JPH087436B2 - Photosensitive diazoquinone compound and positive photosensitive resin composition using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photosensitive diazoquinone compound excellent in transparency and pattern forming ability, and a positive photosensitive resin composition using the same.

[Prior Art] Certain diazoquinone compounds, for example, 1,2-naphthoquinonediazide-5-sulfonate are known to have photoreactivity. Utilizing this property, a coating film having a diazoquinone compound is exposed to light to form a pattern of the coating film. The mechanism is believed to be as described below. This diazoquinone compound is hardly soluble in an alkaline solution in the unreacted state. However, when this compound is exposed to light, a chemical reaction occurs, a carboxyl group is generated in the molecule, and the solubility in an alkaline solution increases. Therefore, a photosensitive diazoquinone compound coating film formed on a substrate or the like is exposed through a mask or the like only to a region to be removed, and then the soluble region is dissolved and removed by an alkaline solution to remove the coating film. The pattern is obtained. Furthermore, by adding a photosensitive diazoquinone compound to a polymer soluble in an alkaline solution or a precursor thereof, for example, polyvinylphenol, novolac resin, polyamidephenol, polyamic acid, polyimide having a phenolic hydroxyl group, etc. It is possible to impart photopatterning ability to the coating film. That is, in the unexposed area, the presence of a photosensitive diazoquinone compound that is poorly soluble in an alkaline solution, and the formation of a coupling compound or complex between the photosensitive diazoquinone compound and the polymer, dissolves the coating film in an alkaline solution. Sex decreases. On the other hand, in the exposed area, the photosensitive diazoquinone compound is also solubilized, and the coating film becomes soluble in the alkaline solution together with the polymer or the precursor thereof which is soluble in the alkaline solution, and a coating pattern excellent in strength and heat resistance is obtained. Can be formed.

The "positive type" photosensitive resin composition that obtains a pattern by removing these exposed regions is a coating film during development as compared with the "negative type" that obtains a pattern by insolubilizing the exposed regions by a method such as crosslinking. Since it does not swell, it is possible to form a fine pattern. It has various characteristics such as using only alkaline solution as a developing solution and not using harmful organic solvents. Therefore, it is currently being used as a resist for microfabrication when manufacturing semiconductor devices with higher density, as an interlayer insulating film for multilayer wiring that can be patterned, as a coating resin for semiconductor protection, or is expected to be used in the future. There is.

Properties required for these photosensitive resin compositions for semiconductors include high resolution, high contrast, and thick film processability. Of these, the latter two performances depend largely on the molecular structure of the photosensitive diazoquinone compound. That is, the photosensitive diazoquinone compound is soluble in the polymer or its precursor, and effectively reduces the solubility of the coating film in the alkaline solution in the unexposed state, and after exposure, the polymer or its precursor is adversely affected. It is necessary that the solubility of the photosensitive diazoquinone compound in the alkaline solution be improved and that the photosensitive diazoquinone compound after the reaction has high transparency and sufficient exposure can be performed even in a deep portion of a thick coating film. Generally, as a photosensitive diazoquinone compound, 1,
An ester of 2-naphthoquinonediazide-5-sulfonic acid and various phenols is used, and a polyfunctional photosensitive diazoquinone compound represented by the following structural formulas [II] and [III] is obtained by using a polyfunctional phenol. Are known. However, in these photosensitive diazoquinone compounds, since the absorption of ultraviolet light by the aromatic ring of the phenoxy group cannot be ignored, the light does not reach the deep part of the thick film, and the workability of the thick film is limited. Further, when these photosensitive resins are used as an interlayer insulating film for multilayer wiring of a semiconductor circuit or a coating material for a semiconductor chip, they are required to have a low dielectric constant and a low water absorption rate from the viewpoint of high-speed calculation and reliability. . However, in the conventional positive photosensitive resin, these performances of the coating film were limited by polar phenols remaining in the coating film after curing.

[Problems to be Solved by the Invention] The present invention relates to a photosensitive diazoquinone compound capable of forming a photosensitive resin composition having features such as high contrast and good thick film processability, and a photosensitive resin composition using the same. It is about things.

