Thick-film KrF photoresist composition and preparation and use methods thereof

Abstract

The invention relates to a thick film KrF photoresist composition as well as a preparation method and a use method thereof. The photoresist composition comprises polymer resin, a photoacid generator, an acid diffusion inhibitor, a flatting agent and a solvent, the polymer resin is a hydroxyl styrene compound, a copolymer of a compound shown as a general formula I and a compound shown as a general formula II. The preparation method comprises the following steps: adding all the components into a solvent according to the proportion, and mixing. The use method comprises the following steps: coating a silicon wafer with the photoresist composition, and sequentially carrying out pre-baking, exposure, post-baking and development to obtain a required photoetching pattern. The photoresist composition disclosed by the invention can effectively avoid the defect that bubbles are generated on the surface of the thick-film KrF photoresist.

Description

Technical Field

[0001] The invention relates to the technical field of photoresists, and specifically discloses a thick film KrF photoresist composition and a preparation and use method thereof. Background Art

[0002] Photoresist is a key material for manufacturing integrated circuits, and its performance directly affects the integration, operating speed, power consumption and other performance of the integrated circuit chip.

[0003] Photoresist, also known as photoresist, is a photosensitive polymer material with high sensitivity to light and radiation. After being irradiated or radiated by ultraviolet light, electron beam, excimer laser beam, ion beam, X-ray, etc., it can undergo photochemical reactions, causing the dissolution properties of the film to change before and after exposure. Therefore, it can be divided into positive photoresist and negative photoresist. Photoresist is mainly composed of film-forming resin, photoacid generator, acid diffusion controller and solvent.

[0004] When the photoresist is used as a KrF thick film photoresist (e.g., with a thickness of 5 μm or more), after exposure and baking, due to the volatilization of low-boiling point components in the photoresist, bubble-like defects may appear on the surface of the photoresist film. Therefore, it is of great significance to develop a photoresist that can be used for thicknesses above 5 μm and does not produce bubble-like defects after exposure and baking. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a thick film KrF photoresist composition and a preparation method and a use method thereof, so as to improve the bubble defect generated on the surface of the thick film photoresist.

[0006] In order to achieve the purpose of the present invention, this application provides the following technical solutions.

[0007] In a first aspect, the present application provides a thick film KrF photoresist composition, the photoresist composition comprising a polymer resin, a photoacid generator, an acid diffusion controller, a leveling agent and a solvent;

[0008] The polymer resin is a copolymer of a hydroxystyrene compound, a compound of formula I, and a compound of formula II;

[0009] The structure of the compound of formula I is as follows:

[0010]

[0011] Wherein, R1 is a hydrogen atom or a methyl group, and R2 is a monocyclic hydrocarbon acid-sensitive group;

[0012] The structure of the compound of formula II is as follows:

[0013]

[0014] Among them, R3 is a C1-C5 straight-chain or branched alkyl group, and R4 is a polycyclic hydrocarbon group.

[0015] The polymer resin provided by the present invention contains a monomer compound of general formula I, which contains an R2 monocyclic hydrocarbon acid-sensitive group having higher etching resistance than an aliphatic acid-sensitive group.

[0016] The polymer resin provided by the present invention contains a monomer compound of the general formula II with an acetal structure, which has a low reaction activation energy and can also undergo an acid deprotection reaction under the action of an acid at the bottom of a thick-film photoresist with a weak light intensity after exposure. At the same time, the compound of the general formula II carries an R4 polycyclic hydrocarbon group, and after the acid deprotection reaction occurs, a component containing an R4 structure that is not easily volatile is generated, which is beneficial to improving the bubble defects on the surface of the photoresist.

[0017] In a preferred technical solution of the first aspect, at least one of the following technical features is also included:

[0018] a1) The compound of general formula I is selected from at least one of the following structures:

[0019]

[0020] a2) The compound of formula II is selected from at least one of the following structures:

[0021]

[0022] In a preferred technical solution of the first aspect, the photoresist composition further includes at least one of the following technical features:

[0023] b1) the weight average molecular weight of the polymer resin is 10,000 to 40,000, preferably 13,000 to 25,000;

[0024] b2) the molecular weight distribution coefficient of the polymer resin is PDI<4.0, preferably 1.5 to 2.5;

[0025] b3) The polymer resin is obtained by polymerization of monomers in the following molar ratios;

[0026] Hydroxystyrene compound 55-70%, preferably 55-65%;

[0027] 15-25% of the compound of formula I, preferably 18-23%;

[0028] The compound of formula II is 10-30%, preferably 15-25%.

