JP5317609B2 - Photosensitive compound, photosensitive composition, and pattern forming method - Google Patents

Description

  The present invention relates to a photosensitive composition used for fine processing in a manufacturing process of a semiconductor element or the like, and a pattern forming method using the same.

  Along with the high integration of LSIs and the like, microfabrication technology using photolithography has recently reached a level of 100 nm or less. As a resist using an alkali-soluble low-molecular compound, for example, a positive resist using a phenol derivative composed of 10 benzene rings has been proposed (see, for example, Patent Document 1). Since such a resist is a chemically amplified resist including an acid diffusion mechanism, it is advantageous in terms of high throughput, but a problem arises when an ultrafine pattern is formed. For example, there is a limit in resolution due to the diffusion of acid from the exposed area to the unexposed area, and the roughness may become prominent.

  If it is a non-chemically amplified resist containing no photoacid generator, the problem of acid diffusion can be avoided. As a non-chemically amplified resist using a low-molecular compound, a resist using calixarene has been proposed (see, for example, Non-Patent Document 1), but calixarene has very low sensitivity.

  In optical lithography using i-line (365 nm), an alkali-soluble novolak resin and a non-benzophenone-based naphthoquinonediazide group-containing compound (photosensitive component) are used as a photoresist material capable of forming a resist pattern having a fine dimension of 0.35 μm or less. There have been proposed various positive photoresist compositions containing). In any case, if an alkali-soluble novolak resin is not contained in addition to the naphthoquinone diazide group-containing compound, the film cannot be formed and function as a photoresist.

Due to the novolak resin having a large molecular assembly, the resolution and roughness in a fine region are lowered. A compound obtained by directly binding naphthoquinone diazide to calix resorcinalene, which is an amorphous low-molecular compound, has been demonstrated to have high resolution (for example, see Non-Patent Document 2). However, low sensitivity has been a problem.
JP 2003-183227 A Jpn. J. et al. Appl. Phys. , 42, 3913 (2003) Chem. Mater. , 19, 3780 (2007)

  An object of this invention is to provide the photosensitive composition provided with the high resolution and the outstanding edge roughness.

The compound according to one embodiment of the present invention is represented by the following general formula (I).

(In the above general formula (I), at least a part of R is selected from (NQ1) and (NQ2) shown below, and the remainder is a hydrogen atom.)

  The photosensitive composition concerning 1 aspect of this invention contains the above-mentioned photosensitive compound and solvent, It is characterized by the above-mentioned.

A pattern forming method according to an aspect of the present invention includes a step of forming a photosensitive layer containing the above-described photosensitive composition on a substrate;
Irradiating a predetermined region of the photosensitive layer with ultraviolet rays to perform pattern exposure;
And a step of developing the photosensitive layer after the pattern exposure with an alkaline aqueous solution to selectively remove an exposed portion of the photosensitive layer.

A pattern forming method according to another aspect of the present invention includes a step of forming a photosensitive layer containing the above-described photosensitive composition on a substrate,
Irradiating a predetermined region of the photosensitive layer with ionizing radiation to perform pattern exposure;
And a step of developing the photosensitive layer after the pattern exposure with an organic solvent to selectively remove an unexposed portion of the photosensitive layer.

A pattern forming method according to another aspect of the present invention includes a step of forming a photosensitive layer containing the above-described photosensitive composition on a substrate,
Irradiating a predetermined region of the photosensitive layer with ionizing radiation to perform pattern exposure;
Irradiating the entire region of the photosensitive layer after the pattern exposure with ultraviolet rays to expose the entire surface;
And a step of developing the photosensitive layer after the entire surface exposure with an alkaline aqueous solution to selectively remove an unexposed portion of the photosensitive layer.

  According to the present invention, a photosensitive composition having high resolution and excellent edge roughness is provided.

  Embodiments of the present invention will be described below.

  The photosensitive compound concerning one Embodiment of this invention is represented by the said general formula (I). Such a compound is a low-molecular compound composed of seven benzenes and continuously connected in three directions from the central benzene ring. Since phenylene is present at fixed positions in three directions, the structure itself has high rigidity, and entropy changes are suppressed. When the entropy change is suppressed, the glass transition temperature increases. This suppresses pattern roughness that occurs during development. In addition, since it is composed of seven benzene rings, the size of one molecule is small, and the edge roughness caused by the size of the molecule is reduced.

