KR20060008493A - Aqueous solution for controlling the size of photoresist pattern and method for forming pattern using the same - Google Patents

Abstract

The present invention relates to an aqueous solution for adjusting the photoresist pattern size and a pattern forming method using the same, forming a photoresist film by applying a photoresist on an etched layer formed on a semiconductor substrate, and soft baking the photoresist film; spraying the photoresist film with (i) water or (ii) water and an aqueous solution for pattern sizing comprising at least one water-soluble compound selected from the group consisting of alcohol compounds, basic compounds and surfactants, and A method of forming a photoresist pattern comprising post-baking a photoresist film, exposing the photoresist film, and developing the exposed photoresist film with a developer.

Description

Aqueous Solution for Controlling the Size of Photoresist Pattern and Method for Forming Pattern Using the Same}

1A to 1D are photographs showing pattern shapes of a short axis, a long axis, a space 1 of a peripheral circuit region, and a space 2 of a peripheral circuit region, respectively, for an island pattern.

2 is a graph showing a simulation result of the long-axis CD change of the pattern according to the amount of base.

The present invention relates to an aqueous solution for adjusting the photoresist pattern size and a pattern forming method using the same, and more particularly, by spraying the aqueous solution for adjusting the photoresist pattern size on the semiconductor substrate in the previous step of the exposure process for forming the photoresist pattern It relates to a pattern forming method that can effectively control the size of the.

In general, the photoresist composition is composed of a photoresist polymer, a photoacid generator and an organic solvent. Recently, a basic compound is added to obtain a vertical photoresist pattern.

On the other hand, the simulation results of the pattern formed by the photolithography process and the result of the size of the pattern formed by the actual process show that many cases are well matched in the cell region of the semiconductor substrate but not in the peripheral circuit region. (See Table 1-1 and Table 1-2 below).

TABLE 1-1

Simulation result (a) Actual patterning result (b)  (a)-(b)  Shortening width 90 nm 93 nm -3 nm  Long shaft width 574 nm 564 nm +10 nm  Space width of the peripheral circuit area (1) 123nm Bridge 146 nm -23 nm  Space width of the peripheral circuit area (2) 124nm Bridge 145 nm -21 nm

TABLE 1-2

Simulation result (a) Actual patterning result (b)  (a)-(b)  Shortening width 90 nm 91 nm -1 nm  Long shaft width 541 nm 524 nm +17 nm  Space width of the peripheral circuit area (1) 133nm Bridge 156 nm -23 nm  Space width of the peripheral circuit area (2) 133nm Bridge 153 nm -20 nm

As such, it is assumed that the amount of basic compound added to the photoresist composition is the main reason for the change in the size of the pattern formed by the actual process compared with the result of the simulation, because it is not properly reflected in the simulation. The error seems to be large.

The present inventors have completed the present invention by performing experiments in which the basic compound is not added to the photoresist composition in the light of the assumption that the basic compound will change the size of the pattern as described above.

An object of the present invention is to provide an aqueous solution for adjusting the size of a photoresist pattern to effectively control the size of a specific pattern using a basic compound and a pattern forming method using the same.

In order to achieve the above object, the present invention provides an aqueous solution for adjusting the size of a photoresist pattern including water and at least one water-soluble compound selected from the group consisting of alcohol compounds, basic compounds and surfactants.

Distilled water is preferably used as water in the aqueous solution.

As the alcohol compound, C ₁ -C ₁₀ alkyl alcohol or C ₁ -C ₁₀ alkoxyalcohol is used. Preferably, the C ₁ -C ₁₀ alkyl alcohol is methanol, ethanol, propanol, isopropanol, n-butanol. , sec-butanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol or 2,2-dimethyl-1-propanol, and the like, and 2- as the alkoxyalcohol of C ₁ -C ₁₀ Methoxy ethanol, 2- (2-methoxyethoxy) ethanol, 1-methoxy-2-propanol or 3-methoxy-1,2-propanediol, and the like are used, these may be used alone or in combination, It is preferable to adjust the usage-amount to 0 to 10 weight% with respect to the whole composition.

