self-standing-wave-preventing photoresist, comprising the following steps:

[0026] Step 1: Take a solvent, a modified phenolic resin, a photosensitizer, titanium dioxide loaded with silver nanoparticles, an organosilicon leveling agent, and an adhesion promoter, stir evenly, add a colorant, and stir evenly to obtain a self-standing-wave-preventing photoresist;

[0027] The self-standing-wave-preventing photoresist comprises the following components in parts by mass: 62 parts of a solvent, 31 parts of a modified phenolic resin, 5 parts of a photosensitizer, 2.5 parts of titanium dioxide loaded with silver nanoparticles, 0.3 part of an organosilicon leveling agent, 0.4 part of an adhesion promoter, and 1.5 parts of a colorant;

[0028] The photosensitizer is 2,3,4,4'-tetrahydroxybenzophenone; the solvent is ethyl acetate;

[0029] The silicone leveling agent is polydimethylsiloxane; the adhesion promoter is γ-glycidoxypropyltrimethylsilane; the colorant is solvent red;

[0030] Step 2: Preparation of titanium dioxide loaded with silver nanoparticles, including the following steps:

[0031] S1: Preparation of mercapto-functionalized titanium dioxide:

[0032] Take 2 g of titanium dioxide and 100 mL of deionized water, and disperse them by ultrasonic treatment to obtain a titanium dioxide solution; take 100 mL of ethanol, 2 mL of deionized water, and 30 mL of the titanium dioxide solution, add 2 g of 3-mercaptopropyltrimethoxysilane, and react for 23 h to obtain mercapto-functionalized titanium dioxide;

[0033] S2: Take 5 g of silver nitrate and 100 mL of deionized water, stir evenly, add 1 g of mercapto-functionalized titanium dioxide, heat up to 68 °C, react for 11 h, filter and wash, add 100 mL of deionized water, stir evenly, add 5 mL of sodium borohydride with a concentration of 50 mM, stir for 25 min, filter, wash and dry to obtain titanium dioxide loaded with silver nanoparticles;

[0034] Step 3: Preparation of epoxy-functionalized branched polymer:

[0035] Take 11 g of diethanolamine and 10 mL of anhydrous methanol, stir evenly, pass nitrogen, dropwise add 13 g of methyl acrylate, heat up to 38 °C, react for 4.5 h, perform rotary evaporation and extraction to obtain compound A; take 14 g of trimethylolpropane and 0.8 g of p-toluenesulfonic acid, heat up to 111 °C, dropwise add compound A, heat up to 121 °C, stir for 5.5 h, and purify to obtain a hydroxyl-functionalized branched polymer;

[0036] Take 7.5 g of the hydroxyl-functionalized branched polymer and 10 g of N,N-dimethylformamide, stir evenly, add 0.2 g of boron trifluoride diethyl etherate, dropwise add 40 g of epichlorohydrin, heat up to 67 °C, react for 2.5 h, perform rotary evaporation, dropwise add 0.3 mol of an aqueous sodium hydroxide solution with a concentration of 25%, heat up to 82 °C, react for 2.5 h, perform rotary evaporation and filtration to obtain an epoxy-functionalized branched polymer;

[0037] Step 4: Preparation of modified phenolic resin, including the following steps:

[0038] S1: Take 10 g of 3,5-xylenol, 70 g of p-cresol, 132 g of m-cresol, 120 g of a 37% formalin solution, and 2 g of oxalic acid, pass nitrogen, heat up to 41 °C, react for 65 min, heat up to 62 °C, react for 2.3 h, add 2 g of oxalic acid, heat up to 100 °C, react for 4 h, and distill to obtain phenolic resin;

[0039] S2: Take 100 g of phenolic resin and 20 g of epoxy-based branched polymer, stir for 2.5 h to obtain modified phenolic resin.

