JP2011145557A - Developing solution for photolithography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing solution for photolithography which has smaller swelling action on a resist pattern and restrains a contained component from being precipitated. <P>SOLUTION: (A) the developing solution for photolithography contains a basic compound represented by a general formula (1), wherein R<SP>1</SP>and R<SP>2</SP>combine with each other to form an aliphatic cyclic structure which may include a hetero atom, and R<SP>3</SP>and R<SP>4</SP>are each alkyl groups which may have branches, or combine with each other to form an aliphatic cyclic structure which may have a hetero atom, and the total number of the carbon atoms included in R<SP>1</SP>-R<SP>4</SP>respectively is 6-13. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a developer for photolithography.

  In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has rapidly progressed due to the advancement of photolithography technology. Such a fine pattern is achieved by miniaturizing a resist pattern formed on the surface of a substrate or the like. The resist pattern is formed by forming a resist film made of a resist composition containing a photosensitive compound on the surface of a substrate or the like, and a light, electron beam through a mask pattern in which a predetermined pattern is formed on the resist film. It is produced by performing selective exposure with an active energy ray such as a developing process. At this time, a portion of the resist film corresponding to a figure provided on the mask pattern becomes a resist pattern. Then, for example, a semiconductor element is manufactured through a process of processing the substrate by etching using this resist pattern as a mask. Among the above resist compositions, a resist composition that changes to a property in which the exposed portion dissolves in the developer is referred to as a positive type, and a resist composition that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.

  In the development process of the semiconductor element manufacturing process, an alkaline aqueous solution of tetramethylammonium hydroxide (TMAH) is commonly used as the developer. TMAH is preferably used in the production of semiconductor elements because it does not contain metal ions that affect the semiconductor elements. However, when the degree of integration of semiconductor elements increases and the half pitch (HP) size becomes 49 nm or less, the swelling phenomenon that TMAH swells the resist pattern during development becomes a problem. When the resist pattern is swollen by TMAH, the rectilinearity of the resist pattern is reduced, or the resist pattern is tilted in the cleaning process after development, which causes a reduction in pattern reproducibility.

  For this reason, Non-Patent Document 1 proposes that an aqueous solution of tetrabutylammonium hydroxide (TBAH) is used as a developer instead of an aqueous solution of TMAH. By using an aqueous solution of TBAH as the developing solution, the swelling phenomenon of the resist pattern during development is alleviated, and the reproducibility of the pattern is improved.

The 70th JSAP Academic Lecture Presentation 2, 635 pages, Study of new developer for EUV resist, Semiconductor Leading Edge Technologies, Julius Joseph Santillan, Toshiro Iya

  By the way, TBAH is less soluble in water than TMAH that has been used in conventional developers. As a result of investigation and examination by the present inventors, when the TBAH is an aqueous solution of 0.262N (6.79% by mass), which is a concentration used as an example of a developer, the precipitation temperature is about 5 ° C. Therefore, the possibility of precipitation during development is small, but in the case of an aqueous solution of around 30% by mass, the precipitation temperature becomes maximum and is around 27 ° C. For this reason, TBAH contained in the developer may be precipitated when the concentrated developer is transported or when the concentrated developer is diluted. Even in the case of a 0.262N aqueous solution having a concentration used as an example of a developer, TBAH contained in the developer may be precipitated during transportation in the winter. TBAH deposited in the developer does not easily re-dissolve unless heating or the like is performed. Therefore, the developer with TBAH deposited cannot be used in the developing process as it is, and a troublesome operation such as filter operation is required. Further, if the deposited TBAH is removed by a filter, the concentration of TBAH contained in the developer changes, which causes a problem that the concentration management of the developer becomes complicated.

  The present invention has been made in view of the above circumstances. First, it is intended to provide a photolithography developer that has a small swelling effect on a resist pattern and that suppresses precipitation of contained components. Objective. Another object of the present invention is to provide a photolithography developer that has a small swelling effect on a resist pattern and that suppresses precipitation of components contained in a concentrated state.

  As a result of intensive studies to solve the above problems, the present inventors have used a basic compound having a cyclic structure in the molecule as a basic compound that imparts basic liquidity to the developer. The inventors have found that the suppression of the swelling of the resist pattern and the suppression of the precipitation of the components contained in the developer can both be achieved, and the present invention has been completed.

  A first aspect of the present invention is (A) a developer for photolithography containing a basic compound represented by the following general formula (1).

