A phenol formaldehyde resin and a photoresist

Abstract

The application provides a phenolic resin and a photoresist, and belongs to the field of photoetching technology. The phenolic resin comprises a product obtained by condensation of specified phenols, the specified phenols comprising a first type of phenol and a second type of phenol, the first type of phenol having a structural formula as shown in formula I, and the second type of phenol comprising at least one of cresol, dimethyl phenol and trimethyl phenol. The photoresist comprises the above phenolic resin, which can effectively improve the photosensitivity of the photoresist, and enable the photoresist to have good heat resistance and morphology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photoetching technology, in particular, a phenolic resin and photoresist. BACKGROUND

[0002] With the development of Moore's law, the device integration of semiconductor is higher and higher, and the device size is smaller and smaller, and various photoresist components for laser exposure are also developed, and the mainstream photoresist currently has KrF, ArF and EUV types. However, the above photoetching technology for laser exposure needs expensive exposure equipment, which increases the production cost, and the photoresist for laser is also very delicate and needs special treatment during storage, transportation and other processes.

[0003] In order to avoid or improve the above problems, G / I line positive photoresist is proposed in some technologies. The G / I line positive photoresist mainly includes phenolic resin and photosensitizer, and usually has certain resolution, sensitivity and etching resistance, so it is also widely used in the production of semiconductor devices and liquid crystal displays. However, since the G / I line positive photoresist is not a chemical amplification mechanism, with the increase of film thickness, the exposure energy increases rapidly, and the exposure time increases, which brings great challenges to the improvement of production capacity and exposure machine lens.

[0004] In order to improve the above problems of G / I line positive photoresist, some technologies add a dissolving agent to the photoresist to improve the photosensitivity and speed of the photoresist. However, the photoresist with dissolving agent currently proposed usually has the problem of reduced heat resistance; and the dissolving agent is usually unevenly distributed, which can easily cause a series of morphology problems such as scum, undercut and necking. SUMMARY

[0005] The purpose of the present application is to provide a phenolic resin and photoresist, which is applied to photoresist, can effectively improve the photosensitivity of photoresist, and can make the photoresist maintain good heat resistance and morphology.

[0006] Embodiments of the present application are implemented as follows:

[0007] In a first aspect, the embodiments of the present application provide a phenolic resin, which includes a product obtained by condensation of specified phenol and aldehyde, the specified phenol includes a first type of phenol and a second type of phenol, the structural formula of the first type of phenol is shown as formula I, and the second type of phenol includes at least one of cresol, dimethyl phenol and trimethyl phenol.

[0008]

[0009] wherein X is at least one of hydrogen and an alkyl group of 1-5 carbon atoms; R1 and R2 are at least one of hydrogen, an alkyl group of 1-4 carbon atoms, and an alkoxy group of 1-4 carbon atoms; 3≥a≥0, 3≥b≥0, 3≥m≥0, 3≥n≥0, and m+n≥2.

[0010] In some possible embodiments, 4≥m+n≥2.

[0011] In some possible embodiments, the first type of phenol includes at least one of 2,3,4-trihydroxydiphenyl, 2,2',3',4'-tetrahydroxydiphenyl, 2,2',4',4'-tetrahydroxydiphenyl, 2',2,4-trihydroxydiphenyl, and 4',4'-dihydroxydiphenyl.

[0012] In some possible embodiments, R1 and R2 are hydrogen or methyl.

[0013] In some possible embodiments, the first type of phenol has a connection structure in the phenolic resin as shown in Formula II and / or Formula III.

[0014]

[0015] In some possible embodiments, the mass percentage of the first type of phenol in the specified phenol is 1%-20%.

[0016] In some possible embodiments, the second type of phenol includes cresol and trimethylphenol.

[0017] Optionally, the cresol is m-cresol.

[0018] Optionally, the trimethylphenol is 2,3,5-trimethylphenol.

[0019] In some possible embodiments, the mass percentage of the cresol in the specified phenol is 30%-95%, and the mass percentage of the trimethylphenol is 2%-50%.

[0020] In a second aspect, an embodiment of the present application provides a photoresist, including the phenolic resin provided in the first aspect and a photosensitive agent.

[0021] In some possible embodiments, the photosensitive agent includes diazonaphthoquinone sulfonic acid ester.

[0022] Optionally, the photoresist includes 40-70 parts by weight of the phenolic resin and 10-30 parts by weight of the diazonaphthoquinone sulfonic acid ester.

[0023] The phenolic resin and the photoresist provided in the embodiments of the present application have the following beneficial effects.

