NOVEL ETCHING PATTERN FORMING METHOD IN SEMICONDUCTOR MANUFACTURING PROCESS

Abstract

The present disclosure relates to a method of forming an etching pattern in a semiconductor manufacturing process. Unlike a conventional method of forming a four-layer structure composed of a photoresist film, an anti-reflective film, a SiON film, and an organic hard mask film on a wafer, as preparation for an etching process, the method according to the present disclosure is an innovative etching pattern forming method capable of implementing the same etching pattern as is formed by the conventional method, using a double-layer structure composed of a photoresist film and a multifunctional organic-inorganic mask film.

Claims

1. A method of forming an etching pattern for a silicon or silicon compound layer, the etching pattern being a double-layer structure composed of a photoresist film and a multifunctional organic-inorganic mask film instead of a four-layer structure composed of a photoresist film, an anti-reflective film, a SiON film, and an organic hard mask film formed on a wafer to be etched, the method comprising the steps of: i) primarily forming a multifunctional organic-inorganic mask film by applying a liquid multifunctional organic-inorganic mask film composition containing a solvent, a silicon compound, a crosslinking agent, an additive, and a surfactant and capable of being spin coated onto the wafer to be etched, using a spin coater, at a speed of 100 to 4000 rpm, and then by heating the composition to a temperature of 100° C. to 400° C. for 20 to 600 seconds; ii) secondarily forming a photoresist film for pattern formation on the formed multifunctional organic-inorganic mask film; iii) forming a photoresist pattern through exposure and development; and iv) performing dry etching with an etching gas by using the photoresist pattern as a mask to form the pattern for the silicon or silicon compound layer.

2. The method of claim 1, wherein multifunctional organic-inorganic mask film in step i) comprises 20% to 79% by weight of carbon, 20% to 79% by weight of silicon, and 1% to 20% by weight of other elements including oxygen and hydrogen.

3. The method of claim 1, wherein a light source for forming the pattern in step iii) is selected from the group consisting of light sources having wavelengths of 13.5 nm, 193 nm, 248 nm, and 365 nm, and E-beam.

4. The method of claim 1, wherein the etching gas used for the dry etching in step iv) after the pattern is formed is one gas selected from or a gas mixture of at least two selected from the group consisting of: inert gas such as argon or nitrogen; gas having molecules containing at least one fluorine atom; and oxygen gas.

5. The method of claim 1, wherein the solvent has sufficient solubility for the Si compound and is one selected from or a mixture of at least two selected from the group consisting of propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), ethyl 3-ethoxypropionate (EEP), ethyl lactate (EL), cyclohexanone, and gamma butyrolactone (GBL).

6. The method of claim 1, wherein the Si compound is one selected from or a mixture of at least two selected from the group consisting of poly[dimethylsiloxane-co-(2-(3,4-epoxycyclohexyl)ethyl)methylsiloxane], poly[dimethylsiloxane-co-2-(9,9-bis(4-hydroxyphenyl)fluorene)methylsiloxane], poly(dimethylsiloxane), diglycidyl ether terminated, poly(dimethylsiloxane), bis(hydroxyalkyl)terminated, poly(dimethylsiloxane-co-diphenylsiloxane), dihydroxyterminated, poly(dimethylsiloxane-co-methylhydrosiloxane), trimethylsilylterminated, poly(dimethylsiloxane)-graft-polyacrylate, and poly[dimethylsiloxane-co-methyl(3-hydroxypropyl)siloxane]-graft-poly(ethylene glycol) methyl ether.