When the amount of the alcohol compound exceeds 10% by weight, the effect of melting the coated photoresist film or dissolving the photoacid generator or basic compound, which is a component included in the photoresist composition, may be large.

The alcohol compound is included in the aqueous solution to help the interaction between the aqueous solution and the surface of the hydrophobic photoresist film and to enhance the cleaning effect of the photoacid generator and the base on the surface of the photoresist film.

The basic compound is preferably a weakly basic compound having a pH of 7 to 10, more preferably a pH of 7 to 9, and N-methyl-2-pyrrolidone, polyvinyl alcohol, polyethylene glycol or 18-crown-6. It is preferable to use etc., and the usage-amount is adjusted to 0 to 2 weight% with respect to the whole composition.

If the amount of the basic compound exceeds 2% by weight, the exposure energy (Eop) is too high or there is a problem that the pattern is not formed at all.

The basic compound is included in the aqueous solution to neutralize the acid generated after exposure or serves to suppress the diffusion of the acid through hydrogen bonding.

The surfactant may be any of nonionic, ionic or amphoteric surfactants, but may be poly (ethylene glycol-propylene glycol), polyethylene glycol, polyvinylpyrrolidone, polyoxyethylene alkyl ether or polyoxyethylene alkyl. It is preferable to use an amine ether etc., and it is preferable to adjust the usage-amount to 0-1 weight% with respect to the whole composition.

If the amount of the surfactant exceeds 1% by weight, there is a problem that Eop is too high or a pattern is not formed at all.                     

The surfactant is included in the aqueous solution to enhance the cleaning power or to help the interaction between the aqueous solution and the interface of the photoresist film.

The aqueous solution for adjusting the photoresist pattern size of the present invention is prepared by dissolving at least one water-soluble compound selected from the group consisting of an alcohol compound, a basic compound and a surfactant in water, followed by filtration with a 0.2 μm filter.

The present invention also provides a method of forming a photoresist pattern using the aqueous solution for adjusting the photoresist pattern size:

(a) forming a photoresist film by applying a photoresist on the etched layer formed on the semiconductor substrate;

(b) soft baking the photoresist film;

(c) spraying the photoresist film using an aqueous solution for adjusting the size of the photoresist pattern of the present invention or water;

(d) post-baking the photoresist film;

(e) exposing the photoresist film; And

(f) developing the exposed photoresist film with a developer.

In the above process, the soft bake and post bake process is preferably performed at 70 to 200 ℃.

In addition, the exposure process is an exposure source of 0.1 to 50mJ / cm ² using KrF (248nm), ArF (193nm), VUV (157nm), EUV (13nm), E-beam, X-ray or ion beam as an exposure source It is preferably carried out with energy.

On the other hand, the developing step (c) in the above may be carried out using an alkaline developer, the alkali developer is preferably 0.01 to 5% by weight of tetramethylammonium hydroxide (TMAH) aqueous solution.

In addition, the present invention provides a semiconductor device manufactured using the pattern forming method.

Hereinafter, the present invention will be described in detail by examples. However, the examples are only to illustrate the invention and the present invention is not limited by the following examples.

Preparation Example 1 Preparation of Aqueous Solution for Adjusting Photoresist Pattern Size (1)

0.2 g of N-methyl-2-pyrrolidone (Aldrich) was dissolved in 100 g of distilled water and filtered through a 0.2 μm filter to prepare an aqueous photoresist pattern size solution containing 0.2 wt% of N-methyl-2-pyrrolidone. .

Preparation Example 2 Preparation of Aqueous Solution for Adjusting Photoresist Pattern Size (2)

0.2 g of poly (ethylene glycol-propylene glycol) (Aldrich) was dissolved in 100 g of distilled water, and filtered through a 0.2 μm filter to prepare a photoresist pattern size aqueous solution containing 0.2 wt% of poly (ethylene glycol-propylene glycol).

