KR20080102928A - Method of forming an amorphous carbon film and method of manufacturing semiconductor device using the same - Google Patents

Abstract

A formation method of amorphous carbon film and a manufacturing method of semiconductor element using the same are provided to form the desired pattern without the diffuse reflection by forming the amorphous carbon film having the low light extinction coefficient. A formation method of amorphous carbon film includes the step for loading the substrate(110) within the chamber; the step for vaporizing the hydrocarbon compound having one double bond which is the liquid state within the chamber of the chain structure; the step for supplying the vaporized hydrocarbon compound; the step for ionizing the hydrocarbon compound; the step for forming the amorphous carbon film(130) on the top of the substrate.

Description

Method of forming an amorphous carbon film and method of manufacturing semiconductor device using the same}

The present invention relates to a method of forming an amorphous carbon film, and more particularly, to an amorphous carbon film forming method having a wide refractive index and a low light absorption coefficient using a liquid hydrocarbon compound and a method of manufacturing a semiconductor device using the same.

A semiconductor device is composed of several devices such as word lines, bit lines, capacitors, and metal wires interacting with each other. As the integration and performance of semiconductor devices become higher, the demand for materials or process technologies used in the manufacture of semiconductor devices is increasing. . In particular, research on a method of forming a fine pattern of various structures formed on a semiconductor substrate is continuously progressed due to a reduction in device size due to high integration of semiconductor devices.

As the demand for a photolithography process for forming fine patterns increases, the wavelength of an exposure light source is gradually shortened. That is, according to the high integration of the semiconductor device, the exposure light source uses a KrF laser having a wavelength of 248 nm or an ArF laser having a wavelength of 193 nm from a G-line having a wavelength of 436 nm and a 365 nm, or an i-line. X-rays or electron beams may be used as exposure light sources for pattern formation.

As the pattern size decreases as described above, the thickness of the energy-sensitive photoresist pattern must be reduced to control the pattern resolution. However, when the thickness of the photoresist pattern becomes thin, the photoresist pattern is first removed by an etching solution or the like before the lower material layer thicker than the photoresist pattern is etched, so that the lower material layer pattern cannot be formed. Therefore, a hard mask film such as an oxide film (SiO ₂ ), a nitride film (Si ₃ N ₄ ), etc. is additionally formed on the lower material layer in addition to the photoresist pattern to secure a process margin during the etching process for forming the pattern. .

In a highly integrated semiconductor device, for example, a semiconductor device of 100 nm or less, the width and spacing of the metal wiring are reduced, and the height of the metal wiring is increased to compensate for the increase in resistance. In addition to this, the width and spacing of the polysilicon film, oxide film or nitride film are reduced, and the thickness is increased. Therefore, the thickness of the hard mask film is increased to prevent the hard mask film from being etched before all the material layers are etched. When the thickness of the hard mask film is increased, the thickness of the photosensitive film is also increased. However, due to the narrow line width during the etching process of the hard mask, the photoresist pattern may not be maintained and collapses. This makes it impossible to pattern not only the hard mask film but also the underlying material layer. In addition, when the thickness of the hard mask film is increased, productivity per unit time of the equipment is decreased, and productivity is decreased and generation of foreign matters is also increased in a subsequent etching process.

In addition, when the conventional hard mask layer is formed on the metal layer having an increased thickness, the conventional hard mask layer has high light absorption coefficient k, thereby causing diffuse reflection by the metal layer. Due to such diffuse reflection, a necking phenomenon occurs in which the lower portion of the photoresist pattern is narrowed during the development process, and a footing phenomenon occurs in which the lower portion of the photoresist layer is gently widened. When the metal layer is patterned using such a photoresist pattern, the cross-sectional area of the pattern decreases, which occurs more severely as the pattern interval is narrower, and the resistance of the wiring is increased to decrease the speed of the device and to promote the movement of electrons. There is a problem of lowering reliability. Therefore, in order to prevent diffuse reflection of the hard mask film, an anti-reflection film should be additionally formed.

