JP5613011B2 - Concentrated developer for photolithography - Google Patents

Description

The present invention relates to a developer concentrate 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 inventor, when the TBAH is an aqueous solution having a concentration of 6.79% by mass which is used as an example of a developing solution, the precipitation temperature thereof is about 5 ° C. Although the possibility of causing precipitation is small, in the case of an aqueous solution in the vicinity of 30% by mass, the precipitation temperature reaches a maximum of 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. Further, even in an aqueous solution of 6.79% by mass, which is a concentration used as an example of a developer, TBAH contained in the developer may be precipitated during transportation in 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 consideration of the above situation, the water oxidation tetrabutylammonium (TBAH) is used as the alkali in the developing solution, and, in concentrated form, photo lithography precipitation of TBAH is suppressed and purpose thereof is to provide a developer.

  As a result of intensive studies to solve the above problems, the present inventors have found that a developer containing TBAH contains at least one component selected from the group consisting of a water-soluble organic solvent, a surfactant, and an inclusion compound. It was found that the precipitation of TBAH in the developer can be suppressed by adding, and the present invention has been completed.

According to a first aspect of the present invention, (A) at least one selected from the group consisting of tetrabutylammonium hydroxide, (B1) a water-soluble organic solvent, (B2) a surfactant, and (B3) an inclusion compound , A developer for photolithography.
The second aspect of the present invention is a resist pattern forming method using the photolithography developer of the first aspect.
The third aspect of the present invention is at least selected from the group consisting of (A) tetrabutylammonium hydroxide, (B1) a water-soluble organic solvent, (B2) a surfactant, and (B3) an inclusion compound. And a concentrated developer for photolithography in which the component (A) is 10% by mass or more.

According to the present invention, water oxidation tetrabutylammonium (TBAH) is used as the alkali in the developing solution, and, in concentrated form, for photolithography developer deposited is suppressed in TBAH is provided.

  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 comprises (A) tetrabutylammonium hydroxide, (B1) a water-soluble organic solvent, (B2) a surfactant, and (B3) at least one selected from the group consisting of inclusion compounds. Including. (B1), (B2) and (B3) (hereinafter collectively referred to as (B) solubilizing component or (B) component) are used to assist the dissolution of component (A) in water. Is done. Hereinafter, these components will be described.

[(A) Tetrabutylammonium hydroxide]
Tetrabutylammonium hydroxide (TBAH) used as the component (A) in the developer of the present invention imparts an alkaline solution necessary for developing the resist film after the exposure processing 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 the present invention, TBAH (component (A)), which is less swellable with respect to the resist pattern than TMAH, is used as a compound for imparting alkaline liquidity to the developer.

  The content of the component (A) in the developer is preferably 0.1 to 20% by mass. When the content of the component (A) in the developer is 0.1% by mass or more, good developability can be imparted to the developer. Moreover, when the content of the component (A) in the developer is 20% by mass or less, the effect of suppressing the precipitation of the component (A) by the component (B) described later can be obtained. The content of the component (A) in the developer is more preferably 1 to 10% by mass, and most preferably 3 to 7% by mass. In a developer using TMAH as an alkali component, the content of TMAH is generally 2.38% by mass. From the viewpoint of setting the same molar concentration as the TMAH at this time, the content of the component (A) may be 6.79% by mass.

  Further, 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. % Is preferable, and 20 to 50% by mass is more preferable. In addition, the preferable density | concentration of each (B) component demonstrated later represents the density | concentration when it is used as a developing solution.

[(B) Solubilizing component]
A solubilizing component is added to the developer of the present invention as the component (B). The component (B) is at least one component selected from the group consisting of (B1) a water-soluble organic solvent, (B2) a surfactant, and (B3) an inclusion compound. In other words, the component (B) is one or more components selected from the group consisting of (B1) a water-soluble organic solvent, (B2) a surfactant, and (B3) an inclusion compound. By adding the component (B) to the developer, the solubility of the component (A) increases, and the deposition temperature of the component (A) in the developer can be lowered. By lowering the deposition temperature of the component (A), the deposition of the component (A) in the developer is suppressed, and the stability of the developer is improved. In particular, when the developer is in a concentrated state (when the concentration of TBAH is high), TBAH is likely to precipitate in a low-temperature environment. Therefore, it is preferable that the TBAH precipitation temperature be lowered by the addition of component (B). . Hereinafter, each component added as the component (B) will be described.