[0029] In a preferred technical solution of the first aspect, the photoresist composition further includes at least one of the following technical features:

[0030] c1) the photoacid generator is selected from at least one of the following structures;

[0031]

[0032]

[0033] c2) the acid diffusion control agent is selected from at least one of tetrabutylammonium hydroxide, tri(3,6-dioxaheptyl)amine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, triethanolamine, triisopropanolamine, triethylenediamine, 2-ethyl-N,N-bis(2-ethylhexyl)-1-hexylamine, 2,6-di-tert-butylpyridine, 1-(tert-butoxycarbonyl)-4-hydroxypiperidine, 2-phenylbenzimidazole, and diphenylamine;

[0034] c3) the leveling agent is selected from at least one of 3M fluorocarbon surfactant FC-4430 and Troysol S366;

[0035] c4) the solvent is selected from at least one of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, anisole, propylene glycol monoacetate, propylene glycol monoethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol methyl ethyl ether, butyl acetate, neopentyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, diacetone alcohol, and gamma-butyrolactone.

[0036] In a preferred technical solution of the first aspect, the photoresist composition comprises the following components in percentage by mass:

[0037]

[0038] In a second aspect, the present application also provides a method for preparing the photoresist composition as described above, the preparation method comprising the following steps: adding the polymer resin, the photoacid generator, the acid diffusion controller, and the leveling agent to a solvent in proportion and mixing, and filtering to obtain a photoresist.

[0039] In a preferred technical solution of the second aspect, the pore size of the membrane used for filtration is a nylon membrane of 1.0 μm+1.0 μm+1.0 μm.

[0040] In a third aspect, the present application also provides a method for using the photoresist composition as described above, the method comprising the following steps:

[0041] The photoresist composition is coated on a silicon wafer, and is sequentially subjected to pre-baking, exposure, post-baking and development to obtain a desired photolithography pattern.

[0042] In a preferred technical solution of the third aspect, the method of use further includes at least one of the following technical features:

[0043] c1) the pre-baking temperature is 100-150° C., preferably 130-150° C., and the pre-baking time is 70-150 s, preferably 100-150 s;

[0044] c2) The exposure energy is 30~60mj / cm 2 ;

[0045] c3) the post-baking temperature is 110 to 150° C., preferably 110 to 130° C., and the post-baking time is 50 to 150 seconds, preferably 70 to 150 seconds;

[0046] c4) The developer used in the development is 2.38% TMAH, and the developing time is 60 to 150 seconds.

[0047] Compared with the prior art, the photoresist composition provided by the present invention selects a suitable polymer as the base resin and selects a suitable photoacid generator. It can be applied to KrF photoresists with a thickness of more than 5 μm and can effectively avoid the defect of bubbles generated on the surface of thick film photoresists after exposure and baking. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 This is the photolithographic pattern after the photoresist prepared in Example 1-4 is used.

[0049] Figure 2 This is the photolithographic pattern after the photoresist prepared in Comparative Example 1 is used.

[0050] Figure 3 This is the photolithographic pattern after the photoresist prepared in Comparative Example 2 is used. DETAILED DESCRIPTION

[0051] Unless otherwise indicated, implied from the context, or customary in the prior art, all parts and percentages in this application are based on weight, and the test and characterization methods used are all current as of the filing date of this application. Where applicable, the contents of any patent, patent application or publication referred to in this application are fully incorporated herein by reference, and their equivalent patent families are also incorporated by reference, especially the definitions of synthesis techniques, product and processing designs, polymers, comonomers, initiators or catalysts disclosed in these documents in the art. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in this application, the definition of the term provided in this application shall prevail.

[0052] Numerical ranges in this application are approximate values, so unless otherwise specified, they may include values ​​outside the range. Numerical ranges include all values ​​from the lower limit to the upper limit increased by 1 unit, provided that there is an interval of at least 2 units between any lower value and any higher value. For example, if the recorded component, physical or other properties (such as molecular weight, melt index, etc.) are 100 to 1000, it means that all single values ​​are clearly listed, such as 100, 101, 102, etc., and all sub-ranges, such as 100 to 166, 155 to 170, 198 to 200, etc. For a range comprising a value less than 1 or comprising a fraction greater than 1 (such as 1.1, 1.5, etc.), 1 unit is appropriately regarded as 0.0001, 0.001, 0.01 or 0.1. For ranges containing single digit numbers less than 10 (e.g., 1 to 5), 1 unit is generally considered to be 0.1. These are only specific examples of what is intended, and all possible combinations of numerical values ​​between the lowest and highest values ​​recited are considered to be expressly stated in this application. The numerical ranges within this application provide, among other things, calcium-containing filler content, stirring temperature, and various features and properties of these components.

