KR20050116572A - Photosensitive resin composition of dry-film photoresist for the manufacturing tft pattern - Google Patents

Abstract

The present invention is a photosensitive resin composition comprising a binder resin, a photopolymerizable oligomer, a photoinitiator, and an additive, and includes a novolak resin derivative having both an unsaturated group and an acid group in the binder resin, thereby improving adhesion to metals and inorganic substances, thereby improving resistance to developers. In addition, the process stability can be improved, and the dry film photoresist can serve as an etching resist for a special metal, which has lacked resistance, and can be applied to molybdenum, chromium, ITO, silicon, etc. Provided is a photosensitive resin composition for a resist.

Description

Photosensitive resin composition of dry-film photoresist for the manufacturing TFT pattern suitable for forming TFT patterns

The present invention relates to a photosensitive resin composition, and more particularly, to a photosensitive resin composition which can be used for TFT panel formation or other inner layers, outer layers, flexible printed circuit boards and lead frames by exhibiting strong adhesion to metals and inorganic materials. It is about.

Panel manufacturers of TFT-LCDs are increasing the area of panels to improve economics and added value, and manufacturing equipment costs are also increasing. Although liquid photoresists have been used to form patterns of TFT-LCDs, spin coating, which is a conventional coating method, has a problem in that it is sensitive to vibration, and thus, considerable difficulty is expected in large-area panels. There is also a disadvantage that most of the liquid photoresist is lost during spin coating.

If dry film photoresist is used to form TFT panel, lamination method is used instead of the conventional spin coating method, so it is not sensitive to vibration, so it is advantageous in terms of equipment and has less material loss than liquid photoresist. have.

In general, a dry film photoresist is widely used for the purpose of being laminated on a copper clad laminate. Therefore, a manufacturing process of a printed circuit board (PCB) using a dry film photoresist (hereinafter referred to as DFR) is as follows.

In order to laminate the copper clad laminate, which is the raw material of PCB, it is first pretreated. The pretreatment process is followed by drilling, deburring, and front in the outer layer process, and goes through the front or pickling process in the inner layer process. Bristle brush and jet pumice processes are mainly used in the frontal process, and the pickling is subjected to soft etching and 5 wt% sulfuric acid pickling.

In order to form a circuit on a copper clad laminate which has been subjected to a pretreatment process, a DFR is generally laminated on a copper layer of the copper clad laminate. In this process, the photoresist layer of the DFR is laminated onto the copper surface while the protective film of the DFR is peeled off using a laminator. In general, the lamination speed is 0.5 to 3.5 m / min, temperature 100 to 130 ℃, roller pressure heating roll pressure 10 to 90 psi.

After the lamination process, the printed circuit board is left to stand for at least 15 minutes to stabilize the substrate, and then exposed to the photoresist of the DFR using a photomask having a desired circuit pattern. In this process, when ultraviolet rays are irradiated to the photomask, the photoresist irradiated with ultraviolet rays is initiated by the photoinitiator contained in the irradiated portion. Initially, oxygen in the photoresist is consumed, and then the activated monomer is polymerized to cause crosslinking reaction, and then a large amount of monomer is consumed to proceed with the polymerization reaction. On the other hand, unexposed sites are present in a state where the crosslinking reaction is not in progress.

Next, a developing process of removing unexposed portions of the photoresist is performed. In the case of an alkaline developing DFR, an aqueous solution of potassium carbonate and sodium carbonate of 0.8 to 1.2 wt% is used as a developer. In this process, the photoresist of the unexposed portion is washed away by the saponification reaction of the developer polymer with the carboxylic acid of the binder polymer in the developer, and the cured photoresist remains on the copper surface.

Next, a circuit is formed through different processes depending on the inner layer and outer layer processes. In the inner layer process, a circuit is formed on the substrate through a corrosion and peeling process, and in the outer layer process, after the plating and tenting process, etching and solder peeling are performed to form a predetermined circuit.

As described above, the general DFR is laminated and laminated on the copper clad laminate and irradiated with ultraviolet rays to develop an image through a developing process. When the DFR is applied to the metal and inorganic materials of the TFT, it is impossible to secure the same adhesion as on the copper clad laminate, so that the lower part of the film is separated from the metal and the inorganic material during the development process with the developer to secure desired circuit properties. Is difficult. Therefore, in order for DFR to be applied for forming panels of TFTs, it is necessary to develop a composition having a stronger adhesion to metal and inorganic materials than conventional DFR.