（上記一般式（１）中、Ｒ^１及びＲ^２は、互いに結合してヘテロ原子を含んでもよい脂肪環構造を形成し、Ｒ^３及びＲ^４は、分枝を有してもよいアルキル基、又は、互いに結合してヘテロ原子を含んでもよい脂肪環構造を形成する。また、上記一般式（１）中、Ｒ^１〜Ｒ^４にそれぞれ含まれる炭素原子の数の和は、６〜１３である。）

(In the general formula (1), R ¹ and R ² are bonded to each other to form an alicyclic structure which may contain a hetero atom, and R ³ and R ⁴ are alkyl groups which may have a branch. In addition, in the general formula (1), the sum of the number of carbon atoms contained in each of R ^{1 to} R ⁴ is 6 to 13 .)

  The second aspect of the present invention is a resist pattern forming method using the photolithography developer of the first aspect.

  According to the present invention, firstly, there is provided a photolithography developer that has a small swelling effect on a resist pattern and that suppresses precipitation of components contained therein. In addition, according to the present invention, secondly, there is provided a photolithography developer that has a small swelling effect on a resist pattern and that suppresses precipitation of contained components in a concentrated state.

  The photolithography developer of the present invention will be described below. The developer for photolithography of the present invention is a development in which a resist composition film containing a photosensitive compound is selectively exposed with active energy rays such as ultraviolet rays and electron beams, and then an alkali-soluble portion is dissolved and removed from the resist film. Used in processing. By undergoing such processing, the resist film becomes a resist pattern having a predetermined pattern shape. The developer of the present invention is preferably used in the formation of an ultrafine resist pattern for forming a fine semiconductor element having a half pitch (HP) size of 49 nm or less, in which the resist pattern swells. It may be used for forming a semiconductor element having a half pitch size larger than that, or may be used for forming a color filter other than the semiconductor element, for example, for a liquid crystal display device.

  The developer of the present invention contains (A) a basic compound represented by the above general formula (1), and preferably contains (B) tetrabutylammonium hydroxide (TBAH) and (C) a solubilizing component. Hereinafter, these components will be described.

[(A) Basic compound]
The basic compound used as the component (A) in the developer of the present invention is a compound represented by the following general formula (1), and is an alkaline solution necessary for developing a resist film after exposure processing. Imparts properties to the developer. If the resist film is a positive resist that is alkali-insoluble in the unexposed state, the exposed portion changes to alkali-soluble, and if it is a negative resist that is alkali-soluble in the unexposed state, the exposed portion changes to alkali-insoluble. To do. Therefore, by processing with an alkaline developer after exposure, an alkali-insoluble portion remains as a resist pattern. In order to impart an alkaline liquid property required for such processing to the developer, the component (A) is added to the developer.

  As already described, tetramethylammonium hydroxide (TMAH) is generally used to impart alkaline liquidity to the developer, but TMAH has the property of slightly swelling the resist pattern. . The swelling action of the resist pattern by TMAH was hardly a problem when a pattern having a half pitch size of 50 nm or more was produced. However, when a pattern having a half pitch size of less than 50 nm was produced, It may cause problems such as reduced straightness and pattern collapse. For this reason, in this invention, the said (A) component whose swelling property with respect to a resist pattern is smaller than TMAH is used as a compound for providing alkaline liquid property to a developing solution. Since the component (A) has a smaller effect of swelling the resist pattern than TMAH, the use of the developer of the present invention containing the component suppresses the swelling of the resist pattern by the developer.

  In addition, as already described, in order to suppress swelling of the resist pattern by the developer, in Non-Patent Document 1, tetrabutylammonium hydroxide (TBAH) may be used as a basic compound in the developer. Proposed. However, TBAH is poorer in water solubility than TMAH that has been used as a basic compound. For this reason, in the developer using TBAH, TBAH may be precipitated during transportation and concentration in winter. In this regard, the developer of the present invention uses the component (A), which is more water-soluble than TBAH, as a basic compound, so that precipitation of components during transportation or in a concentrated state is suppressed.

  For the above reasons, in the developer of the present invention using the component (A) as the basic compound, suppression of swelling with respect to the resist pattern and suppression of precipitation of components contained in the developer are compatible. And in the developing solution of this invention, precipitation of the component contained in a developing solution is suppressed also in a concentrated state.

