WO2007058443A1

WO2007058443A1 - Thinner composition for removing photoresist

Info

Publication number: WO2007058443A1
Application number: PCT/KR2006/004638
Authority: WO
Inventors: Hee-Jin Park; Sung-Gun Shin; Suk-Il Yoon; Byung-Uk Kim
Original assignee: Dongjin Semichem Co., Ltd.
Priority date: 2005-11-18
Filing date: 2006-11-07
Publication date: 2007-05-24
Also published as: CN101300529A; TW200728939A; KR20070052943A

Abstract

The present invention relates to a thinner composition for removing photoresist used in the manufacture of semiconductor devices, liquid crystal displays, or organic light emitting devices, and more particularly, to a thinner composition for removing photoresist comprising a glycol ether compound, specially a fluorinated acrylic copolymer as the surfactant, an organic solvent, or a mixture thereof. The thinner composition for removing photoresist of the present invention is capable of effectively removing unwanted photoresist at the edge and the back side of glass substrates for organic ELs, as well as those used for manufacturing liquid crystal displays, in a short period of time regardless of the particular photoresist used.

Description

TITLE OF THE INVENTION

THINNER COMPOSITION FOR REMOVING PHOTORESIST

BACKGROUND OF THE INVENTION (a) Field of the Invention

The present invention relates to a thinner composition for removing photoresist, and more particularly to a thinner composition that is capable of effectively removing undesired photoresist from the edge and the back side of a glass substrate used in a manufacturing process of liquid crystal displays and a wafer used in the manufacture of semiconductor devices in a short time, and is applicable to a variety of processes and is capable of reducing cost, simplifying manufacturing processes, and improving production yield. (b) Description of the Related Art

The TFT-array process in the manufacture of thin film transistor liquid crystal displays (TFT-LCDs) is similar to the silicon semiconductor manufacturing process using photolithography. The photolithographic process is a process for coating a photoresist film on a substrate, transcribing and developing a photomask pattern, and etching the substrate to obtain an electronic circuit.

To manufacture a TFT-LCD by the photolithographic process, a TFT-array needs to be formed on a substrate. In the process, the thinner composition may penetrate into the interface of the photoresist, resulting in several defects in subsequent processes, such as etching or ion implantation, and a decrease of the overall production yield.

The penetration of the thinner composition into the interface of the photoresist becomes a cause of defocusing during light exposure following the baking process, and lowers the TFT-LCD manufacturing yield.

In addition, the thinner should be considered simultaneously from economic and efficiency points of view. If the thinner composition of the related art is applied to a wafer by only considering efficiency, there is a problem that it deteriorates the edge bead removal (EBR) performance due to a difference in a component of the photoresist.

In particular, in contrast with the round edge of a silicon wafer, where centrifugal force is applied, the glass substrate of the TFT-LCD has a square edge, and thus removal of the photoresist by spin EBR is impossible. Also, since the glass substrate is fixed and the injection nozzle travels rectilinearly along the four edges of the glass substrate, retarded evaporation after the photoresist has been coated may lead to penetration into the interface of the photoresist even after the photoresist has been removed at the edge. This presents a sharp contrast with the spin EBR, in which even a less volatile thinner can be prevented from penetrating into the interface of the photoresist if the silicon wafer is spun at a high rate. That is, since the LCD glass substrate is fixed and only the thinner injection nozzle moves, a use of the conventional highly-soluble thinners for rinsing results in penetration into the interface of the photoresist at the edge, and lowers the overall production yield. Examples of such conventional thinner compositions are as follows. Japanese Patent Laid-Open No. Sho 63-69563 discloses a method of removing undesired photoresist by contacting a thinner at the substrate. This patent uses an organic solvent, for example ethers and ether acetates such as cellosolve, cellosolve acetate, propylene glycol ether, and propylene glycol ether acetate, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, and esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, and butyl acetate as a thinner. Japanese Patent Laid-Open No. Hei 4-49938 discloses the use of propylene glycol methyl ether acetate as a thinner, and Japanese Patent Laid-Open No. Hei 4-42523 discloses the use of alkyl alkoxy propionate as a thinner. These solvents have been used alone or admixed with one another to improve physical properties and stability. They have been used in the manufacture of semiconductor devices in which EBR is performed at a high spinning rate, rather than in the manufacture of TFT-LCDs in which the substrate is fixed and EBR is performed rectilinearly. However, the problem of penetration into the interface of the photoresist has not been solved.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above-mentioned problem, and to provide a thinner composition that is capable of effectively removing unwanted photoresist in a short period of time not only from the substrate used in the manufacture of LCD devices but also from the large-sized glass substrate used in the manufacture of organic EL displays, without regard to the particular photoresist used.

