JP3456937B2 - Base material composition for lithography - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel undercoat material composition for lithography, and more specifically, it is provided between a substrate and a resist layer to obtain an excimer laser beam, an electron beam,
Even when X-rays are used as a light source, a resist pattern having a rectangular cross-sectional shape can be provided without causing a phenomenon such as bottoming or constriction that occurs at the bottom of the pattern, and a high-resistivity that corresponds to thinning of the photoresist film. The present invention relates to a base material composition for lithography having etch rate characteristics.

[0002]

2. Description of the Related Art When manufacturing a fine semiconductor device by using photolithography, a standing wave caused by reflection of irradiation light from a substrate interferes with the formation of a fine resist pattern. To prevent this, an antireflection film is generally provided between the resist layer and the substrate.

By the way, in recent years, with the miniaturization of semiconductor integrated circuits, the wavelength of irradiation light has been shortened, and excimer laser light such as KrF or ArF, or electron beam or X-ray has come to be used. There has been a need for an antireflection film that responds to such short wavelength light. And
As the antireflection film when using the excimer laser light as irradiation light, a film-forming resin, a composition having a light-absorbing substance for absorbing reflected light and a cross-linking agent for thermally crosslinking them as main constituents Various investigations have been made so far, for example, a base material for lithography containing a crosslinking agent substituted with a hydroxyalkyl group or an alkoxyalkyl group, a benzophenone type, a diphenylsulfone type or a sulfoxide type dye, and an acrylic resin has been proposed. (JP-A-8-87115, JP-A-9-2927)
No. 15, JP-A-10-228113, etc.).

On the other hand, it has been considered to introduce a light-absorbing substituent into the skeleton of the film-forming resin to impart light-absorbing property to the film-forming resin. As such, a quinolinyl group has been used so far. , An antireflective coating composition comprising a resin binder containing a quinolinyl derivative group having a ring substituent having N, O or S as a hetero atom, a phenanthrenyl group, an acridinyl group or an alkylene anthryl group, and a cross-linking agent such as glycoluril ( JP 10-2
No. 04328), a resin obtained by polymerizing an epoxy resin with a dye having a substituent having an anthracene ring, a naphthalene ring, or the like, and an antireflection agent containing a crosslinking agent such as melamine, urea, benzoguanamine, or glycoluril as a main component. An antireflection coating composition mainly composed of two components such as a coating composition (WO97 / 07145) has been proposed.

However, although such a base material and coating composition can suppress the influence of standing waves and improve the cross-sectional shape of the resist pattern to some extent in the conventional pattern size, in recent years, the accuracy is further improved. Is required, the effect is still insufficient for irradiation light of a short wavelength corresponding to a finer pattern dimension,
In the actually formed resist pattern, phenomena such as skirting and constriction occur at the bottom of the pattern, and the reality is that a resist pattern having a rectangular cross section with respect to the substrate cannot be obtained. In addition, regarding a coating composition containing a light-absorbing substance, sublimation of the coating composition to contaminate the device has been proposed as a new problem to be solved. Further, as an antireflection film material, a material composed of hexamethoxymethylmelamine, propylene glycol monomethyl ether acetate and 2,4-dimethylbenzenesulfonic acid has been proposed (JP-A-10-301268),
With such a material, the standing wave cannot be sufficiently suppressed, and it is difficult to control the resist pattern.

[0006]

Under the above circumstances, the present invention can be generated under the pattern even if an excimer laser beam, an electron beam, an X-ray or the like is used as a light source for finer processing. Provide a base material composition for lithography that gives a resist pattern having a rectangular cross-sectional shape to a substrate without causing a phenomenon such as tailing or constriction, and has a high etch rate characteristic corresponding to thinning of a photoresist film It was made for the purpose of doing.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted various researches on a base material composition for lithography applied between a substrate and a resist layer, and as a result, have identified a guanamine derivative having a specific structure or an oligomer thereof. It was found that the composition comprising the organic solvent in which the acid is dissolved is effective in forming a finer pattern, and the present invention has been completed based on this finding.