In the general formula (1), R ¹ and R ² are bonded to each other to form an alicyclic structure that may contain a hetero atom, and R ³ and R ⁴ are alkyl groups that may have a branch, Alternatively, they are bonded to each other to form an alicyclic structure that may contain a hetero atom. In the general formula (1), the sum of the number of carbon atoms contained in each of R ^{1 to} R ⁴ is 6 to 13. In the general formula (1), when R ¹ and R ² form an alicyclic structure, swelling of the resist pattern is suppressed. Here, the alicyclic structure formed by bonding R ¹ and R ² to each other includes a nitrogen atom to which R ¹ and R ² are bonded together as shown in the general formula (1). In addition to the nitrogen atom, the alicyclic structure may contain heteroatoms such as a nitrogen atom, an oxygen atom, and a sulfur atom. That is, R ¹ and / or R ² may contain a hetero atom such as a nitrogen atom, an oxygen atom, or a sulfur atom. This is the same even when R ³ and R ⁴ are bonded to each other to form an alicyclic structure, and R ³ and / or R ⁴ includes a hetero atom such as a nitrogen atom, an oxygen atom, or a sulfur atom. May be. Moreover, when the sum of the number of carbon atoms contained in R ^{1 to} R ⁴ is in the above range, the component (A) has a good balance between solubility in the developer and suppression of swelling of the resist pattern.

Knowledge that the present invention can suppress swelling of the resist pattern and precipitation of components contained in the developer by using the basic compound having the alicyclic structure as the component (A). It was completed by. Therefore, the basic compound used as component (A) contains at least one alicyclic structure in the molecule. Further, from the viewpoint of suppressing swelling with respect to the resist pattern, the basic compound used as the component (A) preferably contains two of the above alicyclic structures in the molecule. As described above, when two alicyclic structures are included in the molecule, the basic compound as the component (A) is a compound represented by R ¹ and R ² and R ³ and R ^{4 in} the general formula (1). Each pair forms a ring structure and becomes a spiro compound.

In the general formula (1), the alicyclic structure that may contain a hetero atom formed by bonding R ¹ and R ² to each other is preferably a 5-membered ring or a 6-membered ring. In the general formula (1), when R ³ and R ⁴ is an alkyl group which may have a branched, R ³ and R ⁴ are each preferably an alkyl group having 1 to 4 carbon atoms . Examples of such an alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, and a t-butyl group. Furthermore, when R ³ and R ⁴ are bonded to each other to form an alicyclic structure that may contain a hetero atom, the alicyclic structure is preferably a 5-membered ring or a 6-membered ring. As already described, examples of the hetero atom that may be contained in the alicyclic structure include an oxygen atom, a sulfur atom, and a nitrogen atom.

  As such component (A), N, N-dimethylpyrrolidinium hydroxide, N, N-diethylpyrrolidinium hydroxide, N, N-dipropylpyrrolidinium hydroxide, N, N-dibutyl hydroxide Pyrrolidinium, N-methyl-N-ethylpyrrolidinium hydroxide, N-methyl-N-propylpyrrolidinium hydroxide, N-methyl-N-butylpyrrolidinium hydroxide, N-ethyl-N hydroxide -Propylpyrrolidinium, N-ethyl-N-butylpyrrolidinium hydroxide, N-propyl-N-butylpyrrolidinium hydroxide, N, N-dimethylpiperidinium hydroxide, N, N-diethyl hydroxide Piperidinium, N, N-dipropylpiperidinium hydroxide, N, N-dibutylpiperidinium hydroxide, N-methyl-N-ethylpiperidinium hydroxide, N-methyl hydroxide N-propyl piperidinium, N-methyl-N-butyl piperidinium hydroxide, N-ethyl-N-propyl piperidinium hydroxide, N-ethyl-N-butyl piperidinium hydroxide, N-hydroxy hydroxide Propyl-N-butylpiperidinium, spiro- (1,1 ′)-bipyrrolidinium hydroxide, spiro- (1,1 ′)-bipiperidinium hydroxide, piperidine-1-spiro-1′-pyrrolidinium hydroxide, hydroxylation N, N-dimethylmorpholinium, N, N-diethylmorpholinium hydroxide, N, N-dipropylmorpholinium hydroxide, N, N-dibutylmorpholinium hydroxide, morpholine-4-spiro-1 '-Azacyclobutyl hydroxide, morpholine-4-spiro-1'-azacyclopentyl hydroxide, morpholine-4-spiro-1'-azashi B hexyl hydroxide and the like. These can be used alone or in combination of two or more.

  Among these, from the viewpoint of suppressing swelling of the resist pattern, a spiro compound is preferably used as the component (A), and spiro- (1,1 ′)-bipyrrolidinium hydroxide, spiro- (1,1 ′) hydroxide. -Bipiperidinium, piperidine-1-spiro-1'-pyrrolidinium hydroxide is more preferably used.