Conventionally, DFR has insufficient adhesion for forming a TFT panel because most copper clad laminates are used as a material for lamination. As a result, it is difficult to obtain a desired resolution due to a decrease in adhesion force, making it impossible to apply for forming a TFT panel. Therefore, the inventors of the present invention, while trying to solve the problem of adhesion, the electron-containing aromatic group having a high electron density capable of strong interaction with the main chain is attached to the main chain and irradiated with ultraviolet rays to increase the crosslinking density of the furnace containing an unsaturated group As a result of including the volac resin in the binder resin, it was found that the adhesion between the DFR and the metal and the inorganic substance was improved, thereby completing the present invention.

Accordingly, an object of the present invention is to provide a photosensitive resin composition for dry film photoresist suitable for TFT pattern formation by improving adhesion to special metals and inorganic materials such as molybdenum, chromium, ITO (Indium / Tin Oxide), silicon, etc. have.

A photosensitive resin composition for a dry film photoresist suitable for forming a TFT pattern of the present invention for achieving the above object includes a binder resin, a photopolymerizable oligomer, a photoinitiator and an additive, wherein the binder resin simultaneously contains an unsaturated group and an acid group. It is characterized by including the novolak resin derivative which has.

The present invention will be described in more detail as follows.

In general, in the case of the photosensitive resin composition for dry film photoresist, a composition comprising a binder resin, a photopolymerizable oligomer, a photoinitiator, and an additive is used. Each specific compound or content ratio may be a person having ordinary knowledge in the art. Of course it is understandable.

In such a conventional composition, a novolak resin derivative is included in the present invention as the binder resin. The novolak resin derivative in the present invention is a compound having an unsaturated group and an acid group by adding epichlorohydrin to the novolak resin, adding an acid having an unsaturated group thereto, and then adding an acid anhydride.

Acrylic acid or methacrylic acid can be used as an acid which has an unsaturated group here, A succinic anhydride, a phthalic anhydride, a maleic anhydride etc. can be used as an acid anhydride.

Such a novolak resin derivative has a weight average molecular weight of 2,000 to 35,000, preferably 5,000 to 10,000, and an acid value of 50 to 150 mgKOH / g.

The content is preferably 10 to 50% by weight of the total solids, more preferably 20 to 30% by weight. If the content is less than 10% by weight, there is no effect of improving adhesion. Sidewalls have a lot of foot, and the resolution decreases due to swelling.

The novolak derivative resin as described above has a structure having an aromatic group in the main chain, which improves adhesion to metals and inorganic substances. Such chemical adhesion means that the resistance to the developer is increased, and the increase in the adhesion is soon expressed as an improvement in process stability. As a result, the conventional dry film photoresist may serve as an etching resist for a special metal, which has lacked resistance, and may be well applied to molybdenum, chromium, ITO, and silicon.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Examples 1-2 and Comparative Example 1

Composition and Preparation Method of Photosensitive Resin Composition

The novolak resin derivative used in the embodiment of the present invention to increase adhesion has epichlorohydrin added to the hydroxyl group of the novolak and acrylic acid added to include an unsaturated group, and maleic acid is added to include an acid group. It was. This is KAYARAD (trade name) commercialized by Nippon Kayaku Co., Ltd.

In addition, as the binder resin, an acrylic copolymer prepared by combining 30% by weight of methacrylic acid, 40% by weight of methyl methacrylate and 30% by weight of styrene in a binder resin solid content was used. However, this is only a method for helping understanding of the present invention, but the present invention is not limited thereto. In the present invention, methyl acrylate, 2-ethylhexyl acrylate, styrene, 2-phenoxymethyl acrylate, 2-phenoxyethyl acrylate, maleic acid, male You may use the acrylic copolymer manufactured from the combination of an acid anhydride, vinyl acetate, etc. as binder resin. The molecular weight of the obtained binder resin was 35,000 and the molecular weight distribution was 1.95.

Specific preparations of the photosensitive resin composition according to Examples 1 to 2 are shown in Table 1 below. In the case of the comparative example, only acrylic resin was used as binder resin in the crude liquid of following Table 1.

However, as shown in Table 2, Examples 1 to 2 and Comparative Example 1 prepared the photosensitive resin composition while changing the use of the novolak resin derivative, its content, specific acid value, weight average molecular weight, and the like.

