JP2007016154A - Polymerizable dendrimer and polymerizable resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymerizable resin composition that has such low viscosity that it can easily be handled and is excellent in processing accuracy and to provide a polymerizable dendrimer that can be utilized in the polymerizable resin composition. <P>SOLUTION: The polymerizable dendrimer has an alkenyl carboxylic acid having a polymerizable vinyl group bonded to a terminal functional group of the dendrimer. The polymerizable resin composition comprises the polymerizable dendrimer, a diluent copolymerizable with the polymerizable dendrimer and a polymerization initiator. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polymerizable dendrimer and a polymerizable resin composition that are cured by energy irradiation.

  Resins that are cured by irradiation with energy such as ultraviolet rays and electron beams are used in various industrial fields. For example, a photocurable resin that is cured by light irradiation is used as a material for lithography in the production of electronic devices. In recent years, the structure of electronic devices has been further miniaturized, and further improvement in processing accuracy has been demanded in lithography technology using a photocurable resin.

Conventionally, as a polymerizable resin composition used in photolithography, a photochemical reaction is initiated with a polymer resin (prepolymer) that causes a photochemical reaction and a polyfunctional low-molecular weight (monomer) as a diluent for the prepolymer. There are some which are comprised from the initiator for making (for example, refer patent documents 1-3).
JP 2001-270973 A Japanese Patent Laid-Open No. 9-5997 Japanese Patent Laid-Open No. 10-60655

Prepolymers include acrylic acid / 1,6-hexanediol / acrylic acid (formula a), phthalic anhydride / propylene oxide / acrylic acid (formula b), trimellitic acid / diethylene glycol / acrylic acid (formula c Polyester-based ultraviolet curable resins having a relatively large molecular weight such as) are often used.

In addition, polymerizable resin compositions using epoxy groups as photopolymerizable functional groups are also known (for example, Patent Documents 4 to 6).
JP 2002-302523 A JP 7-316262 A JP 2001-139663 A

  Since the prepolymer has a very high viscosity and is difficult to handle such as coating, a polyfunctional monomer copolymerizable with the prepolymer is often added as a diluent. This diluent has a lower molecular weight than the prepolymer, and the viscosity can be lowered by adding it to the prepolymer. Although it is possible to reduce the viscosity by diluting the prepolymer with a solvent, this causes the solvent to volatilize before light irradiation, resulting in irregularities on the surface, which reduces the processing accuracy in photocuring. Problems arise. Further, when the prepolymer is diluted with a solvent, the viscosity changes due to volatilization of the solvent, and handling becomes difficult.

On the other hand, as a technique related to the present invention, it has been reported that a photopolymerizable functional group is introduced at the end of a dendrimer and used as a prepolymer of a polymerizable resin composition (Patent Document 7). Since the dendrimer has good compatibility with the dye, a photocurable resin in which the dye is dissolved can be obtained. This photo-curable resin can be subjected to multi-photon lithography using a multi-photon absorption reaction, which improves the processing accuracy in photo-curing. However, there is no description about the relationship between the structure of the dendrimer and the viscosity when the dendrimer is used as a prepolymer of the polymerizable resin composition.
JP 2003-327645 A

  In conventional polymerizable resin compositions as described in Patent Documents 1 to 3, low molecular weight dilution that can be copolymerized with the prepolymer to alleviate the difficulty of handling due to the high viscosity of the prepolymer. Although the viscosity was lowered using an agent, the viscosity was still high and handling was difficult. In addition, since the polymer obtained by photopolymerization has a long-chain molecular structure which is easy to move, there is a disadvantage that the processing accuracy is inferior.

  The present invention has been made in view of the above-described conventional situation, and provides a polymerizable resin composition having a low viscosity and easy to handle, and excellent in processing accuracy, and a polymerizable dendrimer usable for the same. Is a problem to be solved.

  The inventors paid attention to the property that a dendrimer having a unique branched structure has a low molecular weight despite having a large molecular weight. By using a novel dendrimer bonded to a functional group as a prepolymer, it has been found that the polymerizable resin composition has a low viscosity and is easy to handle and has excellent processing accuracy, and has led to the present invention.

