WO2005038530A1

WO2005038530A1 - Thinner composition for removing photoresist

Info

Publication number: WO2005038530A1
Application number: PCT/KR2004/002674
Authority: WO
Inventors: Suk-Il Yoon; Woo-Sik Jun; Hee-Jin Park
Original assignee: Dongjin Semichem Co., Ltd.
Priority date: 2003-10-20
Filing date: 2004-10-19
Publication date: 2005-04-28
Also published as: KR20050037972A; TW200519550A

Abstract

The present invention relates to a thinner composition for removing photoresist, and more particularly, to a thinner composition for removing photoresist comprising (a) 100 weight parts of propylene glycol monoalkyl ether acetate, and (b) 0.001 to 1 weight parts of polyethylene oxide condensate. By applying the thinner composition for removing photoresist according to the present invention on the edges and backsides of glass substrates used in liquid crystal display devices and wafers used in the preparation of semiconductors, it is possible to effectively remove photoresist unnecessarily attached thereto in a short time period. Also, the thinner composition has high safety to the human body and is applicable in various processes by reducing steps at the interface. Further, it can simplify the preparation processes of liquid crystal display devices and semiconductors, thereby economically improving production yields.

Description

Description THINNER COMPOSITION FOR REMOVING PHOTORESIST Technical Field

[1] The present invention relates to a thinner composition for removing photoresist, and more particularly, it relates to a thinner composition for removing photoresist which can effectively remove photoresist that is unnecessarily attached on the edge and backside of glass substrates used in liquid crystal display devices and wafers used in the manufacturing of semiconductors in a short time period, which is highly safe to the human body, which is applicable to various processes by reducing steps at the interface, and which can simplify the manufacturing processes of liqiid crystal display devices and semiconductors, thereby economically improving production yields. Background Art

[2] The photolithography process in the manufacturing process of semiconductors which is one of the most important processes is to form an electronic άrαit accomplished through the steps of coating a photoresist on a wafer, transferring a pattern as originally designed, and cutting the photoresist film a_cording to the transferred pattern, i.e., the etching process.

[3] This photolithography process is accomplished by performing various processes including:

[4] (1) a coating process in which a photoresist is uniformly coated on a surface of a wafer;

[5] (2) a soft baking process in which a solvent is evaporated from the coated photoresist so that the photoresist is adhered to the wafer surface;

[6] (3) an exposing process in which wafer is repeatedly exposed to the consecutive scale-down projection of a light source such as UV through a circuit pattern of a mask so that the mask pattern is transferred on the wafer;

[7] (4) a development process in which parts having different physical properties, such as solubility, resulting from photosensitivity caused by exposure to the light source are selectively removed using a developer;

[8] (5) a hard baking process in which the photoresist remaining on the wafer after the development process is more firmly fixed onto the wafer;

[9] (6) an etching process in which predetermined parts are etched to provide electrical characteristics in accordance with the pattern developed on the wafer; and [10] (7) a stripping process in which unnecessary photoresist is removed after the foregoing processes have been performed.

[11] After the soft baking process (2) of such photolithography method, it is necessary to eliminate unwanted photoresist coated on the edge or backside of the wafer, since when the presence of such photoresist on the edge and backside of the wafer may cause various defects in the subsequent processes, such as etching, ion implantation and the like, resulting in a decrease in the total yield of a semiconductor device.

[12] Conventionally, in order to remove such undesired photoresist remaining on the edge and the backside of the wafer, spray nozzles are installed at the upper and lower portions of the edge part of the wafer and a thinner composition comprising organic solvent components is sprayed onto the edge and backside through the nozzles.