7. The method of claim 1, wherein the crosslinking agent is one selected from or a mixture of at least two selected from the group consisting of tris(2,3-epoxypropyl)isocyanurate), trimethylol methane triglycidyl ether, trimethylol propane triglycidyl ether, triethylol ethane triglycidyl ether, hexamethylolmelamine, hexamethoxymethylmelamine, hexamethoxyethylmelamine, tetramethylol 2,4-diamino-1,3,5-triazine, tetramethoxymethyl-2,4-diamino-1,3,5-triazine, tetramethylol glycoluril, tetramethoxymethylurea, tetramethoxymethyl glycoluril, tetramethoxyethyl glycoluril, tetramethylolurea, tetramethoxyethylurea, and tetramethoxyethyl-2,4-diamino-1,3,5-triazine.

8. The method of claim 1, wherein the additive is a thermal acid generator (TAG) that releases an acid during heat treatment, and is one selected from or a mixture of at least two selected from the group consisting of pyridinium p-toluenesulfonate, benzoin tosylate, tetrabromocyclohexadiene, 2-methylimidazole, 2-phenylimidazole, Ajicure MY-H, and Fujicure FXR-1030.

9. The method of claim 1, wherein the surfactant is one selected from or a mixture of at least two selected from the group consisting of anionic, nonionic, cationic, and amphoteric surfactants.

Description

EXAMPLES 1 TO 5 AND COMPARATIVE EXAMPLES 1 TO 3 EXAMPLE 1

[0052] 7 g of poly[dimethylsiloxane-co-2-(9,9-bi s(4-hydroxyphenyl)fluorene)methylsiloxane], 0.35 g of tetramethoxyethyl glycoluril, 0.1 g of pyridinium p-toluenesulfonate, 0.07 g of polyoxyethylene lauryl ether, and 93 g of propylene glycol monomethyl ether acetate were mixed and stirred well, and then filtered through a 30-nm pore size filter to prepare a multifunctional organic-inorganic mask film coating solution.

[0053] The coating solution was injected on a substrate layer to a thickness of 1000 Å using a spin coater or appropriate coating equipment, followed by baking at a temperature of 240° C. for 2 minutes to form a film. Thereafter, an ArF photoresist was coated on the film to a thickness of 1500 Å, and then exposed with ArF exposure equipment from ASML (manufacturer of ArF Equipment) at 24 mJ to form a mask with a 40 nm pattern. Finally, the film was etched with an etching gas mixture containing CF.sub.4 by using the formed mask, and a silicon oxide layer is etched to a depth of 500 Å.

EXAMPLE 2

[0054] Pattern formation was performed in the same manner as in Example 1 except that 8.5 g of poly[dimethylsiloxane-co-(2-(3,4-epoxycyclohexyl)ethyl)methylsiloxane], 0.43 g of tetramethoxyethyl glycoluril, 0.13 g of pyridinium p-toluenesulfonate, 0.085 g of polyoxyethylene lauryl ether, and 91.5 g of propylene glycol monomethyl ether acetate were mixed and stirred well, and then filtered through a 30-nm pore size filter to prepare a multifunctional organic-inorganic mask film coating solution.

EXAMPLE 3

[0055] Pattern formation was performed in the same manner as in Example 1 except that 8.5 g of poly(dimethylsiloxane-co-diphenylsiloxane), dihydroxyterminated, 0.43 g of tetramethoxyethyl glycoluril, 0.13 g of pyridinium p-toluenesulfonate, 0.085 g of polyoxyethylene lauryl ether, and 91.5 g of propylene glycol monomethyl ether acetate were mixed and stirred well, and then filtered through a 30-nm pore size filter to prepare a multifunctional organic-inorganic mask film coating solution.

EXAMPLE 4

[0056] 7 g of poly[dimethylsiloxane-co-2-(9,9-bi s(4-hydroxyphenyl)fluorene)methylsiloxane], 0.35 g of tetramethoxyethyl glycoluril, 0.1 g of pyridinium p-toluenesulfonate, 0.087 g of polyoxyethylene lauryl ether, and 93 g of propylene glycol monomethyl ether acetate were mixed and stirred well, and then filtered through a 30-nm pore size filter to prepare a multifunctional organic-inorganic mask film coating solution.

