WO2004107057A1

WO2004107057A1 - Thinner composition for removing photosensitive resin

Info

Publication number: WO2004107057A1
Application number: PCT/KR2004/001168
Authority: WO
Inventors: Suk-Il Yoon; Woo-Sik Jun; Hee-Jin Park
Original assignee: Dongjin Semichem Co., Ltd.
Priority date: 2003-06-03
Filing date: 2004-05-17
Publication date: 2004-12-09
Also published as: KR100951364B1; KR20040104161A; CN1799007A; TW200504205A; JP4512092B2; JP2007531898A; CN100578367C; TWI309757B

Abstract

The present invention relates to a thinner composition for removing a photoresist, which is used in the manufacturing process of a semiconductor device or a liquid crystal display device, and more particularly to a thinner composition comprising a) a propylene glycol monoalkyl ether; b) an alkyl ethanoate; and c) a cycloketone. The thinner composition of the present invention may further comprise at least one compound selected from the group consisting of d) a polyethylene oxide based surfactant and e) a fluorinated acrylic copolymer. The thinner composition for removing a photoresist of the present invention is capable of effectively removing unwanted photoresist attached to the edge and back of a glass substrate or a wafer used in manufacturing a liquid crystal display device or an organic EL display device in a short time, reducing the gap at the interface, and particularly, preventing penetration into the interface of the photoresist. Therefore, it can be used in a variety of processes to offer an economic advantage, simplify the manufacturing process, and improve productivity.

Description

DESCRIPTION

THINNER COMPOSITION FOR REMOVING PHOTOSENSITIVE RESIN

[Technical Field]

The present invention relates to a thinner composition for removing a

photoresist, and more particularly to a thinner composition capable of effectively

removing an unwanted photoresist in the manufacturing process of a semiconductor

device or a liquid crystal display device.

[Background Art]

The TFT-array process during the manufacturing process of a TFT-LCD is

similar to the silicon semiconductor manufacturing process using photolithography.

The photolithographic process is a process of obtaining an electronic circuit by coating

a photosensitive film on a substrate, forming a photomask pattern, developing, and

etching.

A TFT-array is formed on a substrate to manufacture a TFT-LCD by the

photolithographic process. In the process, if the thinner composition penetrates the

interface of the photoresist, the subsequent processes including etching, ion

implantation, etc., may be negatively affected. This may reduce productivity of the

entire process.

Such penetration into the interface of the photoresist may cause defocusing

during exposure after the baking process, and thus reduces productivity of the

TFT-LCD manufacture process.

Differently from the edge part of a silicon wafer where a centrifugal force is exerted, the glass substrate of a TFT-LCD is a square, and thus EBR (edge bead

removing: removal of photoresist at the edge part) by rotation is impossible. Also,

because the glass substrate is fixed and the spray nozzle moves along the four planes

of the glass substrate, the penetration from the edge of the photoresist into the interface

may happen even after the photoresist at the edge part has been removed, if the

thinner does not volatilize quickly. This is different from the rotational EBR where the

silicon wafer is rotated at high speed and penetration from the edge of the photoresist

into the interface is reduced even if the thinner does not volatilize quickly. That is,

because the LCD glass substrate is fixed and only the thinner spray nozzle moves, use

of the conventional highly soluble thinner may cause penetration into the interface of

the photoresist during rinsing of the edge part, thereby reducing productivity of the

entire process.

The conventional thinner compositions are as follows.

Japanese Patent Publication No. Sho 63-69563 discloses a method of

removing unwanted photoresist by contacting a thinner with substrate. In the method,

an organic solvent for cleansing, e.g., ethers or ether acetates such as cellosolve,

cellosolve acetate, propylene glycol ether, propylene glycol ether acetate, etc.; ketones

such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; or

esters such as methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate,

etc., is used as a thinner. Japanese Patent Publication No. Hei 4-49938 discloses use

of propylene glycol methyl ether acetate as a thinner, and Japanese Patent Publication

No. Hei 4-42523 discloses use of alkyl alkoxy propionate as a thinner. These solvents are used alone or in combination considering physical

properties and safety. Differently from the TFT-LCD process where the substrate is

fixed and a linear EBR is employed, these solvents have been used in the rotational

EBR process at an elevated rotational speed.

However, they do not solve the problem of the penetration into the interface of

the photoresist.

