A positive chemically amplified photoresist and its use method

Abstract

The present invention provides a positive chemical amplification photoresist and a method for using the same. The photoresist comprises the following components in percentage by mass: polymer resin, 5% to 15% of the photoresist; photoacid generator, 2.0% to 7.0% of the polymer resin; acid quencher, 5% to 30% of the photoacid generator; dissolution promoter, 1.0% to 5.0% of the polymer resin; leveling agent, 0.01% to 0.5% of the photoresist; solvent, 100% supplemented; the polymer resin is a methacrylate copolymer, which is formed by copolymerization of a methacrylate compound containing an acid-sensitive group and a methacrylate compound containing a polar group. The method for using the photoresist comprises the following steps: coating the positive amplification photoresist on a silicon wafer, and sequentially performing pre-baking, exposure, post-baking and development to obtain a pattern after photolithography. The photoresist provided by the present invention can effectively improve the problem of line peeling after exposure and development.

Description

Technical Field

[0001] The invention relates to the technical field of photoresists, and in particular to a positive chemically amplified photoresist and a use method thereof. Background Art

[0002] 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 solubility properties of the film to change before and after exposure. Therefore, it can be divided into positive photoresist and negative photoresist. After exposure, the solubility of the photoresist in the developer increases, and the photoresist with the same pattern as the mask is called a positive photoresist, and vice versa, it is a negative photoresist. Photoresist is mainly composed of film-forming resin, photoacid generator, acid diffusion controller and solvent.

[0003] Photoresist is an indispensable raw material for chip manufacturing. With the improvement of process nodes, the requirements for the performance of photoresist are getting higher and higher. Among them, the resolution of ArF photoresist can meet the needs of 90nm to 28nm technology nodes. As the critical dimension decreases, when the aspect ratio reaches a certain ratio, the lines of the photoresist will collapse (peeling). Summary of the invention

[0004] The purpose of the present invention is to provide a positive chemical amplification type photoresist and a method of using the same to solve the problem of line peeling after exposure and development of ArF photoresist patterns.

[0005] In order to achieve the purpose of the present invention, this application provides the following technical solutions.

[0006] In a first aspect, the present application provides a positive chemically amplified photoresist, wherein the photoresist comprises the following components in percentage by mass:

[0007]

[0008]

[0009] The polymer resin is a methacrylate copolymer, which is formed by copolymerizing a methacrylate compound containing an acid-sensitive group and a methacrylate compound containing a polar group.

[0010] In one embodiment of the first aspect, the methacrylate compound containing an acid-sensitive group is selected from at least one of 2-ethyl-2-adamantanol methacrylate, 2-isopropyl-2-adamantanol methacrylate, 1-ethyl-cyclopentanol methacrylate and 1-isopropyl-1-cyclopentanol methacrylate;

[0011] The polar group-containing methacrylate compound comprises a hydroxyl-containing methacrylate compound and / or an inner lipid-containing methacrylate compound, wherein the molar ratio of the hydroxyl-containing methacrylate compound to the inner lipid-containing methacrylate compound is 1:2 to 1:5;

[0012] The methacrylate compound containing a polar group is selected from at least one of 3-hydroxy-1-adamantyl methacrylate, γ-butyrolactone methacrylate and 3,5-dihydroxy-1-adamantyl methacrylate.

[0013] In one implementation of the first aspect, the photoresist further includes at least one of the following technical features:

[0014] a1) the weight average molecular weight of the polymer resin is 4000 to 12000;

[0015] a2) the molecular weight distribution coefficient PDI of the polymer resin is less than 2.5;

[0016] a3) The polymer resin contains the following components in molar ratio:

[0017] 30% to 60% of methacrylate compounds containing acid-sensitive groups;

[0018] The methacrylate compounds containing polar groups are 40% to 70%.

