Modified polyacrylic resin and preparation method therefor, and photoresist

Abstract

A modified polyacrylic resin and a preparation method therefor, and a photoresist, relating to the technical field of photoresists. The modified polyacrylic resin comprises a structural unit as shown in a formula I, a structural unit as shown in formula II, a structural unit as shown in formula III, a structural unit as shown in formula IV, and a structural unit as shown in formula V. The modified polyacrylic resin can be used as a film-forming resin in a negative electroplating mask photoresist; upon development, the mask layer can present trench patterns having a small top opening and a large bottom opening; in this way, copper grid lines having a regular trapezoidal cross-section can be subsequently formed in the trenches by means of electroplating; when removing the mask layer, a photoresist stripper can easily diffuse into the mask layer around the copper grid lines, so that little residue is left after photoresist stripping.

Description

Modified polyacrylic acid resin, preparation method thereof and photoresist Technical Field

[0001] The present invention relates to the technical field of photoresists, in particular to a modified polyacrylic acid resin and a preparation method thereof, and a photoresist. Background Art

[0002] Improving the photoelectric conversion efficiency of photovoltaic cells and reducing photovoltaic electricity costs are the development goals of the photovoltaic industry. As the energy conversion efficiency of the currently mainstream passivated emitter rear-field contact (PERC) cell is approaching its limit, heterojunction (HJT) photovoltaic cells, which offer higher photoelectric conversion efficiency, lower light-induced degradation (LID), and lower silicon wafer costs, are gradually gaining industrialization and are expected to replace PERC cells in the market within the next few years. Currently, one of the key technical bottlenecks that needs to be overcome for the industrialization of HJT photovoltaic cells is the electrode metallization on the cell surface. Because HJT cells are prone to failure due to crystal morphology changes within the cell during high-temperature processing, the production of electrode gridlines on the cell surface mainly relies on applying low-temperature silver paste on the cell surface and sintering it at temperatures not exceeding 250°C. However, low-temperature silver paste is expensive, and its technology and supply are almost entirely controlled by foreign manufacturers, leaving them at risk of supply disruption. Furthermore, the low sintering temperature of low-temperature silver paste prevents the elimination of large pores between the silver particles within the resulting silver electrode gridlines, which in turn increases the internal resistance of the electrode and the internal power loss of the cell.

[0003] Copper electroplating, based on photolithographic patterning, is the primary method for achieving micro-pattern metallization. The metal lines obtained by low-temperature copper electroplating have conductivity comparable to pure copper and can achieve a high aspect ratio. Currently, using copper electroplating to create copper grid electrodes on HJT cells, replacing traditional silver electrodes and thus eliminating silver from HJT cells, is considered the most ideal solution for achieving the goals of reducing costs and improving efficiency of HJT cells.

[0004] The production of copper grid lines on the surface of HJT cells using the copper electroplating process mainly includes four basic steps: (1) introducing a copper seed layer on the surface of the transparent conductive oxide layer (TCO) of the cell; (2) coating the surface of the copper seed layer with photoresist and obtaining a patterned mask layer through pre-baking, exposure, and development steps, wherein the positions where copper grid lines need to be formed appear as hollow grooves on the patterned mask layer, while the positions where copper grid lines do not need to be formed are completely blocked by the mask layer; (3) immersing the cell in a copper electroplating solution, and reducing the copper ions in the electroplating solution to deposit copper in the grooves on the patterned mask layer to form copper grid lines; (4) removing the mask layer and the copper seed layer on the cell that is not blocked by the copper grid lines, and electroplating tin treatment on the surface of the copper grid line electrode to prevent electrode oxidation. Among the above four steps, the patterned mask plays a dominant role in controlling the size and morphology of the final copper grid lines, so the selection of photoresist used to make the patterned mask is particularly important.

[0005] At present, there are relatively few types of electroplating mask photoresists used to make copper grid lines in the HJT battery field, and the problem of debonding residue is common.

[0006] Summary of the Invention

[0007] Based on this, the present invention provides a modified polyacrylic acid resin and a preparation method thereof and a photoresist to solve the above problems.

[0008] The first aspect of the present invention provides a modified polyacrylic acid resin, and the technical solution thereof is as follows:

[0009] A modified polyacrylic resin comprises a structural unit represented by formula I, a structural unit represented by formula II, a structural unit represented by formula III, a structural unit represented by formula IV, and a structural unit represented by formula V:

[0010] Formula I is selected from Formula I-1 or Formula I-2:

[0011] Wherein, R1 is selected from C 1-6 Alkenyl, -CH2OR 1a or -CH2OC(O)R 1a ;

[0012] R 1a Selected from C 1-6 alkenyl;

[0013] R2 is selected from H or C 1-3 alkyl;

[0014] Each occurrence of R3 is independently selected from H or C 1-3 alkyl;

[0015] R4 is selected from C1-3 alkenyl;

[0016] R5 is selected from C 1-6 Alkyl or one of the following substituents:

[0017] R6 is selected from H or C 1-3 alkyl;

[0018] m, r, q, n, and p represent molar fractions, satisfying the following conditions:

[0019] 1) The ratio of m, n, p and q is 5:(0.5-2):(2-4):(0.5-2);

[0020] 2) r accounts for 2% to 6% of the total of m, n, p and q.