[13] A thinner composition which has been conventionally used to remove unnecessary photoresist is disclosed in Japanese Patent Laid-open Publication N). Sho63-69563, in which the unnecessary photoresist in the upside part, edge side part and backside part of a substrate is contacted with the thinner composition comprising ether and ether acetates such as cellosolve, cellosolve acetate, propylene gljool ether, propylene gly_ol ether acetate and the like, ketones such as acetone, methylethyl ketone, methylisobutyl ketone, qclohexanone and the like, esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate and the like, thereby eliminating the photoresist. Also, Japanese Patent Laid-open Publication N). Hei4-49938 discloses a method using a thinner composition comprising propylenegly_ol methyl ether acetate and Japanese Patent Laid-open Publication N). Hei4-42523 discloses a method using a thinner composition comprising alkylalkoxy propionate.

[14] In these conventional thinner compositions, although ethylene gljool monoethyl ether acetate is excellent in terms of its dissolution rate, there are problems in that it has high volatility and flammability and particularly, shows reproduction toxiάty such as leucopenia and stillbirth. Also, ethyl lactate cannot obtain a sufficient rinsing effect by itself due to its high viscosity and low dissolution rate.

[15] Therefore, there is the urgent need for a study on a thinner composition which can effectively remove photoresist unnecessarily attached on the edge and backside of glass substrates used in liquid crystal display devices and wafers used in the manufacturing of semiconductors in a short time period. Disclosure of Invention Technical Problem [16] Therefore, It is an object of the present invention to provide a thinner composition for removing photoresist which can effectively remove photoresist unnecessarily attached on the edge and backside of glass substrates used in liquid crystal display devices and wafers used in the manufacturing of semiconductors in a short time period.

[17] It is another object of the present invention to provide a thinner composition for removing photoresist which is safe to the human body and applicable in various processes and can improve production yields in the preparation processes of liquid crystal display devices and semiconductors. Technical Solution

[18] In order to accomplish the above objects, according to the present invention, there is provided a thinner composition for removing photoresist, comprising:

[19] a) 100 weight parts of propylene gljool monoalkyl ether acetate; and

[20] b) 0.001 to 1 weight parts of polyethylene oxide condensate.

[21] N)w, the present invention will be explained in further detail.

[22] The present inventors have studied a thinner composition which is harmless to the human body while being capable of efficiently removing photoresist in a short time period, and found that by using a thinner composition prepared using propylene glycol monoalkyl ether acetate and polyethylene oxide condensate on the edges and backsides of glass substrates used in liquid crystal display devices and wafers used in the preparation of semiconductors, it is possible to effectively remove photoresist unnecessarily attached thereto in a short time period. Also, it has found the thinner composition shows high safety to the human body and is applicable in various processes. Further, it can advantageously simplify the preparation processes of liquid crystal display devices and semiconductors, thereby economically improving production yields. This completed the present invention.

[23] The thinner composition for removing photoresist according to the present invention is characterized by comprising a) 100 weight parts of propylene gljool monoalkyl ether acetate; and b) 0.001 to 1 weight parts of polyethylene oxide condensate.

[24] In accordance with the present invention, the propylene gljool monoalkyl ether acetate of (a) is used as a solvent of the thinner composition and its useful example includes an extremely pure semiconductor grade material and a VLSI-grade material, filtered (<0.1 jωn).

[25] The propylene gljool monoalkyl ether acetate may preferably contain 1 to 5 carbon atoms in the alkyl group, and its more preferable example include propylene gljool monomethyl ether acetate, propylene gljool monoethyl ether acetate, propylene glycol monopropyl ether acetate, or propylene glycol monobutyl ether acetate, and propylene gly_ol monomethyl ether acetate which has an excellent solubility to a polymer is particularly preferred. [26] The propylene gljool monomethyl ether acetate has a high safety profile to the human body upon exposure to air and is also safe in the metabolic aspect since it is to be rapidly decomposed into propylene gljool and alcohol in the human body. Further, in a toxicological test, it shows 8.5 g/kg of LD (mouse) which is a 50% fatal dose 50 caused by oral administration to a mouse and is rapidly decomposed by hydrolysis. It has physical properties of b.p. 146°C, a flash point (measured by the closed cup method) of 42°C, a viscosity (25°C) of 1.17 cps, and a surface tension of 26 dyne/cπf.

