KR100254039B1 - Method for partial removal of photoresist layer on the surface of substrate - Google Patents

Abstract

A method of partially removing the photoresist layer formed on the surface of a substrate such as a glass plate from the edge region, the periphery and the back surface around the region for patterning of the substrate formed as a result of the widespread photoresist composition has been proposed. This method is to remove dipropylene glycol monomethyl ether (DPM) or a mixed solvent containing 60% by weight or more of the photoresist layer on an unnecessary area before the pattern-shaped exposure treatment to actinic rays of the photoresist layer. The solvent is brought into contact with the solvent for 2 to 20 seconds to dissolve and remove the unnecessary photoresist layer. For example, a common agent such as lower alkyl acetate, which forms a mixed solvent with DPM, needs to have good volatility defined by boiling point and vapor pressure at 20 ° C., and can improve dryness. According to the method of the present invention, it is advantageous over the conventional method in terms of good dissolving power, superiority of orthogonal contours of the photoresist layer remaining after the partial removal treatment along the boundary line, and the like.

Description

Partial removal method of photoresist layer on substrate surface

The present invention relates to a method of partial removal of a photoresist layer formed on a substrate surface. In particular, in the manufacturing process of electronic devices such as liquid crystal display panels and plasma display panels, and electronic components, unrelated regions (i.e., unnecessary regions) formed on the substrate surface are dissolved in a specific organic solvent. To a valid method of partial removal.

The so-called photolithography patterning technique is a well-known method in the manufacture of various electronic devices and electronic components such as liquid crystal display panels and plasma display panels. In this photolithography patterning method, first, a positive or negative photoresist composition is applied to a surface of a substrate such as a semiconductor silicon wafer or a glass plate to form a photoresist layer, and then pattern-shaped exposure to actinic rays such as ultraviolet rays. Then, a latent image of a pattern is formed, and then a latent image development process is performed using a developing solution to form a patterned resist layer that is a positive or negative regeneration pattern.

In the process of applying the photoresist composition to the surface of the substrate, the spreading of the photoresist composition liquid is not limited to the region for accurate patterning, and the photoresist composition is applied to the edge region of the substrate surface, the periphery of the substrate, and sometimes even to the substrate. It is almost inevitable that the unnecessary photoresist layer is spread and the unnecessary photoresist layer is caused to cause various troubles in the subsequent steps, so that it must be removed before the subsequent steps. Since the most practical method of partially removing the photoresist layer from the surface of the substrate in the unnecessary area is to remove the photoresist layer by using a removal solvent, various removal solvents have been conventionally proposed for this purpose. The most widely used in the manufacture of semiconductor devices, propylene glycol monomethyl ether acetate, which is a solvent of the photoresist composition itself, or a mixture thereof with propylene glycol monomethyl ether, in view of relatively low toxicity to the human body.

Although the solvent or mixed solvent is satisfactory for the partial removal of the photoresist layer from the surface of the semiconductor silicon wafer as the substrate, the application to the partial removal of the photoresist layer when using a glass plate as the substrate such as a liquid crystal display panel, There is a problem. In other words, when the photoresist layer on the glass substrate is dissolved by the organic solvent and partially removed, the resist layer remaining on the patterning area forms a weir along the boundary line or the intersection of the resist layer remaining along the boundary line is formed. Orthogonal and not straight. In addition, scum of the resist material may occur after the photoresist layer on the substrate surface is partially removed.

It goes without saying that the formation of the boundary bank of the resist layer and the generation of the resist debris in the above method are very detrimental to the quality of the liquid crystal display panel as the final product obtained by performing the subsequent step. Therefore, the photoresist layer is partially removed from the surface of the glass substrate without the problem of reducing verticality or orthogonality of the cross-section outline by the formation of the weir along the boundary line of the remaining resist layer and the problem caused by the occurrence of the resist debris. There is an urgent need for the development of effective methods of removal. There is also a need for a method in which there is no problem with the removal solvent remaining after the photoresist layer is partially removed using the removal solvent.