[Technical Problem]

It is an aspect of the present invention to provide a thinner composition for

removing a photoresist capable of preventing penetration into the interface of the

photoresist at the edge of a substrate used to manufacture a liquid crystal display

device, particularly a large-sized glass substrate for an organic EL

(electroluminescence) display device, and removing the photoresist effectively in a

short time.

[Technical Solution]

In order to attain the aspect, the present invention provides a thinner

composition for removing a photoresist comprising a) a propylene glycol monoalkyl

ether; b) an alkyl ethanoate; and c) a cycloketone.

Preferably, the thinner composition comprises a) 10 to 90 parts by weight of a

propylene glycol monoalkyl ether; b) 10 to 70 parts by weight of an alkyl ethanoate; and

c) 1 to 70 parts by weight of a cycloketone.

The thinner composition of the present invention may further comprise at least

one compound selected from the group consisting of d) a fluorinated acrylic copolymer; and e) a polyethylene oxide condensate.

Preferably, the thinner composition may comprise a) 10 to 90 parts by weight of

a propylene glycol monoalkyl ether; b) 10 to 70 parts by weight of an alkyl ethanoate; c)

1 to 70 parts by weight of a cycloketone; and d) 0.001 to 1 part by weight of a

fluorinated acrylic copolymer.

Also, the thinner composition may comprise a) 10 to 90 parts by weight of a

propylene glycol monoalkyl ether; b) 10 to 70 parts by weight of an alkyl ethanoate; c) 1

to 70 parts by weight of a cycloketone; and e) 0.001 to 1 part by weight of a

polyethylene oxide condensate.

The thinner composition may also comprise a) 10 to 90 parts by weight of a

to 70 parts by weight of a cycloketone; d) 0.001 to 1 part by weight of a fluorinated

acrylic copolymer; and e) 0.001 to 1 part by weight of a polyethylene oxide condensate.

Hereinafter, the present invention is described in more detail.

The present invention is characterized by being capable of preventing

penetration into the interface of the photoresist, and thus is effective for use in

manufacturing a semiconductor device or a liquid crystal display device.

The thinner composition for removing a photoresist of the present invention

comprises a propylene glycol monoalkyl ether; an alkyl ethanoate; and a cycloketone.

The propylene glycol monoalkyl ether, the alkyl ethanoate, and the cycloketone,

which are used as solvents in the present invention, may be ultrapure and of the

semiconductor level. For a VLSI level, they are preferably ones that are filtered to the level of 0.1 μm.

The alkyl group of the propylene glycol monoalkyl ether may have 1 to 5 carbon

atoms. To be specific, the propylene glycol monoalkyl ether is preferably at least one

selected from the group consisting of propylene glycol monomethyl ether, propylene

glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol

monobutyl ether. Among these, propylene glycol monomethyl ether, which has an

outstanding dissolving power to polymers, is more preferable.

Propylene glycol monomethyl ether is harmless to humans when exposed to

air, and is quickly decomposed to propylene glycol and alcohol in the human body.

According to a toxicity test by oral administration into a mouse, it has an LD₅₀ of 4.4 g/kg.

And, it is quickly decomposed by hydrolysis. It has a boiling point of 132.8 °C, a flash

point (measured by the closed cup method) of 32 °C , a viscosity (at 25 °C ) of 1.86 cps,

a surface tension of 26.5 dyne/cm², and a solubility parameter of 10.4.

Preferably, the propylene glycol monoalkyl ether is comprised at 10 to 90 parts

by weight per 100 parts by weight of the composition. If the content of the propylene

glycol monoalkyl ether is below 10 parts by weight, dissolving power to the

photosensitive film is reduced. Otherwise, if it exceeds 90 parts by weight of, the

volatility decreases, so that the thinner may remain on the surface after drying.

Also, preferably, the alkyl group of the alkyl ethanoate has 1 to 4 carbon atoms.

To be specific, the alkyl ethanoate is at least one selected from the group consisting of

methyl ethanoate, ethyl ethanoate, isopropyl ethanoate, n-propyl ethanoate, and butyl

ethanoate. Among these, such solvents as isopropyl ethanoate, n-propyl ethanoate, and butyl ethanoate are more preferable. They have adequate volatilities and

relatively low viscosities. Preferably, the alkyl ethanoate is comprised at 10 to 70 parts

by weight per 100 parts by weight of the composition. If the content of the alkyl

ethanoate is below 10 parts by weight, the thinner becomes less volatile, so that the

thinner may remain on the substrate after drying. Otherwise, if it exceeds 70 parts by

weight, dissolving power of the thinner may decrease.