In order to solve the problem, an amorphous carbon film is used as a hard mask. The amorphous carbon film may have a high resolution even with a thin film, and fine patterning is possible regardless of the etching rate of the photoresist film. In order to form an amorphous carbon film, a benzene ring or a hydrocarbon compound having a plurality of double bonds, such as benzene (C ₆ H ₆ ) and toluene (C ₇ H ₈ ), is conventionally used. However, these materials cannot adjust the deposition rate, etching selectivity, refractive index (n), light absorption coefficient (k), and stress characteristics to a desired value. For example, benzene (C ₆ H ₆ ) and toluene (C ₇ H ₈ ) have a high deposition rate but low etching selectivity. In addition, all of these materials generate a lot of reaction by-products. When a lot of reaction by-products are generated, not only the deposition rate of the amorphous carbon film is lowered, but also particles remain in the amorphous carbon film, thereby degrading the film quality and characteristics of the amorphous carbon film. The reaction by-products are then attached to the interior of the chamber, and because of their high amount, more reaction by-products are attached. Therefore, cleaning processes to remove reaction by-products must be frequently performed, which not only increases the processing time but also increases the cost. However, these reaction by-products are not easily separated from the chamber during the cleaning process, resulting in a decrease in the quality of the amorphous carbon film and shortening the replacement cycle of the chamber.

The present invention provides a method for forming an amorphous carbon film capable of finely controlling the refractive index and forming a desired pattern without diffuse reflection by forming an amorphous carbon film having a low light absorption coefficient.

The present invention provides a method for forming an amorphous carbon film which generates less reaction by-products and does not contaminate the inside of the chamber and can be easily removed during the cleaning process, thereby reducing costs and processing time.

The present invention provides a method for manufacturing a semiconductor device using an amorphous carbon film capable of accurately patterning a photosensitive film without using an antireflection film by vaporizing a liquid hydrocarbon compound in a liquid state to form an amorphous carbon film. .

An amorphous carbon film forming method according to an aspect of the present invention includes the steps of loading a substrate into a chamber; And vaporizing, supplying and ionizing a chain structured hydrocarbon compound having one double bond in a liquid state in the chamber to form an amorphous carbon film on the substrate.

The hydrocarbon compound includes at least one of hexene (C ₆ H ₁₂ ), nonene (C ₉ H ₁₈ ), dodecene (C ₁₂ H ₂₄ ), pentacene (C ₁₅ H ₃₀ ).

The hydrocarbon compound is supplied in an amount of 0.3 g / min to 0.8 g / min.

A high frequency power of 800-2000 W is applied to the chamber to ionize the vaporized reaction source.

A low frequency power of 150 to 400 W is further applied to the chamber.

The amorphous carbon film is formed by maintaining the pressure of the chamber at 4.5 Torr to 8 Torr.

The chamber includes a showerhead for supplying and spraying the vaporized hydrocarbon compound, and maintains a distance of 250Mils to 400Mils between the showerhead and the substrate.

The amorphous carbon film is formed at a temperature of 300 ° C to 550 ° C.

The amorphous carbon film is formed at a deposition rate of 15 to 80 kW / sec.

The amorphous carbon film includes carbon and hydrogen, and the ratio of carbon to hydrogen is adjusted according to the high frequency power, the amount of hydrocarbon compound, the chamber pressure, and the deposition temperature.

The hydrogen content of the amorphous carbon film is controlled by further introducing hydrogen or ammonia gas.

The amorphous carbon film has a refractive index of 1.7 to 2.2 and a light absorption coefficient of 0.1 to 0.5.

The amorphous carbon film has an etch selectivity with an oxide film of 1 to 5 to 1 to 40, and an etching selectivity with a nitride film of 1 to 1 to 1 to 20.

The amorphous carbon film is formed by introducing an inert gas to control the deposition rate and the etching selectivity.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device using an amorphous carbon film, the method including: forming a material layer on a substrate on which a predetermined structure is formed; Loading the substrate on which the material layer is formed into a chamber; Vaporizing, supplying and ionizing a chain structured hydrocarbon compound having one double bond in the liquid state to form an amorphous carbon film on the substrate; Forming a photoresist pattern on the amorphous carbon layer, and then etching the amorphous carbon layer using the photoresist pattern as an etching mask; And removing the amorphous carbon film and the photoresist pattern after etching the exposed material layer.

The amorphous carbon film is etched by reactive ion etching.

The amorphous carbon film is etched using a remote plasma system by mixing C ₄ F ₈ plasma, oxygen (O ₂ ) plasma and ozone (O ₃ ) plasma, respectively, or at least one or each of oxygen and NF ₃ .

According to the present invention, an amorphous carbon film is formed by using a source gas in which a hydrocarbon compound having a chain structure having one double bond containing at least one of hexene, nonene, dodecene, pentadecene and the like in a liquid state is vaporized.

