High-thickness spin-on carbon hard mask composition and patterning method using the same

Abstract

In order to provide a hard mask composition with high thickness useful in semiconductor lithography process, the present invention provides a spin-coated hard mask composition and a patterning method of forming a hard mask layer by a process of coating the composition on the upper part of the etched layer by spin coating and performing a baking process. The hard mask according to the present invention has the effects of showing high thickness, high etching resistance capable of withstanding multiple etching processes and excellent mechanical properties due to excellent solubility characteristics.

Description

Technical Field

[0001] The present invention relates to a hard mask composition having a high thickness useful in a semiconductor lithography process, and a hard mask composition and a patterning method capable of achieving a high thickness due to excellent solubility characteristics. Background Art

[0002] Recently, with the miniaturization and integration of semiconductor devices, it is necessary to realize fine patterns. As a method for forming such fine patterns, miniaturization of photoresist patterns by developing exposure equipment or introducing additional processes is effective.

[0003] As a method of increasing the integration density of semiconductor devices and enabling the formation of structures having finer dimensions in the nanometer range, photoresists and photolithography process tools having high resolution are being developed.

[0004] In the process of manufacturing semiconductors, an i-line light source with a wavelength of 365 nm is conventionally used to form a pattern on a semiconductor substrate. However, a light source with a smaller wavelength band is required to form finer patterns.

[0005] In fact, starting from KrF (248nm), lithography technology using ArF (198nm) and EUV (extreme ultraviolet, 13.5nm) light sources has been developed and is currently commercialized or in the process of commercialization, and it can achieve even finer wavelengths.

[0006] As the size of the pattern becomes smaller, the thickness of the photoresist becomes thinner and thinner in order to prevent the collapse of the photoresist pattern. Since the etched layer cannot be etched using the thinned photoresist pattern, a film with excellent etching resistance is introduced between the photoresist layer and the etched layer. This film is called a hard mask. The hard mask process refers to a process in which the etched layer is etched using the pattern of the hard mask after patterning by etching the hard mask using the photoresist pattern. The hard mask is manufactured by chemical vapor deposition (CVD) or spin coating.

[0007] Hard masks manufactured by CVD have disadvantages such as increased initial cost and process time due to the use of deposition equipment, particle problems, etc., and efforts are continuing to reduce costs and shorten process time by using spin-coated materials instead of deposition for hard mask processing.

[0008] Compared with the CVD method, the hard mask process using the spin coating method has the advantages of low initial investment cost, uniform coating, easy control of coating thickness, and shortened process time.

[0009] On the other hand, as semiconductor processes have become increasingly miniaturized, in order to reduce line widths, it has become necessary to develop a new and improved hard mask material that can achieve a high thickness and excellent solubility to form a higher hard mask layer. Summary of the invention

[0010] Technical issues to be solved

[0011] The present invention relates to a patterning method and composition using a spin-on carbon hard mask capable of achieving a high thickness in a semiconductor manufacturing process, and an object of the present invention is to provide a hard mask composition having excellent solubility and a patterning method using the composition.

[0012] Solutions to the problem

[0013] According to an embodiment of the present invention, a spin-on carbon hard mask composition is provided, characterized in that it has a structure represented by the following Chemical Formula 1 and has a weight average molecular weight of 2,000 to 200,000.

[0014] [Chemical formula 1]

[0015]

[0016] In the above formula, l, m and n are in the range of 1≤l≤40, 1≤m≤40, 1≤n≤40 respectively.

[0017] R1 includes hydrogen (H), hydroxyl (OH), Any one of

[0018] R2 includes Any one of

[0019] R3 includes Any one of .

[0020] In the above formula R1, X1 to X 35 Each independently includes: hydrogen, hydroxyl, substituted or unsubstituted C1 to C3 alkyl, or a combination thereof.

[0021] According to another embodiment of the present invention, the hard mask composition includes: 1 wt % to 50 wt % of the polymer represented by the above Chemical Formula 1; 50 wt % to 99 wt % of an organic solvent; and 0 to 2 wt % of a surfactant.

[0022] According to another embodiment of the present invention, the organic solvent may be one selected from the group consisting of propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, γ-butyrolactone, ethyl lactate (EL), methyl ethyl ketone, n-butyl acetate, N-methylpyrrolidone (NMP), methyl 3-methoxypropionate (MMP), ethyl 3-ethoxypropionate (EEP), and dimethylformamide (DMF), or a mixture of two or more thereof.