  The compound represented by the general formula (I) according to the embodiment of the present invention has at most 3 sites in the molecule to react, and high sensitivity is obtained. Furthermore, since the benzene ring has another benzene ring at the para position of the benzene ring protruding in three directions from the central benzene ring, the benzene rings are likely to cause a resonance effect. In addition, since the terminal benzene ring has (-OR) at the para position, the resonance effect is further enhanced. If the resonance effect is high, it is considered that the terminal naphthoquinonediazide is likely to react.

  The compound represented by the general formula (I) can be synthesized, for example, by the following method. First, using 1,3,5-tris (para-bromophenyl) benzene and 4- (methoxyphenyl) boronic acid as starting materials, 1,3,5-tris (para- (para-methoxyphenyl) Phenyl) benzene is obtained.

  Then, all methoxy groups are replaced with hydroxy groups to synthesize 1,3,5-tris (para- (para-hydroxyphenyl) phenyl) benzene. What is obtained here is a compound in which hydrogen atoms are introduced into all R in the general formula (I).

  By reacting 1,3,5-tris (para- (para-hydroxyphenyl) phenyl) benzene with 1,2-naphthoquinone-2-diazido-4-sulfonyl chloride, the hydrogen atom as R is converted to (NQ1) Can be replaced. When 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride is used, the hydrogen atom as R can be replaced with (NQ2).

Since (NQ1) and (NQ2) serve as reaction points, it is desirable that such a substituent is introduced in at least 33% of R. The substitution rate is more preferably 66% or more, and most preferably 100%. When it is desired to dissolve a large amount in various solvents, when improvement in solubility in the solvent is required, 33% or more of R may be a hydrogen atom. The replacement rate can be controlled by the following method, for example. First, the charging ratio of 1,3,5-tris (para- (para-hydroxyphenyl) phenyl) benzene and 1,2-naphthoquinone-2-diazide-4-sulfonyl chloride was changed and dissolved in tetrahydrofuran (THF). Let Subsequently, the target compound can be obtained by adding Na ₂ CO ₃ as a catalyst and phenyltriethylamine for reaction.

In the compound represented by the general formula (I), (NQ1) and (NQ2) may be present simultaneously. For example, the following method can be employed. First, 1,3,5-tris (para- (para-hydroxyphenyl) phenyl) benzene, 1,2-naphthoquinone-2-diazide-4-sulfonyl chloride and 1,2-naphthoquinone-2-diazide-5 All of the sulfonyl chloride is dissolved and mixed in THF simultaneously. Subsequently, the compound containing (NQ1) and (NQ2) at the same time can be synthesized by adding Na ₂ CO ₃ as a catalyst and phenyltriethylamine for reaction.

  The photosensitive composition concerning embodiment of this invention can be prepared by melt | dissolving each component mentioned above in the solvent, and filtering with a membrane filter etc. Examples of the solvent include organic solvents such as ketones, cellosolves, and esters. Specifically, examples of the ketone include cyclohexanone, acetone, ethyl methyl ketone, and methyl isobutyl ketone. Examples of cellosolves include methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, and butyl cellosolve acetate. Examples of the esters include ethyl acetate, butyl acetate, isoamyl acetate, γ-butyrolactone, and methyl 3-methoxypropionate. The above-mentioned solvents can be used in combination of two or more as necessary.

  Depending on the type of photosensitive composition, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidinone, anisole, monochlorobenzene, or orthodichlorobenzene may be used as part of the solvent to improve solubility. You can also. Furthermore, lactic acid esters such as ethyl lactate, propylene glycol monoethyl acetate and the like may be used as the low toxicity solvent.

  Basically, the photosensitive composition according to the embodiment of the present invention is prepared by the compound represented by the general formula (I) and the solvent.

  If necessary, additives can be further blended. For example, when patterning a photosensitive layer containing a photosensitive composition according to an embodiment of the present invention to form a pattern, reduction in film forming property of the photosensitive layer, adhesion of the pattern, variation in development speed, etc. Is required, a surfactant may be added to the photosensitive composition.