[0021] The second aspect of the present invention provides a method for preparing a modified polyacrylic acid resin, and the technical solution thereof is as follows:

[0022] A method for preparing a modified polyacrylic acid resin comprises the following steps:

[0023] Allowing monomers to undergo copolymerization to obtain a polyacrylic acid resin, wherein the monomers include a monomer having a structure represented by formula ii, a monomer having a structure represented by formula iii, a monomer having a structure represented by formula iv, and / or a monomer having a structure represented by formula v;

[0024] reacting a compound having a structure represented by formula i-1 or i-2 with the polyacrylic acid resin to prepare a modified polyacrylic acid resin;

[0025] Wherein, R1 is selected from C 1-6 Alkenyl, -CH2OR 1a or -CH2OC(O)R 1a ;

[0026] R 1a Selected from C 1-6 alkenyl;

[0027] R2 is selected from H or C 1-3 alkyl;

[0028] Each occurrence of R3 is independently selected from H or C 1-3 alkyl;

[0029] R4 is selected from C 1-3 Alkenyl.

[0030] R5 is selected from C 1-6 Alkyl or one of the following substituents:

[0031] R6 is selected from H or C1-3 alkyl;

[0032] And the following conditions are met:

[0033] (1) The molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula iii is 5:(0.5-2);

[0034] (2) the molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula iv is 5:(0.5-2);

[0035] (3) the molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula v is 5:(2-4);

[0036] (4) the molar number of the compound having the structure represented by formula i-1 accounts for 2% to 6% of the total molar number of the monomer having the structure represented by formula ii, the monomer having the structure represented by formula iii, the monomer having the structure represented by formula iv, and the monomer having the structure represented by formula v;

[0037] (5) The molar number of the compound having the structure represented by formula i-2 accounts for 2% to 6% of the total molar number of the monomer having the structure represented by formula ii, the monomer having the structure represented by formula iii, the monomer having the structure represented by formula iv and the monomer having the structure represented by formula v.

[0038] A third aspect of the present invention provides a photoresist comprising the modified polyacrylic resin, a photoactive monomer, a photoinitiator and a solvent.

[0039] Compared with the traditional solution, the present invention has the following beneficial effects:

[0040] The present invention introduces anthracene groups with light-absorbing properties into a polymer and grafts groups containing hydroxyl groups and double bonds onto a portion of the carboxyl groups. The modified polypropylene resin can be used as a film-forming resin in negative-tone electroplating mask photoresists. Photoresists containing this film-forming resin have high light-absorbing properties. When the photoresist layer undergoes patterned exposure, the photoinitiator activity decreases along the thickness of the layer from the surface to the bonding surface, causing the crosslinking strength of the photoresist layer to gradually decrease from the surface to the bonding surface. The crosslinking strength of the layer along the thickness of the layer is related to its alkali solubility. Specifically, higher crosslinking strength indicates lower alkali solubility, while lower crosslinking strength indicates better alkali solubility. After development, the mask layer can present a groove pattern with a small top opening and a large bottom opening. This allows subsequent electroplating to form copper grid lines with a positive trapezoidal cross-section within the grooves. When the mask layer is removed, the debonding solution easily diffuses into the mask layer surrounding the copper grid lines, resulting in minimal debonding residue. Furthermore, the greater the difference in photoinitiator activity along the thickness of the photoresist layer, the greater the difference in opening size between the top and bottom openings of the resulting grooves, and the smaller the debonding residue. Negative photoresists containing the modified polypropylene resin of the present invention can form grooves with a large gap between the top and bottom openings, which helps reduce mask layer residue during subsequent debonding. Furthermore, the minimum size of the top opening of the grooves formed by the negative photoresist containing the modified polypropylene resin of the present invention can reach 15 μm, resulting in high resolution. Furthermore, the positive trapezoidal copper grid lines have a large contact area with the seed layer at the bottom, which helps improve the adhesion of the grid lines to the cell surface and avoids the problem of grid line collapse. Furthermore, another advantage of introducing anthracene groups into the polypropylene resin is that it facilitates the dispersion of the light absorber in the photoresist system. Furthermore, compared to photoresist systems containing small molecule light absorbers, photoresists formed from polypropylene resins containing anthracene groups avoid the problem of small molecule light absorbers leaching into the plating solution and subsequently contaminating it. Furthermore, the introduction of double bonds into polypropylene resins offers another advantage: their photosensitivity allows them to participate in free radical polymerization, which improves the photoresist's exposure sensitivity and reduces the exposure energy required for patterning. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention and to provide a more complete understanding of the present invention and its beneficial effects, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present application. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0042] FIG1 is a hydrogen nuclear magnetic resonance spectrum of the polyacrylic acid resin P01 of Example 1;

[0043] FIG2 is an infrared spectrum of the polyacrylic acid resin P01 of Example 1;

[0044] FIG3 is a hydrogen nuclear magnetic resonance spectrum of the modified polypropylene resin P01m of Example 1;

[0045] FIG4 is a hydrogen nuclear magnetic resonance spectrum of the polyacrylic acid resin P01c of Comparative Example 1;