[0053] When used with respect to chemical compounds, unless expressly specified otherwise, the singular includes all isomeric forms and vice versa (e.g., "hexane" includes all isomers of hexane, individually or collectively). In addition, nouns using "a," "an," or "the" also include their plural forms unless expressly specified otherwise.

[0054] The terms "comprising", "including", "having" and their derivatives do not exclude the presence of any other components, steps or processes, and are irrelevant to whether these other components, steps or processes are disclosed in this application. To eliminate any doubt, unless explicitly stated, all compositions using the terms "comprising", "including", or "having" in this application may include any additional additives, adjuvants or compounds. On the contrary, except for those necessary for operating performance, the term "essentially consisting of..." excludes any other components, steps or processes from the scope of any description of the term below. The term "consisting of..." does not include any components, steps or processes that are not specifically described or listed. Unless explicitly stated, the term "or" refers to the listed individual members or any combination thereof.

[0055] Example

[0056] The embodiments of the present invention will be described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0057] Preparation of polymer resins

[0058] Polymer resin A-1 was obtained by the following synthesis method:

[0059]

[0060] In a 500ml dry four-necked flask protected by nitrogen equipped with a stirrer and a condenser, acetoxystyrene (90.0g, 0.555mol), compound I-1 (31.1g, 0.185mol) and (compound II-1) (55.6g, 0.185mol) and solvent tetrahydrofuran (176.7g) were added. The reaction system was decompressed and evacuated, and then nitrogen was replaced three times. The reaction solution was stirred and mixed, cooled to 0°C, and then initiator AIBN (16g) was added and stirred for 10 minutes. The reaction system was heated to 65°C and reacted for 18h. After the polymerization was complete, the reaction system was cooled to room temperature.

[0061] The system device was changed into a distillation device, methanol (150g) was added to dilute the system, triethylamine (15g) and water (5g) were added dropwise, the system temperature was raised to 62-65°C, and after reacting for 8h (during this process, the acetyl group in acetoxystyrene was removed to form a hydroxyl group), the mixed solution was slowly added dropwise to 5L of deionized water to precipitate, and a solid compound was obtained. The solid compound was collected by 40# filter paper, and then tetrahydrofuran was used to dissolve the solid compound to about 20%, and the compound was precipitated in 5L of deionized water again, and the above operation was repeated twice. The solid compound was collected and placed in a vacuum oven at 45°C for 48h to obtain polymer resin A-1 (120.8g, weight average molecular weight 14700, molecular weight distribution coefficient 1.8).

[0062] Polymer resin A-2 was obtained by the following synthesis method:

[0063] The synthesis method of polymer resin A-2 is the same as the synthesis method of polymer resin A-1 and the related process parameters are the same, except that the monomers used are acetoxystyrene (90.0 g, 0.555 mol), compound I-1 (31.1 g, 0.185 mol) and compound II-2 (57.8 g, 0.185 mol), and the reaction route is as follows:

[0064]

[0065] Finally, polymer resin A-2 (128.1 g, weight average molecular weight 15200, molecular weight distribution coefficient 1.8) was obtained.

[0066] Polymer resin A-3 was obtained by the following synthesis method:

[0067] The synthesis method of polymer resin A-3 is the same as the synthesis method of polymer resin A-1 and the related process parameters are the same, except that the monomers used are acetoxystyrene (90.0 g, 0.555 mol), compound I-3 (31.1 g, 0.185 mol) and compound II-3 (55.2 g, 0.185 mol), and the reaction route is as follows:

[0068]

[0069] Finally, polymer resin A-3 (122.9 g, weight average molecular weight 14200, molecular weight distribution coefficient 1.9) was obtained.

[0070] Polymer resin A-4 was obtained by the following synthesis method:

[0071] The synthesis method of polymer resin A-4 is the same as the synthesis method of polymer resin A-1 and the related process parameters are the same, except that the monomers used are acetoxystyrene (90.0 g, 0.555 mol), compound I-2 (36.3 g, 0.185 mol) and compound II-1 (55.6 g, 0.185 mol), and the reaction route is as follows:

[0072]

[0073] Finally, polymer resin A-4 (127.3 g, weight average molecular weight 15600, molecular weight distribution coefficient 2.0) was obtained.

