JP5047595B2 - Photoresist composition - Google Patents

Description

  The present invention relates to a photoresist composition used for the production of a fine circuit such as a liquid crystal display device circuit or a semiconductor integrated circuit, and more specifically, by introducing a component that improves the fluidity of the photoresist composition, The present invention relates to a photoresist composition having excellent pattern uniformity and adhesion.

  In order to form a fine circuit pattern such as a liquid crystal display device circuit or a semiconductor integrated circuit, first, a photoresist composition is uniformly coated or applied to an insulating film or a conductive metal film on a substrate. Next, the photoresist composition coated or applied using a mask having a predetermined shape is exposed and developed to form a fine circuit pattern having a desired shape. Thereafter, the metal film or the insulating film is etched using a mask to remove the remaining photoresist composition, and a fine circuit pattern is formed on the substrate. For the coating or coating process, a spin coating method or a slit coating method is used.

  In general, a photoresist composition includes a polymer resin, a photosensitive compound, and a solvent. To date, coating uniformity of photoresist film formed using a photoresist composition, photosensitive speed, development contrast, resolution, adhesion to substrate, remaining film ratio, circuit line width uniformity (CD uniformity), Many attempts have been made to improve human safety and the like.

  For example, the following Patent Document 1 discloses the use of a mixture of two types of phenol formaldehyde novolak resins and a typical photosensitive compound, and the following Patent Document 2 discloses phenol resins in order to improve the photosensitive speed. And a composition of a photoresist composition in which an organic acid cyclic anhydride is added to a naphthoquinone diazide photosensitizer is disclosed, and Patent Document 3 discloses a novolac resin for improving the photosensitivity and improving human safety. , A composition of a photoresist composition using an o-quinonediazide photosensitive compound and a propylene glycol alkyl ether acetate as a solvent is disclosed.

  However, there are still photosensitivity speed, residual film rate, residual film uniformity in the half-exposed area, development contrast, resolution, solubility of the polymer resin, adhesion to the substrate, and circuit line width uniformity. Attempts have been made for a variety of photoresist compositions suitable for each industrial process without sacrificing any of the preferred characteristics of the photoresist composition.

US Pat. No. 3,666,473 U.S. Pat. No. 4,115,128 U.S. Pat. No. 4,550,069

  In consideration of the problems of the conventional technique, the present invention has a photoresist film speed, remaining film ratio, development contrast, resolution, polymer resin solubility, adhesion to a substrate, and circuit line. An object of the present invention is to provide a photoresist composition capable of improving the CD uniformity.

  Another object of the present invention is to provide a photoresist composition having excellent pattern uniformity and pattern fluidity after a hard bake process and excellent dry etching and wet etching process characteristics. To do.

  Furthermore, an object of this invention is to provide the liquid crystal display device or semiconductor element manufactured using the said photoresist composition.

  In order to achieve the above object, the present invention provides (a) a novolak resin; (b) a diazide-based photosensitive compound; (c) a fluidity improver; (d) a sensitivity enhancer; and (e) an organic solvent. A photoresist composition is provided.

  In addition, the present invention provides a liquid crystal display device or a semiconductor element manufactured using the photoresist composition.

  The photoresist composition according to the present invention uses a fluidity improver and a sensitivity enhancer to prevent pattern deformation due to strong vacuum drying and improve pattern uniformity. Contrast, resolution, polymer resin solubility, adhesion to the substrate, and circuit line width uniformity are all excellent at the same time. Accordingly, the present invention can be easily applied to industrial sites and has effects such as reduction of usage amount and reduction of mass production time during mass production, so that the working environment can be changed efficiently.

  Hereinafter, the present invention will be described in detail.

  The present invention relates to a photoresist composition that can improve the fluidity of a photoresist film during a hard bake process using a fluidity improver and a sensitivity enhancer.

  The photoresist composition of the present invention comprises (a) a novolak resin; (b) a diazide-based photosensitive compound; (c) a fluidity improver; (d) a sensitivity enhancer; and (e) an organic solvent.

  In the photoresist composition of the present invention, (a) the novolak resin is a high molecular polymer synthesized by reacting an aromatic alcohol such as metacresol or paracresol and formaldehyde, and has a weight average molecular weight of 2,000 to 2,000. 10,000 is preferred.

  The (a) novolak resin has different material properties such as the photosensitive speed and the remaining film ratio depending on the mixing ratio of metacresol / paracresol. Specifically, the (a) novolak resin preferably has a metacresol / paracresol content ratio of 30 to 70:70 to 30 parts by weight. If the content of metacresol exceeds the above range, the photosensitivity speed increases and the remaining film rate decreases, and if the content of paracresol exceeds the above range, the photosensitivity speed decreases. .

  The content of the (a) novolak resin is preferably 5% by weight or more so that it can be easily applied to a desired thickness, and 30% so that uniform coating can be performed. % Or less is preferable.