  Specific examples include the following compounds. For example, polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene oleyl ether; polyoxyethylene such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether Alkyl allyl ethers; polyoxyethylene / polyoxypropylene block copolymers; sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate Polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmite Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitan tristearate, and fluorine-based interfaces such as hexafluoropropene oligomers Activators, silicon surfactants such as polyoxyethylene / methylpolysiloxane copolymers, and the like.

  If the additive as described above is contained in an amount of about 50 to 400 ppm of the whole composition, the effect of the additive can be obtained.

  When forming a pattern using the photosensitive composition concerning embodiment of this invention, first, a photosensitive composition is apply | coated on a board | substrate and a photosensitive layer is formed. Any substrate can be used. Specifically, as a substrate, a silicon wafer, a doped silicon wafer, a silicon wafer having various insulating films, electrodes, or wirings formed on its surface, a mask blank, a III-V group compound semiconductor wafer such as GaAs or AlGaAs, etc. And so on. Further, a chromium or chromium oxide deposition substrate, an aluminum deposition substrate, an IBSPG coated substrate, an SOG coated substrate, or a SiN coated substrate can be used.

  Arbitrary methods can be adopted to apply the photosensitive composition on such a substrate, and examples thereof include spin coating, dip coating, doctor blade method, and curtain coating.

  The applied photosensitive composition is dried by heating to form a photosensitive layer. Even when the photosensitive compound is unexposed, the temperature of the heat drying is preferably 170 ° C. or lower, preferably 70 to 120 ° C. .

  Next, pattern exposure is performed by irradiating a predetermined region of the photosensitive layer with actinic radiation. The exposure can be performed by irradiating the photosensitive layer with actinic radiation through a predetermined mask pattern. Alternatively, exposure may be performed by directly scanning the photosensitive layer with ionizing radiation without using a mask pattern.

  In the pattern forming method according to an embodiment of the present invention, pattern exposure is performed by irradiating a predetermined region of the photosensitive layer with ultraviolet rays.

  As the ultraviolet ray used for exposure, any light can be used as long as it has a wavelength with which the photosensitive composition has sensitivity. Specifically, ultraviolet rays, i-line, h-line, or g-line of a mercury lamp, xenon lamp light, deep ultraviolet UV light (for example, excimer laser light such as KrF or ArF), and other light can be used.

  When the compound represented by the general formula (I) is irradiated with ultraviolet rays, the naphthoquinonediazides represented by (NQ1) or (NQ2) are chemically changed to indenecarboxylic acid and exhibit alkali solubility. As a result, the exposed portion of the photosensitive layer can be selectively dissolved and removed by developing with an alkaline aqueous solution.

  As an alkali developer for development processing, either an organic alkali aqueous solution or an inorganic alkali aqueous solution may be used. Examples of the organic alkaline aqueous solution include a tetramethylammonium hydroxide aqueous solution, a tetraethylammonium hydroxide aqueous solution, and a choline aqueous solution. Examples of the inorganic alkaline aqueous solution include a potassium hydroxide aqueous solution and a sodium hydroxide aqueous solution. When the pH of the alkaline developer is 11 or less, it is advantageous in that the waste liquid treatment has a low load on the environment.

  The concentration of the alkali developer is not limited, but the concentration may be 15 mol% or less in order to increase the dissolution rate difference between the exposed and unexposed portions of the photosensitive layer and ensure sufficient dissolution contrast. preferable. This concentration needs to be adjusted according to the amount of protecting groups introduced into the matrix compound.

  Moreover, arbitrary additives can also be added to these developers as necessary. For example, a surfactant can be added to lower the surface tension of the developer, or a neutral salt can be added to activate development.

  Examples of the surfactant include polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene alkylphenyl ether, polyoxyethylene glycol, polyoxyethylene polyoxy Propylene glycol, polyoxypropylene glycol, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid monoester, sucrose fatty acid ester, fatty acid alkanolamide, polyoxyethylene alkylamide, polyoxyethylene polyoxy Propylene alkylamide, polyoxyethylene alkylamino ether, polyoxyethylene Nonionic surfactants such as polyoxypropylene alkylamino ether, polyoxyethylene acetylene glycol, polyoxyethylene polyoxypropylene acetylene glycol, and alkyl phosphate ester salts; monoalkylamine and salts thereof, alkyltrimethylamine and salts thereof, Cationic surfactants such as dialkyldimethylamine and salts thereof, imidazolinium and salts thereof, alkylbenzyldimethyl quaternary ammonium and salts thereof, benzylpyridinium and salts thereof, alkylpyridinium and salts thereof, and polyoxyethylene alkylbenzylammonium Can be used.