[27] In accordance with the present invention, the polyethylene oxide condensate of (b) acts as a non-ionic surfactant in the thinner composition. The propylene glycol monoalkyl ether acetate is excellent in solubility and effectively reduces steps at the interface where the thinner contacts with photoresist.

[28] The polyethylene oxide condensate preferably includes a condensation product of alkylphenol having an alkyl group containing 6 to 12 carbon atoms in either a straight chain or branched chain configuration with 5 to 25 moles of ethylene oxide per mole of the alkylphenol. The alkyl substituent in such compounds may be derived from polymerized propylene, diisobutylene, octane or nonene. Other examples of the condensate include nonylphenol condensed with about 9.5 moles of ethylene oxide per mole of nonylphenol, dodecyl phenol condensed with about 12 moles of ethylene oxide per mole of phenol, or diisooctylphenol condensed with about 15 moles of ethylene oxide per mole of phenol.

[29] The polyethylene oxide condensate is preferably contained in the thinner composition in an amount of 0.001 to 1 weight parts based on 100 weight parts of propylene gljool monoalkyl ether acetate, and if the content is within the foregoing range it is possible to continuously maintain the volatility and cleaning effect of the thinner at the edge of a substrate and to readily use the thinner without foaming.

[30] Also, the thinner composition for removing photoresist according to the present invention may further comprise c) fluorinated acrylic copolymer.

[31] The fluorinated acrylic copolymer has excellent solubility to the propylene glycol monoalkyl ether acetate.

[32] The fluorinated acrylic copolymer which is useful in the present invention has preferably a weight average molecular weight of 3000 to 10000, and has properties of a flash point (measured by open cup method) of 200°C, a specific gravity of 1.10 g/mL (25°C), a viscosity (20°C) of 2100 cst, a surface tension (on ethyl lactate) of 24.0 mN/ m (Wilhermy method).

[33] The fluorinated acrylic copolymer is preferably contained in an amount of 0.001 to 0.1 weight parts based on 100 weight parts of propylene gljool monoalkyl ether acetate, and if the content is within the foregoing range it is possible to effectively remove the photoresist by reducing dynamic surface tension on the interface to the photoresist.

[34] The thinner composition for removing photoresist comprising the above-described ingredients according to the present invention can be applied on a substrate by dropping or spraying through a nozzle to remove unnecessary photoresist formed at the edge and the backside of the substrate.

[35] Also, the dropped or sprayed amount of the thinner composition for removing photoresist can be adjusted according to types of the used photosensitive resin and film thickness, and is preferably in the range of 5 to 100 cc/min. According to the present invention, it is possible to form a micro άrαit pattern by spraying the thinner composition, followed by photolithography.

[36] By applying the thinner composition for removing photoresist according to the present invention on the edges and backsides of glass substrates used in liquid crystal display devices and wafers used in the preparation of semiconductors, it is possible to effectively remove photoresist unnecessarily attached thereto in a short time period. Also, the thinner composition is safe to users due to its high safety to the human body and is applicable in various processes. Further, it can advantageously simplify the preparation processes of liquid crystal display devices and semiconductors, thereby economically improving production yields.

[37] N)w, preferred examples are presented to help understanding of the present invention. However, the following examples are merely for illustrative purposes and are not intended to restrict the scope of the invention thereto.

[38]

[39] [Examples]

[40] Example 1

[41] 100 weight parts of propylene glycol monoethyl ether acetate and 0.1 weight parts of polyethylene oxide condensate were thoroughly mixed to prepare a thinner composition.

[42] Examples 2 to 3. and Comparative Example 1 [43] Thinner compositions were prepared by performing the same procedures as described in Example 1, except that ingredients and compositional ratios shown in Table 1 were used. Here, the unit in Table 1 is weight part.