[0040] Example 2: A preparation process of a lithographic resin with self anti-standing wave includes the following steps:

[0041] Step 1: Take a solvent, modified phenolic resin, photosensitizer, titanium dioxide loaded with nano silver, silicone leveling agent, adhesion promoter, stir evenly, add a colorant, stir evenly to obtain a lithographic resin with self anti-standing wave;

[0042] The lithographic resin with self anti-standing wave includes the following components by mass fraction: 60 parts of solvent, 30 parts of modified phenolic resin, 5 parts of photosensitizer, 2 parts of titanium dioxide loaded with nano silver, 0.2 part of silicone leveling agent, 0.3 part of adhesion promoter, 1 part of colorant;

[0043] The photosensitizer is 2,2',4,4'-tetrahydroxybenzophenone; the solvent is n-butyl acetate; the silicone leveling agent is polydimethylsiloxane; the adhesion promoter is γ-glycidoxypropyltrimethylsilane; the colorant is solvent red;

[0044] Step 2: The preparation of titanium dioxide loaded with nano silver includes the following steps:

[0045] S1: The preparation of mercapto-functionalized titanium dioxide:

[0046] Take 2 g of titanium dioxide and 100 mL of deionized water, ultrasonically disperse to obtain a titanium dioxide solution; take 100 mL of ethanol, 2 mL of deionized water, 30 mL of titanium dioxide solution, add 2 g of 3-mercaptopropyltrimethoxysilane, react for 22 h to obtain mercapto-functionalized titanium dioxide;

[0047] S2: Take 5 g of silver nitrate and 100 mL of deionized water, stir evenly, add 1 g of mercapto-functionalized titanium dioxide, heat up to 65 °C, react for 10 h, filter and wash, add 100 mL of deionized water, stir evenly, add 5 mL of sodium borohydride with a concentration of 50 mM, stir for 20 min, filter, wash and dry to obtain titanium dioxide loaded with nano silver;

[0048] Step 3: The preparation of epoxy-based branched polymer:

[0049] Take 11 g of diethanolamine and 10 mL of anhydrous methanol, stir evenly, pass nitrogen, dropwise add 13 g of methyl acrylate, heat up to 35 °C, react for 4 h, rotary evaporate and extract to obtain compound A; take 14 g of trimethylolpropane and 0.8 g of p-toluenesulfonic acid, heat up to 110 °C, dropwise add compound A, heat up to 120 °C, stir for 5 h, purify to obtain hydroxy-branched polymer;

[0050] Take 7.5 g of hydroxyl-branched polymer, 10 g of N,N-dimethylformamide, stir evenly, add 0.2 g of boron trifluoride diethyl ether, dropwise add 40 g of epichlorohydrin, heat up to 65 °C, react for 2 h, perform rotary evaporation, dropwise add 0.3 mol of 25% sodium hydroxide aqueous solution, heat up to 80 °C, react for 2 h, perform rotary evaporation, filter to obtain epoxy-group branched polymer;

[0051] Step Four: Preparation of modified phenolic resin, including the following steps:

[0052] S1: Take 10 g of 3,5-xylenol, 70 g of p-cresol, 132 g of m-cresol, 120 g of 37% formalin solution, 2 g of oxalic acid, pass nitrogen, heat up to 40 °C, react for 60 min, heat up to 60 °C, react for 2 h, add 2 g of oxalic acid, heat up to 100 °C, react for 3 h, distill to obtain phenolic resin;

[0053] S2: Take 100 g of phenolic resin, 20 g of epoxy-group branched polymer, stir for 2 h to obtain modified phenolic resin.