[0024] The phenolic resin provided in the present application has a polyhydroxy phenol structure as shown in Formula I inserted in the molecular structure, the polyhydroxy phenol structure can play a role of promoting solubility, and when the phenolic resin is applied to a photoresist, the photosensitivity of the photoresist can be effectively improved. Meanwhile, in the phenolic resin, the polyhydroxy phenol structure is connected in the phenolic resin, on the one hand, the free small molecule polyhydroxy phenol in the phenolic resin can be effectively avoided to affect the heat resistance, and the photoresist can keep good heat resistance, on the other hand, the polyhydroxy phenol structure can be more uniformly distributed in the phenolic resin, and the photoresist can keep good morphology. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced below, and it should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0026] Figure 1 A schematic diagram for a slice morphology of a photoresist with good morphology;

[0027] Figure 2 A schematic diagram for a slice morphology of a photoresist with poor morphology;

[0028] Figure 3 Another schematic diagram for a slice morphology of a photoresist with poor morphology. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below. The specific conditions are not specified in the embodiments, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be obtained by market purchase.

[0030] It should be noted that in the present application, "and / or", such as "feature 1 and / or feature 2", means that it can be "feature 1" alone, "feature 2" alone, or "feature 1" plus "feature 2".

[0031] In addition, in the description of the present application, unless otherwise specified, the meaning of "multiple" in "one or more" is two or more; the range of "value a~value b" includes both end values "a" and "b", and "unit of measurement" in "value a~value b+unit of measurement" represents the "unit of measurement" of both "value a" and "value b".

[0032] The phenolic resin and photoresist according to the embodiments of the present application are described in detail as follows.

[0033] In a first aspect, the embodiments of the present application provide a phenolic resin, which comprises a product of condensation of a specified phenol with an aldehyde, the specified phenol comprising a first type of phenol and a second type of phenol, the first type of phenol having a structural formula as shown in Formula I, and the second type of phenol comprising at least one of cresol, dimethyl phenol and trimethyl phenol.

[0034]

[0035] wherein X is at least one of hydrogen and an alkyl group having 1-5 carbon atoms; R1 and R2 are at least one of hydrogen, an alkyl group having 1-4 carbon atoms and an alkoxy group having 1-4 carbon atoms; 3≥a≥0, 3≥b≥0, 3≥m≥0, 3≥n≥0, and m+n≥2.

[0036] In the present application, the types of aldehyde and ketone that are condensed with the specified phenol are not limited, and both can be selected according to the types commonly used in the art.

[0037] As an example, the aldehyde condensed with the specified phenol is selected from one or more of formaldehyde, acetaldehyde, propyl aldehyde, benzaldehyde, phenylacetaldehyde, o-methyl benzaldehyde, m-methyl benzaldehyde, p-methyl benzaldehyde, o-hydroxy benzaldehyde, m-hydroxy benzaldehyde, p-hydroxy benzaldehyde and salicylaldehyde, and the aldehyde is, for example, formaldehyde.

[0038] Regarding the first type of phenol, in Formula I, a, b, m and n are respectively a positive integer of 0 or greater than 0; the X groups at different substitution positions can be the same or different. In order to reduce the steric hindrance of the substituent groups, optionally, the X groups at different substitution positions are, for example, hydrogen or methyl, and R1 and R2 are respectively hydrogen or methyl.

[0039] Regarding the second type of phenol, cresol refers to phenol substituted with one methyl group on the benzene ring, and in the present application, it can include one or more of o-cresol, m-cresol and p-cresol; dimethyl phenol refers to phenol substituted with two methyl groups on the benzene ring, and in the present application, it can include 2,3-dimethyl phenol, 2,4-dimethyl phenol, 2,5-dimethyl phenol, 2,6-dimethyl phenol, 3,4-dimethyl phenol and 3,5-dimethyl phenol; trimethyl phenol refers to phenol substituted with three methyl groups on the benzene ring, and in the present application, it can include one or more of 2,3,5-trimethyl phenol, 2,3,6-trimethyl phenol, 2,4,5-trimethyl phenol, 2,4,6-trimethyl phenol and 3,4,5-trimethyl phenol.

[0040] The phenolic resin provided in the embodiments of the present application has a plurality of hydroxyl phenol structures as shown in Formula I in the molecular structure, the plurality of hydroxyl phenol structures can play a role of promoting solubility, and when the phenolic resin is applied to a photoresist, the photosensitivity of the photoresist can be effectively improved. Meanwhile, in the phenolic resin, the plurality of hydroxyl phenol structures are connected in the phenolic resin, on the one hand, the free small molecule plurality of hydroxyl phenol in the phenolic resin can be effectively avoided to affect the heat resistance, and the photoresist can keep good heat resistance, on the other hand, the plurality of hydroxyl phenol structures can be uniformly distributed in the phenolic resin, and the photoresist can keep good morphology.