  In the photoresist composition of the present invention, (b) the diazide-based photosensitive compound is obtained by reacting a compound such as polyhydroxybenzophenone, 1,2-naphthoquinonediazide, and 2-diazo-1-naphthol-5-sulfonic acid. Can be manufactured.

  For example, the (b) diazide-based photosensitive compound is produced by esterification of trihydroxybenzophenone and 2-diazo-1-naphthol-5-sulfonic acid, 2,3,4-trihydroxybenzophenone-1 , 2-naphthoquinonediazide-5-sulfonate; or 2,3,4,4′-tetrahydroxy prepared by esterification of tetrahydroxybenzophenone and 2-diazo-1-naphthol-5-sulfonic acid Benzophenone-1,2-naphthoquinonediazide-5-sulfonate can be used alone or in combination. Preferably, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate and 2,3,4,4′-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonic acid The salt can be mixed and used at a ratio of 40 to 60:60 to 40 parts by weight.

  The content of the (b) diazide photosensitive compound is preferably 2 to 10% by weight in order to maintain an appropriate photosensitivity.

  The photoresist composition of the present invention includes (c) a fluidity improver in order to maintain the fluidity and maximize the pattern fluidity, particularly during the hard bake process.

  The (c) fluidity improver is preferably a glycol or pyrrolidone having a boiling point of 180 ° C. or higher, and representative examples thereof include dipropylene glycol monomethyl ether, 2,2 ′, 4-trimethyl-1, 3-Pentanediol monoisobutyrate (2,2 ′, 4-trimethyl-1,3-pentanediolmonoisobutyrate), 1- (2-hydroxyethyl) -2-pyrrolidone, gamma-butyllactone and the like can be used. .

  In addition, the content of the fluidity improver (c) is preferably 0.5% by weight or more in order to realize a sufficient fluidity effect, and improves the coating property by increasing the remaining film ratio. Therefore, the content is preferably 5% by weight or less.

  In the photoresist composition of the present invention, (d) a sensitivity enhancer is used for improving the sensitivity and pattern fluidity during the hard baking process.

  The (d) sensitivity enhancer is preferably a polyhydroxy compound containing a phenolic hydroxy group and having a molecular weight of less than 500. Representative examples include 2,3,4-trihydroxybenzophenone, 2,3,4,4′-tetrahydroxybenzophenone, 2,3,4,3 ′, 4 ′, 5-hexahydroxybenzophenone, acetone- Pyrogallol condensate, 4,4- [1- [4- [1- (1,4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol (TPPA), and 4,4 ′-[2-hydroxy One or more selected from the group consisting of phenyl] methylene] bis [2,6-dimethylphenol] (BI26X-SA) can be used.

  The content of the (d) sensitivity enhancer is preferably 0.1% by weight or more in order to realize a sufficient sensitivity enhancement effect, and 10% in order to prevent a rapid decrease in the remaining film ratio. It is preferable that it is less than weight%.

  In the photoresist composition of the present invention, (e) the organic solvent is composed of propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), 2-methoxyethyl acetate (MMP), and propylene glycol monomethyl ether (PGME). One or more selected from the above can be used, and more preferably, PGMEA and MMP can be mixed and used in a ratio of 70 to 90:30 to 10 parts by weight.

  In addition, the photoresist composition of the present invention is selected from the group consisting of a colorant, a dye, an anti-scratch agent, a plasticizer, an adhesion promoter, a speed enhancer, and a surfactant as necessary 1 By additionally adding more than one kind of additive and coating the substrate, it is possible to realize an improvement in performance due to the characteristics of individual processes.

  In addition, the present invention can manufacture a semiconductor element using the photoresist composition manufactured as described above. As a preferable example, it can be used in the manufacturing process of the following liquid crystal display device circuit among semiconductor elements.

  First, the photoresist composition according to the present invention is applied on a substrate by a usual coating method including dipping, spraying, and spin coating. For example, when spin coating is performed, a coating having a desired thickness can be formed by appropriately changing the solid content of the photoresist composition according to the type and method of the spinning apparatus.

  Examples of the substrate include silicon, aluminum, indium tin oxide (ITO), indium zinc oxide (IZO), molybdenum, silicon dioxide, doped silicon dioxide, silicon nitride, tantalum, copper, polysilicon, ceramic, and aluminum / copper mixture. And those selected from the group consisting of polymerizable resins can be used.

  In order to remove the residual solvent, the photoresist composition coated on the substrate by the above method may be subjected to a vacuum drying process in which the photoresist composition is maintained for a certain period of time under a reduced pressure condition below normal pressure.

  At this time, the larger the substrate is, the stronger the decompression condition is. Therefore, the pattern shape is deformed after the subsequent development and hard bake steps, and the pattern uniformity is reduced at the center and end portions of the substrate. Problems may occur.