[0054] Example 3: A preparation process of a lithographic resin with self-prevention of standing waves, including the following steps:

[0055] Step One: Take a solvent, modified phenolic resin, photosensitizer, titanium dioxide loaded with nano silver, silicone leveling agent, adhesion promoter, stir evenly, add a colorant, stir evenly to obtain a lithographic resin with self-prevention of standing waves;

[0056] The lithographic resin with self-prevention of standing waves includes the following components, by mass: 65 parts of solvent, 33 parts of modified phenolic resin, 5.5 parts of photosensitizer, 3 parts of titanium dioxide loaded with nano silver, 0.4 part of silicone leveling agent, 0.6 part of adhesion promoter, 2 parts of colorant;

[0057] The photosensitizer is 2,3,4,4'-tetrahydroxybenzophenone; the solvent is ethyl acetate;

[0058] The silicone leveling agent is polydimethylsiloxane; the adhesion promoter is γ-glycidoxypropyltrimethylsilane; the colorant is solvent red;

[0059] Step Two: Preparation of titanium dioxide loaded with nano silver, including the following steps:

[0060] S1: Preparation of mercapto-functionalized titanium dioxide:

[0061] Take 2 g of titanium dioxide, 100 mL of deionized water, perform ultrasonic dispersion to obtain a titanium dioxide solution; take 100 mL of ethanol, 2 mL of deionized water, 30 mL of titanium dioxide solution, add 2 g of 3-mercaptopropyltrimethoxysilane, react for 24 h to obtain mercapto-functionalized titanium dioxide;

[0062] S2: Take 5 g of silver nitrate and 100 mL of deionized water, stir evenly, add 1 g of mercapto-functionalized titanium dioxide, heat up to 70 °C, react for 12 h, filter, wash, add 100 mL of deionized water, stir evenly, add 5 mL of sodium borohydride with a concentration of 50 mM, stir for 30 min, filter, wash, and dry to obtain titanium dioxide loaded with silver nanoparticles;

[0063] Step Three: Preparation of epoxy-functionalized branched polymer:

[0064] Take 11 g of diethanolamine and 10 mL of anhydrous methanol, stir evenly, pass nitrogen, dropwise add 13 g of methyl acrylate, heat up to 40 °C, react for 5 h, rotary evaporate and extract to obtain Compound A; take 14 g of trimethylolpropane and 0.8 g of p-toluenesulfonic acid, heat up to 112 °C, dropwise add Compound A, heat up to 122 °C, stir for 6 h, and purify to obtain a hydroxyl-functionalized branched polymer;

[0065] Take 7.5 g of the hydroxyl-functionalized branched polymer and 10 g of N,N-dimethylformamide, stir evenly, add 0.2 g of boron trifluoride diethyl etherate, dropwise add 40 g of epichlorohydrin, heat up to 70 °C, react for 3 h, rotary evaporate, dropwise add 0.3 mol of a 25% aqueous sodium hydroxide solution, heat up to 85 °C, react for 3 h, rotary evaporate, and filter to obtain an epoxy-functionalized branched polymer;

[0066] Step Four: Preparation of modified phenolic resin, including the following steps:

[0067] S1: Take 10 g of 3,5-xylenol, 70 g of p-cresol, 132 g of m-cresol, 120 g of a 37% formalin solution, and 2 g of oxalic acid, pass nitrogen, heat up to 42 °C, react for 70 min, heat up to 65 °C, react for 2.5 h, add 2 g of oxalic acid, heat up to 100 °C, react for 5 h, and distill to obtain phenolic resin;

[0068] S2: Take 100 g of phenolic resin and 20 g of epoxy-functionalized branched polymer, stir for 3 h to obtain modified phenolic resin.

[0069] Comparative Example 1: Without loading silver nanoparticles, the rest is the same as in Example 1:

[0070] Step One: Take a solvent, modified phenolic resin, photosensitizer, mercapto-functionalized titanium dioxide, silicone leveling agent, adhesion promoter, stir evenly, add a colorant, and stir evenly to obtain a lithographic resist with self anti-standing wave;

[0071] The lithographic resist with self anti-standing wave includes the following components, by mass: 62 parts of solvent, 31 parts of modified phenolic resin, 5 parts of photosensitizer, 2.5 parts of mercapto-functionalized titanium dioxide, 0.3 part of silicone leveling agent, 0.4 part of adhesion promoter, and 1.5 parts of colorant;