[0041] In some possible embodiments, the connection structure of the first type of phenol in the phenolic resin is as shown in Formula II and / or Formula III.

[0042]

[0043] In the above technical solution, the first type of phenol is connected to the phenolic resin through two sites, the first type of phenol is connected in the molecular chain of the phenolic resin, and sufficient plurality of hydroxyl phenol structures can be connected in the phenolic resin.

[0044] It can be understood that in the present application, when the phenolic resin is prepared, the structure of the plurality of hydroxyl phenol as shown in Formula I or the type of reaction raw material can be regulated, so that the plurality of hydroxyl phenol as shown in Formula I can be connected to the phenolic resin in the structure as shown in Formula II and / or Formula III.

[0045] The inventors have found that in the embodiments of the present application, when the plurality of hydroxyl phenol as shown in Formula I has 2-4 phenolic hydroxyl groups, it can be conveniently connected in the phenolic resin and better play a role of promoting solubility.

[0046] Based on this, in some possible embodiments, 4≥m+n≥2; wherein the value of m+n is 2, 3 or 4.

[0047] In the embodiments of the present application, the substitution position of 2-4 hydroxyl groups in Formula I is not limited, when the number of hydroxyl groups is ≤3, the plurality of hydroxyl groups can be located on the same benzene ring or different benzene rings.

[0048] Based on this, as an example, the first type of phenol includes at least one of 2,3,4-trihydroxy diphenyl compounds, 2,2',3',4'-tetrahydroxy diphenyl compounds, 2,2',4,4'-tetrahydroxy diphenyl compounds, 2',2,4-trihydroxy diphenyl compounds and 4',4'-dihydroxy diphenyl compounds.

[0049] Optionally, the 2,3,4-trihydroxy diphenyl compound has a structure as shown in the following Formula IV, the 2,2',3',4'-tetrahydroxy diphenyl compound has a structure as shown in the following Formula V, and the 2,2',4,4'-tetrahydroxy diphenyl compound has a structure as shown in the following Formula VI.

[0050] wherein the R1 group and the R2 group are each a hydrogen group or a methyl group.

[0051] wherein the R1 group and the R2 group are each a hydrogen group or a methyl group.

[0052] wherein the R1 group, the R2 group, the R3 group and the R4 group are each a hydrogen group or a methyl group.

[0053] It should be noted that in the embodiments of the present application, the first type of phenol is exemplarily used as an auxiliary component in the specified phenol in order to make the phenolic resin maintain good comprehensive performance, that is, in the specified phenol, the second type of phenol is the main component, and the mass percentage of the first type of phenol is less than 50%.

[0054] Optionally, in the specified phenol, the mass percentage of the first type of phenol is 1% to 20%, which is exemplarily but not limited to any one of 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18% and 20%, or a range value between any two of them.

[0055] In the embodiments of the present application, the combination form of the second type of phenol is not limited, and can be selected according to the types commonly used in the art.

[0056] As a first example, the second type of phenol includes cresol and trimethylphenol, and the second type of phenol is exemplarily composed of cresol and trimethylphenol. The phenolic resin synthesized by such a combination can make the photoresist have better heat resistance.

[0057] Optionally, the cresol is m-cresol.

[0058] Based on the above embodiments, the connection structure of the cresol in the phenolic resin is as shown in Formula VII, which is connected to the phenolic resin through two sites, can be connected to the molecular chain, and can make enough cresol structures be introduced into the phenolic resin.

[0059]

[0060] Optionally, the trimethylphenol is 2,3,5-trimethylphenol.

[0061] Based on the above embodiment, the connecting structure of trimethylphenol in the phenolic resin is shown as formula VIII, which is connected to the phenolic resin through two sites, and can be connected to the molecular chain, compared with being connected to the end of the phenolic resin through only one site, so that enough trimethylphenol structure can be introduced into the phenolic resin.

[0062]

[0063] Based on the above first example, further optionally, the mass percentage of the cresol is 30% to 95%, which is for example but not limited to any one of the point values of 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% and 90% or a range value between any two of them.

[0064] Based on the above first example, further optionally, the mass percentage of the trimethylphenol is 2% to 50%, which is for example but not limited to any one of the point values of 2%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50% or a range value between any two of them. Since the reactivity of trimethylphenol is relatively low, the content of trimethylphenol should not be too high, otherwise it is difficult to synthesize a resin with a large molecular weight.