The amorphous carbon film thus formed can easily adjust characteristics such as deposition rate, etching selectivity, refractive index (n), light absorption coefficient (k), and stress according to the user's requirements, and in particular, the refractive index (n) and the light absorption coefficient ( k) can be precisely adjusted to the desired range, the value can be lowered to perform the photolithography process without forming an anti-reflection film for preventing diffuse reflection of the underlying material layer.

In addition, less reaction by-products are generated, and reaction by-products attached to the inside of the chamber can be easily removed. Therefore, the cleaning process cycle of the chamber can be increased, and the replacement cycle of the chamber accessory can be increased, thereby saving time and cost.

In addition, by applying a low frequency to increase the linearity of the ions formed by the plasma to suppress the overhang generated when forming the amorphous carbon film in the stepped portion of the device can improve the step coverage, thereby preventing the etching of unwanted areas can do.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a schematic cross-sectional view of a deposition apparatus for forming an amorphous carbon film according to the present invention, which is a schematic cross-sectional view of a plasma enhanced chemical mechanical deposition (PECVD) equipment.

Referring to FIG. 1, the deposition apparatus includes a vacuum unit 10, a chamber 20, a gas supply unit 30, and a power supply unit 40.

The vacuum section 10 includes a pump 11, for example a turbo molecular pump, a valve 12, and an exhaust port 13, to maintain the interior of the chamber 20 in a vacuum suitable for deposition. . In addition, the vacuum unit 10 is used to discharge the unreacted gas remaining in the chamber 20.

The chamber 20 is formed in a rectangular parallelepiped or cylindrical shape according to the shape of the substrate 1 to form an internal space in which the process proceeds, and the substrate support 21, the shower head 22, the pressure gauge 23, and the liner 24 are formed. ) And a pump plat 25. The substrate support 21 is disposed below the inside of the chamber 20 so that the substrate 1 for forming the amorphous carbon film is seated. In addition, the substrate support 21 may be provided with a cooling water flow path so that the cooling water continuously flows so that the temperature of the substrate 1 does not rise above a proper temperature. The shower head 22 receives a source gas from the gas supply unit 30, and receives a high frequency power from the power supply unit 40. Therefore, the source gas supplied through the gas supply unit 30 and injected through the shower head 22 is ionized by the high frequency power applied from the power supply unit 40 and deposited on the substrate 1. In addition, the shower head 22 is insulated from the inner wall of the chamber 22. The pressure gauge 23 measures the pressure in the chamber 20, and the pressure measured by the pressure gauge 23 is reflected in the opening degree of the valve 12, thereby adjusting the pressure in the chamber 20 to an appropriate level. Can be maintained. The liner 24 is provided on the inner wall of the chamber 20 to protect the inner wall of the chamber 20 made of aluminum from being damaged by plasma or the reactant is not deposited on the inner wall of the chamber 20, and preferably, a ceramic material is used. The pump flat 25 allows the residual gas discharged through the exhaust port 13 by the pump 11 to be exhausted uniformly. The pump flat 25 is provided in a plate shape in which a plurality of holes are formed.

The gas supply unit 30 includes a vaporizer 31 for vaporizing a liquid reaction source required to form an amorphous carbon film on the substrate 1, a reaction source vaporized by the vaporizer 31, and an argon gas. And a gas supply pipe 32 for supplying a carrier gas into the chamber 20.

The power supply unit 40 includes a high frequency generator 41 and a matching unit 42, and applies a high frequency power to the showerhead 22 so that the source gas is ionized and deposited on the substrate 1. The power supply unit 40 is a high frequency generator 41 is applied to a high frequency power of 800 ~ 2000W to generate a high frequency of 13.56 MHz.

On the other hand, in addition to the power supply unit 40 for generating a high frequency including the high frequency generator 41 and the matching unit 42, a power supply unit for generating a low frequency including a low frequency generator (not shown) and a matching unit (not shown) (not shown) May be further included. The low-frequency power supply unit may be connected to the lower portion of the chamber 20, for example, the substrate support 21. When the low-frequency power supply is generated, the amorphous carbon film on the substrate 1 may be improved by improving the linearity of ions of the source gas. The deposition is uniformly performed and the stress of the thin film is relieved to improve the film quality. The power supply unit for generating such a low frequency causes the low frequency generator to be supplied with a low frequency power of 150 to 400 W to generate a low frequency of 400 Hz.

Referring to the amorphous carbon film forming method according to the present invention using the deposition equipment as follows.