  The content of the component (A) in the developer may be appropriately determined in consideration of the basicity required for the developer. As an example, the content of the component (A) in the developer is preferably 0.026 to 1.310N, more preferably 0.052 to 0.524N, and particularly 0.131 to 0.393N. Preferably mentioned. When the content of the component (A) in the developer is 0.026 N or more, good developability can be imparted to the developer, and the content of the component (A) in the developer is 1.310 N or less. By being, it can suppress the economical fall by adding (A) component excessively. When the developer of the present invention is used for a semiconductor element manufacturing process, the content of the component (A) in the developer is most preferably 0.262N. In addition, when the following (B) component is contained in the developing solution of this invention, it is preferable that the total content of (A) component and (B) component in a developing solution becomes the said density | concentration. Further, the unit “N” in the present specification indicates the normality. Since the component (A) is a monoacid base, an aqueous solution of the 1N component (A) is an aqueous solution of the component (A) of 1 mol / L.

  The developer of the present invention may be concentrated at the time of transportation or storage and may be diluted to the above concentration with a solvent when used as a developer. Such a concentrated developer is also included in the developer of the present invention. The content of the component (A) in the concentrated state is not particularly limited and may be appropriately determined in consideration of the content of the component (A) when used as a developer. 2.31N is mentioned preferably and 0.772-1.93N is mentioned more preferably.

[(B) Tetrabutylammonium hydroxide (TBAH)]
The developer of the present invention preferably contains tetrabutylammonium hydroxide (TBAH) as the component (B). The component (B) has a larger number of carbon atoms in one molecule than the component (A), and the swelling action on the resist pattern is smaller than the component (A). For this reason, the amount of the component (A) contained in the developer is reduced by using the component (A) and the component (B) together as a component for imparting basic liquidity to the developer of the present invention. And the swelling action of the developer on the resist pattern can be further reduced.

  The content of the component (B) in the developer is preferably 0.001 to 1.091N. When the content of the component (B) in the developer is 0.001 N or more, the amount of the component (A) in the developer can be reduced to such an extent that the swelling of the resist pattern can be sufficiently suppressed. . Moreover, precipitation of (B) component in a developing solution can be suppressed because content of (B) component in a developing solution is 1.091N or less. The content of the component (B) in the developer is preferably within 5 times the normality of the component (A) within the above range, and is less than 1 normality of the component (A). Is most preferred. Here, the component (B) is a monoacid base. Accordingly, the 1N component (B) aqueous solution is a 1 mol / L component (B) aqueous solution. The concentration of the component (B) refers to the concentration in the developer actually used, and does not refer to the concentration of the developer in the concentrated state.

[(C) Solubilizing component]
It is preferable that a solubilizing component is added as the component (C) to the developer of the present invention. The component (C) is at least one component selected from the group consisting of (C1) a water-soluble organic solvent, (C2) a surfactant, and (C3) an inclusion compound. In other words, the component (C) is one or more components selected from the group consisting of (C1) a water-soluble organic solvent, (C2) a surfactant, and (C3) an inclusion compound. By adding the component (C) to the developer, the solubility of the component (A) and the component (B) contained in the developer is increased, and the deposition temperature of these components in the developer can be lowered. By lowering the precipitation temperature of the component contained in the developer, the precipitation of the component contained in the developer is suppressed, and the stability of the developer is improved. In particular, when the developer is in a concentrated state, the components contained in the developer are likely to precipitate in a low-temperature environment, so the addition temperature of the component (C) lowers the precipitation temperature of the components contained in the developer. It is preferable to become. Hereinafter, each component added as the component (C) will be described.

[(C1) Water-soluble organic solvent]
By adding a water-soluble organic solvent (component (C1)) as the component (C) to the developer, the solubility of the components (A) and (B) in the developer can be increased. Precipitation of contained components can be suppressed. Such an effect is particularly remarkable when the developer is in a concentrated state.

  The component (C1) is not particularly limited as long as it causes little damage to the photoresist film. Polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin; diisopropyl ether, diisobutyl ether, diisopentyl ether, di -Ethers such as n-butyl ether, di-n-pentyl ether, di-sec-butyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-amyl ether; ethylene glycol monomethyl ether, ethylene glycol monoethyl Ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol Glycol ethers such as nobutyl ether; methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol Examples thereof include alcohols. Among these, alcohols such as isopropanol, n-butanol, isobutanol and sec-butanol are preferable from the viewpoint of sufficiently improving the solubility of TBAH while suppressing dissolution and swelling of the resist pattern during development. Illustrated. The component (C1) can be used alone or in combination of two or more.