  Examples of neutral salts include tetraalkylammonium, such as tetramethylammonium, trimethylethylammonium, tetraethylammonium, trimethylhydroxyethylammonium, methyltrihydroxyethylammonium, dimethyldihydroxyethylammonium, dimethylamine, trimethylamine, monoethylamine, and diethylamine. And carbonates and hydrogen carbonates such as alkanolamines such as ethanolamine, ethanolamine, diethanolamine, and triethanolamine. The temperature of the developer is also arbitrary and may be appropriately determined within the range of 0 to 100 ° C.

  Thus, a positive pattern is formed by pattern exposure using ultraviolet rays and development processing using an alkaline aqueous solution.

  In the pattern forming method according to another embodiment of the present invention, pattern exposure is performed by irradiating a predetermined region of the photosensitive layer with ionizing radiation.

  As the ionizing radiation used for exposure, any ionizing radiation can be used as long as the compound represented by formula (I) causes a self-polymerization reaction. Specifically, X-rays, synchrotron orbital radiation (SR), electron beams, γ-rays, ion beams, and other light can be used.

  When the compound represented by the general formula (I) is irradiated with ionizing radiation, the naphthoquinonediazide represented by (NQ1) or (NQ2) undergoes self-polymerization and becomes high molecular weight. Since the exposed portion becomes insoluble in the organic solvent, the unexposed portion of the photosensitive layer can be selectively dissolved and removed by developing with the organic solvent.

  Examples of the organic solvent include ketones, cellosolves, and esters. Specifically, examples of the ketone include cyclohexanone, acetone, ethyl methyl ketone, and methyl isobutyl ketone. Examples of cellosolves include methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, and butyl cellosolve acetate. Examples of the esters include ethyl acetate, butyl acetate, isoamyl acetate, γ-butyrolactone, and methyl 3-methoxypropionate. The above-mentioned solvents can be used in combination of two or more as necessary.

  Further, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidinone, anisole, monochlorobenzene, or orthodichlorobenzene can be used as a part of the solvent. Furthermore, lactic acid esters such as ethyl lactate, propylene glycol monoethyl acetate and the like may be used as the low toxicity solvent.

  In this way, a negative pattern is formed by pattern exposure using ionizing radiation and development processing using an organic solvent.

  In the pattern forming method according to another embodiment of the present invention, pattern exposure is performed by irradiating a predetermined region of the photosensitive layer with ionizing radiation. As described above, any ionizing radiation that causes the compound represented by the general formula (I) to undergo a self-polymerization reaction can be used. By irradiating a predetermined region of the photosensitive layer with ionizing radiation, a self-polymerization reaction occurs in the exposed portion.

  Following pattern exposure by ionizing radiation, the entire surface of the photosensitive layer is irradiated with ultraviolet rays. In the unexposed portion of the photosensitive layer that has not been irradiated with ionizing radiation, the naphthoquinonediazides represented by (NQ1) or (NQ2) are chemically changed to indenecarboxylic acid and exhibit alkali solubility. As a result, the exposed portion of the photosensitive layer can be selectively dissolved and removed by developing with an alkaline aqueous solution.

  As the ionizing radiation for pattern exposure, the ultraviolet rays for overall exposure, and the alkaline aqueous solution for development processing, those already described can be used.

  In this way, a negative pattern is formed by pattern exposure using ionizing radiation, overall exposure using ultraviolet rays, and development processing using an alkaline aqueous solution.

  In any of the methods described above, additional steps can be added as necessary. For example, a step of forming a planarization layer before forming a photosensitive layer on a substrate, a step of forming an antireflection layer for reducing reflection of exposure light, and washing the substrate after development with water, A rinsing step for removing the developer and the like, and a step of irradiating the patterned resist layer with ultraviolet rays again in order to control dry etching resistance can be combined with the above-described steps.