Furtherance Content (% by weight) Binder resin 30% by weight of novolac resin derivative + acrylic resin 60 Photoinitiator Benzophenone 1.0 4,4 '-(bisdiethylamino) benzophenone 0.5 Lucoco Crystal Violet 3.0 Toluenesulfonic Acid Monohydrate 0.5 Diamond Green GH 0.5 Photopolymerizable oligomer 9G 5.0 APG-400 5.0 BPE-500 10.0 menstruum Methyl ethyl ketone 14.5 9G: Shinnakamura, APG-400: Shinnakamura, BPE-500: Shinnakamura

Acrylic resin content (% by weight) Novolac resin derivatives Content (% by weight) Acid value (mgKOH / g) Weight average molecular weight Example 1 10 50 110 to 120 5,000 to 10,000 Example 2 40 20 50-70 30,000-35,000 Comparative Example 1 60 - - -

As a composition as shown in Table 1, a photosensitive resin composition was prepared by the following method;

1) Pour solvent into reactor.

2) The photoinitiators are metered into the reactor.

3) Mix at room temperature for 1 hour (500 rpm).

4) input photopolymerizable oligomers.

5) Mix at room temperature for 1 hour (500 rpm).

6) Input binder resin.

7) Mix at room temperature for 1 hour (500 rpm).

8) Leave at room temperature for 1 hour.

9) Coating preparation.

After the coating solution is prepared as described above, the photosensitive resin composition is coated on a base film (PET) with a thickness of 10 μm. Then, the cover film was laminated to complete the final dry film photoresist.

Using the dry film photoresist as described above, the developer resistance and fine wire adhesion were measured, and the results are shown in Table 3 below.

The specific property evaluation method is as follows;

1) Lamination: Manual Laminator, Temperature 110 ℃, Pressure 60psi, Speed 25m / min

2) Exposure: 5kW parallel light exposure machine (test artwork: KOLON test artwork for fine pattern, exposure energy measured by UV photometer on artwork)

3) Phenomenon: 2.38wt% tetramethylammonium hydroxide, immersion, break point 50%

4) Developer resistance was observed by peeling the photosensitive resin composition.

5) Independent fine lines are the minimum line widths that remain independent after the development.

6) Resolution is the value measured by 1: 1 of the space between circuit line and circuit line.

Cr  Mo ITO SiNx Example 1 Example 2 Comparative Example 1 Example 1 Example 2 Comparative Example 1 Example 1 Example 2 Comparative Example 1 Example 1 Example 2 Comparative Example 1 Developing time (sec.) 55 41 39 37 28 22 61 54 48 54 50 43 Exposure energy (mJ / ㎠) 40 Developer resistance × × × ○ × × × × × × × × Independent fine wire (㎛) - - - 24 - - - - - - - - Resolution (μm) - - - 17 - - - - - - - - 80 Developer resistance ○ ○ × ○ ○ × ○ ○ × ○ ○ × Independent fine wire (㎛) 23 12 - 20 12 - 21 14 - 19 13 - Resolution (μm) 20 13 - 17 13 - 19 17 - 23 15 - 120 Developer resistance ○ ○ × ○ ○ × ○ ○ × ○ ○ × Independent fine wire (㎛) 22 11 - 19 10 - 19 13 - 19 8 - Resolution (μm) 23 15 - 21 14 - 24 18 - 24 14 -

As described in detail above, in the case of the photosensitive resin composition including a novolac derivative resin having an aromatic group in the main chain of the binder resin according to the present invention, adhesion to metal and inorganic materials is improved, and resistance to developer is increased, and process stability In addition, the dry film photoresist can serve as an etching resist for a special metal that has lacked resistance, and can also be applied to molybdenum, chromium, ITO, and silicon.

Claims (4)

In the photosensitive resin composition containing a binder resin, a photopolymerizable oligomer, a photoinitiator and an additive, The binder resin is a photosensitive resin composition for a dry film photoresist suitable for forming a TFT pattern, characterized in that it comprises a novolak resin derivative having an unsaturated group and an acid group at the same time. The TFT according to claim 1, wherein the novolak resin derivative is a compound having an unsaturated group and an acid group by adding epichlorohydrin to the novolak resin, adding an unsaturated group thereto, and then adding an acid anhydride. Photosensitive resin composition for dry film photoresist suitable for pattern formation. The photosensitive resin composition for dry film photoresists according to claim 1 or 2, wherein the novolak resin derivative has a weight average molecular weight of 2,000 to 35,000 and an acid value of 50 to 150 mgKOH / g. The photosensitive resin composition for dry film photoresists according to claim 1 or 2, wherein the novolak resin derivative is contained so as to be 10 to 50% by weight of the total solids.