  That is, the polymerizable dendrimer of the present invention is characterized in that an alkenylcarboxylic acid having a polymerizable vinyl group is bonded to a terminal functional group of the dendrimer.

The alkenyl carboxylic acid is not particularly limited as long as it is an alkenyl carboxylic acid having a polymerizable vinyl group, and examples thereof include the following carboxylic acids (1) to (3). In addition, methacrylic acid and the like are also included.

In the present invention, the dendrimer is a highly branched multi-branched compound having high regularity, and is a concept that does not include a hyper-branched compound having low regularity. The type of dendrimer is not particularly limited as long as it has a functional group at its end. As an easily available dendrimer, (1) an ester-type dendrimer in which triol and dicarboxylic acid alternately form ester bonds starting from a carboxyl group of a dicarboxylic acid as a core molecule (for example, the following compound (4 ), Etc.), (2) Amide-amine type dendrimers in which amide bonds and tertiary amines are alternately formed and branched from the amino group of the diamine as the core molecule (for example, the following compound (5), etc.) (3) An imine-type dendrimer (for example, the following compound (6) etc.) in which a tertiary amine is formed starting from the amino group of the diamine as the core molecule and is branched.

  In general, a regular dendrimer has a branched structure in which a branched molecular structure as a basic unit is repeatedly bonded from a polyfunctional compound at the center of a molecular structure called a core molecule. The number of regular repeats of the branched molecular structure that is the basic unit is represented by the concept term generation. Although there is no generally accepted definition of how to count this generation, a dendrimer in which a branched molecular structure as a basic unit is linked n times around a core molecule is defined as an (n-1) generation dendrimer. . As the number of generations of dendrimers increases, the synthetic cost of the dendrimer becomes multi-step and complicated, resulting in an increase in manufacturing cost. In addition, the inventors have confirmed that even when the number of generations of dendrimers is zero, it becomes sufficiently hard by light irradiation and can be used as a prepolymer of the polymerizable resin composition. For this reason, the number of generations is preferably 0th generation to 4th generation, and more preferably 0th generation to 2nd generation.

As the polymerizable dendrimer of the present invention, a compound represented by the following general formula (7) (wherein R is an alkyl group having a vinyl group) has a low viscosity and is easy to handle when used in a polymerizable resin composition. It is particularly suitable because it is excellent in processing accuracy.

  A polymerizable resin composition can be constituted by using the polymerizable dendrimer of the present invention as a prepolymer. That is, the polymerizable resin composition of the present invention is a polymerizable resin composition comprising a polymerizable prepolymer, a diluent copolymerizable with the prepolymer, and a polymerization initiator. The polymerizable dendrimer according to any one of claims 1 to 4 is included.

  As described above, since the polymerizable dendrimer of the present invention has a low viscosity, if this is used as a prepolymer, a diluent that can be copolymerized with the prepolymer and a polymerization initiator are mixed to form a polymerizable resin composition. Low viscosity makes it easy to handle. Further, according to the test results of the inventors, the processing accuracy is also excellent. This is presumably due to the fact that the polymerizable dendrimer has a compact and compact shape in spite of its high molecular weight, and therefore the movement of the existing position is less than that of the long-chain compound.

  The blending ratio of the prepolymer and the diluent is preferably 5:95 to 50:50 by mass ratio, more preferably 10:90 to 40:60, and most preferably 15:85. 35:65. When the blending ratio of the prepolymer is small, the hardness of the polymer polymerized by light irradiation is lowered. On the other hand, when the proportion of the prepolymer is too large, the viscosity becomes high and handling becomes difficult.