[0074] Comparative Example polymer resin B-1 was obtained by the following synthesis method:

[0075]

[0076] In a 500ml dry four-necked flask protected by nitrogen equipped with a stirrer and a condenser, acetoxystyrene (90.0g, 0.555mol), P-(1-ethoxyethoxy)styrene (16.4g, 0.085mol), compound I-1 (35.9g, 0.213mol) and solvent methanol (140g) were added. The reaction system was decompressed and evacuated, and nitrogen was replaced three times. The reaction solution was stirred and mixed, cooled to 0°C, and then initiator V601 (17g) was added and stirred for 10 minutes. The reaction system was heated to 65°C and reacted for 18h. After the polymerization was complete, the reaction system was cooled to room temperature.

[0077] The system device was changed into a distillation device, methanol (150g) was added to dilute the system, triethylamine (15g) and water (5g) were added dropwise, the system was heated to 62-65°C, and the reaction was continued for 8h (during this process, the acetyl group in acetoxystyrene was removed to form a hydroxyl group), the mixed solution was slowly added dropwise to 5L of deionized water for precipitation to obtain a solid compound, and the solid compound was collected by 40# filter paper, and then the solid compound was dissolved to about 20% by tetrahydrofuran, and the compound was precipitated in 5L of deionized water again, and the above operation was repeated twice. The solid compound was collected and placed in a vacuum oven at 45°C for 48h to obtain 4-hydroxystyrene-P-(1-ethoxyethoxy)styrene-compound I-1 terpolymer B-1 (113.57g, weight average molecular weight 11600, molecular weight distribution coefficient 1.84).

[0078] Comparative Example polymer resin B-2 was obtained by the following synthesis method:

[0079] The synthesis method of polymer resin B-2 is the same as that of polymer resin B-1 and the related process parameters are the same, except that the monomers used are acetoxystyrene (90.0 g, 0.555 mol), P-(1-ethoxyethoxy)styrene (16.4 g, 0.085 mol) and compound I-3 (41.8 g, 0.213 mol), and the reaction route is as follows:

[0080]

[0081] The second polymer resin B-2 (113.94 g, weight average molecular weight 12600, molecular weight distribution coefficient 1.81) was finally obtained.

[0082] The remaining components used in the embodiments and comparative examples are described as follows:

[0083] Photoacid generator:

[0084]

[0085] Acid Diffusion Controller:

[0086] Tri-n-pentylamine (D-1)

[0087] Solvent:

[0088] Propylene glycol monomethyl ether acetate (S-1)

[0089] Propylene glycol monomethyl ether (S-2)

[0090] The following is a description of the components used in the Examples and Comparative Examples, in parts by weight, as shown in Table 1.

[0091] Table 1

[0092]

[0093] The present invention also provides a method for preparing the photoresist composition provided in the above-mentioned embodiments and comparative examples, comprising the following steps:

[0094] The components were added according to the formula, mixed and stirred evenly, and then filtered through a 1.0 μm+1.0 μm+1.0 μm nylon membrane to complete the preparation of the photoresist.

[0095] The prepared photoresist composition is used according to the following method:

[0096] The prepared photoresist composition was spin-coated at 1000-3000 rpm on an 8-inch bare silicon wafer provided with HMDS primer to form a 5.0 μm film. Pre-baked on a 130°C hot plate for 90 seconds, then selectively exposed (2 μm Line / Space) using a KrF exposure machine XT860M (Conventional: NA0.55Sigma 0.6), then post-baked on a 110°C hot plate for 90 seconds, and after the wafer was cooled to room temperature, developed with a 2.38% TMAH developer for 60 seconds, and finally rinsed with deionized water for 30 seconds to form the desired photolithography pattern.

[0097] The photoresist photolithography patterns of Examples 1 to 4 are as follows: Figure 1 As shown, the photoresist patterns of Comparative Examples 1-2 are respectively as follows Figures 2-3 shown.

[0098] Depend on Figure 1 The results show that in Examples 1 to 4, the polymer resins A-1 to A-4 were used, and bubble-like defects were not generated in the exposed areas.

[0099] Comparative Examples 1 and 2 used resins B-1 and B-2 containing P-(1-ethoxyethoxy)styrene monomer, and obvious bubble-like defects were generated in the exposed areas.