[0057] The coating solution was injected on a substrate layer to a thickness of 1000 Å using a spin coater or appropriate coating equipment, followed by baking at a temperature of 240° C. for 2 minutes to form a film. Thereafter, a KrF photoresist was coated on the film to a thickness of 5400 Å, and then exposed with KrF exposure equipment from Nikon at 30 mJ to form a mask with a 250 nm pattern. Finally, the film was etched with an etching gas mixture containing CF.sub.4 by using the formed mask, and a silicon oxide layer is etched to a depth of 500 Å.

EXAMPLE 5

[0058] 7 g of poly[dimethylsiloxane-co-2-(9,9-bi s(4-hydroxyphenyl)fluorene)methylsiloxane], 0.35 g of tetramethoxyethyl glycoluril, 0.1 g of pyridinium p-toluenesulfonate, 0.07 g of polyoxyethylene lauryl ether, and 93 g of propylene glycol monomethyl ether acetate were mixed and stirred well, and then filtered through a 30-nm pore size filter to prepare a multifunctional organic-inorganic mask film coating solution.

[0059] The coating solution was injected on a substrate layer to a thickness of 1000 Å using a spin coater or appropriate coating equipment, followed by baking at a temperature of 240° C. for 2 minutes to form a film. Thereafter, an I-line photoresist was coated on the film to a thickness of 6500 Å, and then exposed with I-line exposure equipment from Nikon at 140 mJ to form a mask with a 500 nm pattern. Finally, the film was etched with an etching gas mixture containing CF.sub.4 by using the formed mask, and a silicon oxide layer is etched to a depth of 500 Å.

Comparative Example 1

[0060] An organic hard mask film was coated on a substrate layer to a thickness of 3100 Å using a spin coater, followed by baking at a temperature of 240° C. for 2 minutes to form a film. Thereafter, a SiON film was formed to a thickness of 500 Å using deposition equipment, and an anti-reflective film was coated to a thickness of 300 Å using a spin coater, followed by baking at a temperature of 240° C. for 1 minute to form a film. Thereafter, an ArF photoresist was coated on the film to a thickness of 1500 Å, and then exposed with ArF exposure equipment from ASML (manufacturer of ArF Equipment) at 24 mJ to form a mask with a 40 nm pattern. Finally, the films were sequentially etched with an etching gas mixture containing CF.sub.4 and an etching gas mixture containing O.sub.2 by using the formed mask, and a silicon oxide layer is etched to a depth of 500 Å.

Comparative Example 2

[0061] An organic hard mask film was coated on a substrate layer to a thickness of 3100 Å using a spin coater, followed by baking at a temperature of 240° C. for 2 minutes to form a film. Thereafter, a SiON film was formed to a thickness of 500 Å using deposition equipment, and an anti-reflective film was coated to a thickness of 300 Å using a spin coater, followed by baking at a temperature of 240° C. for 1 minute to form a film. Thereafter, a KrF photoresist was coated on the film to a thickness of 3200 Å, and then exposed with KrF exposure equipment from Nikon at 30 mJ to form a mask with a 250 nm pattern. Finally, the films were sequentially etched with an etching gas mixture containing CF.sub.4 and an etching gas mixture containing O.sub.2 by using the formed mask, and a silicon oxide layer is etched to a depth of 500 Å.

Comparative Example 3

[0062] An organic hard mask film was coated on a substrate layer to a thickness of 3100 Å using a spin coater, followed by baking at a temperature of 240° C. for 2 minutes to form a film. Thereafter, a SiON film was formed to a thickness of 500 Å using deposition equipment, and an anti-reflective film was coated to a thickness of 300 Å using a spin coater, followed by baking at a temperature of 240° C. for 1 minute to form a film. Thereafter, an I-line photoresist was coated on the film to a thickness of 6500 Å, and then exposed with I-line exposure equipment from Nikon at 140 mJ to form a mask with a 500 nm pattern. Finally, the films were sequentially etched with an etching gas mixture containing CF.sub.4 and an etching gas mixture containing O.sub.2 by using the formed mask, and a silicon oxide layer is etched to a depth of 500 Å.