[0072] The photosensitizer is 2,3,4,4'-tetrahydroxybenzophenone; the solvent is ethyl acetate;

[0073] The organosilicon leveling agent is polydimethylsiloxane; the adhesion promoter is γ-glycidoxypropyltrimethylsilane; the colorant is solvent red;

[0074] Step 2: Preparation of mercapto-functionalized titanium dioxide:

[0075] Take 2 g of titanium dioxide and 100 mL of deionized water, ultrasonically disperse to obtain a titanium dioxide solution; take 100 mL of ethanol, 2 mL of deionized water, and 30 mL of the titanium dioxide solution, add 2 g of 3-mercaptopropyltrimethoxysilane, and react for 23 h to obtain mercapto-functionalized titanium dioxide;

[0076] Step 3: Preparation of epoxy-functionalized branched polymer:

[0077] Take 11 g of diethanolamine and 10 mL of anhydrous methanol, stir evenly, pass nitrogen, dropwise add 13 g of methyl acrylate, heat up to 38 °C, react for 4.5 h, perform rotary evaporation and extraction to obtain compound A; take 14 g of trimethylolpropane and 0.8 g of p-toluenesulfonic acid, heat up to 111 °C, dropwise add compound A, heat up to 121 °C, stir for 5.5 h, and purify to obtain a hydroxyl-functionalized branched polymer;

[0078] Take 7.5 g of the hydroxyl-functionalized branched polymer and 10 g of N,N-dimethylformamide, stir evenly, add 0.2 g of boron trifluoride diethyl etherate, dropwise add 40 g of epichlorohydrin, heat up to 67 °C, react for 2.5 h, perform rotary evaporation, dropwise add 0.3 mol of 25% sodium hydroxide aqueous solution, heat up to 82 °C, react for 2.5 h, perform rotary evaporation and filtration to obtain the epoxy-functionalized branched polymer;

[0079] Step 4: Preparation of modified phenolic resin, including the following steps:

[0080] S1: Take 10 g of 3,5-xylenol, 70 g of p-cresol, 132 g of m-cresol, 120 g of 37% formalin solution, and 2 g of oxalic acid, pass nitrogen, heat up to 41 °C, react for 65 min, heat up to 62 °C, react for 2.3 h, add 2 g of oxalic acid, heat up to 100 °C, react for 4 h, and distill to obtain phenolic resin;

[0081] S2: Take 100 g of phenolic resin and 20 g of the epoxy-functionalized branched polymer, stir for 2.5 h to obtain the modified phenolic resin.

[0082] Comparative Example 2: Reduce the amount of 3-mercaptopropyltrimethoxysilane used, and the rest is the same as in Example 1:

[0083] Step 1: Take a solvent, a modified phenolic resin, a photosensitizer, titanium dioxide loaded with silver nanoparticles, an organosilicon leveling agent, and an adhesion promoter, stir evenly, add a colorant, and stir evenly to obtain a lithographic resin with self anti-standing wave;

[0084] The lithographic resin with self anti-standing wave includes the following components by mass: 62 parts of solvent, 31 parts of modified phenolic resin, 5 parts of photosensitizer, 2.5 parts of titanium dioxide loaded with silver nanoparticles, 0.3 parts of organosilicon leveling agent, 0.4 parts of adhesion promoter, and 1.5 parts of colorant;

[0085] The photosensitizer is 2,3,4,4'-tetrahydroxybenzophenone; the solvent is ethyl acetate;

[0086] The organosilicon leveling agent is polydimethylsiloxane; the adhesion promoter is γ-glycidoxypropyltrimethylsilane; the colorant is solvent red;

[0087] Step 2: Preparation of titanium dioxide loaded with silver nanoparticles, including the following steps:

[0088] S1: Preparation of mercapto-functionalized titanium dioxide:

[0089] Take 2 g of titanium dioxide and 100 mL of deionized water, ultrasonically disperse to obtain a titanium dioxide solution; take 100 mL of ethanol, 2 mL of deionized water, and 30 mL of the titanium dioxide solution, add 0.5 g of 3-mercaptopropyltrimethoxysilane, react for 23 h to obtain mercapto-functionalized titanium dioxide;

[0090] S2: Take 5 g of silver nitrate and 100 mL of deionized water, stir evenly, add 1 g of mercapto-functionalized titanium dioxide, heat up to 68 °C, react for 11 h, filter and wash, add 100 mL of deionized water, stir evenly, add 5 mL of sodium borohydride with a concentration of 50 mM, stir for 25 min, filter, wash, and dry to obtain titanium dioxide loaded with silver nanoparticles;

[0091] Step 3: Preparation of epoxy-functionalized branched polymer:

[0092] Take 11 g of diethanolamine and 10 mL of anhydrous methanol, stir evenly, pass nitrogen, dropwise add 13 g of methyl acrylate, heat up to 38 °C, react for 4.5 h, rotary evaporate and extract to obtain compound A; take 14 g of trimethylolpropane and 0.8 g of p-toluenesulfonic acid, heat up to 111 °C, dropwise add compound A, heat up to 121 °C, stir for 5.5 h, and purify to obtain a hydroxyl-functionalized branched polymer;

[0093] Take 7.5 g of hydroxyl-branched polymer, 10 g of N,N-dimethylformamide, stir evenly, add 0.2 g of boron trifluoride diethyl etherate, dropwise add 40 g of epichlorohydrin, heat up to 67 °C, react for 2.5 h, perform rotary evaporation, dropwise add 0.3 mol of 25% sodium hydroxide aqueous solution, heat up to 82 °C, react for 2.5 h, perform rotary evaporation, filter, and obtain epoxy-group-branched polymer;

[0094] Step Four: Preparation of modified phenolic resin, including the following steps:

[0095] S1: Take 10 g of 3,5-xylenol, 70 g of p-cresol, 132 g of m-cresol, 120 g of 37% formalin solution, 2 g of oxalic acid, pass nitrogen, heat up to 41 °C, react for 65 min, heat up to 62 °C, react for 2.3 h, add 2 g of oxalic acid, heat up to 100 °C, react for 4 h, distill, and obtain phenolic resin;

[0096] S2: Take 100 g of phenolic resin, 20 g of epoxy-group-branched polymer, stir for 2.5 h, and obtain modified phenolic resin.

[0097] Comparative Example 3: Do not use epoxy-group-branched polymer to modify phenolic resin, and the rest is the same as in Example 1:

[0098] Step One: Take solvent, phenolic resin, photosensitizer, titanium dioxide loaded with nano silver, silicone leveling agent, adhesion promoter, stir evenly, add colorant, stir evenly, and obtain a lithographic resist with self anti-standing wave;

[0099] The lithographic resist with self anti-standing wave includes the following components, by mass: 62 parts of solvent, 31 parts of phenolic resin, 5 parts of photosensitizer, 2.5 parts of titanium dioxide loaded with nano silver, 0.3 part of silicone leveling agent, 0.4 part of adhesion promoter, 1.5 parts of colorant;

[0100] The photosensitizer is 2,3,4,4'-tetrahydroxybenzophenone; the solvent is ethyl acetate;

[0101] The silicone leveling agent is polydimethylsiloxane; the adhesion promoter is γ-glycidoxypropyltrimethylsilane; the colorant is solvent red;

[0102] Step Two: Preparation of titanium dioxide loaded with nano silver, including the following steps:

[0103] S1: Preparation of mercapto-functionalized titanium dioxide:

[0104] Take 2 g of titanium dioxide and 100 mL of deionized water, and ultrasonically disperse them to obtain a titanium dioxide solution; take 100 mL of ethanol, 2 mL of deionized water, and 30 mL of the titanium dioxide solution, add 2 g of 3-mercaptopropyltrimethoxysilane, and react for 23 h to obtain thiolated titanium dioxide;