To attain the object, the present invention provides a thinner composition for removing photoresist comprising a glycol ether compound. Preferably, the thinner composition further may comprise a fiuorinated acrylic copolymer as the surfactant, an organic solvent, or a mixture thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Figs. 1 to 3 show photographs of the Edge Bead Removing test results (EBR surface treatment properties) for the thinner composition according to Examples 1 to 11 of one embodiment of the present invention.

Fig. 4 shows photographs of the Edge Bead Removing test results (EBR surface treatment properties) for the thinner composition according to Comparatives Examples 1 to 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereunder is given a detailed description of the present invention. The thinner composition for removing photoresist in accordance with the present invention is capable of effectively removing unwanted photoresist from the edge and the back side of a glass substrate used in a photolithographic process of, for example, the manufacture of semiconductor devices, LCDs and plasma display panels (PDPs), in a short time.

In addition, the thinner composition of the present invention is applicable to a variety of processes and is capable of reducing cost, simplifying manufacturing processes, and improving production yield. Preferably, the thinner composition of the present invention can be used in the photolithographic process for organic EL displays or LCDs.

The thinner composition for removing photoresist of the present invention comprises a glycol ether compound, and the glycol ether compound may be at least one selected from the group consisting of alkylene glycol alkyl ether having an alkyl group with 1 to 6 carbon atoms. The alkylene glycol alkyl ether has an alkylene with 1 to 6 carbon atoms and an alkyl group with 1 to 6 carbon atoms. Specifically, it may be selected from the group consisting of ethylene glycol methyl ether, ethylene glycol ethyl ether, diethylene glycol methyl ether, propyleneglycol monomethyl ether (PGME), and a mixture thereof. The content of the glycol ether compound may be comprised at 100 wt% of the thinner composition.

In addition, the thinner composition for removing photoresist of the present invention may further comprises a fluorinated acrylic copolymer as a surfactant, an organic solvent, or a mixture thereof. In the thinner composition of the present invention, it is preferable that the fluorinated acrylic copolymer is used as a nonionic surfactant. For the fluorinated acrylic copolymer, one having a weight average molecular weight ranging from 1,000 to 10,000, and preferably one having a flash point (measured by open-cup test) of 200°C, a specific gravity of 1.10 g/mL (at 25⁰C), a viscosity of 2100 cst (20⁰C), and a surface tension in ethyl lactate of 24.0 mN/m (Wilhermy method) where the surface tension is measured as diluted in ethyl lactaste, is used.

The fluorinated acrylic copolymer can be from the Megaface series that is commercially available from Dainippon Ink and Chemicals. Preferably, the content of fluorinated acrylic copolymer is comprised at 0.001 to 1 parts by weight, and more preferably 0.01 to 0.3 parts by weight, per 100 parts by weight of the glycol ether compound. If the content of the fluorinated acrylic copolymer is below 0.001 parts by weight, dissolving power for the photoresist decreases significantly. In contrast, if it exceeds 1 part by weight, severe foaming may cause malfunction of the liquid level sensor, although superior removal capacity can be obtained as the dynamic surface tension at the interface is lowered. Preferably, the organic solvent is at least one selected from the group consisting of iV-Methyl-2-pyrrolidone (NMP), dimethylsulfoxide (DMSO), dimethylacetamide (DMAc), methyl isobutyl ketone (MIBK), gamma-butyrolactone (GBL), ethyl lactate (EL), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and ethyl 3-ethoxypropionate (EEP). The content of the organic solvent is comprised at 20 to 50 parts by weight per 100 parts by weight of the glycol ether compound.

