Positive photoresist composition and application thereof

Abstract

The invention discloses a positive photoresist composition and application thereof. The positive photoresist composition comprises a polythioether high-molecular compound and a photoresist solvent. The polythioether high-molecular compound comprises the following structure: # imgabs0. The polythioether high-molecular compound is prepared by polymerizing 9 parts by mole of a multi-core antimony unit, 7.0-9.0 parts by mole of binary thiol, 1.0-0 part by mole of polythiol, a photoinitiator and a solvent in an air atmosphere at room temperature through thiol alkene click reaction initiated by ultraviolet light. And after the reaction, performing rotary evaporation on the solvent to obtain the product. The mass of the polythioether high-molecular compound accounts for 1wt%-20wt% of the total mass of the positive photoresist composition, and the balance is the photoresist solvent. The positive photoresist composition can realize a positive photoetching effect under exposure of electron beams and extreme ultraviolet light (EUV), can reach a higher resolution ratio under a lower electron beam exposure dose, and can reach a resolution ratio of 25 nm under a wider extreme ultraviolet light exposure dose of 32.9-217.4 mJ / cm < 2 >.

Description

Technical Field

[0001] The invention belongs to the technical field of photoresists, and in particular relates to a positive photoresist composition and application thereof. Background Art

[0002] Polymer compounds were the first materials used in positive photoresists. Their mechanism for achieving positive lithography primarily relies on solubility changes caused by changes in photosensitive groups or main chain scission after exposure. However, their high molecular weight, large molecular size, and weak absorption of extreme ultraviolet (EUV) light make them unsuitable for the resolution and sensitivity requirements of state-of-the-art extreme ultraviolet (EUV) lithography processes. Therefore, the development of new photoresist materials is urgently needed.

[0003] Metal oxo clusters have been widely used in EUV lithography research due to their simple and clear molecular structure, uniform particle size, adjustable ligand modification, high etching resistance, and strong light absorption in the extreme ultraviolet band. Metal oxo cluster photoresists based on elements such as titanium (Ti), zirconium (Zr), hafnium (Hf), zinc (Zn), tin (Sn), and antimony (Sb) have been developed for lithography. All of the above photoresists have achieved a limit resolution of more than 50nm and a resolution of less than 500uc / cm 2 (Electron beam exposure dose used to verify EUV lithography performance) high-sensitivity lithography.

[0004] However, during the photolithography process, metal oxide cluster photoresists often undergo free radical crosslinking reactions based on ligand loss, resulting in negative-tone photoresists with poor developer solubility in the exposed areas. This makes them unsuitable for the EUV photolithography process logic currently used for integrated circuits, making them a difficult replacement for the already established polymer photoresists. Therefore, developing a new photoresist that combines the high sensitivity and resolution of metal oxide cluster photoresists with the positive-tone photoresist properties of polymer photoresists has important industrial application value. Summary of the Invention

[0005] The present invention aims to solve the problems of metal oxo compounds being difficult to implement in positive photolithography and conventional polymer photoresists having low EUV sensitivity, and provides a positive photoresist composition. The positive photoresist composition of the present invention can be used in electron beam lithography, 248nm lithography, 193nm lithography, or extreme ultraviolet lithography.

[0006] In a second aspect, the present invention provides a method for synthesizing the polysulfide polymer compound in the positive photoresist composition.

[0007] In a third aspect, the present invention provides a use of the positive photoresist composition in an electron beam or EUV lithography process for an integrated circuit.

[0008] Based on this, in order to achieve the above purpose, the technical solution adopted by the present invention is:

[0009] A positive photoresist composition comprising a polysulfide polymer compound and a photoresist solvent;

[0010] The polysulfide polymer compound comprises the following structure:

[0011]

[0012] The mass of the polysulfide polymer compound accounts for 1 wt% to 20 wt% of the total mass of the positive photoresist composition, and the rest is photoresist solvent.

[0013] The photoresist solvent is selected from one or more of methanol, isopropyl alcohol (IPA), N,N-dimethylformamide (DMF), acetone, ethyl acetate, propylene glycol methyl ether acetate (PGMEA), chloroform, cyclohexanone or tetrahydrofuran (THF).