Accordingly, it is an object of the present invention to eliminate the problems and disadvantages of the prior art methods associated with weir formation of resist material along the boundary and generation of resist debris, and at the same time not only before drying the photoresist layer, Due to the low solubility of the removal solvent in the photoresist composition and the low vaporization of the removal solvent, i.e., volatility, there is no problem of permanently remaining on the surface of the substrate after the removal treatment, and a specific removal solvent that is less toxic to the human body after partial drying. To provide a novel and effective method for partially removing the photoresist layer formed on the surface of the substrate from regions other than the region for photolithographic patterning even when using a glass plate as a substrate such as a liquid crystal display panel or a plasma display panel. It is.

That is, the method of partially removing the photoresist layer before the pattern-shaped exposure to the actinic rays of the photoresist layer formed on the substrate surface of the present invention comprises the following steps.

(a) A part of the photoresist layer formed on the surface of the substrate by application of the photoresist composition before or after drying the photoresist composition is dipropylene glycol monoalkyl ether having 1 to 4 carbon atoms or an dipropylene. Alkyl acetate solvents, ketone solvents and alkylene glycol monoalkyl ether solvents in an amount of not more than 35% by weight, preferably 5 to 35% by weight, based on the total amount of the glycol monoalkyl ether and the mixed solvent. Photoresist from the substrate surface in contact with a removal solvent which is a mixed solvent mixed with a highly volatile solvent having a boiling point at atmospheric pressure in the range of 75 to 130 ° C. and a vapor pressure at 20 ° C. in the range of 5 to 75 mmHg selected from the group consisting of Dissolving and removing the layer; And (b) drying the substrate surface wetted with the removal solvent after contacting the removal solvent.

Examples of the removal solvent used in the method of the present invention include a mixed solvent of dipropylene glycol monoalkyl ether or a limited amount of highly volatile organic solvent as a co-solvent selected from a specific organic solvent. . The alkyl group of the dipropylene glycol monoalkyl ether preferably has 1 to 4 carbon atoms, and the dipropylene glycol monoalkyl ether is dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, It can be selected from the group consisting of dipropylene glycol monobutyl ether, although not particularly limited, the dipropylene glycol monomethyl ether has a good solubility in the photoresist layer compared to other solvents, and at the same time less toxic to human body It is more preferable at the point that the volatility is favorable and drying of the processed substrate surface can be performed quickly. These dipropylene glycol monoalkyl ethers can be used individually or in the form of 2 or more types of mixtures as needed.

As described above, the removal solvent may be a mixed solvent of dipropylene glycol monoalkyl ether and one or more other highly volatile organic solvents. The common solvent needs to have a boiling point under normal pressure in the range of 75 to 130 ° C., and a vapor pressure at 20 ° C. in the range of 5 to 75 mmHg. Examples of organic solvents that meet these requirements include n-propyl acetate (102 ° C. and 25 mm Hg), these propyl acetates (89 ° C. and 43 mm Hg), n-butyl acetate (126 ° C. and 10 mm Hg) and isobutyl acetate (118 ° C. and 13 mm Hg). Lower ketone agents such as lower alkyl acetate solvents, methyl ethyl ketone (80 ° C., 71 mm Hg), methyl propyl ketone (102 ° C., 12 mm Hg), and methyl isobutyl ketone (116 ° C., 17 mm Hg), and propylene glycol monomethyl. The lower alkylene glycol mono (lower alkyl) ether type solvent, such as ether (120 degreeC, 8 mmHg) and ethylene glycol monomethyl ether (125 degreeC, 6 mmHg), is mentioned. Vapor pressure). You may use these highly volatile auxiliary solvents individually or in combination of 2 or more types as needed. Although optional, these auxiliary solvents do not exceed 35% by weight based on the total amount of the mixed solvent with dipropylene glycol monoalkyl ether in view of the reduction of the remaining amount of the remaining resist layer and the drying behavior. Preferably, it can be used in the ratio of 5 to 35 weight% range, More preferably, it is 10 to 30 weight% range. If the proportion of these highly volatile cosolvents is too high, the dissolution of the resist layer is incomplete, leaving a residue of the incompletely removed resist layer on the substrate surface. In addition, the main advantage of the mixture of these common agents is to ensure good drying behavior of the substrate surface after the removal treatment.

