KR20010018906A - Organic polymer used for prevention of random reflection and process for preparation thereof - Google Patents

Abstract

PURPOSE: An organic polymer for preventing diffuse reflection is provided for blocking reflection at bottom layer of photoresist film in ultra-micro pattern process of semiconductor field. CONSTITUTION: An organic polymer for preventing diffuse reflection is prepared by comprising a polymer of formula 1 as hardening agent and a polyvinylphenol as photo-absorbing agent. The organic polymer film has improved absorbency for far-infrared ray to remarkably reduce standing wave effect. In formula, where R1 and R2 represent displaced branched chain or main chain alkyl groups having 1-10 carbon atoms, and R3 is hydrogen or methyl group. The organic polymer is available in ultra-micro pattern forming process using substantially ArF(193nm) light source.

Description

Organic anti-reflective coating polymer and its manufacturing method {Organic polymer used for prevention of random reflection and process for preparation}

The present invention relates to a polymer for an organic anti-reflective coating that can prevent reflection in a lower layer of a photoresist film in an ultra-fine pattern forming process of a semiconductor manufacturing process, and more particularly, a polymer used as a curing agent of an organic anti-reflective coating and The present invention relates to an organic anti-reflective coating composition comprising a light absorbent, a thermal acid generator, and an organic solvent together with the polymer.

In the ultra-fine pattern forming process, CD (Critical Dimension) by standing wave and reflective notching due to the optical properties of the lower layer of the photoresist layer and the variation of the resist thickness and diffraction and reflected light from the lower layer Fluctuations inevitably occur. Therefore, an anti-reflection film that can prevent reflection in the lower layer by introducing a material that absorbs light well in the wavelength range of light used as the exposure source can be used in the microfabrication process by laminating it under the photoresist.

When the ultraviolet light is received from the light source, light transmitted through the photoresist film is scattered or reflected from the lower part of the photoresist film. The organic anti-reflective film absorbs the scattered or reflected light and directly affects the microprocessing of the photoresist. Given.

The antireflection film can be largely classified into inorganic antireflection film and organic antireflection film according to the type of material, and can be divided into absorbing antireflection film and interferometer antireflection film according to the mechanism.

In the micropattern forming process using i line (365 nm), inorganic antireflection films have been mainly used. Among them, TiN and amorphous carbon (a-C) are used as the antireflective films, and SiON is mainly used as the antireflection films. In addition, in the ultrafine pattern formation using KrF light (248 nm), SiON, which is an inorganic antireflection film, was mainly used, but an organic antireflection film was also often used.

However, in the ultrafine pattern formation process using ArF light, no suitable antireflection film has been developed. In the case of the inorganic anti-reflection film, a material for controlling the interference at 193 nm, which is a light source, has not been published yet. Recently, efforts have been made to develop an organic material that can be used as an anti-reflection film.

Generally, the basic conditions that the organic anti-reflective coating should have are as follows.

First, there should be no phenomenon that the antireflection film is dissolved and peeled off by the photoresist solvent during the process application. To this end, the molded film must be designed to achieve a crosslinked structure, and chemicals should not be generated at this time.

Second, there should be no entry of chemicals such as acids or amines from the antireflection film. In the case of positive photoresist, when acid is migrated from the anti-reflection film to the photoresist film of the non-exposed part, undercutting occurs at the bottom of the photoresist pattern, and footing is performed when base such as amine is transferred to the photoresist film. ) Tends to cause symptoms.

Third, the anti-reflection film should have a relatively high etching rate compared to the upper photoresist film, so that the etching process can be performed smoothly using the photoresist film as a mask during etching.

Fourth, the anti-reflection film should be able to function as an anti-reflection film sufficiently thin as possible.

Accordingly, the present inventors have continued research to develop suitable organic antireflective coating resins, and have developed an antireflective coating resin that satisfies all the above requirements and can be used to form an ultrafine pattern using ArF light. The invention has been completed.

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic anti-reflective coating polymer and an organic anti-reflection coating composition comprising the same, which are mainly used in an ultra-fine pattern forming process using an ArF (193 nm) light source during a semiconductor manufacturing process.