First, the substrate 1 having a predetermined structure is mounted on the substrate support 21 to be loaded into the chamber 20. After vacuuming the inside of the chamber 20 using the vacuum unit 10, the reaction source is vaporized and sprayed through the gas supply unit 30 and the shower head 12. At this time, a high frequency (RF) power is applied to the shower head 12 from the power supply 40 to the chamber 20. Plasma is generated inside the chamber 20 by the high frequency power, and the reaction source is ionized to move to the substrate 1. In addition, a low frequency power source is further applied to the substrate support 21 to improve the linearity of ions by the low frequency power source, thereby forming an amorphous carbon film having improved uniformity and film quality on the substrate 1.

Here, as a reaction source for forming the amorphous carbon film, a liquid hydrocarbon compound is vaporized and used. The hydrocarbon compound may be gasified by gasification, generate a plasma according to reaction conditions, and include a hydrocarbon compound having a chain structure having one double bond by constituting molecules with only carbon and hydrogen atoms. These hydrocarbon compounds may be hexene (C ₆ H ₁₂ ), nonene (C ₉ H ₁₈ ), dodecene (C ₁₂ H ₂₄ ), pentacene (C ₁₅ H ₃₀ ) shown in [Formula 1] to [Formula 4], respectively. At least any one of). These hydrocarbon compounds are easier to control deposition rate, etching selectivity, refractive index (n), light absorption coefficient (k), and stress characteristics than other hydrocarbon compounds. In addition, less reaction by-products are generated compared to other hydrocarbon compounds, and less by-products are attached to the inside of the chamber 20. Therefore, the process of removing contaminants on the inner wall of the chamber 20 can be reduced.

In addition, an inert gas including argon, helium gas, or the like is used as a carrier gas and a plasma generating gas for carrying the source gas. Here, the hydrocarbon compound is supplied in an amount of 0.3 g / min to 0.8 g / min in the liquid state. In particular, argon gas is used in the inert gas used as the carrier gas to improve the uniformity of the plasma and the thickness and uniformity of the amorphous carbon film. In addition, hydrogen (H ₂ ) or ammonia (NH ₃ ) gas may be used to adjust the concentration of hydrogen in the amorphous carbon film.

In addition, a high frequency of 13.56 MHz, a chamber pressure of 4.5 Torr to 8 Torr, a temperature of 300 to 550 ° C., a substrate of 250 Mils to 400 Mils, and a showerhead generated by applying a high frequency power of 800 to 2000 W to form an amorphous carbon film. It is desirable to maintain the distance between them. At this time, the amorphous carbon film is formed to have a thickness of 15 to 80 mW / sec. In addition, in order to uniformly deposit the amorphous carbon film, and to reduce the stress of the thin film to improve the film quality, a low frequency of 400 Hz generated by applying a low frequency power of 150 to 400 W may be further applied.

Here, when the high frequency power is low, the deposition rate is lowered, and thus a film is not deposited. When the high frequency power is high, the deposition rate is high, the film is not deposited densely and the film quality is degraded. In addition, when the reaction source inflow is small, the deposition rate is lowered, so that the film is not deposited at a desired thickness at a desired time, and in many cases, the deposition rate is increased, and the film is not densely deposited, resulting in particle quality as well as particles. In addition, when the gap between the showerhead and the substrate is narrow, arcing occurs, and when it is wide, the deposition rate is lowered so that the film is not deposited. If the pressure is high, particles are generated. If the pressure is low, the refractive index and light absorption coefficient characteristics are lowered. If the temperature is low, the film quality is lowered. If the temperature is high, the refractive index and light absorption coefficient characteristics are lowered. Therefore, it is preferable to adjust the formation conditions of the amorphous carbon film as described above.

On the other hand, the amorphous carbon film contains hydrogen, and the ratio of carbon to hydrogen can be adjusted from 9 to 1 to 6 to 4, which can be controlled by controlling high frequency power, amount of hydrocarbon compound, chamber pressure and deposition temperature. . In other words, in order to increase the hydrogen ratio, the high frequency power and temperature are lowered, and the chamber pressure and the amount of hydrocarbon compound are increased. Conversely, in order to lower the hydrogen ratio, the high frequency power and temperature are increased, and the chamber pressure and the amount of hydrocarbon compound are lowered.