  Next, a soft bake process in which heat treatment is performed at a temperature of 20 to 130 ° C. can be performed. The heat treatment is performed to evaporate the solvent without thermally decomposing solid components in the photoresist composition. In general, it is preferable to minimize the concentration of the solvent by a soft baking process, and it is preferable to carry out until the photoresist film having a thickness of 2 μm or less remains on the substrate.

  Next, the substrate on which the photoresist film is formed is exposed to light, particularly ultraviolet rays, using an appropriate mask or template, thereby forming a pattern having a desired shape. After the substrate thus exposed is sufficiently immersed in an alkaline developing aqueous solution, it is allowed to stand until the exposed photoresist film is completely or almost dissolved. At this time, the developing aqueous solution may be an aqueous solution containing alkali hydroxide, ammonium hydroxide, or tetramethylammonium hydroxide.

  The substrate having the exposed portion dissolved and removed as described above is taken out of the developing aqueous solution and then heat-treated again by a hard bake process to improve the adhesion and chemical resistance of the photoresist film. . Such heat treatment is preferably performed at a temperature below the softening point of the photoresist film, and particularly preferably at a temperature of 90 to 140 ° C.

  As described above, the substrate that has been developed is treated with a corrosive solution or gas plasma to treat the exposed portion of the substrate. At this time, the unexposed portion of the substrate is protected by a photoresist film. After the substrate is processed in this manner, a fine circuit pattern can be formed on the substrate by removing the photoresist film with an appropriate stripper.

  In order to understand the present invention, examples and comparative examples are presented below. However, the following examples are for illustrating the present invention, and the scope of the present invention is not limited to the following examples.

Example 1
20 g of novolak resin (weight average molecular weight: 4,325) having a weight ratio of metacresol: paracresol of 4: 6, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide as a diazide photosensitive compound As a fluidity improver, 4 g of a mixture of -5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate in 50/50 parts by weight 2.8 g of dipropylene glycol monomethyl ether (DPGME) and 4,4- [1- [4- [1- (1,4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol as a sensitivity enhancer 2.8 g and 6 propylene glycol methyl ether acetate (PGMEA) as the organic solvent By mixing g homogeneously, to prepare a photoresist composition.

Example 2
20 g of novolak resin (weight average molecular weight: 4,325) having a weight ratio of metacresol: paracresol of 4: 6, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide as a diazide photosensitive compound As a fluidity improver, 4 g of a mixture of -5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate in 50/50 parts by weight 2.8 g of 2,2 ′, 4-trimethyl-1,3-pentanediol monoisobutyrate (TMPMB) and 4,4- [1- [4- [1- (1,4-hydroxy) as a sensitivity enhancer 2.8 g of phenyl) -1-methylethyl] phenyl] ethylidene] bisphenol, and propylene glycol methyl ether as an organic solvent A photoresist composition was prepared by uniformly mixing 60 g of cetate (PGMEA).

Example 3
20 g of novolak resin (weight average molecular weight: 4,325) having a weight ratio of metacresol: paracresol of 4: 6, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide as a diazide photosensitive compound As a fluidity improver, 4 g of a mixture of -5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate in 50/50 parts by weight 2.8 g of 1- (2-hydroxyethyl) -2-pyrrolidone, 4,4- [1- [4- [1- (1,4-hydroxyphenyl) -1-methylethyl] phenyl] as a sensitivity enhancer Ethylidene] 2.8 g of bisphenol and 60 g of propylene glycol methyl ether acetate (PGMEA) as an organic solvent Mixed and to produce a photoresist composition.

Comparative Example 3
20 g of novolak resin (weight average molecular weight: 4,325) having a weight ratio of metacresol: paracresol of 4: 6, 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide as a diazide photosensitive compound As a fluidity improver, 4 g of a mixture of -5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate in 50/50 parts by weight 2.8 g of gamma-butyrolactone (GBL) and 2,4- [1- [4- [1- (1,4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol as a sensitivity enhancer 2. 8 g and 60 g of propylene glycol methyl ether acetate (PGMEA) as an organic solvent are uniformly mixed, The resist composition was prepared.

Comparative Example 1
20 g of novolak resin (weight average molecular weight: 4,325) having a weight ratio of metacresol: paracresol of 4: 6, and 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide as an azide-based photosensitive compound 4 g of a mixture of -5-sulfonate and 2,3,4,4'-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate in 50/50 parts by weight, and propylene as the organic solvent A photoresist composition was prepared by uniformly mixing 60 g of glycol methyl ether acetate (PGMEA).