Alternatively, of course, in addition to the dipropylene glycol monoalkyl ether and the highly volatile co-agent, the removal solvent used in the present invention may be added to other organic solvents in a limited amount without substantial adverse effects on the present invention. .

The method of the present invention by the use of the specific removal solvent can provide a developable resist layer to an alkaline aqueous solution as a developer suitable for patterning purposes in the manufacture of various electronic devices without specific restrictions, and at the same time, a general photosensitive material and a film forming material. Applicable to the photoresist layer formed from the photoresist composition consisting of.

Particularly important photoresist compositions in the method of the present invention include positive type photoresist compositions capable of satisfying various required characteristics to sufficiently adapt to ultrafine patterning in recent photolithography techniques. In particular, the positive photoresist composition contains a quinonediazide compound and a film-forming resin component as photosensitive materials.

As a quinone diazide type compound as said photosensitive substance, The compound which has sulfonate, phenolic hydroxyl group, or amino group of quinone diazide compounds, such as o-benzoquinone diazide, o-naphthoquinone diazide, o-anthraquinone diazide, etc. Full or partial esterification products or amidation products of the liver. Examples of the compound having a phenolic hydroxyl group or an amino group include 2,3,4-trihydroxy benzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone and 2,3,4,4'-tetrahydrate Polyhydroxybenzophenones such as oxybenzophenone, alkyl gallate, aryl gallate, phenol, 4-methoxyphenol, dimethylphenol, hydroquinone, bisphenol A, naphthol, pyrocatechol, pyrogallol, pyrogallol monomethyl ether, Pyrogallol 1,3-dimethylether, gallic acid, some esterified or etherified gallic acid with some hydroxyl groups, aniline, p-aminodiphenylamine, and the like. Preferred quinonediazido group-containing compounds include full or partial ester compounds of the above polyhydroxybenzophenone compounds with naphthoquinone-1,2-diazido-5- or -4-sulfonyl chloride, The degree of esterification at this time is at least 70%.

The film-forming resin component is, for example, a novolac resin obtained from a phenolic compound such as phenol, cresol and xyleneol and an aldehyde compound, an acrylic resin, a copolymer resin of styrene and acrylic acid, and a poly (vinylhydroxybenzoate) resin. And alkali-soluble resins such as poly (vinylhydroxybenzal) resin.

One of the positive type photoresist compounds to which the method of the present invention can be most successfully applied is a film forming resin component, in which the weight average molecular weight after removal of low molecular weight species by the classification method is 2000-20000, or in particular 5000-15000. There is a composition consisting of cresol novolak resins.

The positive photoresist compound to which the present invention is applied contains a susceptible substance in an amount in the range of 10 to 40 parts by weight, or particularly 15 to 30 parts by weight, per 100 parts by weight of the film-forming resin component. If the amount of photosensitive material is too large, the photosensitivity of the photoresist layer formed from the composition is greatly reduced, while if the amount of photosensitive material is too small, the patterned resist layer will not have the desired orthogonal contour.

Optionally, the photoresist composition includes dyes having miscibility with major components such as coumarin dyes and azo dyes, colorants that enhance the visibility of additional resins, plasticizers, stabilizers, and patterned resist layers after development. It goes without saying that various additives used in the conventional photoresist composition including the enhancer and the like may be mixed.

Hereinafter, the method of this invention which removes the photoresist layer formed on the board | substrate before using pattern specific exposure of the photoresist layer by light partially by using the said specific removal solvent is demonstrated in detail.