[0046] FIG5 is an infrared spectrum of the polyacrylic acid resin P01c of Comparative Example 1;

[0047] FIG6 is a hydrogen nuclear magnetic resonance spectrum of the modified polyacrylic acid resin P01cm of Comparative Example 1;

[0048] FIG. 7 is a morphology image of a mask layer formed by using the photoresist prepared with the modified polyacrylic acid resin of Example 1, taken under an electron microscope. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below with reference to specific embodiments. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the present disclosure.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0051] the term

[0052] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0053] In the present invention, the selection range of "and / or", "or / and", and "and / or" includes any one of two or more related listed items, and also includes any and all combinations of the related listed items, and the said any and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that the technical solution undoubtedly includes technical solutions connected by "logical and" and technical solutions connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution of all being connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the four-item combination of A, B, C, and D (that is, the technical solution of all being connected by "logical AND").

[0054] In the present invention, "plurality", "multiple", "multiple times", "multiple", etc., unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0055] In this disclosure, the terms "optionally," "optional," and "optional" are optional and refer to either option, i.e., to the selection of either option from the two parallel options of "optional" or "optional." If multiple "optional" terms appear in a technical solution, each "optional" term is independent unless otherwise specified and there are no conflicts or constraints.

[0056] In the present invention, in the "first aspect," "second aspect," "third aspect," "fourth aspect," etc., the terms "first," "second," "third," "fourth," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or quantity, nor as implicitly indicating the importance or quantity of the technical features indicated. Furthermore, "first," "second," "third," "fourth," etc. serve only as non-exhaustive enumeration and description and should be understood not to constitute a closed-ended limitation on quantity.

[0057] In view of the common problem of degumming residue in the mask layer formed by the electroplating mask photoresist for making copper grid lines in the HJT battery field, the inventors conducted the following analysis: Since copper is mainly deposited in the grooves formed by photolithographic patterning during the copper electroplating process, if the opening at the top of the groove is large and the opening at the bottom is small, the cross-section of the deposited copper grid line will form an inverted trapezoid. The narrow space formed by the left and right outer sides of the inverted trapezoid and the bottom seed layer will make it difficult for the degumming liquid to be subsequently removed from the mask layer, resulting in the problem of residual removal of the mask layer. If a photoresist that can produce vertical grooves is selected, it is difficult to avoid the beveling phenomenon at the bottom of the groove, resulting in the subsequent "glue sandwiching" situation, which also causes the problem of residual mask layer. Based on this, in order to obtain a copper grid line electrode with functionality and construction convenience on the surface of the HJT battery, it is necessary to ensure that the top opening of the groove formed by the patterned mask layer is small and the bottom opening is large, that is, the cross-section of the mask layer needs to be an inverted trapezoid and the cross-section of the copper grid line formed is a regular trapezoid. Electroplating mask photoresists primarily consist of a film-forming resin, photoactive monomers, photoinitiators, solvents, and pigments. The film-forming resin is crucial, decisive for various mask layer properties, such as latitude, sensitivity, and stripping time. Based on this, the first aspect of the present invention provides a modified polyacrylic resin that can be used as a film-forming resin for negative-tone electroplating mask photoresists, addressing the problem of residual resin residue during mask layer stripping.

[0058] In some embodiments, the modified polyacrylic resin includes a structural unit having formula I, a structural unit having formula II, a structural unit having formula III, a structural unit having formula IV, and a structural unit having formula V:

[0059] Formula I is selected from Formula I-1 or Formula I-2:

[0060] Wherein, R1 is selected from C 1-6 Alkenyl, -CH2OR 1a or -CH2OC(O)R 1a ;

[0061] R 1a Selected from C 1-6 alkenyl;

[0062] R2 is selected from H or C 1-3 alkyl;

[0063] Each occurrence of R3 is independently selected from H or C 1-3 alkyl;

[0064] R4 is selected from C 1-3 alkenyl;

[0065] R5 is selected from C 1-6 Alkyl or one of the following substituents:

[0066] R6 is selected from H or C 1-3 alkyl;

[0067] m, r, q, n, and p represent molar fractions, satisfying the following conditions:

[0068] 1) The ratio of m, n, p and q is 5:(0.5-2):(2-4):(0.5-2);

[0069] 2) r accounts for 2% to 6% of the total of m, n, p and q.