Characteristic Measurement

[0063] <Optical Property Test>

[0064] The refractive index n and extinction coefficient k of multifunctional organic-inorganic mask films including organic and inorganic materials formed in Examples 1 to 5 and organic hard mask films and SiON films formed in Comparative Examples 1 to 3 were measured, and the results are illustrated in Table 1. As a measurement device, an ellipsometer (Horiba) was used.

TABLE-US-00001 TABLE 1 Refractive index Extinction coefficient Sample (n@193 nm) (k@193 nm) Example 1 1.64 0.52 Example 2 1.74 0.55 Example 3 1.66 0.64 Example 4 1.64 0.52 Example 5 1.64 0.52 Comparative Organic 1.38 0.48 Example 1 hard Comparative mask 1.38 0.48 Example 2 film Comparative 1.38 0.48 Example 3 Comparative SiON 1.54 0.02 Example 1 Comparative 1.54 0.02 Example 2 Comparative 1.54 0.02 Example 3

[0065] As a result of comparing Examples 1 to 5 in which a multifunctional organic-inorganic mask film including organic and inorganic materials was coated on an object to be etched instead of a three-layer structure composed of an organic carbon film, a SiON film, and an anti-reflective film and then a photoresist was coated and patterned, with Comparative Examples 1 to 3 in which a three-layer structure composed of an organic carbon film, a SiON film, and an anti-reflective film was coated on an object to be etched and then a photoresist was coated and patterned, it was found that there was no difference in both the refractive index value and the extinction coefficient value.

[0066] <Pattern Formation Test>

[0067] The width and depth of patterns formed by dry etching the films formed in Examples 1 to 5 and Comparative Examples 1 to 3 were measured. The cross-sections of the patterns were observed using a scanning electron microscope (FE-SEM, Hitachi), and the measurement results are illustrated in Table 2.

TABLE-US-00002 TABLE 2 Sample Pattern width Pattern depth Example 1 39 nm 500 Å Example 2 39 nm 500 Å Example 3 39 nm 500 Å Example 4 251 nm 500 Å Example 5 495 nm 500 Å Comparative Example 1 39 nm 500 Å Comparative Example 2 252 nm 500 Å Comparative Example 3 495 nm 500 Å

[0068] The following results were obtained by comparing Examples 1 to 5 in which the multifunctional organic-inorganic mask film including organic and inorganic materials was coated on the object to be etched instead of the three-layer structure of composed of the organic carbon film, the SiON film, and the anti-reflective film and then the photoresist was coated and patterned, with Comparative Examples 1 to 3 in which the three-layer structure composed of the organic carbon film, the SiON film, and the anti-reflective film was coated on the object to be etched and then the photoresist was coated and patterned.

[0069] First, Examples 1 to 3 and Comparative Example 1, in which a mask with a 40 nm pattern was formed by exposure with ArF exposure equipment at 24 mJ, exhibited the same pattern width and the same pattern depth.

[0070] Second, Example 4 and Comparative Example 2, in which a mask with a 250 nm pattern was formed by exposure with KrF exposure equipment at 30 mJ, exhibited the same pattern width and the same pattern depth.

[0071] Third, Example 5 and Comparative Example 3, in which a mask with a 500 nm pattern was formed by exposure with I-line exposure equipment at 140 mJ, exhibited the same pattern width and the same pattern depth.

[0072] Although the present disclosure has been described in detail with reference to the specific features, it will be apparent to those skilled in the art that this description is only for a preferred embodiment and does not limit the scope of the present disclosure. Thus, the substantial scope of the present disclosure will be defined by the appended claims and equivalents thereof