[(B1) Water-soluble organic solvent]
By adding a water-soluble organic solvent (component (B1)) as the component (B) to the developer, the solubility of the component (A) in the developer can be increased, and the component (A) in the developer can be increased. Precipitation can be suppressed. Such an effect is particularly remarkable when the developer is in a concentrated state.

  The component (B1) is not particularly limited as long as it causes little damage to the photoresist film. Methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n -Monohydric alcohols such as amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, ethylene glycol, propylene glycol, butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-hexane Diols, alcohols such as polyhydric alcohols such as 2,4-hexanediol, hexylene glycol, 1,7-heptanediol, octylene glycol, glycerin, 1,2,6-hexanetriol; Ethers such as ether, diisobutyl ether, diisopentyl ether, di-n-butyl ether, di-n-pentyl ether, di-sec-butyl ether, diisopentyl ether, di-sec-pentyl ether, di-tert-amyl ether And glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, and diethylene glycol monobutyl ether. Among these, from the viewpoint of sufficiently improving the solubility of TBAH while suppressing dissolution and swelling of the resist pattern during development, dihydric alcohols such as ethylene glycol and propylene glycol, and trihydric alcohols such as glycerin. And alcohols such as monohydric alcohols such as isopropanol, n-butanol, isobutanol, sec-butanol and the like are preferred, and among them, dihydric alcohols and trihydric alcohols are more preferred. The component (B1) can be used alone or in combination of two or more.

  The content of the component (B1) in the developer is preferably 1 to 10% by mass. When the content of the component (B1) 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 (B1) component is 10 mass% or less, influences, such as melt | dissolution with respect to the resist pattern by a (B1) component, swelling, etc. can be reduced. The content of the component (B1) in the developer is more preferably 3 to 10% by mass, and further preferably 3 to 7% by mass. As described above, the content of the component (B1) here 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.

[(B2) Surfactant]
By adding the surfactant (component (B2)) as the component (B) to the developer, the solubility of the component (A) in the developer can be increased, and the precipitation of the component (A) in the developer Can be suppressed. Such an effect is particularly remarkable when the developer is in a concentrated state. In addition, when the component (B2) is added to the developer, the wettability of the developer is improved, and the effect of suppressing development residue, scum, and the like is obtained.

  The component (B2) 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 (B2) component.

  The content of the component (B2) in the developer is preferably 0.01 to 10% by mass. When the content of the component (B2) is 0.01% 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 (B2) component is 10 mass% or less, influences, such as melt | dissolution with respect to the resist pattern by (B2) component, swelling, etc. can be reduced. The content of the component (B2) in the developer is more preferably 0.02 to 1% by mass, and most preferably 0.03 to 0.5% by mass. As described above, the content of the component (B2) here refers to the concentration in the developer that is actually used in the developing process, and does not refer to the concentration of the developer in the concentrated state.

[(B3) inclusion compound]
By adding an inclusion compound (component (B3)) as the component (B) to the developer, the solubility of the component (A) in the developer can be increased, and the precipitation of the component (A) in the developer Can be suppressed. Such an effect is particularly remarkable when the developer is in a concentrated state.

  The component (B3) is not particularly limited, and a conventionally known water-soluble inclusion 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 (B3) encloses the component (A) (TBAH) having higher hydrophobicity than TMAH conventionally used in the developer, and increases the solubility of the component (A) in the developer. By such an action, precipitation of the component (A) 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)) is taken into this cylindrical shape to form an inclusion compound. 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 component (A) is likely to be precipitated. Therefore, the effect of preventing precipitation of the component (A) according to 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 developer of the present invention has a smaller effect of swelling the resist pattern than conventional developers using TMAH. 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.

[Concentrated developer for photolithography]
As described above, by containing the component (B), precipitation of TBAH as the component (A) is suppressed, and a concentrated developer for photolithography that can be stably transported and stored even at room temperature is prepared. be able to. Such a concentrated developer, that is, a concentrated developer for photolithography containing the component (A) and the component (B) and having a concentration of the component (A) of 10% by mass or more is also one aspect of the present invention. is there. Examples of the concentration of the component (A) in the concentrated developer for photolithography include 10 mass% or more, 20 mass% or more, 30 mass% or more, 40 mass% or more. Since such a concentrated developer is as described above, description thereof is omitted here.

  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.

