KR20020002903A - Method for forming minute patterns of semiconductor device by using organic bottom anti-reflective coating - Google Patents

Abstract

PURPOSE: A fine pattern formation method of a semiconductor device is provided to obtain a profile of a stable fine pattern by irradiating an electron beam on an entire surface after coating an organic bottom anti-reflective coating layer to hard thereof. CONSTITUTION: An organic bottom anti-reflective coating layer(102) is coated on a substrate(100). The organic bottom anti-reflective coating layer(102) is hardened by irradiating an electron beam on an entire surface. A photoresist layer is formed on the organic bottom anti-reflective coating layer. Any of pattern is formed by patterning the photoresist layer and etching the organic bottom anti-reflective coating layer and the substrate using a photo-lithography process. The photoresist layer is removed, thereby forming a fine pattern of a semiconductor device.

Description

Method for forming minute patterns of semiconductor device by using organic bottom anti-reflective coating}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a fine pattern of a semiconductor device, and in particular, after coating an organic bottom anti-reflective coating (BARC), the photoresist is crosslinked by electron beam front irradiation. The present invention relates to a method of forming a fine pattern of a semiconductor device using organic BARC, which can prevent a mixture of BARC and photoresist that may occur during a coating process to obtain a stable pattern profile.

As the degree of integration of semiconductor devices increases, the critical dimension (CD) of the devices also decreases in proportion. In general, CDs are gradually decreasing to 0.81 μm in the 1M class, 0.351 μm in the 64M class, 0.251 μm in the 256M class, and 0.181 μm in the 1G class.

1 is a cross-sectional view showing a reflection effect of light generated during the exposure process according to the prior art.

Referring to FIG. 1, the lithography process to date has formed a desired pattern through an exposure and development process after coating the photoresist 20 on the substrate 10 to be patterned. However, this conventional technique has a difficulty in securing a fine pattern due to the reflectance reflected from the substrate 10 during the exposure process when the CD of the semiconductor device is reduced to about 0.25 μm or less.

Therefore, as the CD of the semiconductor device is gradually reduced, a new technique for securing a fine pattern has been proposed. Among them, a manufacturing method using BACR having a large antireflection effect during the exposure process is widely used.

2 is a cross-sectional view illustrating the use of BARC under the photoresist to reduce reflection of light during the exposure process according to the prior art.

Referring to FIG. 2, the BARC 15 refers to an antireflection film formed on the substrate 10 to be patterned, that is, below the photoresist, before the photoresist 20 is coated.

In general, organic or inorganic anti-reflective coatings (ARC) have an aromatic polysulfone structure, so the anti-reflective effect during the lithography process is great. The BARC 15 prevents the influence of sinusoidal wave, reflection notching and back diffracted light from the substrate during the exposure process, thereby ensuring a stable photoresist pattern.

However, in the case of organic BARC, curing is performed for a long time at a high temperature of 180 ° C to 210 ° C for crosslinking of the BARC material after the organic BARC coating.

When the photoresist is coated in a state in which some BARC films are not sufficiently cured during the high temperature heat curing process, the BARC and the photoresist are mixed. As a result, the photoresist pattern is poorly generated as shown in FIGS. 3A and 3B.

3A and 3B illustrate a photoresist in which footing (F) and undercutting (U) occur when BARC is not sufficiently cured in a curing process performed after coating BARC in a pattern manufacturing process of a semiconductor device. Cross-sectional views each showing a profile of a pattern.

Therefore, when the organic BARC is not partially cured as described above, a stable photoresist pattern cannot be obtained, and thus, it is very difficult to form a fine pattern of the semiconductor device.

In order to overcome the limitations of the organic BARC, a thermal acid generator is used so that a sufficient thermal crosslinking reaction can occur, but in this case, the exposure lens due to the chemical gas generated from the thermal photoacid generator is used. Was contaminated, making it difficult to carry out normal exposure work.

In order to solve the problems of the prior art, the object of the present invention is to conduct active electron beam irradiation after coating BARC to induce vigorous radical bonding of matrix resin in BARC to completely cure BARC and then during photoresist coating process. The present invention provides a method of forming a fine pattern of a semiconductor device using an organic BARC which prevents mixing of BARC and photoresist that may occur to secure a stable photoresist pattern.

1 is a cross-sectional view showing a reflection effect of light generated during the exposure process according to the prior art,

2 is a cross-sectional view showing the use of BARC under the photoresist to reduce the reflection of light during the exposure process according to the prior art,

3A and 3B are cross-sectional views illustrating profiles of a photoresist pattern in which a footing and an undercut phenomenon occur when BARC is not sufficiently cured in a curing process performed after coating BARC in a pattern manufacturing process of a semiconductor device;

4A and 4B are cross-sectional views illustrating a method of forming a fine pattern of a semiconductor device using an organic BARC according to the present invention;

Figures 5a and 5b are cross-sectional views showing the profile of the stable device pattern obtained when the electron beam front irradiation step after coating the BARC by applying the method of the present invention.