  The content of the component (C1) in the developer is preferably 1 to 10% by mass. When the content of the component (C1) is 1% by mass or more, precipitation of the component (A) in the developer is effectively suppressed. This effect is remarkable when the developer is in a concentrated state. Moreover, when content of (C1) component is 10 mass% or less, influences, such as melt | dissolution with respect to the resist pattern by (C1) component, swelling, etc. can be reduced. The content of the component (C1) in the developer is more preferably 3 to 7% by mass. Here, the content of the component (C1) refers to the concentration in the developer that is actually used in the developing treatment, and does not refer to the concentration of the developer in the concentrated state.

[(C2) Surfactant]
By adding a surfactant (component (C2)) as the component (C) to the developer, the solubility of the component (A) and the component (B) in the developer can be increased and included in the developer. The precipitation of the components can be suppressed. Such an effect is particularly remarkable when the developer is in a concentrated state. Further, when the component (C2) is added to the developer, the wettability of the developer is improved, and an effect of suppressing development residue, scum, and the like is obtained.

  The component (C2) is not particularly limited, and a conventionally known surfactant can be used. Specifically, nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants can be used.

  The anionic surfactant is not particularly limited, and a conventionally known surfactant having an anionic group can be used. Examples of such an anionic surfactant include a surfactant having a carboxylic acid group, a sulfonic acid group, or a phosphoric acid group as an anionic group.

  Specifically, higher fatty acids having an alkyl group having 8 to 20 carbon atoms, higher alkyl sulfates, higher alkyl sulfonic acids, higher alkyl aryl sulfonic acids, other surfactants having sulfonic acid groups, or higher alcohol phosphoric acids Examples thereof include esters or salts thereof. Here, the alkyl group possessed by the anionic surfactant may be either linear or branched, and a phenylene group or an oxygen atom may be interposed in the branched chain. Some of the hydrogen atoms may be substituted with a hydroxyl group or a carboxyl group.

  Specific examples of the higher fatty acid include dodecanoic acid, tetradecanoic acid and stearic acid. Specific examples of the higher alkyl sulfate include decyl sulfate and dodecyl sulfate. Examples of the higher alkyl sulfonic acid include decane sulfonic acid, dodecane sulfonic acid, tetradecane sulfonic acid, pentadecane sulfonic acid, and stearic acid sulfonic acid.

  Specific examples of higher alkylaryl sulfonic acids include dodecylbenzene sulfonic acid and decylnaphthalene sulfonic acid.

  Furthermore, examples of other surfactants having a sulfonic acid group include alkyl diphenyl ether disulfonic acids such as dodecyl diphenyl ether disulfonic acid, and dialkyl sulfosuccinates such as dioctyl sulfosuccinate.

  Examples of higher alcohol phosphates include palmityl phosphate, castor oil alkyl phosphate, coconut oil alkyl phosphate, and the like.

  Among the above anionic surfactants, it is preferable to use a surfactant having a sulfonic acid group. Specifically, alkylsulfonic acid, alkylbenzenesulfonic acid, olefinsulfonic acid, alkyldiphenylethersulfonic acid, alkylnaphthalenesulfonic acid. And dialkylsulfosuccinate. Among these, it is preferable to use alkylsulfonic acid, alkylbenzenesulfonic acid, alkyldiphenyl ether disulfonic acid, and dialkylsulfosuccinate. The average carbon number of the alkyl group of the alkyl sulfonic acid is preferably 9 to 21, and more preferably 12 to 18. Moreover, it is preferable that it is 6-18, and, as for the average carbon number of the alkyl group of alkylbenzenesulfonic acid, it is more preferable that it is 9-15. The average carbon number of the alkyl group of the alkyldiphenyl ether disulfonic acid is preferably 6-18, and more preferably 9-15. Furthermore, 4-12 are preferable and, as for the average carbon number of the alkyl group of dialkyl sulfosuccinate, 6-10 are more preferable.

  Among the above anionic surfactants, it is preferable to use alkylsulfonic acid having an alkyl group having an average carbon number of 15 and alkylbenzenesulfonic acid having an alkyl group having an average carbon number of 12.

  Examples of nonionic surfactants include polyoxyethylene alkyl ethers and acetylenic nonionic surfactants. As the nonionic surfactant, those having water solubility are desirable. The range of HLB7-17 is good. When HLB is small and water solubility is insufficient, it may be made water-soluble by mixing with other active agents.