[0019] In one embodiment of the first aspect, the photoacid generator is selected from at least one of the following general formulas;

[0020]

[0021] Wherein, P1, P2 and P3 are each independently a hydrogen atom or a C1-C4 alkyl group, and P4 is a C1-C6 perfluoroalkyl group;

[0022] R1 is C5~C 12 An alicyclic hydrocarbon group, R2 is a C1-C4 alkylene group, and R3 is a hydrogen atom or a C1-C4 alkyl group.

[0023] In one embodiment of the first aspect, the photoacid generator is selected from at least one of the following structures:

[0024]

[0025]

[0026] In one embodiment of the first aspect, the dissolution promoter is selected from at least one of the following general formulas:

[0027]

[0028] wherein R5, R6, R7 and R8 are each independently a hydrogen atom, a carboxyl group or a hydroxyl group, and at least one of R5, R6, R7 and R8 is a carboxyl group;

[0029] P5, P6 and P7 are each independently a hydrogen atom, a carboxyl group or a hydroxyl group, and at least one of P5, P6 and P7 is a carboxyl group.

[0030] In one embodiment of the first aspect, the dissolution promoter is selected from at least one of the following structures:

[0031]

[0032]

[0033] In one implementation of the first aspect, the photoresist further includes at least one of the following technical features:

[0034] b1) the acid quencher is selected from at least one of triethylamine, tributylamine, triethanolamine, triisopropanolamine, trioctylamine, tetrabutylammonium hydroxide, tri(3,6-dioxaheptyl)amine or 2-ethyl-N,N-bis(2-ethylhexyl)-1-hexylamine;

[0035] b2) the leveling agent is selected from at least one of 3M fluorocarbon surfactant FC-4430 or Troysol S366;

[0036] b3) the solvent is selected from at least one of propylene glycol methyl ether acetate, propylene glycol methyl ether, ethyl lactate, 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, diacetone alcohol or gamma-butyrolactone.

[0037] In a second aspect, the present application also provides a method for using the positive chemically amplified photoresist as described above, the method comprising the following steps: coating the positive amplified photoresist on a silicon wafer, and sequentially performing pre-baking, exposure, post-baking and development to obtain a pattern after photolithography.

[0038] In one implementation of the second aspect, the method of use further includes at least one of the following technical features:

[0039] c1) The pre-baking temperature is 90-130°C and the pre-baking time is 60-120s;

[0040] c2) The exposure energy is 20-30 mj / cm 2 ;

[0041] c3) the post-baking temperature is 80-120°C and the post-baking time is 30-90s;

[0042] c4) The developer used in the development is 2.38% TMAH, and the developing time is 20 to 40 seconds.

[0043] Compared with the prior art, the present invention selects a suitable methacrylate copolymer as the base resin, screens a suitable photoacid generator and the amount of the photoacid generator added, and adds a dissolution promoter, which can effectively increase the adhesion of the line after exposure and development, thereby improving the peeling window of the line under a higher aspect ratio condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figures 1 to 4 This is the photolithographic pattern after the photoresist prepared in Example 1 is used.

[0045] Figures 5 to 8 This is the photolithographic pattern after the photoresist prepared in Comparative Example 1 is used. DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The first aspect of the present invention provides a positive chemically amplified photoresist, comprising the following components in percentage by weight:

[0051]

[0052] The polymer resin is a methacrylate copolymer, which is formed by copolymerizing a methacrylate compound containing an acid-sensitive group and a methacrylate compound containing a polar group.

[0053] Preferably, the methacrylate compound containing an acid-sensitive group is selected from at least one of 2-ethyl-2-adamantanol methacrylate, 2-isopropyl-2-adamantanol methacrylate, 1-ethyl-cyclopentanol methacrylate and 1-isopropyl-1-cyclopentanol methacrylate;

[0054] The polar group-containing methacrylate compound comprises a hydroxyl-containing methacrylate compound and / or an inner lipid-containing methacrylate compound, wherein the molar ratio of the hydroxyl-containing methacrylate compound to the inner lipid-containing methacrylate compound is 1:2 to 1:5;

[0055] The methacrylate compound containing a polar group is selected from at least one of 3-hydroxy-1-adamantyl methacrylate, γ-butyrolactone methacrylate and 3,5-dihydroxy-1-adamantyl methacrylate.