[0023] According to another embodiment of the present invention, the surfactant can be one selected from non-ionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene nonylphenyl ethers, polyoxyethylene octylphenyl ethers, polyoxyethylene polyoxypropylenes, polyoxyethylene lauryl ethers, polyoxyethylene sorbitan, etc., or a group consisting of a mixture of two or more thereof.

[0024] According to another embodiment of the present invention, a patterning method is provided. The method forms a hard mask layer by spin coating on an upper portion of an etched layer and performing a baking process.

[0025] According to another embodiment of the present invention, the baking process is a hard mask patterning method in which the baking process is performed at a temperature of 150° C. to 400° C. for 1 minute to 5 minutes to form a pattern.

[0026] Effects of the Invention

[0027] The hard mask composition having high thickness according to the present invention can achieve high thickness due to excellent solubility characteristics, and has high etching selectivity and sufficient resistance to multiple etching, thereby providing excellent performance when forming semiconductor fine patterns. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the 1H-NMR spectrum of the polymer prepared in Example 1.

[0029] Best Mode for Carrying Out the Invention

[0030] Hereinafter, the present invention will be described in more detail.

[0031] The present invention provides a spin-on carbon hard mask composition, characterized in that it has a structure represented by the following chemical formula 1 and has a weight average molecular weight of 2,000 to 200,000, preferably 2,500 to 20,000, and more preferably 3,500 to 15,000.

[0032] [Chemical formula 1]

[0033]

[0034] In the above formula, l, m and n are in the range of 1≤l≤40, 1≤m≤40, 1≤n≤40 respectively.

[0035] R1 includes hydrogen (H), hydroxyl (OH), Any one of

[0036] R2 includes Any one of

[0037] R3 includes Any one of .

[0038] In the above formula R1, X1 to X 35 Each independently includes: hydrogen, hydroxyl, substituted or unsubstituted C1 to C3 alkyl, or a combination thereof.

[0039] In the above formula, R2 is mainly formed under acid catalysis conditions, and has the effect of increasing the solubility of the formed polymer substance in organic solvents.

[0040] In the above formula, R3 mainly plays a role in improving the thermal curing reactivity and etching selectivity of the overall polymer structure.

[0041] The polymer represented by the above Chemical Formula 1 is characterized in that the weight average molecular weight is 2,000 to 200,000, preferably 2,500 to 20,000, and more preferably 3,500 to 15,000.

[0042] When the weight average molecular weight of the polymer represented by the above Chemical Formula 1 is less than 2,500, etching resistance is reduced because a sufficient amount of polymer structure is not generated, and when it exceeds 20,000, physical properties of the coating surface may be non-uniform.

[0043] The hard mask composition may include: 1 wt % to 50 wt % of the polymer represented by the above Chemical Formula 1; 50 wt % to 99 wt % of an organic solvent; and 0 to 2 wt % of a surfactant.

[0044] When the polymer component is less than 1 wt % or exceeds 50 wt %, it is difficult to match an accurate coating thickness because the coating thickness is less than or exceeds a required thickness, and when the coating thickness is exceeded, coating properties may be deteriorated.

[0045] The organic solvent can be one selected from the group consisting of propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), cyclohexanone, γ-butyrolactone, ethyl lactate (EL), methyl ethyl ketone, n-butyl acetate, N-methylpyrrolidone (NMP), methyl 3-methoxypropionate (MMP), ethyl 3-ethoxypropionate (EEP), and dimethylformamide (DMF), or a mixture of two or more thereof.

[0046] The surfactant may be one selected from nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene nonylphenyl ethers, polyoxyethylene octylphenyl ethers, polyoxyethylene polyoxypropylenes, polyoxyethylene lauryl ethers, and polyoxyethylene sorbitans, or a mixture thereof.

[0047] The surfactant can reduce surface tension and increase ductility or permeability, thereby facilitating coating or gap filling performance.

[0048] According to another embodiment of the present invention, a patterning method is provided. The method forms a hard mask layer by spin coating on an upper portion of an etched layer and performing a baking process.

[0049] The spin coating thickness of the composition is not particularly limited, but can be to The thickness of coating.

[0050] The baking process may be performed at a temperature of 150° C. to 400° C. for 1 minute to 5 minutes. During the baking step, the composition may induce a self-crosslinking reaction.