  In addition, 1 type, or 2 or more types of various surfactant can be added to a developing solution as (C2) component.

  The content of the component (C2) in the developer is preferably 0.01 to 10% by mass. (C2) When content of a component is 0.01 mass% or more, precipitation of the component contained in a developing solution is suppressed effectively. This effect is remarkable when the developer is in a concentrated state. Moreover, when content of (C2) component is 10 mass% or less, influences, such as melt | dissolution with respect to a resist pattern by (C2) component, swelling, etc. can be reduced. The content of the component (C2) in the developer is more preferably 0.02 to 1% by mass, and most preferably 0.03 to 0.5% by mass. Here, the content of the component (C2) refers to the concentration in the developer actually used for the developing treatment, and does not refer to the concentration of the developer in the concentrated state.

[(C3) inclusion compound]
By adding the inclusion compound (component (C3)) as the component (C) to the developer, the solubility of the component (A) and the component (B) in the developer can be increased and included in the developer. The precipitation of the components can be suppressed. Such an effect is particularly remarkable when the developer is in a concentrated state.

  The component (C3) is not particularly limited, and a conventionally known water-soluble clathrate compound can be used. The compound to be an inclusion compound is dissolved in an aqueous solution by inclusion of a hydrophobic compound. For this reason, the component (C3) includes the component (A) and the component (B), which are more hydrophobic than TMAH conventionally used in the developer, and becomes the developer of the component (A) and the component (B). Increase the solubility of. By such an action, precipitation of components contained in the developer is suppressed.

  As such an inclusion compound, a cyclic oligosaccharide is exemplified, and among them, cyclodextrin is preferably exemplified. Cyclodextrin has a cylindrical shape whose structure is distorted in a trapezoidal shape (bucket shape), and a guest compound (component (A) and component (B)) is incorporated into this cylindrical shape to form an inclusion compound. To do. Cyclodextrins include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, and δ-cyclodextrin. These cyclodextrins can be used alone or in combination of two or more. Moreover, you may use crown ether as an inclusion compound.

[Other ingredients]
A solvent component may be added to the developer of the present invention as another component. Water is mentioned as a solvent component used for the developing solution of this invention. From the viewpoint of preventing the yield of semiconductor devices to be produced from being reduced by including impurities such as metal salts in the developer, water used as a solvent component is like ion-exchanged water or distilled water. Highly purified water is preferable.

  In the developer of the present invention, the halogen content is preferably 10 ppm or less, more preferably 1 ppm or less. Examples of halogen include bromine and chlorine. When the halogen content is in the above range, the yield of the manufactured semiconductor element can be improved. In the developer of the present invention, the metal ion content is preferably 100 ppb or less, more preferably 10 ppb or less, and the semiconductor produced when the metal ion content is in the above range. The device yield can be improved. Furthermore, in the developer of the present invention, the content of carbonate ions is preferably 1% by mass or less, and more preferably 0.1% by mass or less. When the carbonate ion content is in the above range, the developability can be maintained satisfactorily.

[Method for preparing developer]
The developer of the present invention is prepared by mixing the above components. The method for mixing the above components is not particularly limited. The developer of the present invention may be transported in a state prepared as a developer at a predetermined concentration and used in a developing process in photolithography processing, or transported in a concentrated state. It may be used after being diluted with a solvent component such as purified water in the development step in photolithography. In the latter case, the developer is in a concentrated state at the time of transportation, so that the components contained in the developer are likely to be precipitated. Therefore, the effect of suppressing precipitation in the developer of the present invention is more exhibited.

  According to the developer for photolithography of the present invention, it is possible to suppress swelling of the resist pattern when developing the selectively exposed resist film. The adverse effects caused by the swelling of the resist pattern are particularly prominent when the half pitch size is less than 50 nm, for example, when a semiconductor element is manufactured. For this reason, the developer of the present invention is preferably used when a semiconductor element having a half pitch size of less than 50 nm is produced by photolithography. More specifically, the developer of the present invention is preferably used for producing a semiconductor element having a half pitch size of 49 nm or less.

  The resist pattern forming method using the photolithography developer of the present invention is also one aspect of the present invention. Next, a resist pattern forming method using the photolithography developer of the present invention will be described.

  The resist pattern forming method using the developer for photolithography of the present invention is not particularly limited, except that the development using the developer of the present invention is used for development. Can do. As an example of such a method, a negative or positive photoresist composition is applied to the surface of a substrate such as a silicon wafer, and a light or electron beam is passed through a photomask in which a predetermined pattern is formed. There is a method in which selective exposure is performed with an active energy ray such as, followed by development processing.