In the subsequent etching process, the etching selectivity with the underlying film is controlled according to the ratio of carbon to hydrogen in the subsequent etching process, and has an etching selectivity ratio of 1 to 5 to 1 to 40 with the oxide film (SiO ₂ ) and a nitride film (Si ₃ N ₄ ) has an etching selectivity ratio of 1: 1 to 1:20.

In addition, in the amorphous carbon film, the refractive index n and the light absorption coefficient k are also adjusted according to the composition ratio of carbon and hydrogen, and the refractive index n and the light absorption coefficient k decrease as the composition ratio of hydrogen increases. For example, the refractive index n may be adjusted to 1.7 to 2.2, and the light absorption coefficient k may be adjusted to 0.1 to 0.5.

As described above, the amorphous carbon film formed by using the hydrocarbon compound has a stress, refractive index (n) and light absorption coefficient (k) by controlling process conditions such as a high frequency power supply, a supply amount of a reaction source, and a distance between the showerhead and the substrate. The deposition rate may be adjusted. The characteristics of the amorphous carbon film according to the present invention will be described with reference to the following examples. 2 (a) to 2 (d) are graphs for explaining the characteristic change according to the high frequency power of the amorphous carbon film according to the first embodiment of the present invention, Figures 3 (a) to 3 (d) 4A and 4D are graphs illustrating a characteristic change according to a supply amount of a reaction source of an amorphous carbon film according to a second embodiment of the present invention. FIGS. 4 (a) to 4 (d) illustrate an amorphous carbon film according to a third embodiment of the present invention. It is a graph for explaining the characteristic change according to the distance between the showerhead and the substrate. Each of these graphs shows the change in properties under optimal conditions.

First Embodiment : Change of Characteristics of Amorphous Carbon Film According to High Frequency Power

In the amorphous carbon film according to the first embodiment of the present invention, 0.8 g / min of hexene (C ₆ H ₁₂ ), 300 sccm of argon, and 800 sccm of helium at a pressure of 7 Torr and a temperature of 550 ° C. while changing high frequency power to 900 to 2000 W Was introduced to form an amorphous carbon film. At this time, the distance between the showerhead and the substrate maintained 350 miles. In this case, changes in stress, refractive index (n), light absorption coefficient (k), and deposition rate of the amorphous carbon film according to high frequency power are shown in FIGS. 2A to 2D, respectively.

Figure 2 (a) is a graph showing the change in the stress of the amorphous carbon film according to the high frequency power, the stress is slightly increased with increasing the high frequency power is rapidly reduced from 1600W.

2 (b) is a graph showing the change of the refractive index n of the amorphous carbon film according to the high frequency power, and the refractive index n decreases as the high frequency power increases.

2 (c) is a graph showing the change in the light absorption coefficient (k) of the amorphous carbon film according to the high frequency power, the light absorption coefficient (k) gradually decreases as the high frequency power increases, and rapidly decreases from 1200W to 1600W, It will increase again from 1600W.

2 (d) is a graph showing a change in deposition rate (μs / sec) of the amorphous carbon film according to the high frequency power, and the deposition rate increases as the high frequency power increases.

Therefore, as can be seen in the first embodiment of the present invention, the stress, refractive index (n), light absorption coefficient (k), and deposition rate of the amorphous carbon film can be changed according to the high frequency power. The refractive index n becomes low and the deposition rate becomes high. In addition, as the high frequency power is increased, the stress increases, which is rapidly lowered from 1600W, and the light absorption coefficient k is rapidly lowered and gradually increased from 1600W.

The amorphous carbon film formed by the first embodiment of the present invention has a refractive index (n) in the range of 1.84 to 1.89 and a light absorption coefficient (k) in the range of 0.36 to 0.41. Or it turns out that it has the outstanding optical characteristic as an antireflection film.

Second Embodiment : Change of Characteristics of Amorphous Carbon Membrane According to Supply of Reaction Source

In the amorphous carbon film according to the second embodiment of the present invention, high frequency power is applied at 1600 W, and the flow rate of hexene (C ₆ H ₁₂ ) is changed to 0.3 g / min to 0.8 g / min at a pressure of 7 Torr and a temperature of 550 ° C. 300 sccm of argon and 200 sccm of helium were introduced to form an amorphous carbon film. At this time, the spacing between the showerhead and the substrate was maintained at 320 mils. In this case, changes in stress, refractive index (n), light absorption coefficient (k), and deposition rate of the amorphous carbon film according to the supply amount of the reaction source are shown in FIGS. 3 (a) to 3 (d), respectively.