[0014] The synthesis method of the polysulfide polymer compound comprises the following steps: uniformly mixing 9 mol parts of a multinuclear antimony unit, 7.0-9.0 mol parts of a dihydric thiol, 1.0-0 mol parts of a polythiol, and a photoinitiator in a solvent and air atmosphere, polymerizing the mixture through a thiol-ene click reaction initiated by ultraviolet light at room temperature, and rotary evaporating the solvent after the reaction to obtain the polysulfide polymer compound; the total amount of the multinuclear antimony unit, the dihydric thiol, and the polythiol is calculated as the total amount of monomers; wherein the amount of the photoinitiator is 0.1-5.0 wt% of the total amount of the monomers.

[0015] In some specific embodiments, the molecular formula of the polynuclear antimony unit is (Ph3Sb)2(μ2-O)(L)2, wherein L is selected from an organic ligand having both a carbon-carbon double bond and a carboxyl group, including one of methacrylic acid, acrylic acid, crotonic acid, and p-vinylbenzoic acid.

[0016] In some embodiments, the dihydric thiol is selected from any one of 2,3-dimercaptobutanediol, 1,4-butanedithiol, 1,6-hexanedithiol, benzene-1,4-dithiol, 1,8-octanedithiol, 1,4-benzenedimethylenethiol, ethylene glycol bis(thioglycolate), 1,10-decanedithiol, 1,4-butanediol di(thioglycolate) or 2,2'-(1,2-ethanediyldioxy)bis(ethylenethiol).

[0017] In some embodiments, the polythiol is selected from any one of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetramercaptoacetate, pentaerythritol tetrahydro(3-mercaptopropionate), tetrakis(3-mercaptopropyl)silane, or tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate.

[0018] In some embodiments, the photoinitiator is selected from any one of photoinitiator 184, photoinitiator 1173, photoinitiator 819, or photoinitiator TPO.

[0019] In some embodiments, the solvent is selected from at least one of N,N-dimethylformamide (DMF), methanol, ethanol, tetrahydrofuran (THF), acetone, or dichloromethane, preferably tetrahydrofuran, because the polynuclear antimony unit has good stability in tetrahydrofuran.

[0020] The method for using the positive photoresist composition disclosed above in the electron beam or EUV lithography process of an integrated circuit comprises the following specific steps:

[0021] The photoresist composition is filtered and then dropped onto a silicon wafer or a silicon dioxide substrate and spin-coated to form a film. Specifically, the spin-coating rate can be 100-3000 r / s and the spin-coating time can be 10-60 s.

[0022] The substrate coated with the photoresist composition film is heated to remove the solvent contained therein, the heating temperature may be 40-100° C., and the heating time may be 10-180 seconds;

[0023] The obtained substrate loaded with the photoresist composition film is exposed to light under an electron beam or extreme ultraviolet high energy radiation source, wherein the exposure dose under the electron beam is 50-2000 μc / cm 2 , the exposure dose under extreme ultraviolet light is 10-300mJ / cm 2 ;

[0024] Finally, the exposed substrate is immersed in at least one of the above developers, developed and removed, and the developer remaining on the substrate surface is blown dry with nitrogen. The development time can be 5-60 seconds.

[0025] In some embodiments,

[0026] The photoresist composition uses the following developer: one or more of n-heptane, n-nonane, n-octane, cyclohexane, petroleum ether, diethyl ether or tert-butyl methyl ether.

[0027] Advantages and beneficial effects of the present invention:

[0028] Based on the above technical solutions and the technical problems solved, the present invention achieves the following technical effects:

[0029] 1. The present invention provides a positive photoresist composition, wherein the polysulfide polymer compound contained therein undergoes a thiol-ene click reaction with a dihydric thiol and a polyhydric thiol to obtain a polysulfide network structure with a certain degree of crosslinking, and the degree of crosslinking is just enough to make it easily soluble in common photoresist solvents.

[0030] 2. Under electron beam / EUV exposure, the antimony oxyclusters in the polymer network of the polysulfide polymer compound of the present invention can break, causing the polysulfide network to decompose, thereby changing its solubility and making it easily soluble in some developers, thereby achieving positive photolithography.

[0031] 3. The polysulfide polymer compound of the present invention has numerous antimony atoms. Since the absorption cross-sectional area of antimony for extreme ultraviolet light is more than ten times that of carbon, hydrogen, oxygen and other elements, the positive photoresist composition can well meet the requirements of high-sensitivity lithography.