1 is a graph measuring the absorbance of the organic anti-reflective coating of the present invention,

2 shows a pattern obtained using the organic anti-reflective coating composition of Example 5,

3 shows a pattern obtained using the organic anti-reflective coating composition of Example 6,

4 shows a pattern obtained using the organic anti-reflective coating composition of Example 7,

5 shows a pattern obtained using the organic anti-reflective coating composition of Example 8,

6 shows a pattern obtained when no organic diffuse reflection prevention film is used,

7 illustrates the mechanism of action of the organic anti-reflective coating composition of the present invention by way of example.

In order to achieve the above object, in the present invention, a polymer that can be used as a curing agent of the organic diffuse reflection prevention film; And an organic anti-reflective coating composition comprising a polyvinylphenol, a thermal acid generator, and an organic solvent, which are light absorbents, together with the polymer.

Hereinafter, the present invention will be described in detail.

First, the present invention provides a polymer represented by the following Chemical Formula 1, which may be used as a curing agent of an organic anti-reflective coating layer when forming an ultrafine pattern of a semiconductor device.

[Formula 1]

Wherein R ₁ and R ₂ are branched or main chain substituted alkyl groups having 1 to 10 carbon atoms, and R ₃ is hydrogen or methyl.

The compound of Formula 1 is preferably selected from the group consisting of compounds of Formulas 2 to 5.

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

The compounds of Formulas 2 to 5 cure very well in the presence of acids and other polymers having alcohol groups.

Compound (1) is prepared by (a) polymerizing (meth) acrolein to produce a poly (meth) acrolein; Next, (b) the resultant is prepared by reacting with a side or main chain substituted alkyl alcohol having 1 to 10 carbon atoms.

In step (a), (meth) acrolein is dissolved in an organic solvent, and a polymerization initiator is added thereto, followed by polymerization for 4 to 6 hours at a temperature of 60 to 70 ° C. under vacuum to prepare poly (meth) acrolein.

The polymerization solvent may be a single solvent or a mixed solvent selected from the group consisting of tetrahydrofuran (THF), cyclohexanone, dimethylformamide, dimethyl sulfoxide, dioxane, methyl ethyl ketone, benzene, toluene and xylene.

In addition, the polymerization initiator is 2,2'-azobisisobutyronitrile (AIBN), benzoyl peroxide, acetyl peroxide, lauryl peroxide, t- butyl peracetate, t- butyl hydroperoxide and di-t- Preference is given to using those selected from the group consisting of butyl peroxide.

On the other hand, in step (b), the resultant of step (a) and the branched or main chain substituted alkyl alcohol having 1 to 10 carbon atoms as a catalyst of trifluoromethyl sulfonic acid at room temperature for 20 to 30 hours to react the compound of formula 1 To prepare a side chain or main chain substituted alkyl alcohol of 1 to 10 carbon atoms is preferably methanol or ethanol.

In another aspect, the present invention provides an organic anti-reflective coating composition comprising a compound of the formula (1) as a curing agent, a polyvinylphenol of the formula (6) as a light absorber, a thermal acid generator and an organic solvent.

[Formula 6]

It is preferable that a thermal acid generator is a compound of following General formula (7).

[Formula 7]

The organic solvent is also selected from the group consisting of methyl 3-methoxypropionate (MMP), ethyl 3-ethoxypropionate (EEP), propylene glycol methyl ether acetate (PGMEA) and cyclohexanone.

In the organic anti-reflective coating composition, the polymer of Formula 1 is contained in an amount of 0.3 to 10% by weight based on the organic solvent, the light absorbing agent is 50 to 250% by weight based on the polymer of Formula 1, and the thermal acid generator is 0.5 to the polymer of Formula 1 It is preferable that it is contained by -40 weight%.

When a composition including the above components is applied onto a wafer and a thermal process (baking process) is performed, an acid is generated from a thermal acid generator, and the compound of Chemical Formula 1 is a light absorber by the acid generated as described above. Since it cross-links with polyvinylphenol and hardens to form an organic anti-reflective film, when ultraviolet rays penetrate the photoresist and reach the organic anti-reflective film, light is absorbed. At this time, the organic diffuse reflection prevention film is prevented from being dissolved by the photoresist solution applied thereon due to the crosslinking by the compound of Formula 1, and absorbs far ultraviolet rays by the compound of Formula 6. This mechanism of action is illustrated in FIG. 7, for example.