[0070] In the above embodiment, anthracene groups with light-absorbing properties are introduced into the polymer, and groups containing hydroxyl groups and double bonds are grafted onto a portion of the carboxyl groups. The modified polypropylene resin can be used as a film-forming resin in a negative-tone electroplating mask photoresist. The photoresist containing this film-forming resin exhibits high light-absorbing properties. When the photoresist layer undergoes patterned exposure, the photoinitiator activity decreases along the thickness of the layer from the surface to the bonding surface, resulting in a gradual decrease in the crosslinking strength of the photoresist layer from the surface to the bonding surface. The crosslinking strength of the layer along the thickness of the layer is related to alkali solubility. Specifically, higher crosslinking strength indicates lower alkali solubility, while lower crosslinking strength indicates better alkali solubility. After development, the mask layer can present a groove pattern with a small top opening and a large bottom opening. This allows subsequent electroplating to form copper grid lines with a positive trapezoidal cross-section within the grooves. When the mask layer is removed, the debonding solution easily diffuses into the mask layer surrounding the copper grid lines, resulting in minimal debonding residue. Furthermore, the greater the difference in photoinitiator activity along the thickness of the photoresist layer, the greater the difference in opening size between the top and bottom openings of the resulting grooves, and the smaller the debonding residue. Negative photoresists containing the modified polypropylene resin of the present invention can form grooves with a large gap between the top and bottom openings, which helps reduce mask layer residue during subsequent debonding. Furthermore, the minimum size of the top opening of the grooves formed by the negative photoresist containing the modified polypropylene resin of the present invention can reach 15 μm, resulting in high resolution. Furthermore, the positive trapezoidal copper grid lines have a large contact area with the seed layer at the bottom, which helps improve the adhesion of the grid lines to the cell surface and avoids the problem of grid line collapse. Furthermore, another advantage of introducing anthracene groups into the polypropylene resin is that it facilitates the dispersion of the light absorber in the photoresist system. Furthermore, compared to photoresist systems containing small molecule light absorbers, photoresists formed from polypropylene resins containing anthracene groups avoid the problem of small molecule light absorbers leaching into the plating solution and subsequently contaminating it. Furthermore, the introduction of double bonds into polypropylene resins offers another advantage: their photosensitivity allows them to participate in free radical polymerization, which improves the photoresist's exposure sensitivity and reduces the exposure energy required for patterning.

[0071] Optionally, R1 is selected from one of the following substituents:

[0072] R1 contains a double bond, which is photosensitive and can participate in free radical polymerization.

[0073] Optionally, the weight average molecular weight of the modified polyacrylic acid resin is 10,000 g / mol to 50,000 g / mol.

[0074] The modified polyacrylic acid resin can be a solid and is an alkali-soluble photosensitive modified polyacrylic acid resin. The solubility of the modified polyacrylic acid resin in alkaline solution can be controlled by adjusting the amount of ungrafted carboxyl groups in the resin.

[0075] A second aspect of the present invention provides a method for preparing a modified polyacrylic acid resin. The modified polyacrylic acid resin can be prepared by the preparation method. In some embodiments, the preparation method of the modified polyacrylic acid resin comprises the following steps:

[0076] Allowing monomers to undergo copolymerization to obtain a polyacrylic acid resin, wherein the monomers include a monomer having a structure represented by formula ii, a monomer having a structure represented by formula iii, a monomer having a structure represented by formula iv, and / or a monomer having a structure represented by formula v;

[0077] reacting a compound having a structure represented by formula i-1 or i-2 with the polyacrylic acid resin to prepare a modified polyacrylic acid resin;

[0078] Wherein, R1 is selected from C 1-6 Alkenyl, -CH2OR 1a or -CH2OC(O)R 1a ;

[0079] R 1a Selected from C 1-6 alkenyl;

[0080] R2 is selected from H or C 1-3 alkyl;

[0081] Each occurrence of R3 is independently selected from H or C 1-3 alkyl;

[0082] R4 is selected from C 1-3 Alkenyl.

[0083] R5 is selected from C 1-6 Alkyl or one of the following substituents:

[0084] R6 is selected from H or C 1-3 alkyl;

[0085] And the following conditions are met:

[0086] (1) The molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula iii is 5:(0.5-2);

[0087] (2) the molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula iv is 5:(0.5-2);

[0088] (3) the molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula v is 5:(2-4);

[0089] (4) the molar number of the compound having the structure represented by formula i-1 accounts for 2% to 6% of the total molar number of the monomer having the structure represented by formula ii, the monomer having the structure represented by formula iii, the monomer having the structure represented by formula iv, and the monomer having the structure represented by formula v;

[0090] (5) The molar number of the compound having the structure represented by formula i-2 accounts for 2% to 6% of the total molar number of the monomer having the structure represented by formula ii, the monomer having the structure represented by formula iii, the monomer having the structure represented by formula iv and the monomer having the structure represented by formula v.

[0091] The preparation method first prepares polypropylene resin by copolymerizing monomers, wherein the monomers include anthracene groups, and then grafts epoxy small molecules containing double bonds onto hydroxyl groups to prepare modified polyacrylic acid resin. The process steps are easy to scale up for production.

[0092] Optionally, R1 is selected from one of the following substituents:

[0093] Optionally, the conditions for causing the monomers to undergo copolymerization reaction further include: mixing monomers, a polymerization initiator and a solvent.

[0094] Optionally, the polymerization initiator is azobisisobutyronitrile (AIBN).

[0095] Optionally, the solvent is selected from one of diethylene glycol dimethyl ether, tetramethylbenzene, propylene glycol methyl ether acetate, diethylene glycol monobutyl ether, and a mixture of dibasic acid esters.

[0096] It is understood that the monomer and the polymerization initiator may be mixed first and then the mixture is added to the solvent.

[0097] Optionally, the copolymerization reaction is carried out under nitrogen protection.

[0098] Optionally, the reaction temperature of the copolymerization reaction is 85° C. to 95° C., and the reaction time is 3 hours to 6 hours.