Comparative Example 2
20 g of novolak resin (weight average molecular weight: 4,325) having a weight ratio of metacresol: paracresol of 4: 6, and 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide as an azide-based photosensitive compound 4 g of a mixture of -5-sulfonate and 2,3,4,4′-tetrahydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate at 50/50 parts by weight, 4 as a sensitivity enhancer , 4- [1- [4- [1- (1,4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol, and 60 g of propylene glycol methyl ether acetate (PGMEA) as the organic solvent. Were uniformly mixed to prepare a photoresist composition.

The compositions of the photoresist compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1 below. The unit is grams (g).

Conducted experiments as follows with respect to the photoresist composition prepared in Experimental Example Embodiments 1 to 3 and Comparative Examples 1 to 3 showed the results of experiments in Table 2 below.

Each of the photoresist compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 3 is spin-coated on a glass substrate of 0.7T (thickness, 0.7 mm) at a constant speed, and then 0.1 Torr (Torr). ) In the following, the substrate was dried under reduced pressure for 60 seconds, and the substrate was heated and dried at 110 ° C. for 90 seconds to form a photoresist film having a thickness of 1.50 μm.

  Next, the thickness uniformity of the photoresist film is measured, exposed to ultraviolet light having a wavelength of 365 to 435 nm using a mask, and then subjected to an aqueous solution containing tetramethylammonium hydroxide for 60 seconds. Developed to form a pattern.

After performing the hard baking process (130 degreeC) with respect to the formed pattern, pattern fluidity | liquidity was evaluated using SEM.
1) Photosensitivity speed and remaining film ratio Initial film thickness = lost thickness + remaining film thickness Residual film ratio = (residual film thickness / initial film thickness)
The photosensitivity is calculated by measuring the energy at which the film is completely dissolved under certain development conditions depending on the exposure energy, and after performing exposure and development by performing a soft bake at 110 ° C., measuring the remaining film ratio The difference in thickness before and after development where the result appears was measured.
2) Heat resistance The heat resistance was measured by pattern baking using SEM after hard baking at 130 ° C. for 90 seconds.
3) Adhesion After forming a pattern (fine line width) on the glass coated with molybdenum (Mo), it is treated with a corrosive solution to remove molybdenum in the exposed portion, and the portion not exposed to the corrosive solution. The adhesion of the molybdenum was measured by measuring the thickness of the corrosion.

As shown in Table 2, the photoresist films manufactured using the photoresist compositions of Examples 1 to 3 according to the present invention have a photosensitivity, a remaining film ratio, and It can be seen that the fluidity is excellent.

Claims (6)

(A) a novolac resin;
(B) a diazide-based photosensitive compound;
(C) fluidity improver;
(D) the sensitivity enhancer; and (e) an organic solvent; see contains a
The (b) diazide-based photosensitive compound includes 2,3,4-trihydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate and 2,3,4,4′-tetrahydroxybenzophenone-1,2. Naphthoquinonediazide-5-sulfonate in a ratio of 40 to 60:60 to 40 parts by weight,
The (c) fluidity improver is composed of dipropylene glycol monomethyl ether, 2,2 ′, 4-trimethyl-1,3-pentanediol monoisobutyrate, and 1- (2-hydroxyethyl) -2-pyrrolidone. A photoresist composition which is at least one selected from the group consisting of: (A) 5-30% by weight of novolac resin;
(B) 2 to 10% by weight of a diazide-based photosensitive compound;
(C) 0.5 to 5% by weight of flow improver;
(D) 0.1-10% by weight of a sensitivity enhancer;
The photoresist composition of claim 1 comprising (e) the remaining weight percent of an organic solvent. Wherein (a) the novolak resin, the ratio of the content of the meta / para-cresol is from 30 to 70:70 to 30 parts by weight, the weight average molecular weight of 2,000 to 10,000, to claim 1 or 2 The photoresist composition as described. The (d) sensitivity enhancer is 2,3,4-trihydroxybenzophenone, 2,3,4,4′-tetrahydroxybenzophenone, 2,3,4,3 ′, 4 ′, 5-hexahydroxybenzophenone, Acetone-pyrogallol condensate, 4,4- [1- [4- [1- (1,4-hydroxyphenyl) -1-methylethyl] phenyl] ethylidene] bisphenol (TPPA), and 4,4 ′-[2 The photoresist composition according to any one of claims 1 to 3 , which is at least one selected from the group consisting of -hydroxyphenyl] methylene] bis [2,6-dimethylphenol] (BI26X-SA). . Wherein (e) the organic solvents are propylene glycol methyl ether acetate, ethyl lactate, 2-methoxyethyl acetate, and at least one selected from the group consisting of propylene glycol monomethyl ether, to any one of claims 1-4 one The photoresist composition according to item. The photoresist composition further comprises one or more additives selected from the group consisting of a colorant, a dye, an anti-scratch agent, a plasticizer, an adhesion promoter, a speed enhancer, and a surfactant. Item 6. The photoresist composition according to any one of Items 1 to 5 .