[0051] Hereinafter, preferred embodiments and comparative examples of the present invention will be described. However, the following embodiments are only preferred embodiments of the present invention, and the scope of the present invention is not limited to the following embodiments. DETAILED DESCRIPTION

[0052] Example 1

[0053]

[0054] 18g of 1-hydroxypyrene, 9.5g of 1,4-bismethoxymethylbenzene, 20g of 9,9-bis(6-hydroxy-2-naphthyl)fluorene and 150g of propylene glycol monomethyl ether acetate (PGMEA) were added, and a nitrogen atmosphere was created. 0.20g of diethyl sulfate was added, and the solution was heated to 140°C and refluxed for 18 hours. After the reaction was completed, the above solution was purified with a hexane / ethanol / water (1:1:1) solution, recrystallized with an ethanol / water (10:1) solution, and vacuum dried. According to the GPC measurement results, a polymer compound with a weight average molecular weight (Mw) of 10,500 converted to standard polystyrene was obtained.

[0055] Example 2

[0056]

[0057] The synthesis was carried out in the same manner as in Example 1 except that the solution was heated to 140° C. and then refluxed for 6 hours. The GPC measurement results showed that a polymer compound having a weight average molecular weight (Mw) of 1,900 in terms of standard polystyrene was obtained.

[0058] Example 3

[0059]

[0060] The synthesis was carried out in the same manner as in Example 1 except that 0.40 g of diethyl sulfate was added and the solution was heated to 140° C. and refluxed for 36 hours. The GPC measurement results showed that a polymer compound having a weight average molecular weight (Mw) of 25,000 in terms of standard polystyrene was obtained.

[0061] Example 4

[0062]

[0063] The synthesis was carried out in the same manner as in Example 1 except that 25 g of 3-hydroxyperylene was added instead of 1-hydroxypyrene. The GPC measurement results showed that a polymer compound having a weight average molecular weight (Mw) of 9,500 in terms of standard polystyrene was obtained.

[0064] Example 5

[0065]

[0066] The synthesis was carried out in the same manner as in Example 1 except that 23 g of 1-anthraquinone was added instead of 1-hydroxypyrene. The GPC measurement results showed that a polymer compound having a weight average molecular weight (Mw) of 8,500 in terms of standard polystyrene was obtained.

[0067] Example 6

[0068]

[0069] The synthesis was carried out in the same manner as in Example 1 except that 19 g of 2-naphthol was added instead of 1-hydroxypyrene. The GPC measurement results showed that a polymer compound having a weight average molecular weight (Mw) of 7,500 in terms of standard polystyrene was obtained.

[0070] Comparative Example 1

[0071]

[0072] 70 g of PGMEA and 0.20 g of diethyl sulfate were added to 20 g of 9,9-bis(4-hydroxyphenyl)fluorene and 9.5 g of 1,4-bismethoxymethylbenzene. Synthesis was performed in the same manner as in Example 1. GPC measurement showed that a polymer compound having a weight average molecular weight (Mw) of 9,000 in terms of standard polystyrene was obtained.

[0073] Comparative Example 2

[0074] The synthesis was carried out in the same manner as in Comparative Example 1 except that the reaction time was 6 hours. As a result of GPC measurement, a polymer having a weight average molecular weight (Mw) of 1,800 in terms of standard polystyrene was obtained.

[0075] Comparative Example 3

[0076]

[0077] 150 g of PGMEA and 0.20 g of diethyl sulfate were added to 22 g of 9,9-bis(6-hydroxy-2-naphthyl)fluorene and 9.5 g of 1,4-bismethoxymethylbenzene. After synthesis in the same manner as in Example 1, a polymer compound having a weight average molecular weight (Mw) of 9,700 in terms of standard polystyrene was obtained according to GPC measurement results.

[0078] Experimental Example 1

[0079] 3.0 g of the polymer compound obtained in Example 1, 37.6 g of propylene glycol monomethyl ether acetate, and 9.7 g of cyclohexanone were added and stirred for 20 hours to dissolve. The solution was filtered with a 0.2 μm microfilter to prepare a hard mask forming composition, which was applied on a silicon wafer using a spin coater. The hard mask was formed by heating at 240° C. for 1 minute on a hot plate and then at 400° C. for 1 minute.

[0080] Experimental Example 2

[0081] The same method as in Experimental Example 1 was carried out except that 3.0 g of the polymer compound obtained in Example 2 was used.