[0032] 4. The polysulfide polymer compound of the present invention has a large number of multi-nuclear antimony units, which have many sites that can break after exposure, so that the positive photoresist composition can well meet the requirements of high-resolution lithography. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The infrared spectra of the multi-nuclear antimony unit (Ph3Sb)2(μ2-O)(MMA)2 and polysulfide polymer compounds I-VI of the present invention;

[0034] Figure 2 Thermogravimetric analysis (TG) diagrams of the multi-nuclear antimony unit (Ph3Sb)2(μ2-O)(MMA)2 and polysulfide polymer compounds I-VI of the present invention;

[0035] Figure 3 The differential scanning calorimetry (DSC) diagrams of the polysulfide polymer compounds I-VI of the present invention are shown;

[0036] Figure 4 The positive photoresist composition corresponding to Example 8 of the present invention is 25-1225μC / cm 2 Atomic force microscopy images of the photoresist film under different exposure doses;

[0037] Figure 5 The positive photoresist composition corresponding to Example 8 of the present invention is 350μC / cm 2 Atomic force microscope image of the 50nm lithography line below.

[0038] Figure 6 The positive photoresist composition corresponding to Example 10 of the present invention is 32.9, 139.1, and 217.4 mJ / cm 2 Atomic force microscope image of the 25nm lithography line below. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0040] Examples 1-6

[0041] Examples 1-6 of the present invention provide the structure and synthesis method of a type of polysulfide polymer compound contained in the positive photoresist composition of the present invention.

[0042] The polysulfide polymer compound comprises the following structure:

[0043]

[0044] In this embodiment, the polysulfide polymer compound is obtained by the following method: 9 mol parts of a multinuclear antimony unit, 7.0-9.0 mol parts of a dihydric mercaptan, and 1.0-0 mol parts of a polythiol, with the total amount of the dihydric mercaptan and the polythiol being calculated as the total amount of monomers, adding 1 wt% of a photoinitiator of the total amount of monomers, mixing uniformly in a solvent and air atmosphere, polymerizing under ultraviolet light at room temperature for 1 hour, and after the reaction, evaporating the solvent to obtain polysulfide polymer compounds I-VI;

[0045] In some embodiments, the synthesis solvent can be selected from at least one of N,N-dimethylformamide (DMF), methanol, ethanol, tetrahydrofuran (THF), acetone, or dichloromethane; preferably, tetrahydrofuran. The stability of the polynuclear antimony unit in tetrahydrofuran is good;

[0046] The polynuclear antimony unit is (Ph3Sb)2(μ2-O)(MMA)2, and its molecular structure is

[0047]

[0048] The multi-nuclear antimony unit is (Ph3Sb)2(μ2-O)(MMA)2, and its infrared spectrum is as follows Figure 1 As shown, the Sb-phenyl group can be observed at 465 cm -1 Stretching at 690 cm-1, Sb-O -1 The stretching of the phenyl group at 3060 cm -1 Stretch at

[0049] The polynuclear antimony unit is (Ph3Sb)2(μ2-O)(MMA)2, and its thermogravimetric analysis (TG) is as follows Figure 2 As shown, its thermal decomposition temperature is 242°C;

[0050] The types and amounts of dihydric mercaptan and polyhydric mercaptan required for the synthesis of the polysulfide polymer compounds I-VI (Examples 1-6) are shown in Table 1 below:

[0051] Table 1

[0052]

[0053]

[0054] The molecular structure of the polysulfide polymer compound IV is:

[0055]

[0056] The Fourier transform infrared spectra of the polysulfide polymer compounds I-VI are as follows Figure 1 As shown, the Sb-phenyl group from the multinuclear antimony unit can be observed at 465 cm -1 Stretching at 690 cm-1, Sb-O -1 The stretching of the phenyl group at 3060 cm -1 The stretching at 1350-1050 cm-1 corresponding to the -COO- group after the formation of polysulfide can also be observed. -1 There are two strong absorption peaks at

[0057] The thermal stability (thermogravimetric) of the polysulfide polymer compounds I-VI is as follows Figure 2 As shown, their thermal decomposition temperatures are 167, 173, 187, 172, 172, and 205°C respectively;

[0058] The thermodynamic properties (DSC) of the polysulfide polymer compounds I-VI are as follows: Figure 3 As shown, the glass transition temperatures are 75, 76, 80, 86, 92, and 97°C respectively;

[0059] The polysulfide polymer compound I-VI of the present invention has an appropriate degree of crosslinking and is soluble in a variety of organic solvents, which is conducive to becoming one of the main components of the positive photoresist composition and facilitating the screening of subsequent development conditions;

[0060] The solubility of the polysulfide polymer compounds I-VI of the present invention in different commonly used reagents is shown in Table 2 below:

[0061] Table 2

[0062]

[0063] Based on the above examples, the present invention prepares a variety of antimony units with different types and amounts of dihydric mercaptans and polyhydric mercaptans. The solubility of the obtained polysulfide polymer compound in different organic solvents was also studied, and it was found that the polysulfide polymer compound can be dissolved in a variety of commonly used organic solvents.