[Means for Solving the Problems] The present invention is characterized by having a structure represented by the following formula [I]. (In the formula, Q ₁ to ₄ each represent —H or a monovalent group containing a diazoquinone structure, at least one of which is a monovalent group containing a diazoquinone structure). A photosensitive diazoquinone compound.

One feature of the present invention is that a group having a diazoquinone structure is bonded to a fluorine-containing aromatic aminophenol. As a result, the polarization of the aminophenol moiety to which the group having a diazoquinone structure is bonded is suppressed as compared with the conventional photosensitive diazoquinone compound, and as a result, the transparency of the entire compound is improved, and it is possible to sufficiently expose the coating film to a deep portion. It has become possible. As a result, by adding this compound to a polymer soluble in an alkaline solution or a precursor thereof, it is possible to obtain a photosensitive resin composition having excellent thick film processability and having a sharp pattern cross-section.

Further, by introducing a fluorine atom into the molecular structure of the compound to suppress the polarization in the molecule, the water absorption of the coating film pattern of the polymer obtained or the coating film pattern obtained by curing its precursor It is also possible to reduce the electric charge and improve the electrical characteristics such as the dielectric constant.

The second feature of the present invention is to obtain a photosensitive diazoquinone compound obtained by bonding 1 to 4 groups having a diazoquinone structure to tetrafunctional diaminobisphenol and leaving the remaining functional groups as a hydroxyl group or an amino group. Is to control the solubility of the. As described above, the photosensitive diazoquinone compound is required to reduce the solubility of the coating film in the alkaline solution in the unexposed area and conversely improve the solubility in the exposed area. The former is the use of a photosensitive diazoquinone compound having two or more diazoquinone structures in the molecule, or a photosensitive diazoquinone, so that the polymer is crosslinked by the formation of a coupling or a complex between the polymer and a group having a diazoquinone structure. This is achieved by reducing the solubility of the compound itself. However, when the solubility of the photosensitive diazoquinone compound itself is reduced, the solubility of the polymer or its precursor is also reduced, so that the concentration of the diazoquinone structure that may be present in the photosensitive resin composition is reduced,
The pattern forming ability is reduced. Furthermore, the solubility of the coating film at the time of exposure also decreases, and the pattern contrast decreases. Therefore, it is necessary to introduce two or more diazoquinone structures in the molecule of the photosensitive diazoquinone compound and control the solubility thereof to an optimum value. In the present invention, the number of groups having a diazoquinone structure in the photosensitive diazoquinone compound molecule and the amounts of the hydroxyl group and the amino group are changed from 1 to 4 and 3 to 0, respectively,
Succeeded in controlling the solubility. That is, the solubility is increased by increasing the number of groups having a diazoquinone structure in the molecule, and conversely, the solubility is decreased by decreasing the number of groups having a diazoquinone structure. The number of introduced groups having an optimum diazoquinone structure varies depending on the solubility of the polymer or its precursor, but it is needless to say that two or more groups are desirable in order to cause crosslinking between the polymers. Particularly when the polymer is polyamidephenol which is a precursor of polybenzoxazole, the highest contrast pattern can be obtained by introducing three groups having a diazoquinone structure.

Examples of the group having a diazoquinone structure in the present invention include those having the following structures [IV] to [IX]. Can be mentioned. It is possible to select the optimum diazoquinone structure depending on the wavelength of the exposure light, but g-line (wavelength 436 nm) or i-line (wavelength 365 nm) from a high pressure mercury lamp that is generally used in the semiconductor manufacturing process. ) To get a good pattern, 1,2
It is preferable to select the -naphthoquinonediazide-5-sulfonyl group [IV].

This photosensitive diazoquinone compound was prepared by adding the corresponding diazoquinone sulfonic acid chloride corresponding to the introduction rate required for 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane to a base such as pyridine. It can be easily obtained by condensation in the presence.

Furthermore, a positive type resin composition is obtained by adding the obtained photosensitive diazoquinone compound to a polymer or polymer precursor soluble in an alkaline solution. Here, polyvinylphenol as the alkali-soluble polymer,
Examples thereof include cresol novolac resin, hydroxyl group-containing closed-ring polyimide resin, and the like, and alkali-soluble polymer precursors such as polyamidophenol which is a precursor of polybenzoxazole and polyamic acid which is a polyimide. The amount of the photosensitive diazoquinone compound added per 100 parts by weight of these polymers or polymer precursors is 1 to 100 parts by weight, preferably 5 to 50 parts by weight. When the photosensitive diazoquinone compound is added in an amount of more than 100 parts by weight with respect to the polymer or the polymer precursor, the coating film becomes brittle, and the application as a resin for semiconductor production is extremely limited. On the contrary, when the amount of the photosensitive diazoquinone compound is less than 1 part by weight,
The sensitivity and contrast of the coating film are significantly reduced.