[44] [45] Table 1

[46] [47] In order to determine the unnecessary photoresist removal rates of the thinner compositions prepared from Examples 1 to 3 and Comparative Example 1, the EBR test was performed as follows, and the results are shown in Table 4.

[48] Slicon oxide substrates with a diameter of 8 inch were washed in two bathes, each containing a hydrogen peroxide/sul&ric add mixture (dipped in each bath for 5 minutes) and rinsed with ultra-pure water.

[49] These procedures were carried out in a made-to-order washing equipment. Then, the substrates were spin-dried using a spin drier (manufactured by VERTEQ, Model SRD 1800-6). Subsequently, the top of each substrate was coated with the photoresist shown in Table 2 to a predetermined thickness using a spin coater (EBR TRACK, manufactured by Korea Semiconductor). In the spin coating, 10 cc of photoresist was dropped at the center of each substrate in the stationary state. Then, the photoresist was distributed for 3 seconds on the spin coater at 500 rpm and the revolution speed was accelerated to about 2000 to 4000 rpm to make the photoresist have the predetermined thickness. Here, the revolution time was about 20 to 30 seconds.

[50] The thinner compositions prepared from Examples 1 to 3, and Comparative Example 1 were sprayed on thus-obtained substrates with photoresist coated thereon to remove the photoresist under the conditions of Table 3. Here, each thinner composition was supplied from a pressurized vessel equipped with a pressure gauge. The pressure was 1.0 kgf and the flow rates of the thinner compositions were 10 to 20 cc/min. [51] [52] Table 2

[53] [54] Table 3

[55] [56] Table 4

[57] [58] As can be seen from the above Table 4, all the thinner compositions of Examples 1 to 3 according to the present invention showed excellent EBR properties (EBR line uniformity) on photoresist, and particularly, the composition of Example 3 which further comprised fluorinated acrylic copolymer showed more excellent EBR property. Thus, it was noted that the thinner composition aooording to the present invention had excellent photoresist removing effect of.

[59] Meanwhile, it was noted that Comparative Example 1 which did not comprise propylene gljool monoalkyl ether acetate and polyethylene oxide condensate according to the present invention had much deteriorated capability of preventing the penetration to photoresist as compared to Examples according to the present invention. Industrial Applicability [60] The thinner composition for removing photoresist according to the present invention has an advantageous effect in that by applying the thinner composition for removing photoresist according to the present invention on the edges and backsides of glass substrates used in liquid crystal display devices and wafers used in the preparation of semiconductors, it is possible to effectively remove photoresist unnecessarily attached thereto in a short time period. Also, the thinner composition is safe to users due to its high safety to the human body and is applicable in various processes. Further, it can advantageously simplify the preparation processes of liquid crystal display devices and semiconductors, thereby economically improving production yields.

Claims

[ 1 ] A thinner composition for removing photoresist comprising : (a) 100 weight parts of propylene gljool monoalkyl ether acetate; and (b) 0.001 to 1 weight parts of polyethylene oxide condensate.

[2] The thinner composition of claim 1, which further comprises (c) 0.001 to 0.1 weight parts of fluorinated acrylic copolymer.

[3] The thinner composition of claim 1, wherein the propylene glycol monoalkyl ether acetate of (a) is one or more selected from the group consisting of propylene gljool monomethyl ether acetate, propylene gljool monoethyl ether acetate, propylene gljool monopropyl ether acetate and propylene gljool monobutyl ether acetate, in which the number of carbon atoms in the alkyl group is 1 to 5.

[4] The thinner composition of claim 1, wherein the polyethylene oxide condensate of (b) is a condensation product of alkylphenol having an alkyl group containing 6 to 12 carbon atoms in either a straight chain or branched chain configuration with 5 to 25 moles of ethylene oxide per mole of the alkylphenol.

[5] The thinner composition of claim 2, wherein the fluorinated acrylic copolymer of (c) has a weight average molecular weight of 3,000 to 10,000.