That is, the present invention provides (A) the general formula

[Chemical 2] (R in the formula is a hydrogen atom or a hydrocarbon group, and R ¹ ,
At least two of R ² , R ³ and R ⁴ are substituents selected from a hydroxyalkyl group and an alkoxyalkyl group, and the rest are hydrogen atoms), or a benzoguanamine derivative or an oligomer thereof represented by B) A base material composition for lithography comprising an organic solvent in which an inorganic acid having a sulfur-containing acid residue, an organic acid or an ester thereof is dissolved.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the base material composition for lithography of the present invention, a benzoguanamine derivative represented by the above general formula (I) or an oligomer thereof is used as the component (A). In the general formula (I), examples of the hydrocarbon group of R include an aliphatic saturated or unsaturated hydrocarbon group, an araliphatic hydrocarbon group, and an aromatic hydrocarbon group. These hydrocarbon groups may be further substituted with another substituent.

The hydroxyalkyl group of R ^{1 to} R ⁴ is preferably a hydroxy lower alkyl group,
A hydroxymethyl group is particularly preferable. On the other hand, the alkoxyalkyl group is preferably a lower alkoxy lower alkyl group, particularly a methoxymethyl group, an ethoxymethyl group,
A propoxymethyl group and a butoxymethyl group are preferred. R ^{1 to} R ⁴ may be the same as each other,
At least two of the hydroxyalkyl groups or alkoxyalkyl groups may be different,
The rest must be hydrogen atoms.

In the benzoguanamine derivative represented by the general formula (I) or its oligomer, one amino group may be substituted with two substituents selected from a hydroxyalkyl group and an alkoxyalkyl group. And each of the two amino groups is a substituent 1 selected from a hydroxyalkyl group and an alkoxyalkyl group.
Although it may be substituted with one or more, the latter is preferred. The benzoguanamine derivative of the general formula (I) or its oligomer may have a substituent such as a carboxyl group or an acyl group in addition to the above-mentioned substituents.
Such a substituent may be present on any of R, R ¹ , R ² , R ³ and R ⁴ .

Examples of such compounds include methoxymethylated benzoguanamine [Cymel 1123, manufactured by Mitsui Cyanamid Co., Ltd. (hereinafter the same)], methoxymethylated butoxymethylated benzoguanamine (Cymel 1123).
-10), butoxymethylated benzoguanamine (Cymel 1128), carboxyl group-containing methoxymethylated ethoxymethylated benzoguanamine (Cymel 1125-
80), a low-nuclear body of benzoguanamine (manufactured by Sanwa Chemical Co., BX55H), and the like. Of these, a carboxyl group-containing methoxymethylated ethoxymethylated benzoguanamine (Cymel 1125-80) is particularly preferable. In the present invention, the benzoguanamine derivative or the oligomer thereof as the component (A) may be used alone or in combination of two or more kinds.

In the composition of the present invention, an inorganic or organic acid having a sulfur-containing acid residue is used as the component (B). As the inorganic acid having the sulfur-containing acid residue, sulfuric acid,
Sulfurous acid, thiosulfuric acid and the like can be mentioned, but sulfuric acid is particularly preferable. On the other hand, an organic acid having a sulfur-containing acid residue is organic sulfonic acid. In addition, examples of such esters include organic sulfates and organic sulfites. Of these, particularly represented by an organic sulfonic acid, for example, a general formula R ⁵ —X (II) (wherein R ⁵ is a hydrocarbon group having no or no substituent, and X is a sulfonic acid group). Preferred compounds are:

In the above general formula (II), the hydrocarbon group represented by R ⁵ preferably has 1 to 20 carbon atoms, and the hydrocarbon group may be saturated or unsaturated, or It may be chain-like, branched or cyclic. As the substituent, for example, a halogen atom such as a fluorine atom, a sulfonic acid group, a carboxyl group, a hydroxyl group,
Examples thereof include an amino group and a cyano group, and one or more of these substituents may be introduced.