First, the surface of a substrate such as a glass plate as a base material of the liquid crystal display panel is coated with a photoresist composition solution using a suitable applicator such as a spinner, bar coater, roller coater, or the like. Here, the photoresist composition solution is diffused not only on the exact region to be patterned, but also on the edge region and the periphery of the substrate, and sometimes on the back surface of the substrate, to be removed prior to pattern exposure by the light of the photoresist layer in the present invention. It is unavoidable to form an unnecessary photoresist layer which must be done. In an embodiment of the present invention, the unnecessary or obsolete portion of the photoresist layer is dissolved away before being completely dried using a specific removal solvent, and then the photoresist layer on the correct area for patterning is dried.

Various methods can be applied to dissolution removal by the specific removal solvent of the unnecessary portion of the photoresist layer. For example, the removal solvent is filled in the storage part having the slit, and the edge portion of the substrate on which the photoresist layer is formed is inserted in the slit in the horizontal direction, so that the photoresist layer in contact with the removal solvent is removed by the solvent. There is a method in which an unnecessary portion of the photoresist layer on the surface of the substrate is brought into contact with the removal solvent for a predetermined time at room temperature, for example, 2 to 20 seconds until dissolution is removed.

In another embodiment of the present invention, in the same manner as above, the photoresist layer formed on the surface of the substrate is first dried to form a partially dried resist layer, and then contacted with a removal solvent, so as to contact the edge, periphery and back of the substrate. Unnecessary photoresist layer on the solvent is removed. The method of the present invention can be most successfully applied when an unnecessary photoresist layer to be removed by the method is in a partially dried state in which a part of the solvent of the photoresist composition remains.

According to the above method of the present invention, the partial removal of the photoresist layer from the surface of the substrate is carried out because a specific removal solvent which is less toxic to the human body has a high dissolving ability to the photoresist composition and dissolves and removes unnecessary portions of the photoresist layer in a short time. It works very efficiently and you can get a satisfactory result. In addition, the photoresist layer remaining on the surface of the substrate is advantageous in that it has almost no generation of resist residues resulting in incomplete dissolution of unnecessary portions of the photoresist layer by the removal solvent due to poor dissolving power and good dryness after the removal treatment. In addition, it has a vertical end surface standing upright on the substrate surface without forming a line wire along the boundary of the resist layer. In addition, the specific removal solvent used in the method of the present invention can also be used to remove photoresist compositions accidentally deposited on the surface of machines or apparatuses used for the application of the photoresist composition, for example, by excellent dissolving power of the removal solvents. have.

Hereinafter, the method of the present invention will be described in more detail by Examples and Comparative Examples.

Example 1

A positive photoresist composition containing a quinone diazido group-containing oil compound and a cresol novolak resin on a chrome surface of a 550 mm x 650 mm wide rectangular glass plate having a chromium coating layer as a substrate (Tokyo Okako Co., Ltd.) The coating layer thickness at the time of drying was uniformly applied by the product OFPR PR-11). The solvent of this wet coating layer was partially removed under reduced pressure to obtain a resist layer partially dried on the substrate surface.

The substrate having the photoresist layer is mounted on a trimming machine (model EBR, which the manufacturer sees above) which is part of a resist coating device (model TR-36000, see above). After contacting with the dipropylene glycol monomethyl ether (DPM) filling the reservoir for 8 seconds, the resist layer was partially removed from the edge region of the glass plate surface and from the periphery and the back side of the glass plate, followed by partial removal of the resist layer, followed by drying under reduced pressure. It was. The efficiency of the partial removal treatment of the photoresist layer was evaluated by the following test.

[Removability Test]

In this way, the state of the substrate surface after the partial removal of the resist layer is visually inspected, and the result is grade 3 (that is, completely removed without leaving A: residual residue, and B: resist residue slightly left. Almost completely removed and C: incompletely removed with significant residue left). The results of this removal test are shown in Table 1.

[Intersection Test]

Cross-section contours of the resist layer remaining along the boundary were inspected using a tactile step tester (model DEKTAK, manufactured by Nippon Shinku Kijutsu Co., Ltd.), and the result was grade 2 (ie A: along the boundary). No bank weir and B: There is a bank like this). The results of this intersection test are likewise shown in Table 1.