Examples of the solvent for this resin composition include N-methylpyrrolidone, N, N-dimethylacetamide, 2-ethoxyethyl acetate, diethylene glycol dimethyl ether, and γ-butyrolactone.

Then, the resin composition is applied onto a substrate, solvent is dried, exposed, developed with an alkali solution such as tetramethylammonium hydroxide solution, rinsed with water, heated and dried with a polymer coating or heated with a polymer precursor. By curing, it is possible to obtain a resin pattern from a thick film to a thin film which has a high contrast and a low dielectric constant and a low water absorption.

[Examples] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

(Example 1) 2,3.9 parts by weight of 2,2-bis (3-amino-4-hydroxyphenyl) tetrafluoropropane and 100 parts by weight of dry tetrahydrofuran were placed in a separable flask equipped with a nitrogen introducing part, a thermometer and a stirrer. Was added and the solid content was completely dissolved by starting stirring under a nitrogen stream, and then 6.6 parts by weight of triethylamine was added to the yarn and dissolved. Then, while continuing the nitrogen flow and stirring, cool the flask and
A solution prepared by dissolving 52.5 parts by weight of 1,2-naphthoquinonediazide-5-sulfonyl chloride in 117 parts by weight of dry tetrahydrofuran was added dropwise over 30 minutes while keeping the yarn at a temperature of ℃ to -10 ℃. Then, after returning the temperature of the system to room temperature, another 5
The stirring was continued in a nitrogen stream for an hour. Then, the system was dropped into about 1500 parts by weight of water, the insoluble matter formed was collected by filtration, and dried overnight in a vacuum dryer to obtain 65 parts by weight of a photosensitive diazoquinone compound [X] having the following structure. I got a copy.

Next, 20 parts by weight of the obtained [X], 100 parts by weight of a polybenzoxazole precursor [XI] having the following structure, A photosensitive resin composition was prepared from 400 parts by weight of N-methylpyrrolidone. This resin composition is applied onto a silicon wafer using a spin coater and dried in an oven at 70 ° C. for 1 hour to obtain a coating film having a thickness of about 10 μm. Mask from Toppan Printing Co., Ltd. (Test Chart No. 1; width 50 μm to 0.88)
(The remaining pattern and the blank pattern of μm are drawn.)
After irradiating 200 mJ / cm ² of ultraviolet rays from a high-pressure mercury lamp through, the unexposed portion was dissolved and removed by immersing in a 0.95% tetramethylammonium hydroxide aqueous solution for 30 seconds, and then the developing solution was rinsed with water for 30 seconds ( rinse). As a result, a fine coating film pattern having a film thickness of 6.0 μm and a resolution of 3 μm was formed on the silicon wafer. This pattern in the oven for 30 minutes / 150 ℃, 30 minutes / 250 ℃, 30 minutes
Even if the resin was heated and cured in the order of / 350 ° C., the shape of the pattern was completely retained up to the fine portion and was good. Furthermore, a coating film having a thickness of 15 μm after drying was obtained from this composition, and the same operation was performed except that the paddle development time was extended to 40 seconds. As a result, a fine film having a resolution of 5 μm with a film thickness of 8.8 μm was obtained. A pattern of the coating film was formed, and the shape of the pattern was kept unchanged after the curing.

Further, the resin composition was similarly coated on an aluminum plate, prebaked, and the dielectric constant of the coating film obtained by heating and curing was measured according to the method of JIS-C-6481 to be 3.0 (room temperature, 1 MHz). It showed a good value. The tensile strength (JIS-K-6760) of the film obtained by dissolving and removing the aluminum plate from this coating film with ferric chloride solution is 9.0 kg / mm ² , and the water absorption rate (JIS-K-6911). Was as good as 1.2%.