[0056] Preferably, it also includes at least one of the following technical features:

[0057] a1) the weight average molecular weight of the polymer resin is 4000 to 12000, such as 4000 to 5700 or 5700 to 12000;

[0058] a2) the molecular weight distribution coefficient PDI of the polymer resin is less than 2.5, such as 1.97 to 2.5;

[0059] a3) The polymer resin contains the following components in molar ratio:

[0060] 30-60% of methacrylate compounds containing acid-sensitive groups, such as 30-40% or 40-60%;

[0061] The methacrylate compound containing polar groups is 40-70%, such as 40-60% or 60-70%.

[0062] Preferably, the photoacid generator is selected from at least one of the following general formulas:

[0063]

[0064] Wherein, P1, P2 and P3 are each independently a hydrogen atom or a C1-C5 alkyl group, and P4 is a C1-C6 perfluoroalkyl group;

[0065] R1 is C5~C 12An alicyclic hydrocarbon group, R2 is a C1-C4 alkylene group, and R3 is a hydrogen atom or a C1-C4 alkyl group.

[0066] More preferably, P1, P2 and P3 are each independently selected from a hydrogen atom, a methyl group or a tert-butyl group, and P4 is selected from a trifluoromethyl group or a perfluorobutyl group;

[0067] R1 is adamantyl, R2 is ethylene, and R3 is selected from a hydrogen atom, a methyl group, an ethyl group or a tert-butyl group.

[0068] Preferably, the photoacid generator is selected from at least one of the following structures:

[0069]

[0070]

[0071] Preferably, the dissolution promoter is selected from at least one of the following general formulas:

[0072]

[0073] wherein R5, R6, R7 and R8 are each independently a hydrogen atom, a carboxyl group or a hydroxyl group, and at least one of R5, R6, R7 and R8 is a carboxyl group;

[0074] P5, P6 and P7 are each independently a hydrogen atom, a carboxyl group or a hydroxyl group, and at least one of P5, P6 and P7 is a carboxyl group.

[0075] Preferably, the dissolution promoter is selected from at least one of the following structures:

[0076]

[0077] Preferably, the photoresist further comprises at least one of the following technical features:

[0078] b1) the acid quencher is selected from at least one of triethylamine, tributylamine, triethanolamine, triisopropanolamine, trioctylamine, tetrabutylammonium hydroxide, tri(3,6-dioxaheptyl)amine or 2-ethyl-N,N-bis(2-ethylhexyl)-1-hexylamine;

[0079] b2) the leveling agent is selected from at least one of 3M fluorocarbon surfactant FC-4430 or Troysol S366;

[0080] b3) the solvent is selected from at least one of propylene glycol methyl ether acetate, propylene glycol methyl ether, ethyl lactate, 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, diacetone alcohol or gamma-butyrolactone.

[0081] In a second aspect, the present application also provides a method for using the positive chemically amplified photoresist as described above, the method comprising the following steps: coating the positive amplified photoresist on a silicon wafer, and sequentially performing pre-baking, exposure, post-baking and development to obtain a pattern after photolithography.

[0082] Preferably, the method of use further includes at least one of the following technical features:

[0083] c1) The pre-baking temperature is 90-130°C, such as 110°C, and the pre-baking time is 60-120s, such as 90s;

[0084] c2) The exposure energy is 20-30 mj / cm 2 , such as 26mj / cm 2 、27mj / cm 2 、28mj / cm 2 or 29mj / cm 2 ;

[0085] c3) the post-baking temperature is 80-120°C, such as 100°C, and the post-baking time is 30-90s, such as 60s;

[0086] c4) The developer used in the development is 2.38% TMAH, and the developing time is 20 to 40 seconds, such as 30 seconds.

[0087] 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.