  As described above, when a positive pattern is formed, the exposed portion of the photosensitive layer is selectively dissolved and removed by development processing. On the other hand, when a negative pattern is formed, the unexposed portion of the photosensitive layer is selectively dissolved and removed. Since the photosensitive composition according to the embodiment of the present invention is used, it is possible to form a pattern with reduced edge roughness with high resolution and sensitivity by the method according to the embodiment of the present invention.

  Specific examples of the present invention are shown below.

(Synthesis Example 1)
A commercially available 1,3,5-tris (para-bromophenyl) benzene (5.43 g), 4- (methoxyphenyl) boronic acid (6.08 g) and potassium carbonate (5.53 g) were placed in a three-necked flask. And replaced with argon. To this, 100 ml of dehydrated toluene was added and stirred well, and tetrakis (triphenylphosphine) palladium (0.2 g) was further added. The resulting mixture was stirred at 90 ° C. for 8 hours.

  Upon cooling to room temperature, an off-white precipitate was formed. The precipitate was filtered, and the resulting red filtrate was collected and allowed to stand. On the other hand, the grayish white precipitate was dissolved in a large amount of toluene, stirred and dissolved at 100 ° C., and then hot filtered to obtain a filtrate. The evaporator removed the solvent from the filtrate and a slightly grayish white residue was obtained.

The residue was recrystallized from toluene and suction filtered to yield a pure white product after drying at 60 ° C. in vacuo (yield 3.15 g, yield 50.4%). The results of ¹ H-NMR measurement are as follows.

¹ H-NMR (δ, 270 MHz, CDCl ₃ ): 3.87 (s, 9H, CH ₃ ), 7.00-7.04 (m, 6H, Ph—H), 7.60-7.80 ( m, 18H, Ph-H), 7.87 (s, 3H, Ph-H).
The white product was identified as (1,3,5-tris (para- (para-methoxyphenyl) phenyl) benzene (hereinafter referred to as TMTPPB)) represented by the following chemical formula.

(Synthesis Example 2)
TTMPPB (2 g) obtained in Synthesis Example 1 was placed in a three-necked flask and purged with argon. Dehydrated dichloromethane (120 ml) was added thereto and stirred to dissolve the substrate. Next, 1M tribromoboron / dichloromethane solution (22.4 ml) was gradually added dropwise and stirred at 40 ° C. for 8 hours. Then, it cooled to room temperature, 75 ml of pure water was added gradually, and it stirred for 1-2 hours.

Extraction three times with ethyl acetate yielded an organic layer, which was dried over anhydrous sodium sulfate. The dried organic layer was filtered to remove anhydrous sodium sulfate, and dried with an evaporator to obtain a solid. The obtained solid was washed with a small amount of cold methanol, suction filtered, and dried at 60 ° C. to obtain a pure product (yield 1.11 g, yield 59.4%). The results of ¹ H-NMR measurement are as follows.

¹ H-NMR (δ, 270 MHz, THF-d): 6.82-6.85 (m, 6H, Ph—H), 7.51-7.54 (m, 6H, Ph—H), 7. 67-7.70 (m, 6H, Ph-H), 7.82-7.85 (m, 6H, Ph-H), 7.93 (s, 3H, Ph-H), 8.35 (s , 3H, OH)
The white product was identified as (1,3,5-tris (para- (para-hydroxyphenyl) phenyl) benzene (hereinafter referred to as THTPPB)) represented by the following chemical formula.

From the TG / DTA measurement analysis, the glass transition temperature (T _g ) was 145 ° C. and the melting point (T _m ) was 240 ° C.

The glass transition temperature of 1,3,5-tris [3,5-di (4-tertiarybutoxycarbonyloxylphenyl) phenyl] benzene represented by the following chemical formula was 140 ° C.

(Synthesis Example 3)
THTPPB (0.20 g) obtained in Synthesis Example 2 was placed in a three-necked flask and purged with argon. THF (10 ml) was added to dissolve, and Na ₂ CO ₃ (0.082 g), phenyltriethylamine (0.03 g), and 1,2-naphthoquinone-2-diazide-4-sulfonyl chloride were sequentially added with stirring. . This was stirred at 40 ° C. for 1.5 hours.

Cold methanol (36 ml) containing HCl (0.018 ml) was prepared, and the above reaction solution was dropped therein and left at 5 to 10 ° C. overnight. The purified product was filtered and dried in vacuo to give a yellow powder product (yield 0.27 g, 62.6% yield). The results of ¹ H-NMR measurement are as follows.