(Example 2) A photosensitive resin composition was prepared from 20 parts by weight of the photosensitive diazoquinone compound [X] obtained in Example 1, 100 parts by weight of m-cresol formaldehyde novolac resin, and 400 parts by weight of acetic acid-2-ethoxyethyl. did. By using the resin composition and performing the same patterning operation as in Example 1, a coating film having a thickness after drying of 10 μm and a film thickness of 5.9 μm and a resolution of 1.2 μm and a thickness after drying of 15 μm was applied. A very fine pattern was obtained from the film at a film thickness of 8.7 μm and a resolution of 2 μm.

(Example 3) 20 parts by weight of the photosensitive diazoquinone compound [X] obtained in Example 1, 100 parts by weight of a polyamic acid represented by the following structural formula [XII], A photosensitive resin composition was prepared from 400 parts by weight of N-methylpyrrolidone. By performing the same patterning operation as in Example 1 using this resin composition, from a coating film having a thickness of 10 μm after drying to a film thickness of 5.0 μm and a resolution of 10 μm, and a coating film having a thickness of 15 μm after drying. A fine pattern with a film thickness of 7.2 μm and a resolution of 15 μm was obtained.

(Comparative Example 1) Instead of the photosensitive diazoquinone compound [X] in Example 1, a diazoquinone compound containing no fluorine in the molecule having the structure of the following formula [XIII] was used. When the same patterning operation was carried out using the same, the resolution of the pattern obtained from the coating film having a thickness after drying of 10 μm was still 3 μm, but the film thickness was only 2.9 μm. Furthermore, in the coating film with a thickness of 15 μm after drying,
The fine portions of the pattern were crushed during the development, and the resolution of the obtained pattern was 50 μm and the film thickness was only 4.0 μm. The cured coating film or film had a dielectric constant of 3.4, a tensile strength of 1.9 kg / mm ² , and a water absorption rate of 1.7%, which were all inferior to those obtained in Example 1.

(Comparative Example 2) In Example 1, the addition amount of the photosensitive diazoquinone compound [X] was reduced from 20 parts by weight to 0.5 parts by weight.
The same operation was performed. However, the thickness after drying is 10μ
In each of the coating films of m and 15 μm, the exposed portion at the time of development was not dissolved in the developing solution and a pattern could not be obtained. When the immersion time in the developing solution was further increased to 10 minutes, the unexposed area was dissolved almost at the same time as the exposed area, and the pattern could not be obtained.

(Comparative Example 3) In Example 1, the amount of the photosensitive diazoquinone compound [X] added was increased from 20 parts by weight to 120 parts by weight.
The same operation was performed. However, the coating film after curing was extremely brittle, and a film having self-holding property could not be obtained due to dissolution and removal of the aluminum plate.

 The characteristics of Example 1 and Comparative Examples 1 to 3 are shown in Table 1.

EFFECTS OF THE INVENTION A feature of the present invention is that a photosensitive diazoquinone compound is obtained by introducing a controlled number of groups having a diazoquinone structure into a tetrafunctional diaminobisphenol having a fluorine atom, and this is added to an alkaline solution. That is, the photosensitive resin composition was obtained by adding it to a soluble polymer or polymer precursor. As a result, it has become possible to obtain a polymer coating pattern from a thick film to a thin film having high contrast, low dielectric constant and low water absorption.

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Claims (4)

[Claims] 1. A photosensitive diazoquinone compound having a structure represented by the following formula [I]: (In the formula, Q ₁ to ₄ represent -H or a monovalent group containing a diazoquinone structure, at least one of which is a monovalent group containing a diazoquinone structure) 2. Q ₂ , Q ₃ , and Q ₄ are 1,2-naphthoquinonediazide-
The photosensitive diazoquinone compound according to claim ₁ , which is a 5-sulfonyl group and Q ₁ is —H. 3. A photosensitive diazoquinone compound according to claim 1 in an amount of 1 to 100 parts by weight based on 100 parts by weight of a polymer or a polymer precursor soluble in an alkaline solution. Positive type photosensitive resin composition. 4. A photosensitive diazoquinone compound according to claim 2 in an amount of 1 to 100 parts by weight based on 100 parts by weight of a polymer or a polymer precursor soluble in an alkaline solution. Positive type photosensitive resin composition.