The hydrocarbon group of R ⁵ is an aromatic hydrocarbon group,
For example, it may be a phenyl group, a naphthyl group, an anthryl group or the like, but among these, a phenyl group is particularly preferable. The aromatic ring of these aromatic hydrocarbon groups has 1 carbon atom.
One to more than 20 alkyl groups may be bonded. The hydrocarbon group having 1 to 20 carbon atoms may be saturated or unsaturated, and may be linear, branched or cyclic. In addition, this aromatic ring has a halogen atom such as a fluorine atom, a sulfonic acid group,
It may be substituted with one or a plurality of substituents such as a carboxyl group, a hydroxyl group, an amino group and a cyano group. As such an organic sulfonic acid, nonafluorobutane sulfonic acid, methane sulfonic acid, trifluoro methane sulfonic acid, dodecylbenzene sulfonic acid, or a mixture thereof is particularly preferable from the viewpoint of the effect of improving the shape of the lower portion of the resist pattern.

In the composition of the present invention, the inorganic acid, organic acid or ester thereof as the component (B) may be used alone or in combination of two or more kinds, and the blending amount thereof. Depends on the type of acid used,
It is usually 0.1 to 10 relative to 100 parts by weight of the component (A).
Parts by weight, preferably 1 to 8 parts by weight are selected.

The organic solvent used in the composition of the present invention is not particularly limited as long as it can dissolve the components (A) and (B). Examples of such compounds include ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl isoamyl ketone, 2-heptanone, 1,1,1-trimethylacetone, ethylene glycol, ethylene glycol monoacetate, diethylene glycol or Diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, or polyhydric alcohols such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether or monophenyl ether and derivatives thereof,
Cyclic ethers such as dioxane, esters such as ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, etc. You can These may be used alone or in combination of two or more. The amount of these organic solvents to be used is not particularly limited, but the above (A)
It is preferable to use it so that the total concentration of the component and the component (B) is about 5 to 20% by weight.

If desired, a surfactant for improving coating properties and preventing striation can be added to the composition of the present invention. As such a surfactant, Surflon SC-103, SR-100 (manufactured by Asahi Glass Co., Ltd.),
EF-351 (Tohoku Fertilizer Co., Ltd.), Florard Fc-43
1, Florard Fc-135, Florard Fc-98,
Fluorosurfactants such as Fluorad Fc-430 and Fluorad Fc-176 (manufactured by Sumitomo 3M Ltd.) are mentioned, and the addition amount thereof is 2000 ppm based on the solid content of the composition.
It is better to choose within the range below.

The resist base material composition of the present invention may be any resist, whether negative or positive, as long as it can be developed using an alkaline aqueous solution. Examples of such a resist include a positive resist containing a naphthoquinonediazide compound and a novolac resin, a compound that generates an acid upon exposure, a compound that decomposes with an acid and has increased solubility in an alkaline aqueous solution, and an alkali-soluble resin. Positive resist, a compound that generates an acid upon exposure to light, a positive resist that contains an alkali-soluble resin having a group that decomposes by an acid to increase the solubility in an aqueous alkaline solution, a compound that generates an acid upon exposure, and a crosslinking agent , And a negative resist containing an alkali-soluble resin, but the resist is not necessarily limited thereto.

An example of a suitable method of using the base material composition for lithography of the present invention will be described. First, for example, the composition of the present invention is spin-coated on a substrate by a spinner or the like, and then at 100 to 300 ° C. Heat treatment is performed at a temperature to form a base material layer having a thickness of 0.05 to 0.5 μm. At this temperature, the composition of the present invention undergoes a crosslinking reaction and becomes insoluble in an alkaline solution. After the base material layer is formed in this manner, a resist layer is spin-coated with a spinner or the like and dried to form a resist layer. Then, add KrF to it by, for example, a reduction projection exposure apparatus.
Alternatively, radiation such as ArF excimer laser light is applied through a desired mask pattern. Next, a heat treatment is performed, and this is developed using a developing solution, for example, an alkaline aqueous solution such as a 1 to 10 wt% tetramethylammonium hydroxide aqueous solution. For example, the unexposed portion is selectively dissolved and removed, and a resist pattern faithful to the mask pattern is formed.