[0105] S2: Take 5 g of silver nitrate and 100 mL of deionized water, stir evenly, add 1 g of thiolated titanium dioxide, heat up to 68 °C, react for 11 h, filter and wash, add 100 mL of deionized water, stir evenly, add 5 mL of sodium borohydride with a concentration of 50 mM, stir for 25 min, filter, wash, and dry to obtain titanium dioxide loaded with silver nanoparticles;

[0106] Step 3: Preparation of modified phenolic resin:

[0107] Take 10 g of 3,5-xylenol, 70 g of p-cresol, 132 g of m-cresol, 120 g of a 37% formalin solution, and 2 g of oxalic acid. Pass nitrogen, heat up to 41 °C, react for 65 min, heat up to 62 °C, react for 2.3 h, add 2 g of oxalic acid, heat up to 100 °C, react for 4 h, and distill to obtain phenolic resin.

[0108] Experiment:

[0109] Coat the anti-standing-wave photoresists prepared in Examples 1 to 3 and Comparative Examples 1 to 3 of the present invention on a single-side polished silicon substrate, dry at 100 °C for 60 s, and the film thickness after drying is 0.75 μm. Expose the surface of the substrate, and the exposure energy is 53 mJ / cm 2 , then heat bake at 130 °C for 60 s, spray develop with 2.38 wt% tetramethylammonium hydroxide for 60 s to obtain a post-lithography sample; test the resolution; soak the post-lithography sample in a hydrochloric acid solution with a concentration of 8% for 2 h at an immersion temperature of 25 °C, take it out after 2 h, observe whether the photoresist film has blistering or peeling, test the photoresist film peeling rate, and the obtained data are shown in Table 1 below:

[0110] Table 1

[0111] Resolution / μm Drop-off rate Example 1 0.1 1％～2％ Example 2 0.1 1％～2％ Example 3 0.1 1％～2％ Comparative Example 1 0.1 6％～7％ Comparative Example 2 0.1 3％～4％ Comparative Example 3 0.1 5％～6％

[0112] Conclusion: It can be seen from the data comparison in the table that in Comparative Example 1, no silver nanoparticles are loaded, and at this time, the acid resistance and peeling resistance of the photoresist sample are poor, and the peeling rate increases. In Comparative Example 2, the amount of 3-mercaptopropyltrimethoxysilane is reduced, and the mercapto groups on titanium dioxide are reduced. Therefore, the amount of silver metal loaded on titanium dioxide is reduced, and at this time, the acid resistance and peeling resistance of the photoresist sample are poor, and the peeling rate increases. In Comparative Example 3, no epoxy group-branched polymer is used to modify the phenolic resin. At this time, the dispersion of titanium dioxide loaded with silver nanoparticles in the photoresist is poor, which affects the acid resistance and peeling resistance of the photoresist. In Examples 1 to 3 of the present invention, a mercapto-functionalized titanium dioxide was prepared, and then silver metal was loaded thereon by adding a sodium borohydride reducing agent. Titanium dioxide loaded with silver nanoparticles was added to the photoresist. The synergistic effect of the acid resistance of titanium dioxide and silver nanoparticles can enhance the acid resistance and peeling resistance of the photoresist in the subsequent etching process. In Examples 1 to 3 of the present invention, the phenolic resin was modified by adding an epoxy group-branched polymer, so that the phenolic resin carried epoxy groups. The epoxy groups and the mercapto groups on the titanium dioxide loaded with silver nanoparticles have good compatibility, so that the titanium dioxide loaded with silver nanoparticles has good dispersion in the photoresist, and the acid resistance and peeling resistance, adhesion and exposure efficiency of the photoresist are improved.

[0113] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes that fall within the meaning and scope of the equivalent elements of the claims in the present invention.