[0099] Optionally, the monomer having the structure represented by formula ii is selected from methacrylic acid or acrylic acid.

[0100] Optionally, the monomer having the structure represented by formula iii is selected from 9-anthracenemethyl methacrylate.

[0101] Optionally, the compound having the structure shown in formula i-1 is selected from allyl alcohol glycidyl ether, glycidyl acrylate, epoxybutene, 1,2-epoxy-5-hexene, 2-methoxy-2-vinyl oxirane or glycidyl methacrylate.

[0102] Optionally, the compound having the structure represented by formula i-2 is selected from 1,2-epoxy-4-vinylcyclohexane.

[0103] Alternatively, the monomers having the structure shown in formula IV are methyl methacrylate, butyl methacrylate, hexyl methacrylate, benzyl methacrylate, hydroxyethyl methacrylate, 2-oxo-2-[(5-oxo-4-oxatricyclo[4.2.1.0 3,7 ]nonan-2-yl)oxy]ethyl acrylate, cyclohexyl 1-ethylacrylate or 1-pyrenylmethyl methacrylate.

[0104] Optionally, the monomer having the structure shown in formula v is selected from styrene.

[0105] Optionally, the conditions for reacting the compound having the structure represented by Formula i-1 or i-2 with the polyacrylic acid resin include: adding a catalyst.

[0106] Optionally, the catalyst is selected from one or more of dimethylaniline, dimethylbenzylamine and triphenylphosphine.

[0107] Optionally, the conditions for reacting the compound having the structure represented by Formula i-1 or i-2 with the polyacrylic acid resin include: adding a polymerization inhibitor.

[0108] Optionally, the polymerization inhibitor is selected from one or more of hydroquinone, di-tert-butylhydroquinone, and p-hydroxyanisole.

[0109] Optionally, the conditions for reacting the compound having the structure represented by formula i-1 or i-2 with the polyacrylic acid resin further include: controlling the reaction temperature to be 90° C. to 150° C. and the reaction time to be 8 hours to 13 hours.

[0110] A third aspect of the present invention provides a photoresist, which in some embodiments includes the above-mentioned modified polyacrylic resin, a photoactive monomer, a photoinitiator and a solvent.

[0111] Optionally, the mass percentage of the modified polyacrylic acid resin in the photoresist is 30% to 50%.

[0112] Optionally, the photoactive monomer is selected from one or more of isobornyl acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate and trimethylolpropane triacrylate.

[0113] Optionally, the mass percentage of the photoactive monomer in the photoresist is 5% to 20%.

[0114] Optionally, the photoinitiator is selected from one or more of benzil dimethyl ether, 1-hydroxy-cyclohexyl benzophenone, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-isopropylthioxanthene, 2-chlorothioxanthene and 2-ethylanthraquinone.

[0115] Optionally, the mass percentage of the photoinitiator in the photoresist is 1% to 5%.

[0116] Optionally, the solvent is selected from one or more of diethylene glycol dimethyl ether, propylene glycol methyl ether acetate, 2-heptanone, cyclohexanone, N-methylpyrrolidone, ethyl lactate and ethyl acetate.

[0117] Optionally, the mass percentage of the solvent in the photoresist is 30% to 50%.

[0118] Optionally, the photoresist further comprises pigments and fillers. Optionally, the pigments and fillers account for 1% to 5% of the mass of the photoresist.

[0119] Optionally, the pigment filler is selected from one or more of titanium blue, titanium green, malachite green, and colorless crystal violet.

[0120] The following is further described in conjunction with specific examples and comparative examples. Unless otherwise specified, the raw materials involved in the following specific examples and comparative examples can be sourced from commercial sources. The instruments used can be sourced from commercial sources unless otherwise specified. The processes involved can be selected conventionally by those skilled in the art unless otherwise specified.

[0121] Example 1

[0122] This embodiment provides a modified polyacrylic acid resin and a preparation method thereof, the steps are as follows:

[0123] Step 1: 45.6 g (0.53 mol) of methacrylic acid, 10.6 g (0.106 mol) of methyl methacrylate, 33.1 g (0.318 mol) of styrene, 29.3 g of 9-anthracenemethyl methacrylate (0.106 mol) and 4 g of azobisisobutyronitrile (AIBN) were mixed and added dropwise to a 250 mL flask containing 108.6 g of diethylene glycol dimethyl ether at 90° C. After the addition was complete, the reaction mixture was stirred at 90° C. for 1.5 hours. A solution containing 0.3 g of AIBN and 10 g of diethylene glycol dimethyl ether was added to the reaction mixture, which was then heated to 95° C. under stirring and maintained for 3 hours, and then cooled to room temperature to obtain a solution containing polyacrylic resin P01.

[0124] The nuclear magnetic resonance hydrogen spectrum characterization results of the polyacrylic acid resin P01 are shown in Figure 1, and the infrared spectrum characterization results are shown in Figure 2. The weight average molecular weight of the polyacrylic acid resin P01 is 20,000 g / mol.