  In applying a photoresist composition to the surface of a substrate such as a silicon wafer, any known photoresist composition can be used without any particular limitation. Such a photoresist composition is commercially available and can be easily obtained. Moreover, when apply | coating a photoresist composition to the surface of a base material, a well-known coating method can be used without being specifically limited. An example of such a coating method is a method using a spin coater.

  In order to perform the development treatment, the photoresist composition subjected to selective exposure may be exposed to the developer of the present invention. As an example of such treatment, there are a method of immersing the substrate coated with the photoresist composition in the developer, and a method of spraying the developer onto the photoresist composition present on the surface of the substrate. By such treatment, the alkali-soluble component in the photoresist composition after selective exposure is removed, and a resist pattern is formed.

  The developing solution of the present invention has a smaller effect of swelling the resist pattern than conventional developing solutions in which only TMAH is used as a basic compound. Therefore, according to the resist pattern forming method of the present invention, even when a fine pattern with a half pitch size of 49 nm or less is formed, the occurrence of problems associated with resist pattern swelling such as pattern collapse is suppressed. Can do. Furthermore, in the developer of the present invention, precipitation of components contained in the developer is suppressed as compared with conventional developers in which TBAH is used as a basic compound. For this reason, according to the resist pattern forming method of the present invention, the management of the developer is facilitated, and the operation cost can be reduced.

  Hereinafter, the developer for photolithography of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[Preparation of developer]
As basic compounds, spiro- (1,1 ′)-bipyrrolidinium hydroxide (SBPrH), spiro- (1,1 ′)-bipiperidinium hydroxide (SBPpH), piperidine-1-spiro-1′-pyrrolidinium hydroxide (PSPH) ), Morpholine-4-spiro-1′-azacyclopentyl hydroxide (MSACPH), hydroxide N, N-dimethylpyrrolidinium (DMPrH), hydroxide N-methyl-N-butylpiperidinium (MBPpH) Each developer was dissolved in pure water at the concentration shown in 1 to prepare developers of Examples 1-9. For the developer of Example 9, isopropanol (IPA) was added as a water-soluble organic solvent at a concentration shown in Table 1. Further, only tetrabutylammonium hydroxide (TBAH) was dissolved in pure water at the concentrations shown in Table 1 to prepare a developer of Comparative Example 1. Moreover, only the tetramethylammonium hydroxide (TMAH) was melt | dissolved in the pure water with the density | concentration shown in Table 1, and the developing solution of the comparative example 2 was prepared. Each numerical value of the total addition amount of SBPrH, SBPpH, PSPH, MSCAPH, DMPrH, MBPpH, TBAH, TMAH and base shown in Table 1 is normality (N), and the addition amount of IPA is mass%. Normally, a 0.262N aqueous solution of TMAH is used as the developer in the semiconductor element manufacturing process, which is the same as the developer in Comparative Example 2.

[Swelling evaluation of resist pattern]
The observation of swelling was evaluated using QCM (Quartz Crystal Microbalance) measurement. ARF resist TArF-TAI-6144 ME (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied to a 1-inch Quartz crystal substrate with a spin coater, and PAB was performed at 100 ° C. for 1 min to form a 136 nm thick resist film. The substrate was exposed using VUVES-4500 (manufactured by RISOTEC Japan) at a wavelength of 193 nm and an exposure amount of 3 mJ / cm ² , and subjected to PEB at 100 ° C. for 1 min.
The board | substrate which performed PEB was evaluated for the swelling amount of various developing solution using QCM measuring device RDA-Qz3 (made by Risotech Japan).
The degree of swelling was judged by the time until the impedance value obtained by QCM measurement was saturated. The longer the time until the impedance value is saturated, the greater the amount of swelling, and the shorter, the smaller the amount of swelling.
The evaluation criteria are as follows, and the evaluation results are shown in Table 1.
◎ When developed with a TMAH 0.262N aqueous solution as a reference, the resist is saturated in less than half the time until the impedance is saturated, and the swelling of the resist is extremely smaller than that of TMAH. ○ A TMAH 0.262N aqueous solution as a reference Saturated in a time shorter than the time until the impedance is saturated when developed with the resist, swelling of the resist is smaller than TMAH × Time until the impedance is saturated when developed with the reference TMAH 0.262N aqueous solution Saturated in the same or longer time than that, resist swelling is equal to or greater than TMAH