[0021]

The base material composition for lithography of the present invention is provided between the substrate and the resist layer, so that excimer laser light, electron beam, X-ray or the like is used as a light source for finer processing. Also, it is possible to give a resist pattern having a rectangular cross-sectional shape to the substrate without causing a phenomenon such as skirting or constriction that occurs at the bottom of the pattern.
It has an advantage of having a high etching rate corresponding to the thinning of the photoresist film.

[0022]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 100 g of Cymel 1125-80 (trade name of methoxymethylated ethoxymethylated benzoguanamine containing a carboxyl group, manufactured by Mitsui Cyanamid) and 5 g of dodecylbenzenesulfonic acid were dissolved in 950 g of propylene glycol monomethyl ether to prepare a base material solution. Was prepared. Spin coat the above base material solution on a silicon wafer, and
Drying treatment was performed at 0 ° C. for 90 seconds, and then heating was performed at 180 ° C. for 5 minutes to form a base material layer having a thickness of 1000 Å. Next, a chemically amplified positive photoresist "TDUR-DP604", a chemically amplified positive photoresist "TDUR-P034" or a chemically amplified negative photoresist "TDUR-N908" (both Tokyo Ohka Kogyo Co., Ltd.) is formed on the above-mentioned base material layer. Films manufactured by K.K.) were formed on separate wafers. Reduction projection exposure system Nikon NSR-2005EX8A for each wafer through a mask pattern
(Nikon), and then heat-treated on a hot plate at 130 ° C. for 90 seconds, and then 2.
A photoresist pattern was obtained by developing with a 38 wt% tetramethylammonium hydroxide aqueous solution and washing with pure water. When the obtained resist patterns were observed by SEM (scanning electron microscope), all the cross sections under the resist patterns were vertical.

Example 2 A photoresist pattern was obtained in the same manner as in Example 1, except that methanesulfonic acid was used instead of dodecylbenzenesulfonic acid in the base material solution. When the obtained patterns were observed by SEM (scanning electron microscope), the cross sections under the resist patterns were all vertical.

Example 3 A photoresist pattern was obtained in the same manner as in Example 1, except that nonafluorobutanesulfonic acid was used instead of dodecylbenzenesulfonic acid in the base material solution.
When the obtained patterns were observed by SEM (scanning electron microscope), the cross sections under the resist patterns were all vertical.

Example 4 In Example 1, benzenesulfonic acid monohydrate was used in place of dodecylbenzenesulfonic acid in the base material solution, the addition amount was 3.5 g, and the chemically amplified positive photoresist “TDUR” was used. -DP604 "or" TDUR-P03
4 ”was used to obtain a photoresist pattern by the same method. When the obtained patterns were observed by SEM (scanning electron microscope), the cross sections under the resist patterns were all vertical.

Example 5 In Example 1, 2-naphthalenesulfonic acid monohydrate was used in place of dodecylbenzenesulfonic acid in the base material solution, the addition amount was 3.5 g, and a chemically amplified positive photoresist was used. A photoresist pattern was obtained by the same method except that "TDUR-P034" was used. When the obtained pattern was observed with a SEM (scanning electron microscope), the cross section below the resist pattern was vertical.

Example 6 In Example 1, 1,2-ethanedisulfonic acid was used in place of dodecylbenzenesulfonic acid in the base material solution,
A photoresist pattern was obtained by the same method except that the addition amount was 3.5 g and the chemically amplified positive photoresist "TDUR-DP604" was used. The obtained pattern is S
When observed with an EM (scanning electron microscope), the cross section under the resist pattern was vertical.

Example 7 In Example 1, sulfuric acid was used instead of dodecylbenzenesulfonic acid in the base material solution, and the addition amount was 3.5 g.
Chemically amplified positive photoresist "TDUR-DP60"
4 ”was used to obtain a photoresist pattern by the same method. When the obtained pattern was observed with a SEM (scanning electron microscope), the cross section below the resist pattern was vertical.