  The diluent is preferably a polymerizable compound having 1 to 3 polymerizable functional groups such as an acrylate group, and further preferably has a low viscosity, good solubility, and low volatility. A polyfunctional diluent having a plurality of polymerizable functional groups is particularly preferred because it has a high crosslinkability and becomes a part of the structure of the cured product after the reaction. Specific examples of the diluent include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl acryloyl phosphate, tetrahydrofurfuryl acrylate, dicyclopentenyloxy acrylate, and dicyclopentenyl. Oxyethyl acrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, hydroxypivalate ester neopentyl glycol diacrylate , Tripropylene glycol diacrylate, 1,3-bis (3′-acryloxyethoxy-2′-hydroxypropyl)- , 5-dimethyl hydantoin, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, and the like dipentaerythritol hexaacrylate.

  Among these, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, and 1,6-hexanediol diacrylate are particularly preferable.

As the polymerization initiator, a radical polymerization initiator generally used for photopolymerizing vinyl groups can be used. As such a radical polymerization initiator, one that easily absorbs ultraviolet rays and easily initiates a radical reaction, has high solubility in the prepolymer and the diluent, and has low corrosivity and discoloration is preferable. Specific examples of the radical initiator include 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, 4- (di-n-butylamino) -4 ′-(diethylamino). ) Stilbene, biacetyl, acetophenone, benzophenone, benzyl, benzoin, benzoin isobutyl ether, benzyl dimethyl ketal, tetramethyl thiuram sulfide, azobisisobutyronitrile, benzoyl peroxide, and the like. Moreover, it is also preferable to use the radical polymerization initiator of following Chemical formula (8) and Chemical formula (9). Since these radical initiators generate radicals efficiently even for light with low intensity, a highly sensitive polymerizable resin composition can be obtained. The radical polymerization initiator generates radicals that trigger the initiation of polymerization, and is mixed in a small amount catalytically.

<Synthesis of polymerizable dendrimer>
(Example 1)
In Example 1, a polymerizable dendrimer (13) was synthesized according to the following reaction formula using cis-1,3-O-Benzylideneglycerol (10) as a starting material. The synthesis method will be described in detail below.

Add cis-1,3-O-Benzylideneglycerol (10) (5.0 g, 27.7 mmol), succinic acid (1.55 g, 13.1 mmol) and 4-dimethylaminopyridine (0.36 g, 2.9 mmol) to 60 mL of dichloromethane as a magnetic stirrer. Then, 1-Ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride (5.8 g, 30.3 mmol) was added, and the reaction vessel was purged with nitrogen. After stirring at 0 ° C. (ice cooling) for 3 hours, the mixture was stirred overnight at room temperature. The reaction solution was washed 3 times with 1 / 20N hydrochloric acid, then twice with 100 mL of saturated aqueous sodium carbonate solution, and further once with 100 mL of water, and then the organic solvent phase was dried over anhydrous sodium sulfate. Thereafter, sodium sulfate was removed by decantation, and the solvent was distilled off under reduced pressure. The white solid thus obtained was recrystallized and purified with a chloroform / methanol mixed solution. The precipitated white crystals were taken out by suction filtration and dried under vacuum to obtain first crystals. Further, the solvent was distilled off from the filtrate, and the obtained white solid was recrystallized and purified in the same manner to obtain second to fourth crystals. In this way, a total of 5.05 g of white crystals from the first crystal to the fourth crystal was obtained with a yield of 90%. 1H-NMR of this product was as follows and was identified as having the structure of a benzylidene protected tetrahydroxy compound (11).
1H-NMR (CDCl3) δ (ppm)
2.81 (s, 4H, -C H2 -C H2 -), 4.06~4.14 (m, 4H, -C H2 -CH-C H2 -),
4.24~4.30 (m, 4H, -C H2 -CH-C H2 -), 4.70~4.73 (m, 2H, -CH2-C H -CH2-),
5.53 (s, 2H, O-CH-O), 7.30 ~ 7.40 (m, 6H, Ph), 7.47 ~ 7.52 (m, 4H, Ph)