[Precipitation evaluation]
The aqueous solution of TBAH is most likely to precipitate at a concentration around 1.158N (30% by mass). Therefore, for each of the developers of Examples 1 to 9 and Comparative Examples 1 and 2, the total concentration of the base (the sum of the concentrations of the basic compound and the auxiliary basic compound) is concentrated to 1.158 N and concentrated development. The solution was prepared and then gradually cooled, and the temperature at which the components of the developer were deposited was measured. That is, in Example 1, the precipitation of components was evaluated with an aqueous solution containing SBPrH1.158N. Similarly, SBP pH 1.158N in Example 2, PSPH 1.158N in Example 3, MSACPH 1.158N in Example 4, DMPrH 1.158N in Example 5, MBP pH 1.158N in Example 6, Example 7 is PSPH 0.579N and TBAH 0.579N, Example 8 is DMPrH0.579N and TBAH0.579N, Example 9 is PSPH0.579N, TBAH0.579N and IPA 22.1% by mass, Comparative Example 1 is TBAH1. In 158N and the comparative example 2, it evaluated by TMAH1.158N, respectively. Table 1 shows the measurement results of the deposition temperature. Further, each example and comparative example were evaluated according to the following criteria. The results are also shown in Table 1.
○ Precipitation temperature is less than 23 ° C × Deposition temperature is 23 ° C or more

  As shown in Table 1, when the developers of Examples 1 to 9 and the developers of Comparative Examples 1 and 2 are compared, in the developer of the present invention, precipitation of developer components in a concentrated state is suppressed, and It is understood that swelling with respect to the resist pattern is also suppressed. In addition, referring to Examples 1 to 6, when only the component (A) is added as a basic compound and the component (B) (TBAH) is not added, a spiro hydroxide (1) is used as the component (A). , 1 ′)-bipyrrolidinium (SBPrH), spiro-hydroxy (1,1 ′)-bipiperidinium hydroxide (SBPpH), or piperidine-1-spiro-1′-pyrrolidinium hydroxide (PSPH), a resist pattern It is understood that the swelling with respect to is further suppressed and good. Further, when the developer of Example 5 and the developer of Example 8 are compared, swelling of the resist pattern can be suppressed by using the (A) component and the (B) component together as a basic compound. Understood. Furthermore, when the developer of Example 7 and the developer of Example 9 are compared, by adding a water-soluble organic solvent as a solubilizing component, the TBAH precipitation temperature is lowered, and the TBAH precipitation is further suppressed. It is understood.

Claims (12)

(A) A developer for photolithography containing a basic compound represented by the following general formula (1).

(In the general formula (1), R ¹ and R ² are bonded to each other to form an alicyclic structure which may contain a hetero atom, and R ³ and R ⁴ are alkyl groups which may have a branch. In addition, in the general formula (1), the sum of the number of carbon atoms contained in each of R ^{1 to} R ⁴ is 6 to 13 .)   The developer for photolithography according to claim 1, wherein the basic compound is a spiro compound.   The spiro compound is at least selected from the group consisting of spiro- (1,1 ′)-bipyrrolidinium hydroxide, spiro- (1,1 ′)-bipiperidinium hydroxide and piperidine-1-spiro-1′-pyrrolidinium hydroxide. The developer for photolithography according to claim 2, wherein the number is one.   The developer for photolithography according to any one of claims 1 to 3, further comprising (B) tetrabutylammonium hydroxide.   5. The photolithography according to claim 1, further comprising at least one selected from the group consisting of (C1) a water-soluble organic solvent, (C2) a surfactant, and (C3) an inclusion compound. Developer.   The developer for photolithography according to claim 5, comprising the component (C1), wherein the content of the component (C1) is from 1% by mass to 10% by mass.   The developer for photolithography according to claim 5 or 6, comprising the component (C1), wherein the component (C1) is at least one selected from the group consisting of isopropanol, n-butanol, isobutanol, and sec-butanol. .   The developer for photolithography according to claim 5, comprising the component (C2), wherein the content of the component (C2) is 0.01% by mass to 10% by mass.   The developer for photolithography according to any one of claims 5 to 8, comprising the (C3) component, wherein the (C3) component is at least one selected from the group consisting of cyclodextrin and crown ether.   The developer for photolithography according to any one of claims 1 to 9, which is used for manufacturing a semiconductor device having a half pitch size of 49 nm or less.   11. The development for photolithography according to claim 1, wherein the halogen content is 10 ppm or less, the metal ion content is 100 ppb or less, and the carbonate ion content is 1 mass% or less. liquid. The resist pattern formation method using the developing solution for photolithography of any one of Claim 1 to 11.