Example 8 BX-55H (manufactured by Sanwa Chemical Co., trade name of guanamine oligomer) 1 g, trifluoromethanesulfonic acid 0.1.
1 g of propylene glycol monomethyl ether 24 g
To prepare a base material solution. The above-mentioned base material solution is applied onto a silicon wafer by a spinner, and the temperature is maintained at 150 ° C. for 90 minutes.
By heating for 2 seconds, a base material layer having a film thickness of 1000Å was formed. Next, a film made of a chemically amplified positive photoresist "TArF 6a-37" (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was formed on the base material layer. After exposing the above wafer using an ArF exposure apparatus, the wafer was exposed to 110 ° C. on a hot plate.
At 90 ° C. for 90 seconds, followed by development using a 2.38 wt% tetramethylammonium hydroxide aqueous solution and washing with pure water to obtain a photoresist pattern. Using the obtained photoresist pattern as a mask and an etching apparatus OAPM-406 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), etchant CF ₄ / O ₂ (95 /
5) Etching at a pressure of 200 mTorr, stage temperature of 20 ° C., and high frequency output of 300 W. At that time, the etching rate of the photoresist film and the base material layer (Å /
min) was measured and the photoresist film “TArF
6a-37 ”was 814 Å / min, and the base material layer was 447 Å / min. From this, the selection ratio (etching rate of photoresist layer / etching rate of base material layer) was 1.82.

Comparative Example 1 60 g of bis (4-hydroxyphenyl) sulfone and Cymel 1125-80 (manufactured by Mitsui Cyanamid) 60
g of propylene glycol monomethyl ether 1200
g to prepare a base material solution. This base material solution was applied onto a silicon wafer by spinner, heated at 90 ° C. for 90 seconds, and further heated at 180 ° C. for 90 seconds to form a base material layer having a thickness of 1000 Å. Next, a chemically amplified positive photoresist "TDUR-DP604", a chemically amplified positive photoresist "TDUR-P034" or a chemically amplified negative photoresist "TDUR-N908" (both Tokyo Ohka Kogyo Co., Ltd.) is formed on the above-mentioned base material layer. Films manufactured by K.K.) were formed on different substrates.
Each substrate was exposed using a reduction projection exposure apparatus Nikon NSR-2005EX8A (manufactured by Nikon Corporation) through a mask pattern, and then 130 on a hot plate.
Heat treatment at ℃ for 90 seconds, then 2.38% by weight
A photoresist pattern was obtained by developing with an aqueous solution of tetramethylammonium hydroxide and washing with pure water. Each obtained resist pattern is SEM
When observed with a (scanning electron microscope), the pattern obtained from the positive photoresist has a skirting under the resist pattern, and the pattern obtained from the negative photoresist has a constriction under the resist pattern. Was given.

Comparative Example 2 100 g of hexamethoxymethylmelamine and 5 g of dodecylbenzenesulfonic acid were dissolved in 950 g of propylene glycol monomethyl ether to prepare a base material solution. Using this base material solution, a photoresist pattern was obtained by the same operation as in Comparative Example 1. When each of the obtained patterns was observed by an SEM (scanning electron microscope), the effect of standing waves was great and a resist pattern having a desired line width could not be obtained.

Continuation of front page (56) Reference JP-A-6-118631 (JP, A) JP-A-10-228113 (JP, A) JP-A-11-258814 (JP, A) JP-A-2000-143937 (JP, A) JP 10-69072 (JP, A) JP 10-90880 (JP, A) JP 10-207050 (JP, A) JP 10-301268 (JP, A) (58) Survey Areas (Int.Cl. ⁷ , DB name) G03F 7/11 503 H01L 21/027

Claims (3)

(57) [Claims] 1. A general formula: (R in the formula is a hydrogen atom or a hydrocarbon group, and R ¹ ,
At least two of R ² , R ³ and R ⁴ are substituents selected from a hydroxyalkyl group and an alkoxyalkyl group, and the rest are hydrogen atoms), or a benzoguanamine derivative or an oligomer thereof represented by B) A base material composition for lithography comprising an organic solvent in which an inorganic acid having a sulfur-containing acid residue, an organic acid or an ester thereof is dissolved. 2. The base material composition for lithography according to claim 1, wherein the component (B) contains at least an organic sulfonic acid. 3. The blending amount of the component (B) is 10 parts of the component (A).
The base material composition for lithography according to claim 1, which is 0.1 to 10 parts by weight with respect to 0 parts by weight.