[0065] As a second example, the second type of phenol includes cresol and dimethylphenol, and the second type of phenol is for example composed of cresol and dimethylphenol.

[0066] The cresol is preferably m-cresol and / or p-cresol, and the dimethylphenol is preferably 3,5-dimethylphenol. This component can better achieve the resolution capability of the photoresist.

[0067] As a third example, the second type of phenol includes cresol and trimethylphenol, and the second type of phenol is for example composed of m-cresol, p-cresol and trimethylphenol. This component can simultaneously achieve the resolution capability of the photoresist and good heat resistance.

[0068] It should be noted that in the present application, the phenolic resin can be in the form of a graded resin solution obtained after completing the synthesis by referring to the conventional grading treatment method.

[0069] Optionally, in the graded resin solution, the weight average molecular weight of the phenolic resin is optionally 3000 to 15000; and the mass percentage of the phenolic resin compound is optionally 30% to 50%, for example 40%.

[0070] In a second aspect, the embodiments of the present application provide a photoresist, which comprises the phenolic resin provided in the first aspect and a photosensitive agent.

[0071] As an example, the photoresist provided in the embodiments of the present application is a G-line positive photoresist or an I-line positive photoresist.

[0072] In the embodiments of the present application, the type of the photosensitizer is not limited, and can be selected according to the types commonly used in the art; in addition, the amount of the photosensitizer can also be selected according to the conventional standards or as needed.

[0073] As an example, the photosensitizer includes diazonium naphthoquinone sulfonate, for example, the photosensitizer is diazonium naphthoquinone sulfonate.

[0074] The diazonium naphthoquinone sulfonate is, for example, a compound esterified from a compound shown in formula IX with 1-diazonium-2-naphthoquinone-5-sulfonyl chloride or 1-diazonium-2-naphthoquinone-4-sulfonyl chloride.

[0075] The feeding ratio of the compound shown in formula IX to 2,1,4-diazonium naphthoquinone sulfonate or 2,1,5-diazonium naphthoquinone sulfonate is 1.0-4.0, preferably 2.5-3.5.

[0076] The structural formula of 2,1,5-diazonium naphthoquinone sulfonate is shown in formula X, and the structural formula of 2,1,4-diazonium naphthoquinone sulfonate is shown in formula XI.

[0077]

[0078] As an example, the photoresist includes 40-70 parts of phenolic resin and 10-30 parts of diazonium naphthoquinone sulfonate, by weight.

[0079] The weight parts of the phenolic resin are, for example but not limited to, any one of 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts and 70 parts, or a range value between any two of them. The weight parts of the phenolic resin refer to the mass parts of the graded resin solution of the phenolic resin.

[0080] The weight parts of the diazonium naphthoquinone sulfonate are, for example but not limited to, any one of 10 parts, 15 parts, 20 parts, 25 parts and 30 parts, or a range value between any two of them.

[0081] It should be noted that in the present application, other components such as solvents, sensitizers, surface leveling agents, etc. can also be added to the photoresist as needed or designed, and the amounts of the above components can also be selected according to the conventional standards or as needed.

[0082] As an example, the solvents in the photoresist include diheptyl ketone and n-butyl acetate. Alternatively, on the basis that the photoresist includes 40-70 parts of phenolic resin and 10-30 parts of diazonium naphthoquinone sulfonate, the weight parts of diheptyl ketone are 250-350 parts, for example 300 parts; and the weight parts of n-butyl acetate are 50-80 parts, for example 60 parts.

[0083] As an example, a sensitizer is also included in the photoresist, the structure of which is optionally shown as Formula XII below, which is simply referred to as TPPA (CAS No. 110726-28-8).

[0084] Optionally, on the basis of 40-70 parts of the phenolic resin and 10-30 parts of the diazonaphthoquinone sulfonic acid ester, the weight parts of the sensitizer is 10-30 parts, for example, 20 parts.

[0085]

[0086] The features and performance of the present application are further described in detail below in connection with the examples.

[0087] (I) Preparation of the phenolic resin

[0088] Example 1

[0089] In 200.0 g of γ-butyrolactone, 40.8 g (0.3 mol) of 2,3,5-trimethylphenol, 26.0 g (0.1 mol) of 2',2,3,4-tetrahydroxydiphenylisopropane, and 5.0 g of oxalic acid were added, and then the mixture was heated to 95°C, and then 6 g (0.2 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the dropwise addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the dropwise addition was completed, the mixture was refluxed for 20 hours to perform the reaction.

[0090] After the reaction was completed, 200 g of deionized water was added and stirred, and then left to stand for 2 hours. The supernatant was discarded, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight 8260). In the present application, the average molecular weight is the weight average molecular weight.