[0064] Furthermore, in some embodiments of the present invention, the dihydric thiol can be selected from any one of 2,3-dimercaptobutanediol, 1,4-butanedithiol, 1,6-hexanedithiol, benzene-1,4-dithiol, 1,8-octanedithiol, 1,4-benzenedimethanethiol, 1,4-di(thioglycolic acid)-1,4-butanediol, or 2,2'-(1,2-ethylenedioxy)bis(ethylenethiol), and the polythiol can be selected from any one of pentaerythritol tetrahydro(3-mercaptopropionic acid), tetrakis(3-mercaptopropyl)silane, or tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate. By selecting the above dihydric thiol and polythiol and polymerizing them with multi-core antimony units to prepare the corresponding polythioether polymer compound, the purpose of the present invention can also be achieved and the expected technical effect can be achieved.

[0065] Based on this, the present invention further prepares a positive photoresist composition using the polysulfide polymer compound obtained in the above embodiment. The photoresist composition comprises a polysulfide polymer compound prepared in the above embodiment of the present invention and a photoresist solvent.

[0066] In some embodiments of the present invention, the mass of the polysulfide polymer compound accounts for 1 wt % to 20 wt % of the total mass of the positive photoresist composition, and the rest is photoresist solvent.

[0067] In some embodiments of the present invention, the photoresist solvent is selected from one or more of methanol, isopropyl alcohol (IPA), N,N-dimethylformamide (DMF), acetone, ethyl acetate, propylene glycol methyl ether acetate (PGMEA), chloroform, cyclohexanone or tetrahydrofuran (THF).

[0068] Examples 7-9

[0069] The present invention also provides the components of several positive photoresist compositions and their corresponding photolithography positivity, sensitivity and resolution under electron beam lithography, as shown in Table 3 below:

[0070] Table 3

[0071]

[0072] When several of the positive photoresist compositions (Examples 9-11) are used for electron beam exposure, the exposed areas thereof dissolve in the developer, and thus they exhibit positive lithographic behavior (see Figure 4 ), high sensitivity (<500μC / cm 2 ), and because the polysulfide polymer compound in the positive photoresist composition increases the lithographic stability of the material by forming a cross-linked network structure, the lithographic pattern of the positive photoresist composition can reach a high resolution of 50nm under electron beam (see Figure 5 ).

[0073] Example 10

[0074] The present invention also provides a composition of the positive photoresist composition and the corresponding photolithography positive and negative properties, exposure dose and resolution under extreme ultraviolet lithography, as shown in Table 4 below:

[0075] Table 4

[0076]

[0077] It can be used in a wide range of extreme ultraviolet exposure doses (32.9-217.4mJ / cm 2 ) to a resolution of 25 nm (see Figure 6 The positive photoresist composition of the present invention has great prospects in the application of photolithography as a high-sensitivity and high-resolution photoresist material.

[0078] In some embodiments of the present invention, the photoresist composition may use the following developers: one or more of n-heptane, n-nonane, n-octane, cyclohexane, petroleum ether, diethyl ether, or tert-butyl methyl ether.

[0079] The present invention further provides a method for using the positive photoresist composition in an electron beam or EUV lithography process for an integrated circuit, the specific steps of which are as follows:

[0080] The photoresist composition is filtered and then dropped onto a silicon wafer or a silicon dioxide substrate and spin-coated to form a film. Specifically, the spin-coating rate can be 100-3000 r / s and the spin-coating time can be 10-60 s.

[0081] The substrate coated with the photoresist composition film is heated to remove the solvent contained therein, the heating temperature may be 40-100° C., and the heating time may be 10-180 seconds;

[0082] The obtained substrate loaded with the photoresist composition film is exposed to light under an electron beam or extreme ultraviolet high energy radiation source, wherein the exposure dose under the electron beam is 50-2000 μc / cm 2 , the exposure dose under extreme ultraviolet light is 10-300mJ / cm 2 ;

[0083] Finally, the exposed substrate is immersed in at least one of the above developers, developed and removed, and the developer remaining on the substrate surface is blown dry with nitrogen. The development time can be 5-60 seconds.