3 (a) is a graph showing a change in the stress of the amorphous carbon film according to the reaction source inflow, and the stress decreases as the inflow of the reaction source increases.

3 (b) is a graph showing the change of the refractive index n of the amorphous carbon film according to the inflow rate of the reaction source. The refractive index n decreases as the inflow rate of the reaction source increases.

3 (c) is a graph showing a change in the light absorption coefficient k of the amorphous carbon film according to the flow rate of the reaction source. The light absorption coefficient k decreases as the flow rate of the reaction source increases.

3 (d) is a graph showing a change in deposition rate (μs / sec) of the amorphous carbon film according to the reaction source inflow, and the deposition rate increases as the reaction source inflow increases.

Therefore, as can be seen in the second experimental example of the present invention, the stress, refractive index (n), light absorption coefficient (k), and deposition rate of the amorphous carbon film can be changed according to the reaction source inflow amount. The more, the lower the stress, the refractive index n and the light absorption coefficient k, and the higher the deposition rate.

The amorphous carbon film formed by the second embodiment of the present invention has a refractive index n in the range of 1.86 to 1.91 and a light absorption coefficient k in the range of 0.36 to 0.41. Or it turns out that it has the outstanding optical characteristic as an antireflection film.

Experimental Example 3 Variation of Characteristics of Amorphous Carbon Film According to the Distance between the Shower Head and the Substrate

In the amorphous carbon film according to the third experimental example of the present invention, high frequency power was applied at 1600 W, and 0.8 g / min of hexene (C ₆ H ₁₂ ), 300 sccm of argon, and 800 sccm of helium were introduced at a pressure of 7 Torr and a temperature of 550 ° C. To form an amorphous carbon film. At this time, the distance between the showerhead and the substrate was changed from 250 mils to 350 mils. In this case, changes in stress, refractive index (n), light absorption coefficient (k), and deposition rate of the amorphous carbon film according to the distance between the showerhead and the substrate are shown in FIGS. 4 (a) to 4 (d), respectively.

4 (a) is a graph showing a change in stress of the amorphous carbon film according to the distance between the showerhead and the substrate, and the stress decreases as the distance between the showerhead and the substrate increases.

4 (b) is a graph showing the change of the refractive index n of the amorphous carbon film with the spacing between the showerhead and the substrate. The refractive index n increases with increasing spacing between the showerhead and the substrate. Done.

4 (c) is a graph showing the change in the light absorption coefficient k of the amorphous carbon film according to the distance between the showerhead and the substrate. The light absorption coefficient k is rapidly increased as the distance between the showerhead and the substrate increases. It increases and gradually decreases from 300 mils.

4 (d) is a graph showing a change in deposition rate (μs / sec) of the amorphous carbon film according to the distance between the showerhead and the substrate, and the deposition rate decreases as the distance between the showerhead and the substrate increases.

Therefore, as can be seen in the third experimental example of the present invention, the stress, refractive index (n), light absorption coefficient (k), and deposition rate of the amorphous carbon film can be changed according to the distance between the showerhead and the substrate. The larger the distance between the showerhead and the substrate, the lower the stress and deposition rate. In addition, as the distance between the showerhead and the substrate increases, the refractive index n increases and decreases from 300 mils, and the light absorption coefficient k increases rapidly and gradually decreases from 300 mils.

The amorphous carbon film formed by the third embodiment of the present invention has a refractive index n in the range of 1.86 to 1.89 and a light absorption coefficient k in the range of 0.36 to 0.41. Or it turns out that it has the outstanding optical characteristic as an antireflection film.

In the above embodiments, the characteristics of the amorphous carbon film formed under various process conditions using hexene (C ₆ H ₁₂ ) were described, but nonene (C ₉ H ₁₈ ), dodecene (C ₁₂ H ₂₄ ), and pentacene (C ₁₅ H) were used. ₃₀ ) may be used to form an amorphous carbon film having various properties under various process conditions, or may be used by mixing at least one of them.

In addition to the above hexene (C ₆ H ₁₂ ), an amorphous carbon film formed using nonene (C ₉ H ₁₈ ), dodecene (C ₁₂ H ₂₄ ), pentacene (C ₁₅ H ₃₀ ), or the like used in the present invention is also 1.7 to It has a refractive index n of 2.2, preferably 1.85 to 1.88, and an optical absorption coefficient k of 0.1 to 0.5, preferably 0.36 to 0.4.