Comparative Example: Experiment for Observing Magnitude Width, Shortening Width, and Space Width of Peripheral Circuit Area of Island Pattern (1)

Shipley SL4000, a KrF sensitizer, was spin-coated on a silicon wafer and soft baked at 110 ° C. for 90 seconds. After baking, it was post-baked again at 110 ° C. for 90 seconds after exposure with a KrF laser exposure apparatus. After the baking was completed, developed in a 2.38% by weight tetramethylammonium hydroxide aqueous solution for 40 seconds to obtain an island pattern.

Table 2 shows the results of observing the size of the long axis width, short axis width, and space width of the peripheral circuit region of the island pattern obtained above. 1A to 1D show the pattern shapes of the short axis, the long axis, the space 1 of the peripheral circuit region and the space 2 of the peripheral circuit region, respectively, for the island pattern.

Example 1 Experiment for Observing Magnitude, Shortening, and Spacewidth of Peripheral Circuit Region of Island Pattern (2)

Shipley SL4000, a KrF sensitizer, was spin-coated on a silicon wafer and soft baked at 110 ° C. for 90 seconds. After baking, the resultant was sprinkled with distilled water and then post-baked at 110 ° C. for 90 seconds after exposure using a KrF laser exposure apparatus. After the baking was completed, developed in a 2.38% by weight tetramethylammonium hydroxide aqueous solution for 40 seconds to obtain an island pattern.

Table 2 shows the results of observing the size of the long axis width, short axis width, and space width of the peripheral circuit region of the island pattern obtained above.

Example 2 Experiment of Observing the Size of the Long-Axle, Short-Axis-Width and Space-Width of the Peripheral Circuit Area

An island pattern was obtained by performing the same process as in Example 1 except that the aqueous solution prepared in Preparation Example 1 was sprayed instead of distilled water.                     

Table 2 shows the results of observing the size of the long axis width, short axis width, and space width of the peripheral circuit region of the island pattern obtained above.

Example 3 Experiment of Observing the Size of the Long Axle, Short Axle, and Space Width of the Peripheral Circuit Area of the Island Pattern

An island pattern was obtained by performing the same process as in Example 1 except that the aqueous solution prepared in Preparation Example 2 was sprayed instead of distilled water.

Table 2 shows the results of observing the size of the long axis width, short axis width, and space width of the peripheral circuit region of the island pattern obtained above.

[Table 2] Unit: nm

Shortening width Long shaft width Space width of the peripheral circuit area (1) Space width of the peripheral circuit area (2) Eop (mJ / ㎠) simulation 90 574 123 124 Comparative example 93 564 146 145 73 Example 1 92 558 153 159 74 Example 2 93 552 151 157 74 Example 3 90 528 164 164 77

As can be seen from the results obtained from the above examples, an error between the results according to Example 2 using the aqueous solution containing the basic compound N-methyl-2-pyrrolidone according to the present invention and the results by simulation And when comparing the error between the result of the comparative example and the result of the simulation, it can be seen that the change in the size of the pattern was further deepened according to Example 2 with respect to the long axis width and the space width of the peripheral circuit area.

From the above results, in the present invention, since the basic compound is contained in the aqueous solution used before the exposure step, it is confirmed that the basic compound changes much more in the pattern size than the case where the basic compound is contained only in the photoresist composition. It is confirmed that the amount of is the main factor for changing the pattern size.

In addition, when comparing the error between the result of Example 1 using distilled water according to the present invention as well as the basic compound and the result of the simulation and the error of the result of the comparative example and the result of the simulation, the long axis width and According to Example 2, the change in the size of the pattern was further intensified with respect to the space width of the peripheral circuit region, and the same result was obtained with Example 3 using an aqueous solution containing poly (ethylene glycol-propylene glycol) as a surfactant. Appeared.