[0125] Step 2: Heat the solution containing polyacrylic resin P01 obtained in Step 1 to 95°C, add 0.2g of dimethylaniline (catalyst), 0.2g of di-tert-butylhydroquinone (polymerization inhibitor), and 9.04g (0.0636mol) of glycidyl methacrylate, and mechanically mix for half an hour. The mixture is then heated to 120°C and reacted for 10 hours. The reaction solution is then added dropwise to n-heptane to obtain a precipitate, which is filtered and air-dried to obtain the modified polyacrylic resin P01m.

[0126] The nuclear magnetic resonance hydrogen spectrum characterization results of the modified polyacrylic acid resin P01m are shown in Figure 3. The weight average molecular weight of the modified polyacrylic acid resin P01m is 21,000 g / mol.

[0127] Example 2

[0128] This embodiment provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 1, except that the amount of glycidyl methacrylate added is 6.03 g (0.0424 mol), and the weight average molecular weight of the obtained modified polyacrylic acid resin is 21,000 g / mol.

[0129] Example 3

[0130] This embodiment provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 1, except that the amount of glycidyl methacrylate added is 3.01 g (0.0212 mol), and the weight average molecular weight of the obtained modified polyacrylic acid resin is 20,500 g / mol.

[0131] Example 4

[0132] This embodiment provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 1, except that the amount of 9-anthracenemethyl methacrylate added is 43.936 g (0.159 mol), and the weight average molecular weight of the obtained modified polyacrylic acid resin is 23,000 g / mol.

[0133] Example 5

[0134] This embodiment provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 1, except that 13.8 g (0.106 mol) of hydroxyethyl methacrylate is used instead of 10.6 g (0.106 mol) of methyl methacrylate, and the weight-average molecular weight of the obtained modified polyacrylic acid resin is 21,000 g / mol.

[0135] Comparative Example 1

[0136] This comparative example provides a modified polyacrylic acid resin and a preparation method thereof, which is basically the same as Example 1, except that 9-anthracenemethyl methacrylate is not added. The steps are as follows:

[0137] Step 1: 45.6 g (0.53 mol) of methacrylic acid, 10.6 g (0.106 mol) of methyl methacrylate, 33.1 g of styrene (0.318 mol) and 4 g of azobisisobutyronitrile (AIBN) were mixed and added dropwise to a 250 mL flask containing 108.6 g of diethylene glycol dimethyl ether at 90° C. After the addition was complete, the reaction mixture was stirred at 90° C. for 1.5 hours. A solution of 0.3 g of AIBN in 10 g of diethylene glycol dimethyl ether was added to the reaction mixture, which was then heated to 95° C. for 3 hours under stirring and then cooled to room temperature to obtain a solution containing polyacrylic resin P01c.

[0138] The polyacrylic acid resin P01c was characterized by hydrogen nuclear magnetic resonance spectrum, and the results are shown in FIG4 . The polyacrylic acid resin P01c was characterized by infrared spectrum, and the results are shown in FIG5 . The weight average molecular weight of the polyacrylic acid resin P01c was tested to be 21,000 g / mol.

[0139] Step 2: Heat the solution containing polyacrylic resin P01c obtained in Step 1 to 95°C, add 0.2g of dimethylaniline as a catalyst, 0.2g of di-tert-butylhydroquinone as a polymerization inhibitor, and 9.04g (0.0636mol) of glycidyl methacrylate. After half an hour, heat to 120°C and react for 10 hours. Then, add the reaction solution dropwise to n-heptane to obtain a precipitate, which is filtered and air-dried to obtain the modified polyacrylic resin P01cm.

[0140] The modified polyacrylic acid resin P01cm was characterized by hydrogen nuclear magnetic resonance spectroscopy. The results are shown in FIG6 . The weight average molecular weight of the modified polyacrylic acid resin P01cm was 22,000 g / mol.

[0141] Comparative Example 2

[0142] This comparative example provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 2, except that 9-anthracenemethyl methacrylate is not added. The weight average molecular weight of the obtained modified polyacrylic acid resin is 22,000 g / mol.

[0143] Comparative Example 3

[0144] This comparative example provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 3, except that 9-anthracenemethyl methacrylate is not added. The weight average molecular weight of the obtained modified polyacrylic acid resin is 22,000 g / mol.

[0145] Comparative Example 4

[0146] This embodiment provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 1, except that the amount of 9-anthracenemethyl methacrylate added is 8.787 g (0.0318 mol), and the weight average molecular weight of the obtained modified polyacrylic acid resin is 21,000 g / mol.

[0147] Comparative Example 5

[0148] This comparative example provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 1, except that the amount of 9-anthracenemethyl methacrylate added is 73.227 g (0.265 mol), and the weight average molecular weight of the obtained modified polyacrylic acid resin is 26,000 g / mol.

[0149] Comparative Example 6

[0150] This comparative example provides a modified polyacrylic acid resin and a preparation method thereof, which is substantially the same as Example 1, except that 1.51 g (0.0106 mol) of glycidyl methacrylate is added. The weight-average molecular weight of the resulting modified polyacrylic acid resin is 21,000 g / mol.

[0151] Comparative Example 7

[0152] This comparative example provides a modified polyacrylic acid resin and a preparation method thereof, which are basically the same as Example 1, except that the amount of glycidyl methacrylate added is 12.06 g (0.0848 mol), and the weight average molecular weight of the obtained modified polyacrylic acid resin is 23,000 g / mol.