* Description of symbols on the main parts of the drawings *

100 substrate 102 organic BARC film

104: photoresist film

In order to achieve the above object, the present invention provides a method for forming a fine pattern of a semiconductor device by adding an organic BARC film between the substrate to be patterned and the photoresist film, coating the organic BARC film on the substrate, electron beam front irradiation Performing a process to cure the organic BARC film, forming a photoresist film on the organic BARC film, and performing a photo process to pattern the photoresist film, and etching the organic BARC film and the substrate exposed by the photoresist pattern. Forming a pattern of and removing the photoresist pattern.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

4A and 4B are cross-sectional views illustrating a method of forming a fine pattern of a semiconductor device using an organic BARC according to the present invention. Referring to this, the method of the present invention will be described below.

First, as shown in FIG. 4A, the organic BARC film 102 is coated with 200 1 to 1500 Å on the substrate 100 to be selectively etched in the semiconductor substrate, and an electron beam front irradiation process is performed to perform the organic BARC film 102. Harden.

In the electron beam front irradiation process, electron beam irradiation conditions and uniform front irradiation conditions are very important in order to secure a CD having a desired pattern. Process conditions for this are 10mmTorr-50mmTorr, 1keV-50keV acceleration voltage, 0.1㎛-12㎛ electron region, process temperature 20 ℃ -400 ℃, and proceed under the atmosphere of nitrogen, oxygen, argon and helium. The irradiation control condition is set to multiple irradiation or multiple voltage.

Next, as shown in FIG. 4B, the photoresist film 104 is formed on the organic BARC film 102, and the photoresist film 104 is patterned by performing a normal photographic process. Active radical bonding of the matrix resin is induced in the organic BARC film 102 by the electron beam front irradiation process. That is, a radical bond of a new type is generated by the cleavage of the main chain or the terminal of the matrix resin in the organic BARC film, and crosslinking of the matrix resin occurs by the bond between these radicals, so that the organic BARC film has a completely cured state. Accordingly, the organic BARC film of the present invention increases the optical density and refractive index, thereby eliminating the influence of sinusoidal reflection notching and back diffraction light from the substrate, which is generated during the patterning process, as well as of the cured BARC and photoresist during the photoresist coating process. No mixing occurs to obtain a stable photoresist pattern.

Although not shown in the figure, the organic BARC film and the substrate are etched using the stable photoresist pattern as a mask, and then the photoresist pattern is removed. Then, the fine pattern of the semiconductor element can also be stably formed by the profile of the stable photoresist pattern.

Organic BARC membranes used in the present invention are polyvinyl phenolic, polyhydroxy styrene, polynorbornene-based. Preference is given to homopolymers or copolymers composed of poly adamant series, polyimide series, polyacrylate series, polymethacrylate series, polyfluorine series. Or the organic BARC membrane is ethyl 3-ethoxy propionate. Preference is given to single solvents or mixtures thereof consisting of methyl 3-methoxy propionate, cyclohexanone, propylene glycol methyl ether acetate, methylethylketone, benzene, toluene, dioxane, dimethel formamide.

The organic BARC film used in the present invention uses a thermal photoacid generator or a primary amine, secondary amine or tertiary amine additive. Moreover, the thing containing anthracene which absorbs light with respect to an exposure wavelength is used. In this case, the thermal photoacid generator does not need to be used in the manufacturing process of the present invention, because the thermal crosslinking bond is sufficiently induced even by the electron beam front irradiation process, thereby preventing the generation of chemical gases generated when the thermal photoacid generator is used. Contamination of equipment and process deterioration can be prevented.

The following describes various embodiments of the present invention.

Example 1

In Example 1, an organic BARC film of polyacrylate was coated on a substrate at about 1000 mV, and the electron beam full exposure process was performed in four steps of 10 seconds at a temperature of 50 keV at room temperature. The organic BARC film is sufficiently thermally crosslinked by the front-irradiated electron beam. The chemically amplified polyhydroxy styrene-type resist for KrF was coated on the thermally crosslinked organic BARC film to a thickness of 0.56 μm, followed by soft baking at 90 ° C. for 90 seconds to remove the solvent from the resist. Then, an exposure process was performed to form a pattern of 180 nm lines and spaces using a KrF exposure machine, and an exposure baking process was performed at 110 ° C. for 90 seconds, and then a polyhydroxy styrene-based resist was formed using a 2.38 wt% TMAH phenomenon. By developing, a stable profile photoresist pattern having a 180 nm line and space is formed.