Claims

1. A process for preparing a self-standing wave-proof photoresist, characterized in that: The following steps are involved: Step 1: Take a solvent, a modified phenolic resin, a photosensitizer, titanium dioxide loaded with nano-silver, an organic silicon leveling agent, and an adhesion promoter, stir evenly to obtain a mixed solution; Step 2: Add colorant to the mixed solution and stir evenly to obtain a photoresist with self-preventing standing waves.

2. The process for preparing a self-standing wave-proof photoresist according to claim 1, characterized in that: The self-standing wave-proof photoresist comprises the following components, calculated by weight: 60-65 parts of solvent, 30-33 parts of modified phenolic resin, 5-5.5 parts of photosensitizer, 2-3 parts of nanosilver-loaded titanium dioxide, 0.2-0.4 parts of organic silicon leveling agent, 0.3-0.6 parts of adhesion promoter, and 1-2 parts of colorant.

3. The process for preparing a self-standing wave-proof photoresist according to claim 1, characterized in that: The preparation method of the nano-silver-loaded titanium dioxide is as follows: silver nitrate and deionized water are taken, stirred evenly, thiolated titanium dioxide is added, the temperature is raised to 65-70° C., the reaction is performed for 10-12 hours, filtered, washed, deionized water is added, stirred evenly, sodium borohydride is added, stirred for 20-30 minutes, filtered, washed, and dried to obtain the nano-silver-loaded titanium dioxide.

4. The process for preparing a self-standing wave-preventing photoresist according to claim 3, characterized in that: The preparation method of the mercaptolated titanium dioxide is as follows: titanium dioxide and deionized water are taken and ultrasonically dispersed to obtain a titanium dioxide solution; ethanol, deionized water and the titanium dioxide solution are taken and 3-mercaptopropyltrimethoxysilane is added, and the reaction is carried out for 22-24 hours to obtain the mercaptolated titanium dioxide.

5. The process for preparing a self-standing wave-preventing photoresist according to claim 1, characterized in that: The preparation method of the modified phenolic resin is as follows: 3,5-dimethylphenol, p-cresol, m-cresol, formalin solution and oxalic acid are taken, nitrogen is passed through, the temperature is raised to 40-42°C, the reaction is carried out for 60-70 minutes, the temperature is raised to 60-65°C, the reaction is carried out for 2-2.5 hours, oxalic acid is added, the temperature is raised to 100°C, the reaction is carried out for 3-5 hours, an epoxy branched polymer is added, and the reaction is carried out for 2-3 hours to obtain the modified phenolic resin.

6. The process for preparing a self-standing wave-preventing photoresist according to claim 5, characterized in that: The preparation method of the epoxy branched polymer comprises the following steps: S1: Take diethanolamine and anhydrous methanol, stir evenly, pass nitrogen, add methyl acrylate dropwise, heat to 35-40°C, react for 4-5h, rotary evaporate, extract, and obtain compound A; take trimethylolpropane and p-toluenesulfonic acid, heat to 110-112°C, add compound A dropwise, heat to 120-122°C, stir for 5-6h, purify, and obtain a hydroxyl branched polymer; S2: Take a hydroxyl branched polymer and N,N-dimethylformamide, stir evenly, add boron trifluoride etherate, drop epichlorohydrin, heat to 65-70°C, react for 2-3h, rotary evaporate, drop sodium hydroxide aqueous solution, heat to 80-85°C, react for 2-3h, rotary evaporate, filter, and obtain an epoxy branched polymer.

7. The process for preparing a self-standing wave-preventing photoresist according to claim 1, characterized in that: The photosensitizer is any one of 2,3,4,4'-tetrahydroxybenzophenone or 2,2',4,4'-tetrahydroxybenzophenone; the solvent is any one of ethyl acetate and n-butyl acetate; the organosilicon leveling agent is polydimethylsiloxane; and the adhesion promoter is γ-glycidyloxypropyltrimethylsilane.

8. The photoresist prepared according to the process for preparing a self-standing wave-preventing photoresist according to any one of claims 1 to 7.