Furthermore, 0.75 g (1.70 mmol) of the benzylidene-protected tetrahydroxy compound (11) was placed in an eggplant-shaped flask equipped with a suction stopper, and 12 mL of dehydrated tetrahydrofuran was added and dissolved. Next, 0.15 g of 10% Pd / C was added to this solution, and 20 μL of a solution prepared by dissolving 50 μL of concentrated hydrochloric acid in 2 mL of methanol was added. Then, a balloon filled with nitrogen was connected to the eggplant-shaped flask through a three-way cock, and the remaining mouth of the three-way cock was connected to an aspirator. After reducing the pressure inside the flask with an aspirator, the operation of introducing nitrogen was repeated three times to replace the inside of the flask with nitrogen. Next, the nitrogen balloon was replaced with a balloon filled with hydrogen, and the inside of the flask was replaced with hydrogen by the same operation. Thereafter, the solution was vigorously stirred at room temperature with a magnetic stirrer for 1.5 hours. Then, Pd / C was removed by suction filtration, the solvent of the filtrate was distilled off under reduced pressure, and the tetrahydroxy compound (12) as a colorless viscous liquid was obtained by drying with a vacuum pump. The 1H-NMR of this product is as follows.
1H-NMR (CD3OD) δ (ppm)
2.69 (s, 4H, -C H2 -C H2 -), 3.61~3.73 (m, 8H, -C H2 -CH-C H2 -),
4.85 ~ 4.94 (m, 2H, -CH2-C H -CH2-)

Then, the tetrahydroxy compound (12) (0.19 g, 0.71 mmol), acrylic acid (0.22 g, 3.1 mmol) and 4-dimethylaminopyridine (0.04 g, 0.32 mmol) were placed in 30 mL of dichloromethane, and a magnetic stirrer was used. Stir and further 1-Ethyl-3- (3-dimethyl
Aminopropyl) carbodiimide hydrochloride (0.64 g, 3.3 mmol) was added, and the inside of the reaction vessel was purged with nitrogen. After stirring at 0 ° C. for 2 hours, stirring at room temperature for 12 hours, the reaction solution was washed 3 times with 1 / 20N hydrochloric acid and then twice with 100 mL of saturated aqueous sodium carbonate solution, and then the organic phase was dried over sodium sulfate. I let you. Sodium sulfate was removed by decantation, and the solvent was distilled off under reduced pressure to obtain .12 g of a colorless liquid. 1H-NMR of this product was as follows and was identified to have the structure of a polymerizable dendrimer (13) having a vinyl group.
1H-NMR (CDCl3) δ (ppm)
2.67 (s, 4H, -CO- C H2 -C H2 -CO-), 4.22-4.33 (m, 4H, -C H2 -CH-C H2 -),
4.33-4.47 (m, 4H, -C H2 -CH-C H2 -), 5.29-5.42 (m, 2H, -CH2-C H -CH2-),
5.85-5.93 (m, 4H, -CH = C H2 ) 6.07-6.21 (m, 4H, -C H = CH2),
6.38-6.50 (m, 4H, -CH = C H2 )

(Example 2)
In Example 2, a polymerizable dendrimer (4) was synthesized by ester-bonding 4-pentenoic acid to the tetrahydroxy compound (12) which is an intermediate raw material in Example 1 according to the following reaction formula.

That is, first, the tetrahydroxy compound (12) is obtained by the same method as in Example 1. Then, tetrahydroxy compound (12) (0.48 g, 1.8 mmol), 4-pentenoic acid (0.74 g, 7.4 mmol) and 4-dimethylaminopyridine (0.09 g, 0.74 mmol) were put in 20 mL of dichloromethane, and a magnetic stirrer was used. After stirring, 1-Ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride (1.5 g, 8.1 mmol) was added, and the inside of the reaction vessel was purged with nitrogen. After stirring at 0 ° C. for 3 hours and at room temperature for 12 hours, the reaction solution was washed 3 times with 1 / 20N hydrochloric acid and then twice with 100 mL of saturated aqueous sodium carbonate solution, and then the organic phase was dried over sodium sulfate. I let you. Sodium sulfate was removed by decantation, and the solvent was distilled off under reduced pressure to obtain 0.95 g of a colorless liquid. 1H-NMR of this was as follows, and it was identified to have the structure of a polymerizable dendrimer (4) having a vinyl group.
1H-NMR (CDCl3) δ (ppm)
2.33-2.48 (m, 16H, -CO-C H2 -C H2 -CH =), 2.65 (s, 4H, -CO-C H2 -C H2 -CO-),
4.13-4.21 (m, 4H, -C H2 -CH-C H2 -), 4.27-4.36 (m, 4H, -C H2 -CH-C H2 -)
4.98-5.11 (m, 8H, -CH = C H2 ), 5.22-5.30 (m, 2H, -CH2-C H -CH2-),
5.74-5.89 (m, 4H, -C H = CH2)