[0084] It should be further noted that not every embodiment of the present invention comprises a single independent technical solution. Each embodiment is intended solely to facilitate understanding of the technical solution of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, or improvements to the technical solution of the present invention that fall within the technical concept of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A positive photoresist composition, characterized in that: The photoresist composition comprises a polysulfide polymer compound and a photoresist solvent; The polysulfide polymer compound comprises the following structure: The mass of the polysulfide polymer compound accounts for 1wt% to 20wt% of the total mass of the positive photoresist composition, and the rest is photoresist solvent; The photoresist solvent is selected from one or more of methanol, isopropyl alcohol (IPA), N,N-dimethylformamide (DMF), acetone, ethyl acetate, propylene glycol methyl ether acetate (PGMEA), chloroform, cyclohexanone, or tetrahydrofuran (THF).

2. A method for synthesizing the polysulfide polymer compound according to claim 1, characterized in that: The following steps are involved: 9 mol parts of a multinuclear antimony unit, 7.0-9.0 mol parts of a dihydric thiol, 1.0-0 mol parts of a polythiol, and a photoinitiator are uniformly mixed in a solvent and air atmosphere, and polymerized at room temperature through a thiol-ene click reaction initiated by ultraviolet light. After the reaction, the solvent is evaporated to obtain the polysulfide polymer compound; the total amount of the multinuclear antimony unit, the dihydric thiol and the polythiol is calculated as the total amount of monomers; wherein the amount of the photoinitiator is 0.1-5.0 wt% of the total amount of the monomers.

3. The method for synthesizing the polysulfide polymer compound according to claim 2, wherein: The molecular formula of the polynuclear antimony unit is (Ph3Sb)2(μ2-O)(L)2, wherein L is selected from an organic ligand having both a carbon-carbon double bond and a carboxyl group, including one of methacrylic acid, acrylic acid, crotonic acid, and p-vinylbenzoic acid.

4. The method for synthesizing the polysulfide polymer compound according to claim 2, wherein: The dihydric thiol is selected from any one of 2,3-dimercaptobutanediol, 1,4-butanedithiol, 1,6-hexanedithiol, benzene-1,4-dithiol, 1,8-octanedithiol, 1,4-benzenedimethylenethiol, ethylene glycol bis(thioglycolate), 1,10-decanedithiol, 1,4-butanediol di(thioglycolate) or 2,2'-(1,2-ethylenedioxy)bis(ethylenethiol).

5. The method for synthesizing the polysulfide polymer compound according to claim 2, wherein: The polythiol is selected from any one of trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetramercaptoacetate, pentaerythritol tetrahydro(3-mercaptopropionate), tetrakis(3-mercaptopropyl)silane or tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate.

6. The method for synthesizing the polysulfide polymer compound according to claim 2, wherein: The photoinitiator is selected from any one of photoinitiator 184, photoinitiator 1173, photoinitiator 819 or photoinitiator TPO.

7. The method for synthesizing the polysulfide polymer compound according to claim 2, wherein: The solvent is selected from at least one of N,N-dimethylformamide (DMF), methanol, ethanol, tetrahydrofuran (THF), acetone and dichloromethane.

8. A method for using the positive photoresist composition according to claim 1 in an electron beam or EUV lithography process for an integrated circuit, comprising the following steps: The photoresist composition is filtered and then dropped onto a silicon wafer or a silicon dioxide substrate and spin-coated to form a film. Specifically, the spin-coating rate can be 100-3000 r / s and the spin-coating time can be 10-60 s. The substrate coated with the photoresist composition film is heated to remove the solvent contained therein, the heating temperature may be 40-100° C., and the heating time may be 10-180 seconds; The obtained substrate loaded with the photoresist composition film is subjected to exposure photolithography under an electron beam or extreme ultraviolet high energy radiation source, wherein: The exposure dose under electron beam is 50-2000μc / cm 2 , the exposure dose under extreme ultraviolet light is 10-300mJ / cm 2 ; Finally, the exposed substrate is immersed in at least one developer according to claim 8, developed and removed, and the developer remaining on the substrate surface is blown dry with nitrogen. The development time can be 5-60 seconds.

9. The method for using the positive photoresist composition according to claim 8 in an electron beam or EUV lithography process for an integrated circuit, wherein: The photoresist composition uses the following developer: one or more of n-heptane, n-nonane, n-octane, cyclohexane, petroleum ether, diethyl ether or tert-butyl methyl ether.

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