Butyl ethanoate, one of the alkyl ethanoates, has superior dissolving power to a

variety of resins, a particularly low surface tension, and outstanding volatility, so that it

can offer superior interfacial characteristics with a small amount of addition into the

thinner composition. According to a toxicity test by oral administration into a mouse,

butyl ethanoate has an LD₅₀of 7.0 g/kg. And, it is quickly decomposed by hydrolysis.

It has a boiling point of 126.1 ^°C, a flash point (measured by the closed cup method) of

23 °C , a viscosity (at 25 ^°C) of 0.74 cps, and a surface tension of 25 dyne/cm².

The cycloketone may be cyclopentanone, cyclohexanone, cycloheptanone, etc.

Among these, cyclohexanone, which has superior dissolving power to a variety of

resins, is more preferable.

The cycloketone is comprised at 1 to 70 parts by weight per 100 parts by

weight of the composition. If the content of the cycloketone is below 1 part by weight,

the ability to remove several photosensitive films is reduced. Otherwise, if it exceeds

70 parts by weight, dissolving power to a specific photosensitive film is reduced.

The thinner composition of the present invention may further comprise at least

one compound selected from the group consisting of a fluorinated acrylic copolymer and a polyethylene oxide condensate.

The fluorinated acrylic copolymer is highly soluble in water and a variety of

solvents. An example of the commercially available products is Megaface R-08 of

Dainippon Ink and Chemicals.

Preferably, the fluorinated acrylic copolymer is comprised at 0.001 to 1 part by

weight per 100 parts by weight of the composition. If the content of the copolymer is

below 0.001 part by weight, dissolving power to the photoresist is significantly reduced.

Otherwise, if it exceeds 1 part by weight, the removing capacity is improved as the

dynamic surface tension at the interface is reduced, but the liquid level sensor may

operate abnormally due to excessive foaming.

Preferably, for the fluorinated acrylic copolymer, the one having a

weight-average molecular weight ranging from 3000 to 10,000, a flash point (measured

by the open cup method) of 200 ^°C, a specific gravity of 1.10 g/ml (at 25 °C), a viscosity

(at 20 °C) of 2100 cst, and a surface tension on ethyl lactate of 24.0 mN/m (measured

by the Wilhermy method). Preferably, it is used diluted in ethyl lactate.

The polyethylene oxide condensate acts as a non-ionic surfactant. To be

specific, the condensate may be a condensation product of an alkyl phenol having a

linear or branched alkyl group having 6 to 12 carbon atoms, and 5 to 25 moles of

ethylene oxide per 1 mole of the alkyl phenol. The alkyl group of the alkyl phenol may

be derived from propylene, diisobutylene, octene, or nonene. Examples of the

condensate are nonylphenol obtained from condensation of about 9.5 moles of

ethylene oxide per 1 mole of phenol, dodecylphenol obtained from condensation of about 12 moles of ethylene oxide per 1 mole of phenol, diisooctylphenol obtained from

condensation of about 15 moles of ethylene oxide per 1 mole of phenol, and so forth.

These compounds are highly soluble in water and a variety of solvents. They reduce

the gap at the interface when the thinner contacts the photoresist. An example of a

commercially available product is the non-ionic Monopol series of Dongnam Chemical.

Preferably, the polyethylene oxide condensate is comprised at 0.001 to 1 part

by weight per 100 parts by weight of the composition. If the content is below 0.001

part by weight, volatility and cleansing power of the thinner are significantly reduced at

the edge of the substrate. Otherwise, if it exceeds 1 part by weight, foaming becomes

excessive.

After a photoresist is coated on a substrate using a coater, unwanted

photoresist at the edge and back of the substrate is removed by dropping or spraying

the thinner composition. The amount of dropping or spraying of the thinner

composition of the present invention can be controlled depending on the kind of

photoresist and film thickness. Preferably, the amount is selected from the range of 5

to 100 cc/min. After the thinner composition has been sprayed, a microcircuit pattern

may be formed by the subsequent photolithographic process.

[Advantageous Effects]

As described above, the thinner composition for removing a photoresist of the

present invention is capable of effectively and quickly removing unwanted photoresist

attached at the edge and back of a substrate used in manufacturing a liquid crystal

display device, particularly a large-sized glass substrate for an organic EL display device, reducing the gap at the interface, and especially preventing penetration into the

interface of the photoresist. Therefore, it offers an economic advantage, simplifies

manufacturing processes, and improves productivity.