The present invention also provides a pattern forming method using the organic anti-reflective composition, the method includes the following steps:

(a) applying the organic anti-reflective coating composition on the etched layer;

(b) curing the bake process to form an organic anti-reflective coating;

(c) coating a photoresist on the organic anti-reflective coating, exposing the photoresist, and developing the photoresist pattern to form a photoresist pattern; And

(d) etching the organic anti-reflective coating using the photoresist pattern as an etching mask, and etching the etching target layer to form an etching target layer pattern.

The baking process of step (b) is performed for 1 to 5 minutes at a temperature of 150 to 250 ℃.

In addition, i) before and after exposure of step (c); Or ii) pre- or post-exposure each of which may further comprise a baking process, which is carried out at 70 to 200 ° C.

In addition, the exposure process is performed using an exposure energy of 0.1 to 20 mJ / cm ² using a deep ultra violet (DUV; E-beam, X-ray or ion beam including ArF, KrF and EUV as a light source. .

In particular, the antireflection film of the present invention can effectively prevent reflection from the underlying film layer when applied to an ultrafine pattern formation process using 193 nm ArF light as an exposure source, thereby significantly reducing the standing wave effect.

In addition, the present invention provides a semiconductor device manufactured by forming a pattern using the organic diffuse reflection prevention film.

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.

I. Preparation of Curing Agent Polymer

Example 1

100 g of acrolein, 66 g of THF, and 2 g of AIBN were placed in a 500 ml round bottom flask, made in a vacuum state, and reacted at 65 ° C. for 5 hours. Wipe several times with ethyl ether (yield 80%). 80 g of this white solid and 500 g of methanol were put in a 1000 ml round bottom flask, and 1 ml of trifluoromethyl sulfonic acid was added as a catalyst, followed by reaction at room temperature (25 ° C.) for 24 hours. The white solid (poly acrolein) that was not initially dissolved is dissolved in methanol as the reaction is completed. After completion of the reaction, the absorption spectrum of 1690 cm ^-1 disappeared from the IR Spectrum, neutralized with triethylamine, methanol was removed by distillation to make it thick, and the precipitate was caught in distilled water. Drying in vacuo afforded the compound of formula 2 (yield 65%).

Molecular weight 6,820; Polydispersity 1.60;

¹ H NMR 1.2-2.1 ppb (3H), 3.0-3.8 ppb (6H), 3.8-4.7 (1H).

Example 2)

A polymer similar to that of Chemical Formula 3 was obtained in the same manner as in Example 1 except for using methacrolein instead of acrolein (yield 65%).

Molecular weight 6,800; Polydispersity is 1.63;

¹ H NMR 1.2-2.1 ppb (5H), 3.0-3.8 ppb (6H), 3.8-4.7 (1H).

Example 3

Except for using ethanol instead of methanol in the same manner as in Example 1 to obtain a polymer of the formula (4) (yield 60%).

Molecular weight 7,010; Polydispersity is 1.78;

¹ H NMR 1.2-2.1 ppb (9H), 3.0-3.8 ppb (4H), 3.8-4.7 (1H).

Example 4

A polymer as in Chemical Formula 5 was obtained in the same manner as in Example 1, except that ethanol was used instead of methanol, and methacrolein was used instead of acrolein (yield 61%).

Molecular weight 7,200; Polydispersity 2.0;

¹ H NMR 1.2 to 2.1 ppb (11H), 3.0 to 3.8 ppb (4H), 3.8 to 4.7 (1H).

Compounds of Examples 1 to 4 represented by the formula (1) is very hard to occur in the presence of the acid and other polymer having an alcohol group.

II. Preparation of organic diffuse reflection prevention film composition

Example 5

0.57 g of the curing agent of Formula 2 prepared in Example 1 and 1.0 g of polyvinylphenol of Formula 6 were prepared with 4 g of propylene glycol methyl ether acetate solvent, 10 g of methyl 3-methoxy propionate solvent, 10 g of 2-heptanone solvent, and tetrahydro. It was dissolved in a mixed solvent of 7 g of furan solvent. 0.1 g of the acid generator of Chemical Formula 7 was added thereto, and then dissolved, and then passed through a 0.2 μm microfilter to prepare an organic anti-reflective coating composition.

Example 6

An organic anti-reflective coating composition was prepared in the same manner as in Example 5, except that the curing agent of Chemical Formula 3 was used instead of Chemical Formula 2.