As described above, the amorphous carbon film formed by using a hydrocarbon compound having a chain structure having one double bond generates less reaction by-products than other hydrocarbon compounds, and easily removes reaction by-products attached to the inside of the chamber. have. That is, when amorphous carbon film is formed by using toluene (C ₇ H ₈ ) and ethylbenzene (C ₈ H ₁₀ ) having a benzene ring, a large amount of reaction by-products are generated. It cannot be removed, leaving a residue as shown in FIGS. 5 (a) and 5 (b). However, the formation of an amorphous carbon film using hexene (C ₆ H ₁₂ ) having a chain structure having one double bond generates less reaction by-products, and the cleaning by-products can easily remove the reaction by-products attached to the inside of the chamber. Can leave little residue as shown in FIG.

The amorphous carbon film formed by the above method may be applied as a hard mask in the manufacturing process of the semiconductor device. FIGS. 7 (a) to 7 (f) are sequentially shown to explain the manufacturing method of the semiconductor device. It is a cross section. In this embodiment, since the amorphous carbon film according to the present invention has a low light absorption coefficient, accurate patterning of the photoresist film is possible without separately forming an antireflection film.

First, as shown in FIG. 7A, a material layer 120 to form a pattern is formed on the semiconductor substrate 110. Here, the semiconductor substrate 110 may be a substrate on which a predetermined structure, for example, a transistor, a capacitor, and a plurality of metal wires are formed for manufacturing a semiconductor device of the semiconductor substrate 110. In addition, the material layer 120 may be a metal thin film for forming a metal wiring, and may be a silicon dioxide film or a silicon nitride film used as an interlayer insulating film. The material layer 120 may be a single layer, or a plurality of films may be formed. It may be a laminated layer.

Next, as shown in FIG. 7B, the amorphous carbon film 130 is formed on the material layer 120 by the above-described method. That is, a hydrocarbon compound gas and an argon gas including at least one of hexene (C ₆ H ₁₂ ), nonene (C ₉ H ₁₈ ), dodecene (C ₁₂ H ₂₄ ), pentacene (C ₁₅ H ₃₀ ), and the like. A plasma is generated using a high frequency of 13.56 MHz generated by applying a high frequency power of 800 to 2000 W to the carrier gas to ionize the reaction source to form an amorphous carbon film 130 on the material layer 120. At this time, the chamber is maintained at a pressure of 4.5 Torr to 8 Torr, a temperature of 300 to 550 ° C., a distance between the substrate of 250 Mils to 400 Mils and the showerhead, and an amorphous carbon film having a thickness of 15 to 80 kPa / sec. In addition, a low frequency of 400 kHz generated by applying a low frequency power of 150 to 400 W may be further applied. The amorphous carbon film 130 thus formed has a high etching selectivity with the material layer 120 and serves as a hard mask film having a low light absorption coefficient k.

Next, as shown in FIG. 7C, after forming the photosensitive film 140 on the amorphous carbon film 130, for example, the ArF laser A is irradiated through the mask 150 in which a predetermined pattern is imprinted. The photosensitive film 140 is exposed. As illustrated in FIG. 7D, the exposed portion of the photosensitive film 140 is developed using a developer.

Next, as illustrated in FIG. 7E, the amorphous carbon film 130 is etched using the patterned photosensitive film 140 as an etching mask. In this case, the amorphous carbon film 130 is etched by RF plasma or reactive ion etching (RIE). Here, the amorphous carbon film 130 is etched using a CF ₄ plasma, a C ₄ F ₈ plasma, an oxygen (O ₂ ) plasma and an ozone (O ₃ ) plasma, or at least one of them. In addition, the amorphous carbon film 130 may be mixed with oxygen and NF ₃ to be etched using a remote plasma system.

Next, as illustrated in FIG. 7F, the material layer 120 is etched using the photosensitive film 140 and the amorphous carbon film 130 as an etching mask. In this case, the material layer 120 is etched using various methods according to the material of the material layer 120. Then, the photosensitive film 140 and the amorphous carbon film 130 are removed to complete the pattern formation using the material layer 120.

In addition to the above embodiments, an amorphous carbon film may be used as a hard mask film in a variety of photographic and etching processes, for example, a damascene process, in a semiconductor device manufacturing process.

As mentioned above, although this invention was demonstrated in detail using the preferable embodiment, the scope of the present invention is not limited to a specific embodiment, Comprising: It should be interpreted by the attached Claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

1 is a schematic cross-sectional view of a deposition apparatus used to form an amorphous carbon film according to the present invention.