[0091] In 200 g of the 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, left to stand for 2 hours, and then the supernatant was removed, and 160 g of diheptyl ketone solution was added to precipitate the resin, to obtain a 40% by mass fraction of a fractionated resin solution having an average molecular weight of 11216 (referred to simply as Resin 1).

[0092] Example 2

[0093] To 200.0 g of γ-butyrolactone were added 40.8 g (0.3 mol) of 2,3,5-trimethylphenol, 24.4 g (0.1 mol) of 2',2,4-trihydroxydiphenylisopropane, and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 6 g (0.2 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the dropwise addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the dropwise addition was completed, the mixture was refluxed for 20 hours to perform a reaction.

[0094] After the reaction was completed, 200 g of deionized water was added to perform stirring, and then it was left to stand for 2 hours. The supernatant was discarded, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then it was concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight: 7300).

[0095] To 200 g of the 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, it was left to stand for 2 hours, the supernatant was removed, and 160 g of diheptyl ketone solution was added to precipitate the resin, and then a fractionated resin solution (referred to as resin 2) having a mass fraction of about 40% and an average molecular weight of 10081 was obtained.

[0096] Example 3

[0097] To 200.0 g of γ-butyrolactone were added 40.8 g (0.3 mol) of 2,3,5-trimethylphenol, 26.0 g (0.1 mol) of 2',2,4',4-tetrahydroxydiphenylisopropane, and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 6 g (0.2 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the dropwise addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the dropwise addition was completed, the mixture was refluxed for 20 hours to perform a reaction.

[0098] After the reaction was completed, 200 g of deionized water was added to perform stirring, and then it was left to stand for 2 hours. The supernatant was discarded, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then it was concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight: 8260).

[0099] To 200 g of the 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, it was left to stand for 2 hours, the supernatant was removed, and 160 g of diheptyl ketone solution was added to precipitate the resin, and then a fractionated resin solution (referred to as resin 3) having a mass fraction of about 40% and an average molecular weight of 11216 was obtained.

[0100] Example 4

[0101] To 200.0 g of γ-butyrolactone were added 40.8 g (0.3 mol) of 2,3,5-trimethylphenol, 22.8 g (0.1 mol) of 4',4-dihydroxydiphenylisopropyl propane, and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 6 g (0.2 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the dropwise addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the dropwise addition was completed, the mixture was refluxed for 20 hours to perform the reaction.

[0102] After the reaction was completed, 200 g of deionized water was added to perform stirring, and then it was left to stand for 2 hours. The supernatant was discarded, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then it was concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight 7500).

[0103] To 200 g of the 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, it was left to stand for 2 hours, the supernatant was removed, and 160 g of diheptyl ketone was added to precipitate the resin, to obtain a fractionated resin solution (referred to as resin 4) having an average molecular weight of 9800 and a mass fraction of about 40%.

[0104] Example 5

[0105] To 200.0 g of γ-butyrolactone were added 40.8 g (0.3 mol) of 2,3,5-trimethylphenol, 22.8 g (0.1 mol) of 4',4-dihydroxydiphenylisopropyl propane, and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 6 g (0.2 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the dropwise addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the dropwise addition was completed, the mixture was refluxed for 20 hours to perform the reaction.

[0106] After the reaction was completed, 200 g of deionized water was added to perform stirring, and then it was left to stand for 2 hours. The supernatant was discarded, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then it was concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight 7500).

[0107] To 200 g of a 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, it was left to stand for 2 hours, the supernatant was removed, and 160 g of diheptyl ketone solution was added to precipitate the resin, to obtain a 40% by mass diheptyl ketone resin solution (average molecular weight 8500) (referred to as resin 5).

[0108] Example 6

[0109] To 200.0 g of γ-butyrolactone were added 40.8 g (0.3 mol) of 2,3,5-trimethylphenol, 39.0 g (0.15 mol) of 2',2,3,4-tetrahydroxydiphenylisopropane, and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 7.5 g (0.25 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 69 g of a 37% by mass formaldehyde solution was added dropwise, and after the addition was completed, the mixture was refluxed for 20 hours to carry out the reaction.

[0110] After the reaction was completed, 200 g of deionized water was added and stirred, and left to stand for 2 hours. The supernatant was discarded, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight 8450). In the present application, the average molecular weight is the weight average molecular weight.

[0111] To 200 g of a 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, it was left to stand for 2 hours, the supernatant was removed, and 160 g of diheptyl ketone solution was added to precipitate the resin, to obtain a 40% by mass diheptyl ketone resin solution (average molecular weight 8500) (referred to as resin 5).