[0100] The above results indicate that the copolymer of hydroxystyrene, compound of formula I and compound of formula II is used in the photoresist provided by the present invention. Since the monomer compound of formula II carries a polycyclic hydrocarbon group, less volatile components are produced after the deprotection reaction occurs under acidic conditions. Therefore, bubble-like defects in the exposed area of ​​the photoresist can be effectively avoided.

[0101] The above description of the embodiments is to facilitate those of ordinary skill in the art to understand and apply the present application. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to pay creative labor. Therefore, the present application is not limited to the embodiments herein, and improvements and modifications made by those skilled in the art based on the contents disclosed in the present application without departing from the scope and spirit of the present application are within the scope of the present application.

Claims

1. A thick film KrF photoresist composition, characterized in that: The photoresist composition comprises a polymer resin, a photoacid generator, an acid diffusion inhibitor, a leveling agent and a solvent; the polymer resin is a copolymer of a hydroxystyrene compound, such as a compound of formula I and a compound of formula II; The structure of the compound of formula I is as follows: Wherein, R1 is a hydrogen atom or a methyl group, and R2 is a monocyclic hydrocarbon acid-sensitive group; The structure of the compound of formula II is as follows: Among them, R3 is a C1-C5 straight-chain or branched alkyl group, and R4 is a polycyclic hydrocarbon group.

2. The thick film KrF photoresist composition according to claim 1, characterized in that Also includes at least one of the following technical features: a1) The compound of general formula I is selected from at least one of the following structures: a2) The compound of formula II is selected from at least one of the following structures:

3. The thick film KrF photoresist composition according to claim 1, characterized in that The photoresist composition further comprises at least one of the following technical features: b1) the weight average molecular weight of the polymer resin is 10,000 to 40,000; b2) the molecular weight distribution coefficient of the polymer resin is PDI<4.0; b3) The polymer resin is obtained by polymerization of monomers in the following molar ratios; Hydroxystyrene compounds 55-70%; 15-25% of the compound of formula I; 10-30% of the compound of formula II.

4. The thick film KrF photoresist composition according to claim 1, characterized in that The photoresist composition further comprises at least one of the following technical features: c1) The photoacid generator is selected from at least one of the following structures: c2) the acid diffusion control agent is selected from at least one of tetrabutylammonium hydroxide, tri(3,6-dioxaheptyl)amine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, triethanolamine, triisopropanolamine, triethylenediamine, 2-ethyl-N,N-bis(2-ethylhexyl)-1-hexylamine, 2,6-di-tert-butylpyridine, 1-(tert-butoxycarbonyl)-4-hydroxypiperidine, 2-phenylbenzimidazole, and diphenylamine; c3) the leveling agent is selected from at least one of 3M fluorocarbon surfactant FC-4430 and Troysol S366; c4) the solvent is selected from at least one of propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, anisole, propylene glycol monoacetate, propylene glycol monoethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol methyl ethyl ether, butyl acetate, neopentyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, diacetone alcohol, and gamma-butyrolactone.

5. The thick film KrF photoresist composition according to any one of claims 1 to 4, characterized in that: The photoresist composition comprises the following components in percentage by weight:

6. The method for preparing a thick film KrF photoresist composition according to any one of claims 1 to 5, characterized in that: The polymer resin, the photoacid generator, the acid diffusion controller and the leveling agent are added into the solvent in proportion and mixed, and the mixture is filtered to obtain the photoresist.

7. The method for preparing a thick film KrF photoresist composition according to claim 6, characterized in that: The pore size of the membrane used for the filtration is a nylon membrane of 1.0 μm+1.0 μm+1.0 μm.

8. The method for using the thick film KrF photoresist composition according to any one of claims 1 to 5, characterized in that: The method of use comprises the following steps: The photoresist composition is coated on a silicon wafer, and is sequentially subjected to pre-baking, exposure, post-baking and development to obtain a desired photolithography pattern.

9. The method for using the thick film KrF photoresist composition according to claim 8, characterized in that: The method of use also includes at least one of the following technical features: c1) The pre-baking temperature is 100-150°C and the pre-baking time is 70-150s; c2) The exposure energy is 30~60mj / cm 2 ; c3) the post-baking temperature is 110-150°C and the post-baking time is 50-150s; c4) The developer used in the development is 2.38% TMAH, and the developing time is 60 to 150 seconds.

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