¹ H-NMR (δ, 270 MHz, THF-d): 7.05-7.08 (m, 6H, Ph—H), 7.53-7.56 (m, 3H, Ph—H), 7. 61-7.64 (m, 6H, Ph-H), 7.68-7.71 (m, 3H, Ph-H), 7.75-7.78 (m, 3H, Ph-H), 7 83-7.87 (m, 6H, Ph-H), 7.87-7.88 (m, 6H, Ph-H), 7.93 (s, 3H, Ph-H), 8.46- 8.49 (m, 3H, Ph-H), 8.49-8.52 (m, 3H, Ph-H).
The product is identified as (1,3,5-tris (para- (para-1,2-naphthoquinone-2-diazido-4-sulfonylphenyl) phenyl) benzene (hereinafter referred to as NQD4TPPPB)) represented by the following chemical formula: It was done.

(Synthesis Example 4)
THTPPB (0.20 g) obtained in Synthesis Example 2 was placed in a three-necked flask and purged with argon. THF (10 ml) was added to dissolve, and Na ₂ CO ₃ (0.082 g), phenyltriethylamine (0.03 g), and 1,2-naphthoquinone-2-diazide-5-sulfonyl chloride were sequentially added with stirring. . This was stirred at 40 ° C. for 1.5 hours.

Cold methanol (36 ml) containing HCl (0.018 ml) was prepared, and the above reaction solution was dropped therein and left at 5 to 10 ° C. overnight. The purified product was filtered and dried in vacuo to give a yellow powder product (yield 0.28 g, yield 64.3%). The results of ¹ H-NMR measurement are as follows.

¹ H-NMR (δ, 270 MHz, THF-d): 7.01-7.05 (m, 6H, Ph—H), 7.24-7.26 (m, 3H, Ph—H), 7. 24-7.26 (m, 3H, Ph-H), 7.24-7.28 (m, 6H, Ph-H), 7.47-7.50 (m, 6H, Ph-H), 7 50-7.53 (m, 6H, Ph-H), 7.59-7.63 (m, 3H, Ph-H), 7.83 (m, 3H, Ph-H), 8.19- 8.22 (m, 3H, Ph-H), 8.67-8.70 (m, 3H, Ph-H).
The product is identified as (1,3,5-tris (para- (para-1,2-naphthoquinone-2-diazido-5-sulfonylphenyl) phenyl) benzene (hereinafter referred to as NQD5TPPPB)) represented by the following chemical formula. It was done.

As described above, a compound composed of seven benzene rings was synthesized. Each compound was dissolved in anisole as a solvent to prepare a resist solution. The formulation of the resist solution is shown in Table 1 below. The concentration in the table is the weight percent of the matrix compound relative to the solvent.

* 1: Resist No. In No. 2, there was undissolved NAQ5TPPB, which was filtered and used in a saturated solution state.

  A resist film was formed using the resist solution prepared as described above and patterned.

(Examples 1 and 2)
A resist solution was applied onto a silicon wafer by spin coating to form a resist film having a thickness of about 200 nm. The obtained resist film was baked at 110 ° C. for 90 seconds, covered with a photomask, and subjected to pattern exposure with ultraviolet rays for 10 minutes with both ends sandwiched between clips.

After exposure, development was performed with an aqueous tetramethylammonium hydroxide (TMAH) solution to obtain a positive pattern. The processing conditions and results are summarized in Table 2 below. In all the conditions, no peeling of the pattern was observed, and the resolution was 1 μm, which was the limiting resolution when this type of exposure method was used.

  As is clear from the results in Table 2 for reference, when pattern formation is performed using the resist according to the embodiment of the present invention, pattern formation by alkali development is possible in all cases. Considering the photosensitive mechanism, it can be easily estimated that i-line is also exposed. That is, the resist according to the embodiment of the present invention can be sufficiently applied to i-line exposure.

(Examples 3 and 4)
A resist solution was applied onto a silicon wafer by spin coating to form a resist film having a thickness of about 100 nm. After the obtained resist film was baked at 110 ° C. for 90 seconds, an electron beam lithography apparatus (acceleration voltage of the electron beam is 30 keV) and a half pitch within a range of electron beam irradiation doses from 20 μC / cm ² to 330 μC / cm ^2. A 100 nm line and space (1: 1) pattern was drawn.