If the content of the organic solvent is below 20 parts by weight, the performance of the thinner is not noticeable. In contrast, if it exceeds 50 parts by weight, a satisfactory EBR property cannot be obtained.

In addition, when the nonionic surfactant and the solvent is used in the present invention, a weight ratio of the mixture of the compounds is not particularly limited.

After the photoresist has been coated on a substrate, unwanted photoresist at the edge and the back side of the substrate is removed by dripping the thinner composition or by spraying it through a nozzle. The amount of the thinner composition of the present invention to be dripped or sprayed may be adjusted depending on the particular photosensitive resin used and the film thickness.

Preferably, the dripping or spraying rate is in the range of 5 to 100 cc/min. After the thinner composition has been sprayed, a microcircuit pattern may be obtained by a photolithographic process.

Hereinafter, the present invention is described in further detail through examples. However, the following examples are only for the understanding of the present invention and the present invention is not limited to or by them. Examples

Examples 1 to 11 and Comparative Examples 1 to 4 The thinner compositions of Examples 1 to 11 and Comparative Examples 1 to 4 were prepared with the compositions and contents given in Table 1 below.

TABLE 1 classification EGME nBA" PGMEA- PGME' Acetone MIBK- DMAc⁽ NMP' Sur.⁸

Note) In Table 1,

1. EGME: Ethylene glycol monomethyl ether,

2. nBA: n-Buthyl acetate,

3. PGMEA: Propylene glycol monomethyl ether acetate, 4. PGME: Propylene glycol monomethyl ether,

5. MIBK: methyl isobutyl ketone

6. DMAc: dimethylacetamide

7. NMP: N-methyl-2-pyrrolidone 8. Sur. (Surfactant): fluorinated acrylic copolymer (Megaface series, Dainippon Ink and Chemicals)

Removal test of undesired photoresist by usingthe thinner composition

The substrate samples used in the examples were prepared as follows. A silicon oxide substrate 8 inches in diameter was cleansed in two separate baths containing hydrogen peroxide and sulfuric acid, respectively (immersed in each bath for 5 minutes), and then rinsed with ultra-pure water. This process was performed in a specially-designed cleansing apparatus. Subsequently, the substrate was dried using a spin drier (SRD 1800-6, VERTEQ). Then, photoresist was coated on the substrate to a predetermined thickness. The coating of the photoresist was performed using a spin coater (EBR TRACK, Korea Semiconductor System). The spin coating was performed by dripping 10 cc of the photoresist at the center of the stationary substrate. Next, the photoresist was dispersed for 3 seconds at 300 rpm using the spin coater. Subsequently, the substrate was spun at a rate of about 700 to 1000 rpm to form a predetermined thickness. The spinning was performed for about 20 seconds.

Thereafter, photoresist was coated on an 8-inch silicon oxide substrate and the efficiency of removal of unwanted photoresist at the edge was tested with each thinner composition of Examples 1 to 11 and Comparative Examples 1 to 4 (Edge Bead Removing test, hereunder referred to as EBR test). The same spin coater that was used in the coating of the photoresist on the substrate was used for the EBR test.

Each thinner composition shown in Table 1 was sprayed on the photoresist-coated substrate through an EBR nozzle to remove the photoresist under the conditions below. Each thinner composition was supplied from a pressurized container equipped with a pressure gauge. The pressure inside the container was 1.0 kgf and the flow rate of the thinner composition that was supplied through the EBR nozzle was 10 cc/min. The EBR test result of each thinner composition is shown in Figs. 1 to 4 and Table 2 below.