[0153] The modified polyacrylic acid resin of the above-mentioned embodiment and comparative example is used as a film-forming resin, and the film-forming resin 40%, the photoactive monomer isobornyl acrylate 10%, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone 5%, the solvent diethylene glycol dimethyl ether 40% and phthalocyanine blue 5% are mixed according to the following mass percentages to prepare a photoresist.

[0154] The modified polyacrylic acid resins of the examples and comparative examples and the photoresists prepared from the modified polyacrylic acid resins were evaluated for alkali solubility, exposure sensitivity, and photolithographic pattern morphology by the following methods. The specific methods are:

[0155] (1) Evaluation of alkali solubility of modified polyacrylic acid resin

[0156] The modified polyacrylic acid resin prepared in the embodiment and the comparative example was mixed with propylene glycol methyl ether acetate to prepare a mixed solution. The mixed solution was applied to the surface of a silicon wafer using a spin coater and baked at 75°C for 10 minutes to remove the volatile solvent to obtain a photoresist film. The thickness of the photoresist film was controlled within the range of 13μm to 17μm, and the film thickness was measured using a film thickness meter and recorded as δ. The film was immersed in a 1wt% Na2CO3 aqueous solution, and the time t required for the film to be completely dissolved was recorded. The alkali dissolution rate of the modified polyacrylic acid resin is calculated as shown in Formula 1:

[0157] [Formula 1]

[0158] The alkali solubility of the modified polyacrylic acid resins of the above examples and comparative examples can be evaluated according to the following grades:

[0159] I: Alkali dissolution rate above;

[0160] II: Alkali dissolution rate above, the following;

[0161] III: Alkali dissolution rate the following.

[0162] (2) Evaluation of exposure sensitivity of photoresist prepared from modified polyacrylic resin

[0163] The photoresist prepared by the modified polyacrylic acid resin prepared in the embodiment and the comparative example was coated on a silicon wafer by screen printing and dried with forced air at 75° C. for 10 minutes to remove the volatile solvent to obtain a photoresist film. The thickness of the photoresist film was measured using a film thickness meter. The result was recorded as δ1. Afterwards, the photoresist layer was exposed at different exposure energies. Subsequently, the exposed film was spray-developed with a 1wt% Na2CO3 aqueous solution for 60 seconds. The silicon wafer was then rinsed and dried with deionized water. The thickness of the residual photoresist film on the silicon wafer was measured using a film thickness meter, and the result was recorded as δ2. The thickness change rate (i.e., film retention rate) of the photoresist film after exposure and development was calculated as shown in Formula 2:

[0164] [Formula 2]

[0165] Based on the measured results, a photoresist exposure energy vs. film retention curve (i.e., a photoresist contrast curve) is plotted. The contrast curve is normalized for film thickness, and a tangent line is drawn for the linearly varying region of the contrast curve. The intersection of the tangent line and the outer line of the contrast curve where the film retention is near 100% and remains constant corresponds to the exposure energy of the photoresist, which is the exposure sensitivity of the photoresist.

[0166] The exposure sensitivity of the photoresists prepared from the modified polyacrylic acid resins prepared in the above examples and comparative examples can be evaluated according to the following grades:

[0167] A: Exposure sensitivity range is below 5mJ;

[0168] B: Exposure sensitivity range is below 10mJ and above 5mJ;

[0169] C: Exposure sensitivity range is 10mJ or more.

[0170] (3) Evaluation method of photolithographic pattern morphology of photoresist prepared from modified polyacrylic acid resin

[0171] A photoresist prepared from the modified polyacrylic acid resins prepared in the Examples and Comparative Examples was applied to a silicon wafer using a screen printing method and then air-dried at 75°C for 10 minutes to remove volatile solvents, thereby obtaining a photoresist film. The photoresist film was then exposed using a mask having a line pattern at an exposure energy of less than 15 mJ. The exposed film was then spray-developed using a 1 wt% aqueous solution of Na2CO3 for 60 seconds. The silicon wafer was then rinsed with deionized water and dried to obtain a photoresist pattern having a groove pattern.

[0172] The width of the narrowest groove formed on the photoresist pattern was measured using an optical microscope and recorded as the resolution of the photoresist. The cross-section of the photoresist pattern lines was observed using a field emission scanning electron microscope. The morphology of the photoresist was evaluated according to the following grades:

[0173] O: The resolution of the photoresist is ≤15 μm and the cross-section of the lines formed by the photoresist presents an inverted trapezoidal morphology.

[0174] Δ: The resolution of the photoresist is greater than 15 μm but the lines formed by the photoresist have an inverted trapezoidal morphology, or the resolution of the photoresist is less than or equal to 15 μm but the profile of the lines formed by the photoresist cannot have an inverted trapezoidal morphology

[0175] ×: The resolution of the photoresist is greater than 15 μm and the line profile formed by the photoresist cannot present an inverted trapezoidal morphology.

[0176] Note: The inverted trapezoidal shape of the line cross section above refers to the mask layer having a small opening at the top and a large opening at the bottom, see Figure 7. Subsequent electroplating can form a copper grid line with a positive trapezoidal cross section within the trench.