After exposure, development was performed with acetone to obtain a negative pattern. The treatment conditions and the results obtained are summarized in Table 3 below.

  The roughness was evaluated by the following line width roughness (LWR) evaluation method. The resist film was drawn with an electron beam and baked and developed with an aqueous TMAH solution to obtain a constant line and space pattern with a line width of 100 nm. The LWR value (3σ value) of the obtained pattern was calculated in the range of 350 nm × 50 nm (ROI).

The resist 5 used in Comparative Example 1 in Table 3 was prepared by dissolving a novolak resin (Retitoc PSF2807) as a matrix compound and a photosensitive component in a solvent according to the following formulation. As the photosensitive component, a naphthoquinone diazide compound (4NT (4) 300 manufactured by Toyo Gosei Co., Ltd.) into which three naphthoquinone diazide sulfonic acids of naphthoquinone derivative 2,3,4,4′-tetrahydroxybenzophenone were introduced on average was used. As the solvent, propylene glycol monomethyl ether acetate was used.

  The content of the matrix compound is% by weight with respect to the solvent, and the amount of the photosensitive component is% by weight with respect to the matrix compound.

  As a result of observing the formed pattern with a scanning electron microscope, as is clear from the results in Table 5, when the resist according to the embodiment of the present invention is used, a half-pitch 100 nm line and space (1: 1) pattern is formed. However, when the resist 5 of Comparative Example 1 was used, a half pitch 100 nm line and space (1: 1) pattern could not be formed. It was found that the LWR was small when the resist of the example was used. It can be easily estimated that high resolution can be achieved when the LWR is small.

(Examples 5 and 6)
A resist solution was applied onto a silicon wafer by spin coating to form a resist film having a thickness of about 100 nm. The obtained resist film was baked at 110 ° C. for 90 seconds, and then a half pitch 100 nm line and space (1: 1) pattern was drawn with an electron beam drawing apparatus (electron beam acceleration voltage was 30 keV).

After the exposure, the entire surface was exposed with ultraviolet rays, and then developed with an aqueous 2.38% tetramethylammonium hydroxide (TMAH) solution to obtain a negative pattern. The conditions of treatment and the results obtained are summarized in Table 5 below.

  As is clear from the results in Table 5, it was found that development with an alkaline aqueous solution such as a TMAH aqueous solution becomes possible by drawing the entire surface with ultraviolet rays after drawing with an electron beam using the resist of the example. . Moreover, since LWR is small, it can be easily estimated that high resolution can be achieved.

  Considering the photosensitivity mechanism for reference, it can be easily estimated that when pattern formation is performed using the resist according to the embodiment of the present invention, it is also sensitive to EUV light of soft X-rays (13 nm). That is, the resist according to the embodiment of the present invention can be sufficiently applied to future EUV lithography.

Claims (5)

A photosensitive compound represented by the following general formula (I):

(In the above general formula (I), at least a part of R is selected from (NQ1) and (NQ2) shown below, and the remainder is a hydrogen atom.)

  A photosensitive composition comprising the photosensitive compound according to claim 1 and a solvent. Forming a photosensitive layer containing the photosensitive composition according to claim 2 on a substrate;
Irradiating a predetermined region of the photosensitive layer with ultraviolet rays to perform pattern exposure;
And a step of developing the photosensitive layer after the pattern exposure with an alkaline aqueous solution to selectively remove the exposed portion of the photosensitive layer. Forming a photosensitive layer containing the photosensitive composition according to claim 2 on a substrate;
Irradiating a predetermined region of the photosensitive layer with ionizing radiation to perform pattern exposure;
And a step of developing the photosensitive layer after the pattern exposure with an organic solvent to selectively remove an unexposed portion of the photosensitive layer. Forming a photosensitive layer containing the photosensitive composition according to claim 2 on a substrate;
Irradiating a predetermined region of the photosensitive layer with ionizing radiation to perform pattern exposure;
Irradiating the entire region of the photosensitive layer after the pattern exposure with ultraviolet rays to expose the entire surface;
A pattern forming method comprising: developing the photosensitive layer after the entire surface exposure with an alkaline aqueous solution and selectively removing an unexposed portion of the photosensitive layer.