(Test condition) 1) dispense: 300rpm / 3sec

2) coating: PR target thickness rpm/sec (700-1000rpm/20sec)

3) EBR: 200rpm / 10, 15 sec (low rpm process was progressed to plan LCD scan EBR)

4) Dry: 600rpm, lOsec Fig. 1 shows the EBR photographs that were obtained by applying the thinner composition of Examples 1 to 4 of the present invention to an organic EL, Fig. 2 shows the EBR photographs that were obtained by applying the thinner composition of Examples 5 to 7 of the present invention to an organic insulation film, and Fig. 3 shows the EBR photographs that were obtained by applying the thinner composition of Examples 8 to 11 of the present invention to a positive type photoresist. In addition, Fig. 4 shows the EBR photographs that were obtained by applying the thinner composition of Comparative Examples 1 to 4 to an organic insulation film. The EBR photographs were measured by using an Olympus 2D instrument. As shown in Figs. 1 to 4, it is found that the thinner compositions of

Examples 1 to 11 of the present invention have superior EBR surface treatment properties compared with the compositions of Comparative Examples 1 to 4.

The results of the EBR test performed under the conditions using each thinner composition of Examples 1 to 11 and Comparative Examples 1 to 4, are shown in Table 2 below.

TABLE 2

Positive type Photoresists for organic Photoresists for organic photoresists insulation film EL

EBR 200rpm, 200rpm, 200rpm, 200rpm, 200rpm, 200rpm, ondition 10 sec 15 sec 10 sec 15 sec 10 sec 15 sec Example 1

Example 2

Example 3

Example 4

Example 5 O O O

Example 6 O O O

Example 7 O O O

Example 8

Example 9 O O O

Example 10 O O O

Example 11 Δ O Δ O Δ O

Comparative

Δ Δ Example 1

Comparative

Δ Δ Δ Δ Δ Δ Example 2

Comparative Example 3

Comparative

O O Δ Δ Example 4

In Table 2, the symbol "®" means good EBR line uniformity after EBR of the photoresist, the symbol "O" means EBR line uniformity of 80% or better, the symbol "Δ" means line uniformity of 50% or better, and the symbol "x" means EBR line uniformity of 20% or better with tailing phenomenon of the photoresist at the edge.

As seen in Table 2, all the thinner compositions of the present invention showed superior EBR capacity (EBR line uniformity). The thinner composition for removing photoresist in accordance with the present invention is capable of effectively removing unwanted photoresist from the edge and the back side of a glass substrate used in the manufacture of liquid crystal displays and organic EL displays, and the manufacture of semiconductor devices and plasma display panels, in a short period of time. In addition, the thinner composition of the present invention is applicable to a variety of processes and is capable of reducing cost, simplifying manufacturing processes, and improving production yield.

While the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art will appreciate that various modifications and substitutions can be made thereto without departing from the spirit and scope of the present invention as set forth in the appended claims.

Claims

WHAT IS CLAIMED IS;

1. A thinner composition for removing photoresist comprising a glycol ether compound.

2. The thinner composition of Claim 1, which further comprises a fluorinated acrylic copolymer as a surfactant, an organic solvent, or a mixture thereof.

3. The thinner composition of Claim 1, wherein the glycol ether compound is at least one selected from the group consisting of alkylene glycol alkyl ether having Cl to C 6 an alkyl group.

4. The thinner composition of Claim 2, wherein the fluorinated acrylic copolymer has a weight average molecular weight ranging from 1,000 to 10,000.

5. The thinner composition of Claim 2, wherein the organic solvent is at least one selected from the group consisting of iV-methyl-2-pyrrolidone (NMP), dimethylsulfoxide (DMSO), dimethylacetamide (DMAc), methyl isobutyl ketone (MIBK), gamma-butyrolactone (GBL), ethyl lactate (EL), propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) and ethyl 3-ethoxypropionate (EEP).

6. The thinner composition of Claim 2, which comprises 0.001 to 1 parts by weight of the fluorinated acrylic copolymer, per 100 parts by weight of the glycol ether compound.

7. The thinner composition of Claim 2, which comprises 20 to 50 parts by weight of the organic solvent, per 100 parts by weight of the glycol ether compound.

8. The thinner composition of Claim 2, which comprises 0.001 to 1 parts by weight of the fluorinated acrylic copolymer and 20 to 50 parts by weight of the organic solvent, per 100 parts by weight of the glycol ether compound.