[0088] Preparation of polymer resin P1:

[0089] In a 1L four-necked flask equipped with a stirrer, a condenser and nitrogen protection, the monomers 2-ethyl-2-adamantanol methacrylate (99.4g, 0.4mol), 3-hydroxy-1-adamantyl methacrylate (47.3g, 0.2mol), and γ-butyrolactone methacrylate (68.1g, 0.4mol) were dissolved in tetrahydrofuran (600mL) and azobisisobutyronitrile (AIBN) (16.4g, 0.1mol) was added. After nitrogen was introduced to remove the air in the reaction bottle, the system temperature was raised and kept in reflux state and reacted for 12h. After the polymerization reaction was completed, the system was cooled to room temperature.

[0090] The reaction solution was added to n-hexane to obtain a white solid. The solid was redissolved in tetrahydrofuran and added to n-hexane again. The obtained white solid was filtered and dried to obtain the resin product P1 (171.84 g, weight average molecular weight 5700, molecular weight distribution coefficient 1.97).

[0091] Example 1

[0092] A positive chemically amplified photoresist comprises the following components in parts by weight (100 parts in total):

[0093]

[0094]

[0095] The preparation method of the positive chemically amplified photoresist is as follows: each component is added according to a proportion and then fully mixed and stirred, and then filtered with 0.45 μm and 0.1 μm nylon membranes to obtain the desired photoresist.

[0096] The prepared positive chemically amplified photoresist is used as follows:

[0097] The prepared photoresist was coated on a silicon wafer to form a 0.25 μm film. Pre-baked on a 110°C hot plate for 90 seconds, then selectively exposed (S80P160Line / Space) using an ArF exposure machine XT1900i (Annular NA 0.9 Sigma 0.85 / 0.55), then post-baked on a 100°C hot plate for 60 seconds. After the silicon wafer cooled to room temperature, it was developed with a 2.38% TMAH developer for 30 seconds, and finally rinsed with deionized water for 30 seconds to form the desired photolithography pattern. The exposure energy was 26 mj / cm 2 、27mj / cm 2 、28mj / cm 2 、29mj / cm 2 When the photolithography patterns are Figure 1 , Figure 2 , Figure 3 , Figure 4 The obtained data are shown in Table 1.

[0098] Comparative Example 1

[0099] A positive chemically amplified photoresist comprises the following components in parts by weight (100 parts in total):

[0100]

[0101] The preparation, manufacture and use of the photoresist in Comparative Example 1 are the same as those in Example 1, and the exposure energies are 26 mj / cm2 、27mj / cm 2 、28mj / cm 2 、29mj / cm 2 When the photolithography patterns are Figure 5 , Figure 6 , Figure 7 , Figure 8 The obtained data are shown in Table 2.

[0102] Table 1:

[0103]

[0104] Table 2:

[0105]

[0106] Peeling window (CD window for line collapse) is an important parameter for measuring Line / Space photoresist. It determines whether the pattern obtained after exposure and development of the photoresist is prone to defects caused by line collapse at a higher aspect ratio. The line collapse conditions and data evaluation results of the photolithography patterns of the above-mentioned Example 1 and Comparative Example 1 are shown in Tables 1 and 2 below. Example 1 uses a methyl methacrylate copolymer as a base resin, and simultaneously uses a suitable photoacid generator and a dissolution promoter. Compared with Example 1, Comparative Example 1 does not add the dissolution promoter D2. The evaluation results show that under the condition of an aspect ratio of 3.1:1, the photoresist of Comparative Example 1 has a line collapse phenomenon after the groove CD (critical dimension) is greater than 84nm, that is, the peeling window is only 84nm; while the photoresist of Example 1 still does not have a line collapse phenomenon after the groove CD is greater than 94nm, that is, the peeling window is greater than 94nm. It can be seen that selecting a suitable methacrylic copolymer as the base resin in the photoresist, screening a suitable photoacid generator, and adding a dissolution promoter can effectively improve the peeling window of the lines in the ArF photoresist.