[0112] Example 7

[0113] To 200.0 g of γ-butyrolactone were added 40.8 g (0.3 mol) of 2,3,5-trimethylphenol, 39.0 g (0.15 mol) of 2',2,3,4-tetrahydroxydiphenylisopropane, and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 7.5 g (0.25 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 69 g of a 37% by mass formaldehyde solution was added dropwise, and after the addition was completed, the mixture was refluxed for 20 hours to carry out the reaction.

[0114] After the reaction is completed, 200 g of deionized water is added to stir, and left to stand for 2 hours. The supernatant is discarded, and 500 g of diheptyl ketone is added to dissolve the precipitated resin, and then concentrated to a diheptyl ketone resin solution having a mass fraction of 40% (average molecular weight 9000). In this application, the average molecular weight is the weight average molecular weight.

[0115] To 200 g of the diheptyl ketone resin solution having a mass fraction of 40%, 800 g of n-heptane is added dropwise, and after the addition is completed, left to stand for 2 hours, the supernatant is removed, and 160 g of diheptyl ketone solution is added to precipitate the resin, to obtain a fractionated resin solution having a mass fraction of about 40% and an average molecular weight of 12100 (referred to as resin 7).

[0116] Example 8

[0117] To 200.0 g of γ-butyrolactone, 37.2 g (0.3 mol) of 3,5-dimethylphenol, 26 g (0.10 mol) of 2',2,3,4-tetrahydroxydiphenylisopropane, and 5.0 g of oxalic acid are added, and then the mixture is heated to 95°C, and then 7.5 g (0.25 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone is added dropwise. After the dropwise addition is completed, the mixture is stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol is added to the solution, and 72.9 g of a formaldehyde solution having a mass fraction of 37% is added dropwise, and after the dropwise addition is completed, the mixture is refluxed for 20 hours to react.

[0118] After the reaction is completed, 200 g of deionized water is added to stir, and left to stand for 2 hours. The supernatant is discarded, and 500 g of diheptyl ketone is added to dissolve the precipitated resin, and then concentrated to a diheptyl ketone resin solution having a mass fraction of 40% (average molecular weight 8650). In this application, the average molecular weight is the weight average molecular weight.

[0119] To 200 g of the diheptyl ketone resin solution having a mass fraction of 40%, 800 g of n-heptane is added dropwise, and after the addition is completed, left to stand for 2 hours, the supernatant is removed, and 160 g of diheptyl ketone solution is added to precipitate the resin, to obtain a fractionated resin solution having a mass fraction of about 40% and an average molecular weight of 10000 (referred to as resin 8).

[0120] Example 9

[0121] To 200.0 g of γ-butyrolactone were added 43.2 g (0.4 mol) of p-cresol, 26 g (0.10 mol) of 2',2,3,4-tetrahydroxydiphenylisopropane, and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 12 g (0.4 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the dropwise addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the dropwise addition was completed, the mixture was refluxed for 20 hours to perform a reaction.

[0122] After the reaction was completed, 200 g of deionized water was added to perform stirring, and then it was left to stand for 2 hours. The supernatant was discarded, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then it was concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight 6500). In the present application, the average molecular weight means the weight average molecular weight.

[0123] To 200 g of the 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, it was left to stand for 2 hours, and then the supernatant was removed, and 160 g of diheptyl ketone was added to precipitate the resin, and then a 40% by mass average molecular weight 8900 fraction resin solution (referred to as resin 9) was obtained.

[0124] Example 10

[0125] To 200.0 g of γ-butyrolactone were added 21.6 g (0.2 mol) of o-cresol, 26 g (0.10 mol) of 2',2,3,4-tetrahydroxydiphenylisopropane, and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 6 g (0.2 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the dropwise addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the dropwise addition was completed, the mixture was refluxed for 20 hours to perform a reaction.

[0126] After the reaction was completed, 200 g of deionized water was added to perform stirring, and then it was left to stand for 2 hours. The supernatant was discarded, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then it was concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight 8300). In the present application, the average molecular weight means the weight average molecular weight.

[0127] To 200 g of a 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, the mixture was left to stand for 2 hours, the supernatant was removed, and 160 g of diheptyl ketone was added to precipitate the resin, thereby obtaining a fractionated resin solution (referred to as resin 10) having an average molecular weight of 11500 and a mass fraction of about 40%.

[0128] Comparative Example 1

[0129] To 200.0 g of γ-butyrolactone were added 40.8 g (0.3 mol) of 2,3,5-trimethylphenol and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 6 g (0.2 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the addition was completed, the mixture was refluxed for 20 hours to perform the reaction.