<Production of photopolymerizable resin composition>
Using the polymerizable dendrimer (4) of Example 2 above, a photopolymerizable resin composition was produced as follows.

Example 3
In Example 3, the polymerizable dendrimer (4) synthesized in Example 2 above and trimethylolpropane triacrylate (hereinafter abbreviated as “TPA”) as a diluent were mixed at 25:75 (weight ratio) to initiate polymerization. A photopolymerizable resin composition was prepared by adding 0.5% by weight of 4,4′-bis (diethylamino) benzophenone as an agent.

(Comparative Examples 1-3)
In Comparative Examples 1 to 3, polyacrylates manufactured by Toa Gosei Co., Ltd. having a number of polymerizable functional groups of 3 or more as a prepolymer (Aronix M-7100 in Comparative Example 1 and Aronix M-8030 in Comparative Example 2 were compared. In Example 3, Aronix M-8060) and TPA were mixed at a mass ratio of 25:75, and a photopolymerizable resin composition containing 0.5% by weight of 4,4′-bis (diethylamino) benzophenone as a polymerization initiator was added. It was.

(Comparative Examples 4-6)
In Comparative Examples 4 to 6, polymerizable polyacrylates manufactured by Toa Gosei Co., Ltd. (Aronix M-7100 in Comparative Example 4, Aronix M-8030 in Comparative Example 5, and Aronix M-8060 in Comparative Example 6) were used as prepolymers. A photopolymerizable resin composition containing 0.5% by weight of 4,4′-bis (diethylamino) benzophenone as a polymerization initiator was used, and no diluent was added.

(Comparative Example 7)
In Comparative Example 7, a photopolymerizable resin composition obtained by adding 0.5% by weight of 4,4′-bis (diethylamino) benzophenone as a polymerization initiator to TPA was used, and no prepolymer was added.

(Comparative Example 8)
In Comparative Example 8, a photopolymerizable resin composition was prepared by using the polymerizable dendrimer (4) of Example 2 as a prepolymer and adding 0.5% by weight of 4,4′-bis (diethylamino) benzophenone as a polymerization initiator. No diluent was added.

The viscosities of the photopolymerizable resin compositions of Example 3 and Comparative Examples 1 to 8 were measured. Viscosity was measured using a vibration viscometer (Viscomate VM-100A manufactured by Yamaichi Denki). The results are shown in Table 1.

  From Table 1, the viscosity of the photopolymerizable resin composition of Example 3 using the polymerizable dendrimer (4) as the prepolymer is the photopolymerizable resin of Comparative Examples 1 to 6 using the polymerizable polyacrylate as the prepolymer. It can be seen that it is much lower than the viscosity of the composition and is easy to handle and easy to apply.