[0107] 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 positive chemically amplified photoresist, characterized in that: The photoresist comprises the following components in percentage by mass: The polymer resin is a methacrylate copolymer, which is formed by copolymerizing a methacrylate compound containing an acid-sensitive group and a methacrylate compound containing a polar group; The dissolution promoter is selected from at least one of the following general formulas: wherein R5, R6, R7 and R8 are each independently a hydrogen atom, a carboxyl group or a hydroxyl group, and at least one of R5, R6, R7 and R8 is a carboxyl group; P5, P6 and P7 are each independently a hydrogen atom, a carboxyl group or a hydroxyl group, and at least one of P5, P6 and P7 is a carboxyl group.

2. The positive chemically amplified photoresist according to claim 1, characterized in that: The methacrylate compound containing an acid-sensitive group is selected from at least one of 2-ethyl-2-adamantanol methacrylate, 2-isopropyl-2-adamantanol methacrylate, 1-ethyl-cyclopentanol methacrylate and 1-isopropyl-1-cyclopentanol methacrylate; The polar group-containing methacrylate compound comprises a hydroxyl-containing methacrylate compound and / or an inner lipid-containing methacrylate compound, wherein the molar ratio of the hydroxyl-containing methacrylate compound to the inner lipid-containing methacrylate compound is 1:2 to 1:5; The methacrylate compound containing a polar group is selected from at least one of 3-hydroxy-1-adamantyl methacrylate, γ-butyrolactone methacrylate and 3,5-dihydroxy-1-adamantyl methacrylate.

3. The positive chemically amplified photoresist according to claim 1, characterized in that: The photoresist further comprises at least one of the following technical features: a1) the weight average molecular weight of the polymer resin is 4000 to 12000; a2) the molecular weight distribution coefficient PDI of the polymer resin is less than 2.5; a3) The polymer resin contains the following components in molar ratio: 30% to 60% of methacrylate compounds containing acid-sensitive groups; The methacrylate compounds containing polar groups are 40% to 70%.

4. The positive chemically amplified photoresist according to claim 1, characterized in that: The photoacid generator is selected from at least one of the following general formulas: wherein P1, P2 and P3 are each independently a hydrogen atom or a C1-C4 alkyl group, P4 is a C1-C6 perfluoroalkyl group, R1 is C5~C 12 An alicyclic hydrocarbon group, R2 is a C1-C4 alkylene group, and R3 is a hydrogen atom or a C1-C4 alkyl group.

5. The positive chemically amplified photoresist according to claim 4, characterized in that: The photoacid generator is selected from at least one of the following structures: 。 6. The positive chemically amplified photoresist according to claim 1, characterized in that: The dissolution promoter is selected from at least one of the following structures: 。 7. The positive chemically amplified photoresist according to claim 1, characterized in that: The photoresist further comprises at least one of the following technical features: b1) the acid quencher is selected from at least one of triethylamine, tributylamine, triethanolamine, triisopropanolamine, trioctylamine, tetrabutylammonium hydroxide, tri(3,6-dioxaheptyl)amine or 2-ethyl-N,N-bis(2-ethylhexyl)-1-hexylamine; b2) the leveling agent is selected from at least one of 3M fluorocarbon surfactant FC-4430 or Troysol S366; b3) the solvent is selected from at least one of propylene glycol methyl ether acetate, propylene glycol methyl ether, ethyl lactate, 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, diacetone alcohol or gamma-butyrolactone.

8. A method for using the positive chemically amplified photoresist according to any one of claims 1 to 7, characterized in that: The use method comprises the following steps: coating the positive amplification type photoresist on a silicon wafer, and sequentially performing pre-baking, exposure, post-baking and development to obtain a photolithographic pattern.

9. The method for using the positive chemically amplified photoresist 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 90-130°C and the pre-baking time is 60-120s; c2) The exposure energy is 20-30 mj / cm 2 ; c3) the post-baking temperature is 80-120°C and the post-baking time is 30-90s; c4) The developer used in the development is 2.38% TMAH, and the developing time is 20 to 40 seconds.

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