[0177] The above test results are shown in Table 1

[0178] Table 1

[0179] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0180] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A modified polyacrylic acid resin, characterized in that: Including a structural unit shown in formula I, a structural unit shown in formula II, a structural unit shown in formula III, a structural unit shown in formula IV and a structural unit shown in formula V: Formula I is selected from Formula I-1 or Formula I-2: Wherein, R1 is selected from C 1-6 Alkenyl, -CH2OR 1a or -CH2OC(O)R 1a ; R 1a Selected from C 1-6 alkenyl; R2 is selected from H or C 1-3 alkyl; Each occurrence of R3 is independently selected from H or C 1-3 alkyl; R4 is selected from C 1-3 alkenyl; R5 is selected from C 1-6 Alkyl or one of the following substituents: R6 is selected from H or C 1-3 alkyl; m, r, q, n and p represent molar fractions, satisfying the following conditions: 1) The ratio of m, n, p and q is 5:(0.5~2):(2~4):(0.5~2); 2) r accounts for 2% to 6% of the total of m, n, p and q.

2. The modified polyacrylic acid resin according to claim 1, characterized in that R1 is selected from one of the following substituents:

3. The modified polyacrylic acid resin according to claim 1 or 2, characterized in that The weight average molecular weight of the modified polyacrylic acid resin is 10000 g / mol to 50000 g / mol.

4. A method for preparing a modified polyacrylic acid resin, characterized in that: The following steps are involved: Allowing monomers to undergo copolymerization to obtain a polyacrylic acid resin, wherein the monomers include a monomer having a structure shown in formula ii, a monomer having a structure shown in formula iii, a monomer having a structure shown in formula iv, and / or a monomer having a structure shown in formula v; Reacting the compound having the structure represented by formula i-1 or i-2 with the polyacrylic acid resin to prepare a modified polyacrylic acid resin; Wherein, R1 is selected from C 1-6 Alkenyl, -CH2OR 1a or -CH2OC(O)R 1a ; R 1a Selected from C 1-6 alkenyl; R2 is selected from H or C 1-3 alkyl; Each occurrence of R3 is independently selected from H or C 1-3 alkyl; R4 is selected from C 1-3 alkenyl; R5 is selected from C 1-6 Alkyl or one of the following substituents: R6 is selected from H or C 1-3 alkyl; And the following conditions are met: (1) The molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula iii is 5:(0.5-2); (2) the molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula iv is 5:(0.5-2); (3) The molar ratio of the monomer having the structure represented by formula ii to the monomer having the structure represented by formula v is 5:(2-4); (4) the molar number of the compound having the structure represented by formula i-1 accounts for 2% to 6% of the total molar number of the monomer having the structure represented by formula ii, the monomer having the structure represented by formula iii, the monomer having the structure represented by formula iv and the monomer having the structure represented by formula v; (5) The molar number of the compound having the structure represented by formula i-2 accounts for 2% to 6% of the total molar number of the monomer having the structure represented by formula ii, the monomer having the structure represented by formula iii, the monomer having the structure represented by formula iv and the monomer having the structure represented by formula v.

5. The method for preparing the modified polyacrylic acid resin according to claim 4, characterized in that: The monomer having the structure shown in formula ii is selected from methacrylic acid or acrylic acid.

6. The method for preparing the modified polyacrylic acid resin according to claim 4, wherein The monomer having the structure shown in formula iii is selected from 9-anthracenemethyl methacrylate.

7. The method for preparing the modified polyacrylic acid resin according to claim 4, characterized in that: The compound having the structure shown in formula i-1 is selected from allyl alcohol glycidyl ether, glycidyl acrylate, epoxybutene, 1,2-epoxy-5-hexene, 2-methoxy-2-vinyl oxirane or glycidyl methacrylate.

8. The method for preparing the modified polyacrylic acid resin according to claim 4, characterized in that: The compound having the structure shown in formula i-2 is selected from 1,2-epoxy-4-vinylcyclohexane.

9. The method for preparing the modified polyacrylic acid resin according to claim 4, characterized in that: The monomer having the structure shown in formula iv is selected from methyl methacrylate, butyl methacrylate, hexyl methacrylate, benzyl methacrylate, hydroxyethyl methacrylate, 2-oxo-2-[(5-oxo-4-oxatricyclo[4.2.1.0 3,7 ]nonan-2-yl)oxy]ethyl ester, 1-ethyl acrylate cyclohexyl or 1-pyrenylmethyl methacrylate.

10. The method for preparing the modified polyacrylic acid resin according to claim 4, characterized in that: The monomer having the structure shown in formula v is selected from styrene.

11. The method for preparing the modified polyacrylic acid resin according to any one of claims 4 to 10, characterized in that: The conditions for reacting the compound having the structure represented by formula i-1 or i-2 with the polyacrylic acid resin include: adding a catalyst.

12. The method for preparing the modified polyacrylic acid resin according to claim 11, characterized in that: The catalyst is selected from one or more of dimethylaniline, dimethylbenzylamine and triphenylphosphine.

13. A photoresist, characterized in that: The invention comprises the modified polyacrylic acid resin according to any one of claims 1 to 3, a photoactive monomer, a photoinitiator and a solvent.

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