Example 2

In Example 2, after coating the poly methacrylate organic BARC film on the substrate at about 1200 Å, the organic BARC film was sufficiently thermally crosslinked by performing an electron beam all-over exposure process in 12 seconds at 30 ° C. under a voltage condition of 50 keV. The chemically amplified polyhydroxy styrene-type resist for KrF on the thermally crosslinked organic BARC film was coated with a thickness of 0.76 μm, followed by soft baking at 90 ° C. for 90 seconds to remove the solvent from the resist. Then, an exposure process was performed to form a pattern of 140 nm lines and spaces using a KrF exposure machine, and an exposure baking process was performed at 110 ° C. for 90 seconds, and then the resist was developed using a 2.38 wt% TMAH phenomenon. A photoresist pattern of stable profile with spaces is formed.

Example 3

In Example 3, an organic BARC film was thermally crosslinked by coating the polymethacrylate-based organic BARC film on a substrate at about 800 kPa and performing an electron beam all-over exposure process by dividing the organic BARC film in four steps of 10 seconds at a temperature of 40 keV at 30 ° C. The chemically amplified polynorbornene-based resist for ArF on the thermally crosslinked organic BARC film was coated with a thickness of 0.35 μm, followed by soft baking at 110 ° C. for 90 seconds to remove the solvent in the resist. Then, an exposure process was performed to form a pattern of a 100 nm line and a space using an ArF exposure machine, and an exposure baking process was performed at 130 ° C. for 90 seconds, and then the resist was developed using a 2.38 wt% TMAH phenomenon to develop a 100 nm line and a space. A photoresist pattern of stable profile with spaces is formed.

5A and 5B are cross-sectional views showing profiles of stable device patterns obtained when an electron beam front irradiation process is performed after coating an organic BARC by applying the method of the present invention.

As shown in FIGS. 5A and 5B, when the manufacturing method of the present invention is applied, a fine pattern 100 of a semiconductor device may be obtained by securing a profile of a stable photoresist pattern in which a footing or undercut phenomenon is removed (see reference numeral A). It can also be formed in a stable form.

As described above, using the method according to the present invention has the following effects.

First, the thermal crosslinking reaction of the organic BARC film becomes active and uniform, thereby increasing the optical density and refractive index of the photoresist and removing the influence of sinusoidal reflection notching and back diffraction light from the substrate, which are generated during the patterning process.

Second, the mixing of the cured BARC and the photoresist does not occur during the photoresist coating process to obtain a stable photoresist pattern. As a result, a uniform and accurate CD of the device pattern can be secured due to the stable profile of the photoresist pattern during the micropattern manufacturing process of the semiconductor device, thereby greatly improving the lithography technology of the highly integrated semiconductor.

Third, the present invention can improve the deterioration of the exposure operation due to the thermal photoacid generator used to overcome the limitations of the conventional organic BARC.

Claims (8)

In the method of forming a fine pattern of a semiconductor device by adding an organic lower anti-reflection film between the substrate to be patterned and the photoresist film, Coating an organic lower antireflection film on the substrate; Performing an electron beam entire surface irradiation process to cure the organic lower anti-reflection film; Forming a photoresist film on the organic lower anti-reflection film; Performing a photolithography process to pattern the photoresist film and etching the organic lower antireflection film and the substrate exposed by the photoresist pattern to form a predetermined pattern; And The method of forming a fine pattern of a semiconductor device using an organic BARC comprising the step of removing the photoresist pattern. The method of claim 1, wherein the organic lower antireflection film is polyvinyl phenol-based, poly hydroxy styrene-based, poly norbornene-based. A method for forming a fine pattern of a semiconductor device using an organic BARC, characterized in that the homopolymer or copolymer consisting of poly adamant, polyimide, poly acrylate, polymethacrylate, polyfluorine. The method of claim 1, wherein the organic lower antireflection film is ethyl 3-ethoxy propionate. Organic BARC characterized by being a single solvent or a mixed solvent of methyl 3-methoxy propionate, cyclohexanone, propylene glycol methyl ether acetate, methylethylketone, benzene, toluene, dioxane, dimethel formamide Method for forming a fine pattern of a semiconductor device using. The method of claim 1, wherein the organic lower anti-reflection film contains a thermal photoacid generator. The method of claim 1, wherein the organic lower anti-reflection film contains a primary amine, a secondary amine, or a tertiary amine additive. The method of claim 1, wherein the organic lower anti-reflective coating contains anthracene that absorbs light with respect to an exposure wavelength. The method of claim 1, wherein the organic anti-reflection coating has a coating thickness of about 200 mW to about 1500 mW. The method of claim 1, wherein the electron beam front irradiation step is performed with a process pressure of 10 mmTorr to 50 mmTorr, an acceleration voltage of 1 keV to 50 keV, an electron range of 0.1 μm to 12 μm, a process temperature of 20 ° C. to 400 ° C., and nitrogen, oxygen, and argon. And forming a fine pattern of a semiconductor device using an organic BARC characterized in that it proceeds in an atmosphere of helium and the irradiation control condition is a multi-irradiation or a multi-voltage.