Example 7

An organic anti-reflective coating composition was prepared in the same manner as in Example 5, except that the curing agent of Formula 4 was used instead of Formula 2.

Example 8

An organic anti-reflective coating composition was prepared in the same manner as in Example 5 except for using the curing agent of Formula 5 instead of Formula 2.

III. Absorbance measurement

Example 9

The organic anti-reflective coating composition prepared in Example 5 was spin coated on a quartz wafer and then baked at 205 ° C. for 2 minutes to cure. As a result of measuring the absorbance against UV after curing, the absorbance was very good at 0.8 nm at 193 nm (see FIG. 1). This shows that the composition of the present invention has suitable properties as an organic anti-reflective coating.

On the other hand, the absorbance for the 193nm was due to the polyvinylphenol of the formula (6) used as the light absorber, so the absorbance evaluation experiments for Examples 6 to 8 were not performed.

Ⅳ. Pattern formation

Example 10)

The organic diffuse reflection prevention film composition prepared in Example 5 was spin coated on a silicon wafer, and then baked by curing at 205 ° C. for 2 minutes. The DHA1001 photosensitive agent was coated on the cured organic anti-reflective coating and then baked at 110 ° C. for 90 seconds. After baking, the resultant was exposed using an ArF microstepper manufactured by ISI, and then baked again at 110 ° C. for 90 seconds. This wafer was developed using a 2.38 wt% developer to obtain a good vertical pattern as shown in FIG. 2.

Example 11

A good vertical pattern as in FIG. 3 was obtained in the same manner as in Example 10 except for using the organic anti-reflection coating composition prepared in Example 6 instead of the organic anti-reflection coating composition prepared in Example 5. .

Example 12)

A good vertical pattern as in FIG. 4 was obtained in the same manner as in Example 10 except for using the organic anti-reflective coating composition prepared in Example 7 instead of the organic anti-reflective coating composition prepared by Example 5. .

Example 13

A good vertical pattern as in FIG. 5 was obtained in the same manner as in Example 10 except for using the organic anti-reflection coating composition prepared in Example 8 instead of the organic anti-reflection coating composition prepared in Example 5.

Comparative example)

Unlike Examples 10 to 13, the DHA1001 photosensitive agent was coated directly on the silicon wafer without using an organic anti-reflective coating, and then baked at 110 ° C. for 90 seconds. After baking, the wafer was exposed using an ArF microstepper of ISI, and then baked again at 110 ° C. for 90 seconds. As a result of developing the wafer using a developer of 2.38 wt%, the sine wave effect was observed on the sidewalls of the pattern as shown in FIG. In other words, when the organic anti-reflective coating is not used, the reflection is generated on the silicon wafer, which adversely affects the profile of the pattern.

Comparing Examples 10 to 13 and Comparative Example as described above, it was found that the organic anti-reflective coating had a good property of absorbing light at 193 nm to eliminate the sine wave effect.

As described above, the curing agent of Chemical Formula 1 of the present invention forms an excellent organic anti-reflective film together with a compound having an alcohol group and a polyvinylphenol which is a light absorbing agent as a compound that hardens well, and is dissolved in a photoresist solution applied thereon. It is possible to significantly reduce the sine wave effect by absorbing the light in the far ultraviolet region which has passed through the photoresist film very well without being influenced by it.

Therefore, the patterns formed by using the organic anti-reflective coating of the present invention have a very excellent pattern shape, thereby further contributing to high integration of the semiconductor.

Claims (19)