[0130] After the reaction was completed, 200 g of deionized water was added and stirred, and the mixture was left to stand for 2 hours. The supernatant was removed, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then the mixture was concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight: 6700).

[0131] To 200 g of a 40% by mass diheptyl ketone resin solution, 800 g of n-heptane was added dropwise, and after the addition was completed, the mixture was left to stand for 2 hours, the supernatant was removed, and 160 g of diheptyl ketone was added to precipitate the resin, thereby obtaining a fractionated resin solution (referred to as resin 1') having an average molecular weight of 9000 and a mass fraction of about 40%.

[0132] Comparative Example 2

[0133] To 200.0 g of γ-butyrolactone were added 43.2 g (0.4 mol) of p-cresol and 5.0 g of oxalic acid, and then the mixture was heated to 95°C, and then 7.5 g (0.25 mol) of formaldehyde dissolved in 100 ml of γ-butyrolactone was added dropwise. After the addition was completed, the mixture was stirred at 95°C for three hours. Subsequently, 108 g (1.0 mol) of m-cresol was added to the solution, and 72.9 g of a 37% by mass formaldehyde solution was added dropwise, and after the addition was completed, the mixture was refluxed for 20 hours to perform the reaction.

[0134] After the reaction was completed, 200 g of deionized water was added and stirred, and the mixture was left to stand for 2 hours. The supernatant was removed, and 500 g of diheptyl ketone was added to dissolve the precipitated resin, and then the mixture was concentrated to a 40% by mass diheptyl ketone resin solution (average molecular weight: 5800). In the present application, the average molecular weight means the weight average molecular weight.

[0135] In 200 g of a 40% by mass solution of diheptyl ketone resin, 800 g of n-heptane was added dropwise, after the addition was completed, it was allowed to stand for 2 hours, the supernatant was removed, 160 g of a diheptyl ketone solution of the precipitated resin was added, to obtain a 40% by mass solution of a resin having an average molecular weight of 7900 (referred to as resin 2').

[0136] (B) Preparation of photoresist

[0137] The phenolic resin (i.e. the fractionated resin solution) prepared in each example and comparative example was mixed with other components.

[0138] The photoresist includes 55 parts by weight of phenolic resin, 25 parts by weight of diazonium naphthoquinone sulfonate, 15 parts by weight of sensitizing agent TPPA, 300 parts by weight of diheptyl ketone and 60 parts by weight of n-butyl acetate.

[0139] The diazonium naphthoquinone sulfonate is a compound obtained by esterification of a compound represented by formula IX with 1-diazo-2-naphthoquinone-5-sulfonyl chloride. The feeding ratio of IX to 1-diazo-2-naphthoquinone-5-sulfonyl chloride is 1:3.

[0140] (C) Test examples

[0141] The performance of the photoresist prepared using the phenolic resin provided in each example and comparative example was tested.

[0142] In each example and comparative example, the relevant important information of the phenolic resin is shown in Table 1 below.

[0143] Table 1

[0144]

[0145]

[0146] In Table 1, the mass percentage is rounded to two decimal places, and the error after rounding is caused by the fact that the first type of phenol and the second type of phenol are not equal to 1.

[0147] The performance test items of the photoresist include the photosensitive speed, heat resistance, resolution and topography of the photoresist.

[0148] Test method and equipment:

[0149] Resolution test method:

[0150] (1) A spin coater (manufacturer: Tokyo Electron Co., Ltd., model: Mark V) was used to spin coat on a 6-inch silicon wafer, the rotation speed was adjusted according to the thickness of the photoresist layer, after the spin coating was completed, the first baking was carried out at a temperature of 90°C for 60 seconds, then the film thickness was measured after cooling, to form a 1 μm thick photoresist layer;

[0151] (2) Then, exposure was performed in an i-line exposure machine (manufactured by Nikon Corporation, model: Nikon i9, numerical aperture (NA) = 0.57) with a mask having a line width of 2-0.25 μm, a line width to grating pitch ratio of 1:1-1:5, and an exposure time of 20-2000 ms, and an exposure amount of 10-1000 mJ;

[0152] (3) Then, development was performed using a 23 °C, 2.38 wt% aqueous solution of tetramethylammonium hydroxide for 60 s;

[0153] (4) Finally, the resolution was evaluated using a scanning electron microscope (CD-SEM) (manufactured by Hitachi, model 8840) for a resist picture.

[0154] Heat resistance test:

[0155] The wafer observed by the CD-SEM was placed again on a hot plate for baking at a temperature of 110-140 °C for 90 s, and then the resist morphology after baking was observed by X-SEM sectioning (manufactured by Hitachi, model 4800).