<Photocuring test of photopolymerizable resin composition>
Regarding the photopolymerizable resin compositions of Example 3 and Comparative Examples 1 to 8, Brian H. Cumpston et al, Nature, vol., Nature, vol. 398, pp. 51-54 (1999) and JP-A 2003-327645 Based on the method described in Japanese Unexamined Patent Publication Nos. 0049 to 0052, optical modeling by a two-photon absorption reaction was performed using the optical apparatus shown in FIG. This optical device irradiates a mirror 1 with a near infrared femtosecond laser (wavelength 700 nm, frequency 80 MHz, pulse width <100 femtoseconds) from a light source in the direction of arrow A. In two-photon lithography, two photons having a wavelength of 700 nm are absorbed simultaneously in the two-photon absorption process, so that absorption in the ultraviolet region of 350 nm, which is a half wavelength, can be excited. The laser irradiated onto the mirror 1 passes through the lens 2 and then passes through the pinhole 3. Subsequently, the laser passes through the lens 4 and is split by the beam splitter 5. A part of the divided laser beam is irradiated toward the objective lens 6 (magnification 80 to 100 times, numerical aperture NA = 0.9). The objective lens 6 adjusts the condensing point of the laser by moving up and down in the direction of arrow B in the figure. The laser with the condensing point adjusted is irradiated to the slide glass 7 on which the photopolymerizable resin composition 8 is applied. Since the slide glass 7 can move in the directions of the arrows x, y, and z in the figure, the photopolymerizable resin composition 8 can be irradiated three-dimensionally to advance the curing reaction. In this case, the beam was moved two-dimensionally to form a pattern having a line interval of 5 μm, a length of 100 μm, and a line width of 0.35 μm or less. A lens 9 and a CCD camera 10 are disposed on the opposite side of the slide glass 7 via the beam splitter 5, and the objective lens 6 and the CCD camera 10 are observed while observing the curing reaction with respect to the photopolymerizable resin composition 8. The slide glass 7 can be moved.

  Using the above optical apparatus, a pattern was formed by irradiating laser light to a sample in which the photopolymerizable resin composition of Example 3 was sandwiched between a slide glass and a cover glass. The results are shown in FIG. As can be seen from this figure, a pattern having a line interval of 5 μm could be clearly formed by two-photon lithography. Moreover, when laser intensity was performed in the range of 4.2 mW-10.2 mW, it turned out that line width becomes thin, so that laser intensity is small. On the other hand, when the photopolymerizable resin compositions of Comparative Examples 1 to 3 are used, it is possible to form a uniform film of the photopolymerizable resin composition between the slide glass and the cover glass because of the high viscosity. It was difficult and the pattern formation was unclear. Moreover, since the photopolymerizable resin compositions of Comparative Examples 4 to 6 had extremely high viscosity, it was extremely difficult to prepare samples to be irradiated with light. Further, since Comparative Example 7 did not contain a prepolymer, curing by light irradiation was insufficient.

  The present invention can be used as a material for photolithography in the production of electronic devices.

It is a schematic diagram of the optical apparatus used for two-photon lithography. It is the optical microscope photograph of the surface which performed two-photon lithography.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mirror 2 ... Lens 3 ... Pinhole 4 ... Lens 5 ... Beam splitter 6 ... Objective lens 7 ... Slide glass 8 ... Photopolymerizable resin composition 9 ... Lens 10 ... CCD camera

Claims (7)

  A polymerizable dendrimer, wherein an alkenylcarboxylic acid having a polymerizable vinyl group is bonded to a terminal functional group of the dendrimer.   The polymerizable dendrimer according to claim 1, wherein the alkenyl group in the alkenylcarboxylic acid has 2 to 4 carbon atoms.   The polymerizable dendrimer according to claim 1 or 2, wherein the number of generations indicating the number of repeating molecular structures of the polymerizable dendrimer is from the 0th generation to the 4th generation. The polymerizable dendrimer according to any one of claims 1 to 3, which is a compound represented by the following general formula (1) (wherein R is an alkenyl group having a vinyl group).
In a polymerizable resin composition containing a polymerizable prepolymer, a diluent copolymerizable with the prepolymer, and a polymerization initiator,
The polymerizable resin composition, wherein the prepolymer contains at least the polymerizable dendrimer according to any one of claims 1 to 4.   6. The polymerizable resin composition according to claim 5, wherein the blending ratio of the prepolymer and the diluent is 5:95 to 50:50 by mass ratio.   The polymerizable resin composition according to claim 5 or 6, wherein the diluent is a polymerizable compound having 1 to 3 polymerizable functional groups.