In forming an ultrafine pattern of a semiconductor device, the polymer for an organic antireflection coating of the formula (1), characterized in that it is used as a curing agent of the organic antireflection coating. [Formula 1] Wherein R ₁ and R ₂ are branched or main chain substituted alkyl groups having 1 to 10 carbon atoms, and R ₃ is hydrogen or methyl. The method of claim 1, The compound of formula 1 is an organic anti-reflective coating polymer, characterized in that selected from the group consisting of the compound of formula 2 to formula 5. [Formula 2] [Formula 3] [Formula 4] [Formula 5] (a) polymerizing (meth) acrolein to produce poly (meth) acrolein; And (b) reacting the resultant with a side chain or main chain substituted alkyl alcohol having 1 to 10 carbon atoms. The method for preparing an organic anti-reflective coating polymer of Chemical Formula 1 used as a curing agent of the organic anti-reflective coating. [Formula 1] Wherein R ₁ and R ₂ are branched or main chain substituted alkyl groups having 1 to 10 carbon atoms, and R ₃ is hydrogen or methyl. The method of claim 3, wherein In the step (a), (meth) acrolein is dissolved in an organic solvent, and a polymerization initiator is added thereto, followed by reaction for 4 to 6 hours at a temperature of 60 to 70 ° C. in a vacuum state, for the organic antireflection coating of Chemical Formula 1 Method of Making Polymers. The method of claim 4, wherein The organic solvent is a tetrahydrofuran (THF), cyclohexanone, dimethylformamide, dimethyl sulfoxide, dioxane, methyl ethyl ketone, benzene, toluene and xylene, characterized in that the sole solvent or a mixed solvent selected from the group consisting of Method for producing a polymer for organic diffuse reflection prevention film of formula (1). The method of claim 4, wherein The polymerization initiator is 2,2'-azobisisobutyronitrile (AIBN), benzoyl peroxide, acetyl peroxide, lauryl peroxide, t-butyl peracetate, t-butyl hydroperoxide and di-t-butyl Method for producing a polymer for organic diffuse reflection film of formula (1), characterized in that selected from the group consisting of peroxides. The method of claim 3, wherein The side chain or main chain substituted alkyl alcohol having 1 to 10 carbon atoms of step (b) is methanol or ethanol. The method of claim 3, wherein Step (b) is a chemical formula characterized in that the reaction of the product of step (a) and the side chain or main chain substituted alkyl alcohol of 1 to 10 carbon atoms with trifluoromethyl sulfonic acid as a catalyst for 20 to 30 hours at room temperature The manufacturing method of the polymer for organic anti-reflective films of 1. An organic anti-reflective coating composition comprising a compound of formula 1 as a curing agent, a polyvinylphenol of formula 6 as a light absorber, a thermal acid generator, and an organic solvent. [Formula 1] Wherein R ₁ and R ₂ are branched or main chain substituted alkyl groups having 1 to 10 carbon atoms, and R ₃ is hydrogen or methyl. [Formula 6] The method of claim 9, The thermal acid generator is an organic diffuse reflection prevention film composition, characterized in that the compound of formula (7). [Formula 7] The method of claim 9, The organic solvent is selected from the group consisting of methyl 3-methoxypropionate (MMP), ethyl 3-ethoxypropionate (EEP), propylene glycol methyl ether acetate (PGMEA) and cyclohexanone. Anti-reflective coating composition. The method of claim 9, The polymer of Chemical Formula 1 is contained in an amount of 0.3 to 10% by weight based on the organic solvent, the light absorbing agent is contained in an amount of 50 to 250% by weight based on the polymer of Chemical Formula 1, and the thermal acid generator is 0.5 to 40% by weight based on a polymer of Formula 1 An organic diffuse reflection prevention film composition, characterized by the above-mentioned. (a) applying the organic anti-reflective coating composition of claim 9 over the etched layer; (b) curing the bake process to form an organic anti-reflective coating; (c) coating a photoresist on the organic anti-reflective coating, exposing the photoresist, and developing the photoresist pattern to form a photoresist pattern; And and (d) etching the organic antireflection film using the photoresist pattern as an etch mask, and etching the etched layer to form an etched layer pattern. The method of claim 13, The baking process of step (b) is an organic diffuse reflection prevention film pattern forming method, characterized in that performed for 1 to 5 minutes at a temperature of 150 to 250 ℃. The method of claim 13, I) pre-exposure and post-exposure of step (c); Or ii) performing a baking process before or after exposure, respectively. The method of claim 15, The baking process is an organic diffuse reflection prevention film pattern forming method, characterized in that carried out at 70 to 200 ℃. The method of claim 13, The exposure process is an organic anti-reflective film pattern forming method using a deep ultraviolet (DUV; E-beam, X-ray or ion beam including ArF, KrF and EUV as a light source. The method of claim 13, The exposure process is an organic anti-reflective film pattern forming method characterized in that carried out with an exposure energy of 0.1 to 20 mJ / cm ² . A semiconductor device manufactured by the method of claim 13.