[Dryness test]

In the trimming as described above, the surface condition of the glass plate kept in open air for 6 seconds after contact with the removal solvent for 8 seconds was visually inspected to evaluate the dryness of the removal solvent. Surface completely dry and B: solvent partially left). The results of this drying test are similarly shown in Table 1.

Example 2

The experiment was conducted in the same manner as in Example 1 except that a mixed solution containing DPM and butyl acetate in a weight ratio of 90:10 was used instead of DPM. The results of this evaluation test are shown in Table 1.

Example 3

The experiment was conducted in the same manner as in Example 1 except that a mixed solution containing DPM and butyl acetate in a weight ratio of 80:20 was used instead of DPM as a removal solvent. The results of this evaluation test are shown in Table 1.

Example 4

An experiment was conducted in the same manner as in Example 1 except that a mixed solution obtained by mixing DPM and butyl acetate in a weight ratio of 70:30 instead of DPM was used as the removal solvent. The results of this evaluation test are shown in Table 1.

Comparative Example 1

The experiment was conducted in the same manner as in Example 1 except that propylene glycol monomethyl ether acetate was used instead of DPM as the removal solvent. The results of this evaluation test are shown in Table 1.

Comparative Example 2

The experiment was conducted in the same manner as in Example 1, except that a mixed solution containing propylene glycol monomethyl ether acetate and propylene glycol monomethyl ether in a weight ratio of 30:70 was used as a removal solvent. The results of this evaluation test are shown in Table 1.

According to the method of the present invention, the partial removal of the photoresist layer from the surface of the substrate is very difficult because a specific removal solvent which is less toxic to the human body has high dissolving power to the photoresist composition and dissolves and removes unnecessary portions of the photoresist layer in a short time. It can be performed efficiently to obtain satisfactory results. In addition to the advantage that the photoresist layer remaining on the surface of the substrate has a poor dissolving power, there is almost no generation of resist residues resulting in incomplete dissolution of unnecessary portions of the photoresist layer by the removal solvent, and the dryness after the removal treatment is good. It has a vertical end surface standing upright on the substrate surface without forming a line dividing line along the boundary of the resist layer. In addition, the specific removal solvent used in the method of the present invention can also be used to remove photoresist compositions accidentally deposited on the surface of machines or apparatuses used for the application of the photoresist compositions, for example, by excellent dissolving power of the removal solvents. .

Claims (8)

A method of partially removing the photoresist layer prior to patterning exposure to actinic rays of a photoresist layer formed on a substrate surface, the method comprising: (a) a photoresist layer formed by applying a photoresist composition onto the substrate surface; A portion of the dialkyl glycol monoalkyl ether having 1 to 4 carbon atoms of the alkyl group, or the dipropylene glycol monoalkyl ether and the boiling point under normal pressure at a ratio of 35% by weight or less based on the total amount of the mixed solvent. Contacting with a removal solvent which is a mixed solvent in which a common solvent in the range of 75 to 130 ° C. and a vapor pressure at 20 ° C. is within a range of 5 to 75 mmHg; And (b) drying the substrate surface wetted by the removal solvent after contact with the removal solvent. The method of claim 1, wherein the coagent is selected from the group consisting of an alkyl acetate solvent, a ketone solvent, and an alkylene glycol monoalkyl ether solvent. The method of claim 1, wherein the photoresist layer in the step (a) is made of a photoresist composition before drying. The method of partially removing a photoresist layer on a substrate surface according to claim 1, wherein the photoresist layer in the step (a) is made of a photoresist composition after partial drying treatment. The method of claim 1, wherein the proportion of the common solvent in the mixed solvent is in the range of 5 to 35% by weight based on the total amount of the mixed solvent. The method of claim 1, wherein in the step (a), the photoresist layer is brought into contact with the removal solvent for 2 to 20 seconds in the vicinity of room temperature. The method of claim 1, wherein the dipropylene glycol monoalkyl ether is dipropylene glycol monomethyl ether. The method of claim 1, wherein the coagent is butyl acetate.