<Prevention of precipitation of TBAH by addition of water-soluble organic solvent>
[Preparation of developer]
Tetrabutylammonium hydroxide (TBAH) and isopropanol (IPA) as a water-soluble organic solvent were dissolved in purified water (ion-exchanged water) at concentrations shown in Table 1 to prepare developers of Reference Examples 1-5. In addition, each numerical value shown in Table 1 shows the mass%. Moreover, only the tetrabutylammonium hydroxide (TBAH) was melt | dissolved in the ion exchange water with the density | concentration shown in Table 1, and the developing solution of the comparative example 1 was prepared. Further, only tetramethylammonium hydroxide (TMAH) was dissolved in ion-exchanged water at the concentrations shown in Table 1 to prepare a developer of Comparative Example 2. The 6.79% by mass aqueous solution of TBAH and the 2.38% by mass aqueous solution of TMAH have the same molar concentration. In general, a 2.38% by mass aqueous solution of TMAH is used as a developer in the semiconductor element manufacturing process, which is the same as the developer in Comparative Example 2.

In addition, tetrabutylammonium hydroxide (TBAH) and polyhydric alcohols such as ethylene glycol (EG), propylene glycol (PG), or glycerin (GC) as water-soluble organic solvents at the concentrations shown in Table 2, respectively. The developer of Examples 1 to 10 was prepared. In addition, each numerical value shown in Table 2 shows the mass%.

[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 at ³ mJ / cm ² using VUVES-4500 (manufactured by RISOTEC Japan) 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 Tables 1 and 2.
○ When developed with 2.38% of reference TMAH, the resist is saturated in less than half the time until impedance is saturated, and resist swelling is much smaller than TMAH. Δ TMAH 2.38% of 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 2.38% of TMAH which is a reference 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 30% by mass. Therefore, for each of the developers of Reference Examples 1 to 5, Examples 1 to 10, and Comparative Examples 1 to 2, a concentrated developer is prepared by concentrating the TBAH or TMAH to a concentration of 30% by mass. The solution was gradually cooled and the temperature at which TBAH or TMAH was precipitated was measured. That is, in Reference Example 1, precipitation of TBAH was evaluated with an aqueous solution of 30% by mass of TBAH and 4.4% by mass of IPA. Similarly, in Reference Example 2, TBAH 30% by mass and IPA 13.3% by mass, in Reference Example 3, TBAH 30% by mass and IPA 22.1% by mass, in Reference Example 4, TBAH 30% by mass and IPA 30.9% by mass, Reference Example 5, TBAH 30% by mass and IPA 44.2% by mass, in Example 1 , TBAH 30% by mass and EG 13.3% by mass, in Example 2 , TBAH 30% by mass and EG 22.1% by mass, in Example 3 , TBAH 30 % by mass % And PG 13.3% by weight, in Example 4 , TBAH 30% by weight and PG 22.1% by weight, in Example 5 , TBAH 30% by weight and PG 30.9% by weight, in Example 6 , TBAH 30% by weight and PG 44.2%. wt%, in example 7, TBAH30 wt% and GC13.3 wt%, in example 8, TBAH30 wt%及GC22.1 mass%, in Example 9, TBAH30 wt% and GC30.9 mass, in Example 10, TBAH30 wt% and GC44.2 wt%, in Comparative Example 1, TBAH30 wt%, in Comparative Example 2, TMAH30 Evaluation was performed in mass%. In Comparative Example 2, the presence or absence of precipitation of TMAH was evaluated. The evaluation criteria are as follows, and the evaluation results are shown in Tables 1 and 2. The lower the precipitation temperature in this evaluation, the lower the temperature of the aqueous solution (concentrated developer) can be maintained in the dissolved state, which means that precipitation is less likely to occur.
AAA The precipitation temperature is less than 5 ° C. AA The precipitation temperature is 5 ° C. or more and less than 10 ° C. A The precipitation temperature is 10 ° C. or more and less than 15 ° C. B The precipitation temperature is 15 ° C. or more and less than 20 ° C. C The precipitation temperature is 20 ℃ ≧ 23 ℃ D Precipitation temperature is ≧ 23 ℃