[0156] Sensitization speed test:

[0157] The exposure amount in the resolution test method step (2), i.e., the exposure energy, was the optimum exposure amount for the line width, and was the sensitization speed value of the formula, i.e., the result of the sensitization speed.

[0158] Morphology test:

[0159] According to the data of the X-SEM sectioning, the side wall angle was measured, which was the included angle a between the side wall and the substrate. Generally, a side wall angle greater than 85° and a vertical side wall (as shown in FIG. 1) were considered to be a good morphology, and were recorded as Good. If the side wall angle was less than 85° (as shown in FIG. 2) or the side wall was not vertical (as shown in FIG. 3), the morphology was considered to be poor, and was recorded as Bad. Figure 1 Figure 2 Figure 3

[0160] The performance test results of the resist are shown in Table 2 below.

[0161] Table 2

[0162]

[0163] According to Tables 1 and 2, it can be seen that:

[0164] ​​​The phenolic resin provided in the embodiments of the present application has a polyhydroxy phenol structure (first type of phenol) as shown in Formula I incorporated in the molecular structure; in the comparative examples, no polyhydroxy phenol structure as shown in Formula I is incorporated in the molecular structure. Compared with the comparative examples, the photosensitive speed of the photoresist is effectively improved.

[0165] In Examples 1-5, the first type of phenol has a suitable proportion and structure, and the second type of phenol has a suitable combination, so that the photoresist can maintain good heat resistance, topography and resolution.

[0166] Compared with Example 1, the content of the first type of phenol in Example 6 is relatively high. The photoresist of Example 1 has better heat resistance, topography and resolution.

[0167] Compared with Example 1, the total amount of hydroxyl groups of the first type of phenol in Example 7 is relatively high. The photoresist of Example 1 has better heat resistance, topography and resolution.

[0168] Compared with Example 1, the combination of the second type of phenol in Example 8 is adjusted. The photoresist of Example 1 has better heat resistance, topography and resolution.

[0169] Compared with Example 1, the combination of the second type of phenol in Examples 9-10 is adjusted. The photoresist of Example 1 has better photosensitive speed, heat resistance and resolution.

[0170] The above-described embodiments are part of the embodiments of the present application, rather than all the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

Claims

1. A phenol-formaldehyde resin, characterized by, The product is obtained by condensation of a specified phenol, the specified phenol including a first type of phenol and a second type of phenol, the first type of phenol having a structural formula as shown in Formula I, and the second type of phenol including cresol and trimethylphenol; (Formula I); wherein the X group is at least one of a hydrogen group and an alkyl group having 1-5 carbon atoms; the R1 group and the R2 group are at least one of a hydrogen group, an alkyl group having 1-4 carbon atoms, and an alkoxy group having 1-4 carbon atoms; 3≥a≥0, 3≥b≥0, 3≥m≥0, 3≥n≥0, and m+n≥2; In the specified phenol, the mass percentage of the first type of phenol is 1-20%.

2. The phenolic resin according to claim 1, characterized in that, 4≥m+n≥2.

3. The phenol-formaldehyde resin according to claim 2, characterized in that The first type of phenol includes at least one of 2,3,4-trihydroxydiphenyl compounds, 2,2',3',4'-tetrahydroxydiphenyl compounds, 2,2',4,4'-tetrahydroxydiphenyl compounds, 2',2,4-trihydroxydiphenyl compounds, and 4',4'-dihydroxydiphenyl compounds.

4. The phenol-formaldehyde resin according to any one of claims 1 to 3, characterized in that The R1 group and the R2 group are each a hydrogen group or a methyl group.

5. The phenolic resin of claim 1, wherein The connection structure of the first type of phenol in the phenolic resin is shown in Formula II and / or Formula III. (Formula II); (Formula III).

6. The phenolic resin of claim 1, wherein The cresol is m-cresol.

7. The phenolic resin according to claim 6, characterized in that The trimethylphenol is 2,3,5-trimethylphenol.

8. The phenolic resin according to claim 7, characterized in that, In the specified phenol, the mass percentage of the cresol is 30-95%, and the mass percentage of the trimethylphenol is 2-50%.

9. A photoresist, characterized by, The photoresist includes the phenolic resin according to any one of claims 1-8 and a photosensitizer.

10. The photoresist of claim 9, wherein The photosensitizer includes diazonium naphthoquinone sulfonate.

11. The photoresist of claim 10, wherein The photoresist includes 40-70 parts by weight of the phenolic resin and 10-30 parts by weight of the diazonium naphthoquinone sulfonate.

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