[0082] Experimental Example 3

[0083] The same method as in Experimental Example 1 was carried out except that 3.0 g of the polymer compound obtained in Example 3 was used.

[0084] Experimental Example 4

[0085] The same method as in Experimental Example 1 was carried out except that 3.0 g of the polymer compound obtained in Example 4 was used.

[0086] Experimental Example 5

[0087] The same method as in Experimental Example 1 was carried out except that 3.0 g of the polymer compound obtained in Example 5 was used.

[0088] Experimental Example 6

[0089] The same method as in Experimental Example 1 was carried out except that 3.0 g of the polymer compound obtained in Example 6 was used.

[0090] Experimental Example 7

[0091] The same method as in Experimental Example 1 was carried out except that 17.0 g of the polymer compound obtained in Example 1, 26.4 g of propylene glycol monomethyl ether acetate, and 6.6 g of cyclohexanone were used.

[0092] Experimental Example 8

[0093] The same method as in Experimental Example 7 was carried out except that 17 g of the polymer compound obtained in Example 2 was used.

[0094] Experimental Example 9

[0095] The same method as in Experimental Example 7 was carried out except that 17.0 g of the polymer compound obtained in Example 3 was used.

[0096] Experimental Example 10

[0097] The same method as in Experimental Example 7 was carried out except that 17.0 g of the polymer compound obtained in Example 4 was used.

[0098] Experimental Example 11

[0099] The same method as in Experimental Example 7 was carried out except that 17.0 g of the polymer compound obtained in Example 5 was used.

[0100] Experimental Example 12

[0101] The same method as in Experimental Example 7 was carried out except that 17.0 g of the polymer compound obtained in Example 6 was used.

[0102] Comparative Experiment Example 1

[0103] The same method as in Experimental Example 1 was carried out except that 3.0 g of the polymer compound obtained in Comparative Example 1 was used.

[0104] Comparative Experiment Example 2

[0105] The same method as in Experimental Example 1 was carried out except that 3.0 g of the polymer compound obtained in Comparative Example 2 was used.

[0106] Comparative Experiment Example 3

[0107] The same method as in Experimental Example 1 was carried out except that 3.0 g of the polymer compound obtained in Comparative Example 3 was used.

[0108] Comparative Experiment Example 4

[0109] The same method as in Experimental Example 7 was carried out except that 17.0 g of the polymer compound obtained in Comparative Example 1 was used.

[0110] Comparative Experiment Example 5

[0111] The same method as in Experimental Example 7 was carried out except that 17.0 g of the polymer compound obtained in Comparative Example 2 was used.

[0112] Comparative Experiment Example 6

[0113] The same method as in Experimental Example 7 was carried out except that 17.0 g of the polymer compound obtained in Comparative Example 3 was used.

[0114] <Weight Average Molecular Weight Determination>

[0115] The weight average molecular weight obtained in the above examples was measured by gel permeation chromatography (GPC). A GPC apparatus manufactured by Waters Corporation was used for the measurement, and the measurement conditions were as follows.

[0116] Column temperature: 40°C; mobile phase: tetrahydrofuran (THF); flow rate: 1 mL / 1 min; GPC column: STYRAGEL KF-801, 802, 803 (manufactured by WATERS, 8X300 mm).

[0117] <Coating Thickness Characteristics Test>

[0118] The thickness of the hard mask formed in Experimental Examples 1 to 12 and Comparative Experimental Examples 1 to 6 was measured, and the results are shown in Table 1. The instrument used was an ellipsometer (Ellipsometer, Horiba Corporation).

[0119]

Table 1

[0120] sample Coating thickness(nm) Coating Experimental Example 1 Example 1 150 good Experimental Example 2 Example 2 110 good Experimental Example 3 Example 3 230 good Experimental Example 4 Example 4 160 good Experimental Example 5 Example 5 145 good Experimental Example 6 Example 6 140 good Experimental Example 7 Example 1 2800 good Experimental Example 8 Example 2 2200 good Experimental Example 9 Example 3 3040 bad Experimental Example 10 Example 4 2870 good Experimental Example 11 Example 5 2650 good Experimental Example 12 Example 6 2520 good Comparative Experiment Example 1 Comparative Example 1 130 good Comparative Experiment Example 2 Comparative Example 2 100 good Comparative Experiment Example 3 Comparative Example 3 139 good Comparative Experiment Example 4 Comparative Example 1 2380 bad Comparative Experiment Example 5 Comparative Example 2 1850 bad Comparative Experiment Example 6 Comparative Example 3 2450 bad

[0121] <Optical properties test>

[0122] The refractive index n and the extinction coefficient k of the hard masks formed in Experimental Examples 1 to 12 and Comparative Experimental Examples 1 to 6 were measured, and the results are shown in Table 2. The instrument used was an ellipsometer (Ellipsometer, Horiba Corporation).