2 (a) to 2 (d) are graphs for explaining the characteristic change according to the high frequency power of the amorphous carbon film according to the present invention.

Figure 3 (a) to Figure 3 (d) is a graph for explaining the characteristic change according to the supply amount of the reaction source of the amorphous carbon film according to the present invention.

4 (a) to 4 (d) are graphs for explaining the characteristic change according to the distance between the showerhead and the substrate of the amorphous carbon film according to the present invention.

5 (a) and 5 (b) are photographs of the lower part of the chamber after forming an amorphous carbon film using toluene (C ₇ H ₈ ) and ethylbenzene (C ₈ H ₁₀ ) and performing a cleaning process.

6 is a photograph of a lower chamber after an amorphous carbon film is formed using hexene (C ₆ H ₁₂ ) and a cleaning process is performed.

7 (a) to 7 (f) are cross-sectional views illustrating one embodiment in which an amorphous carbon film according to the present invention is applied to a manufacturing process of a semiconductor device.

<Explanation of symbols for the main parts of the drawings>

110 semiconductor substrate 120 material layer

130: amorphous carbon film 140: photosensitive film

150: mask

Claims (17)

Loading the substrate into the chamber; And Vaporizing and supplying and ionizing a hydrocarbon compound having a chain structure having one double bond in the liquid state in the chamber to form an amorphous carbon film on the substrate. The amorphous hydrocarbon compound of claim 1, wherein the hydrocarbon compound comprises at least one selected from hexene (C ₆ H ₁₂ ), nonene (C ₉ H ₁₈ ), dodecene (C ₁₂ H ₂₄ ), and pentacene (C ₁₅ H ₃₀ ). Carbon film formation method. The method of claim 1, wherein the hydrocarbon compound is supplied in an amount of 0.3 g / min to 0.8 g / min. The amorphous carbon film forming method of claim 1, wherein the vaporized hydrocarbon compound is ionized by applying a high frequency power of 800 to 2000 W to the chamber. The method of claim 1, wherein a low frequency power of 150 to 400 W is further applied to the chamber. The method of claim 1, wherein the amorphous carbon film is formed by maintaining the pressure of the chamber at 4.5 Torr to 8 Torr. The amorphous carbon film forming method of claim 1, wherein the chamber comprises a shower head supplied with the vaporized hydrocarbon compound and injected therein, wherein the chamber maintains a distance of 250 Mils to 400 Mils between the showerhead and the substrate. The method of claim 1, wherein the amorphous carbon film is formed at a temperature of 300 to 550 ° C. 7. The method of claim 1, wherein the amorphous carbon film is formed at a deposition rate of 15 to 80 kW / sec. 2. The method of claim 1, wherein the amorphous carbon film comprises carbon and hydrogen, wherein the ratio of carbon to hydrogen is controlled in accordance with high frequency power, amount of hydrocarbon compound, chamber pressure, or deposition temperature. The method of claim 10, wherein the hydrogen content of the amorphous carbon film is controlled by further introducing hydrogen or ammonia gas. The method of claim 1, wherein the amorphous carbon film has a refractive index of 1.7 to 2.2 and a light absorption coefficient of 0.1 to 0.5. The method of claim 1, wherein the amorphous carbon film has an etching selectivity ratio of 1 to 5 to 1 40 with an oxide film and an etching selectivity ratio of 1 to 1 to 20 with an nitride film. The method of claim 1, wherein the amorphous carbon film is formed by introducing an inert gas to control a deposition rate and an etching selectivity. Forming a material layer on the substrate on which the predetermined structure is formed; Loading the substrate on which the material layer is formed into a chamber; Vaporizing, supplying and ionizing a chain structured hydrocarbon compound having one double bond in the liquid state to form an amorphous carbon film on the substrate; Forming a photoresist pattern on the amorphous carbon layer, and then etching the amorphous carbon layer using the photoresist pattern as an etching mask; And And removing the amorphous carbon film and the photoresist pattern after etching the exposed material layer. The method of claim 15, wherein the amorphous carbon film is etched by reactive ion etching. The method of claim 15, wherein the amorphous carbon film is a C ₄ F ₈ plasma, oxygen (O ₂ ) plasma and ozone (O ₃ ) plasma, respectively or at least one of the mixture by etching or oxygen and NF ₃ respectively or by mixing a remote plasma A method for manufacturing a semiconductor device etched using a system.

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