On the other hand, Eop, which is the last item in Table 2, is the exposure energy whose uniaxial width is 90 nm. In general, as the basicity of the basic compound included in the photoresist composition increases, Eop increases. From Table 2, as Eop increases, the long axis length of the cell region decreases and the space of the peripheral circuit region tends to increase. Able to know.

From the above experimental results, it is shown that the amount of basic compound included in the photoresist directly affects the long axis length or the space width of the pattern. On the other hand, the simulation result using Solid-C as a simulation tool on the 90nm Brickwall pattern considering the amount of base, the long axis length was decreased as the amount of the basic compound increases, and thus the experimental results Was found to be consistent with the simulation (see FIG. 2).                     

As a result, in the present invention, it is proved that the size of the pattern of the basic compound is changed, but the size of the pattern is not only included in the photoresist composition but also in the aqueous solution used before the exposure process. You can effectively control the size of certain patterns. In addition, the amount of basic compound can be reflected in the simulation performed before the photolithography process.

As described above, in the present invention, when the photoresist pattern is formed by performing a photolithography process, water is selected from the group consisting of an alcohol compound, a basic compound, and a surfactant in water or water in the pre-exposure step after the soft baking process. By spraying an aqueous solution for photoresist pattern size adjustment containing one or more water-soluble compounds on the wafer surface, the long axis length of the island pattern can be adjusted, and the space between patterns can be adjusted.

Claims (11)

An aqueous solution for adjusting the size of a photoresist pattern comprising water and at least one water-soluble compound selected from the group consisting of alcohol compounds, basic compounds and surfactants. The method of claim 1, The alcohol compound is a C ₁ -C ₁₀ alkyl alcohol and C ₁ -C ₁₀ An aqueous solution for adjusting the size of a photoresist pattern, which is used alone or in combination, selected from the group consisting of alkoxyalcohols. The method of claim 2, The alkyl alcohol of C ₁ -C ₁₀ is methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol and 2,2-dimethyl Aqueous solution for photoresist pattern sizing, characterized in that it is selected from the group consisting of -1-propanol. The method of claim 2, The C ₁ -C ₁₀ alkoxyalcohol consists of 2-methoxyethanol, 2- (2-methoxyethoxy) ethanol, 1-methoxy-2-propanol and 3-methoxy-1,2-propanediol An aqueous solution for adjusting the photoresist pattern size, characterized in that it is selected from the group. The method of claim 1, The basic compound has a pH of 7 to 10, characterized in that the aqueous solution for adjusting the size of the photoresist pattern. The method of claim 5, The basic compound is N-methyl-2-pyrrolidone, polyvinyl alcohol, polyethylene glycol and 18-crown-6 aqueous solution for adjusting the size of the photoresist pattern, characterized in that selected from the group consisting of. The method of claim 1, The surfactant is selected from the group consisting of poly (ethylene glycol-propylene glycol), polyethylene glycol, polyvinylpyrrolidone, polyoxyethylene alkyl ether and polyoxyethylene alkylamine ether solution for adjusting the photoresist pattern size . The method of claim 1, The amount of the alcohol compound is 0 to 10% by weight based on the total composition, the amount of the basic compound is 0 to 2% by weight based on the total composition, the amount of the surfactant is 0 to 1% by weight based on the total composition Aqueous solution for photoresist pattern size adjustment characterized by the above-mentioned. (a) forming a photoresist film by applying a photoresist on the etched layer formed on the semiconductor substrate; (b) soft baking the photoresist film; (c) spraying the photoresist film using water or an aqueous solution of claim 1; (d) post-baking the photoresist film; (e) exposing the photoresist film; And and (f) developing the exposed photoresist film with a developer. The method of claim 9, The exposure source of the (e) exposure step is selected from the group consisting of KrF (248 nm), ArF (193 nm), VUV (157 nm), EUV (13 nm), E-beam, X-ray or ion beam. Resist Pattern Formation Method. A semiconductor device manufactured using the method of claim 9.

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