[Evaluation of precipitation in various concentrated developers]
In the above-described precipitation evaluation, TBAH in a concentrated developer (TBAH concentration is 30% by mass) that is more concentrated than a developer having a TBAH concentration (6.79% by mass) assumed in a normal semiconductor element manufacturing process. Was evaluated. Since the developer used as a product is generally transported and stored in a concentrated state in order to reduce the cost during transportation and storage, the above-described precipitation evaluation is performed using such transport and storage. It assumes storage and other aspects. However, the degree of concentration of the developer during transportation and storage of the developer in actual use varies. Therefore, a plurality of developers having different degrees of concentration were prepared for each of the developers of Examples 3 , 7 and 8 and Comparative Example 1, and precipitation evaluation was conducted in these concentrated developers. In this evaluation, the concentration of TBAH in the developer as a product is 6.79% by mass, and the concentration of TBAH is 10, 20, 30, and 40% by mass (10, 20, and 30% by mass in the developer of Example 8 ). ) To be prepared, and the precipitation in each concentrated developer was evaluated. The results are shown in Tables 3 and 4. The evaluation criteria in the “Precipitation Evaluation” column in Tables 3 and 4 are the same as those in the above [Precipitation Evaluation]. In Tables 3 and 4, the deposition evaluation was performed on a concentrated developer containing the component concentrations shown in the “Evaluation Concentration” column, and the “Product Concentration” column was an unconcentrated developer (that is, The component concentration of the developer prepared from the concentrated developer is shown as a reference.

As shown in Table 1 and Table 2, if the developer of Reference Examples 1 to 5 and Examples 1 to 10 and the developer of Comparative Example 1 are compared, by adding a water-soluble organic solvent to the developer, It is understood that the precipitation of TBAH in the concentrated state is suppressed. Further, when Reference Examples 2 to 4 and Reference Examples 1 and 5 are compared, the concentration of the water-soluble organic solvent added to the developer is in the range of 3 to 7% by mass. It is understood that damage to the resist film (resist pattern) caused by the conductive organic solvent is also suppressed. Furthermore, when the developers of Reference Examples 1 to 5 and the developers of Examples 1 to 10 are compared, when alcohol is used as the water-soluble organic solvent added to the developer, a polyhydric alcohol should be used. This shows that the balance between the resist film swelling suppression effect and the TBAH precipitation inhibition effect is improved. And it turns out that this tendency is more remarkable in the case of using trivalent alcohol than in the case of using divalent alcohol among polyhydric alcohols. In addition, in the developer of Comparative Example 2 using TMAH instead of TBAH for imparting alkalinity to the developer, the result was that the swelling of the resist film was extremely large.

Further, as shown in Table 3, when the concentration level in the concentrated developer increases and the concentration of TBAH increases, TBAH contained in the concentrated developer tends to precipitate. By adding (propylene glycol) or GC (glycerin), even in a concentrated developer having a TBAH concentration of about 40% by mass, it was possible to obtain a precipitation suppressing effect to the extent that there was no practical problem. And it turned out that this precipitation inhibitory effect is especially remarkable in GC rather than PG. On the other hand, as shown in Table 4, in the concentrated developer containing no water-soluble organic solvent such as PG or GC, as the degree of concentration in the concentrated developer increases and the concentration of TBAH increases, the TBAH increases. The concentrated developer having a TBAH concentration of 30% by mass or more had a deposition temperature of 23 ° C. or higher. From this, it can be seen that a concentrated developer containing no water-soluble organic solvent such as PG or GC is difficult to transport and store at room temperature, and appropriate measures such as heating are required during transportation.
From the above, the present invention is effective in suppressing precipitation in a developer containing TBAH. In particular, the concentration of TBAH is 10% by mass or more, 20% by mass or more, 30% by mass or more, and 40% by mass or more. It was found to be effective in suppressing precipitation in such a concentrated developer.

Claims (5)

(A) tetrabutylammonium hydroxide, (B1) a water-soluble organic solvent, and water,
The concentration of the component (A) is 20 to 50% by mass,
A concentrated developer for photolithography , wherein the component (B1) is a polyhydric alcohol . The concentrated developer for photolithography according to claim 1, wherein when used as a developer, the solvent is diluted by adding a solvent so that the concentration of the component (A) is 1 to 10% by mass. The concentration development for photolithography according to claim 2, wherein the concentration of the component (B1) when diluted by adding a solvent so that the concentration of the component (A) is 1 to 10% by mass is 1 to 10% by mass. liquid. The concentrated developer for photolithography according to any one of claims 1 to 3, wherein the polyhydric alcohol is at least one selected from the group consisting of ethylene glycol, propylene glycol, and glycerin. For photolithography developer concentrate according to any one of claims 1 to 4, which is used for half-pitch size is the manufacture of semi-conductor elements Ru der below 49 nm.