[0123]

Table 2

[0124]

[0125]

[0126] The measured refractive index n and absorption coefficient k of the hard mask are shown in Table 2, except for Experimental Example 9 and Comparative Experimental Examples 4 to 6 which could not be measured due to poor coating properties.

[0127] <Dry Etching Characteristics Evaluation>

[0128] The hard masks formed in Experimental Examples 1 to 12 and Comparative Experimental Examples 1 to Comparative Experimental Examples 6 were dry-etched for 20 seconds using CF4 gas on a dry etching device. The dry etching rate is defined as: [(film thickness before dry etching - film thickness after dry etching) / time]. The dry etching characteristics represent the dry etching rate of the hard mask when the amorphous carbon layer (ACL) is taken as 100%. The cross section was confirmed using a scanning electron microscope (FE-SEM, Hitachi), and the measurement results are shown in Table 3.

[0129]

Table 3

[0130]

[0131] When the dry etching rate of the hard mask is 90% or more relative to the ACL, it can be defined as excellent etching resistance. Comparing the results of Experimental Examples 1 to 12 and Comparative Experimental Examples 1 to Comparative Experimental Examples 6, it can be confirmed that the etching resistance is excellent at 90% or more.

[0132] The specific parts of the invention of this application are described in detail above. For those skilled in the art, it is obvious that these specific technologies are only preferred embodiments and the scope of the invention is not limited thereby. Therefore, the actual scope of the invention of this application is defined by the claims and their equivalents.

Claims

1. A spin-on hard mask composition, characterized in that: The composition is a polymer having a structure represented by the following Chemical Formula 2, 3 or 4, comprising 1 to 50 weight % of a polymer having a weight average molecular weight of 2,000 to 200,000, 50 to 99 weight % of an organic solvent, and 0 to 2 weight % of a surfactant, [Chemical formula 2] [Chemical formula 3] [Chemical formula 4] In the above formula, l, m and n are in the range of 1≤l≤40, 1≤m≤40, 1≤n≤40, respectively.

2. The spin-on hard mask composition according to claim 1, wherein The organic solvent is one selected from the group consisting of propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, γ-butyrolactone, ethyl lactate, methyl ethyl ketone, n-butyl acetate, N-methylpyrrolidone, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate or dimethylformamide, or a mixture of two or more thereof.

3. The spin-on hard mask composition according to claim 1, wherein: The surfactant is selected from one of polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene nonylphenyl ethers, polyoxyethylene octylphenyl ethers, polyoxyethylene polyoxypropylenes, polyoxyethylene lauryl ethers or polyoxyethylene sorbitan, or a mixture of two or more thereof.

4. The spin-on hard mask composition according to claim 1, wherein: The spin-on hard mask composition consists of 1 wt % to 50 wt % of a polymer, 50 wt % to 99 wt % of an organic solvent, and 0 to 2 wt % of a surfactant.

5. The spin-on hard mask composition according to claim 4, wherein: The organic solvent is one selected from the group consisting of propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, γ-butyrolactone, ethyl lactate, methyl ethyl ketone, n-butyl acetate, N-methylpyrrolidone, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate or dimethylformamide, or a mixture of two or more thereof.

6. The spin-on hard mask composition according to claim 4, wherein: The surfactant is selected from the group consisting of one of polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene nonylphenyl ethers, polyoxyethylene octylphenyl ethers, polyoxyethylene polyoxypropylenes, polyoxyethylene lauryl ethers, and polyoxyethylene sorbitans, or a mixture of two or more thereof.

7. A patterning method for forming a hard mask layer, wherein the patterning method forms the hard mask layer by spin coating the spin-on hard mask composition according to any one of claims 1 to 6 on an upper portion of an etched layer and performing a baking process.

8. The patterning method according to claim 7, wherein: The baking process is performed at a temperature of 150° C. to 400° C. for 1 minute to 5 minutes to form a hard mask layer.

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