[Best Mode]

Hereinafter the present invention is described in more detail through examples.

However, the following examples are only for the understanding of the present

invention and they do not limit the present invention.

EXAMPLES

A substrate sample was prepared as follows.

A silicon oxide substrate having a diameter of 8 inches was used. The

substrate was cleansed in two baths (immersed in each bath for 5 minutes) containing

hydrogen peroxide and sulfuric acid, respectively, and rinsed with ultrapure water.

This process was performed in a specially designed cleansing facility. Then, the

substrate was dried in a spin drier (SRD 1800-6 of VERTEQ). Next, a photoresist was

coated to a predetermined thickness on the substrate. The photoresist was coated

with a spin coater (EBR TRACK of Korea Semiconductor).

In the spin coating, 10 cc of the photoresist was dropped at the center of the

stationary substrate. Then, the photoresist was distributed for 3 seconds using a spin

coater at 500 rpm. Subsequently, the spinning rate was increased to about 2000 to

4000 rpm to obtain a desired thickness. The spinning time at this rate was about 20 to

30 seconds. Examples 1 to 5 and Comparative Examples 1 to 5

Each thinner composition of Examples 1 to 5 and Comparative Examples 1 to 5

was prepared with the composition and content given in Table 1 below.

Table 1

Note)

1. PGME: propylene glycol monomethyl ether

2. PGMEA: propylene glycol monoethyl ether acetate

3. n-PE: n-propyl ethanoate

4. CXN: cyclohexanone

5. GBL: D-butyrolactone 6. OP-1015: Monopol OP-1015 of Dongnam Chemical, a condensate prepared

by condensing 5 moles of ethylene oxide per 1 mole of octylphenol

7. R-08: Megaface R-08 of Dainippon Ink and Chemicals, a fluorinated acrylic

copolymer

Removal of unwanted photoresist

Each photoresist was coated on an 8-inch silicon oxide substrate. Then,

unwanted photoresist at the edge part was removed using each thinner composition of

Examples 1 to 7 and Comparative Examples 1 to 5 (edge bead Removing test:

hereunder referred to as EBR test). During the EBR test, the same spin coater that

had been used to coat the photoresist on the substrate was used.

On each substrate coated with the photoresist given in Table 2 below, each

thinner composition of Table 1 was spayed though an EBR nozzle under the condition

given in Table 3 below. Each thinner composition was fed from a pressured container

equipped with a pressure gauge. He feeding pressure was 1.0 kgf, and the flow rate

of the thinner composition was controlled to 10 to 20 cc/min.

Evaluation of the EBR test result is given in Table 4 below.

Table 2

Photoresists and film thicknesses

Table 3

EBR test condition

Table 4

Evaluation of EBR test

photoresist during the EBR test. "O" means that 80% or more of the penetration into

the interface of the photoresist had a favorable linear shape. "Δ" means that 50% or

more of the penetration into the interface of the photoresist had a favorable linear

shape. "X" means that 20% or more of the penetration into the interface of the

photoresist had a favorable linear shape and that tailing of the film occurred at the edge

part.

As shown in Table 4, all of the thinner compositions of the present invention

(Examples 1 to 7) showed superior EBR performance (prevention of penetration) for all

photoresists. Especially, the thinner compositions of Examples 5 and 7 showed very

superior EBR performance and penetration preventing capability. Therefore, the

thinner composition of the present invention, which comprises a polyethylene oxide

condensate, a fluorinated acrylic copolymer, or mixtures thereof, offers superior

photoresist removal capability.

On the contrary, the thinner compositions of Comparative Examples 1 to 5

showed much worse penetration preventing capability. This reduces productivity of a

semiconductor device or a liquid crystal display device in the subsequent processes.

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

1. A thinner composition for removing a photoresist, comprising

a) a propylene glycol monoalkyl ether;

b) an alkyl ethanoate; and

c) a cycloketone.

2. The thinner composition of claim 1 , which comprises

a) 10 to 90 parts by weight of a propylene glycol monoalkyl ether;

b) 10 to 70 parts by weight of an alkyl ethanoate; and

c) 1 to 70 parts by weight of a cycloketone.

3. The thinner composition of claim 1 , which further comprises at leas one

compound selected from the group consisting of

d) a fluorinated acrylic copolymer; and

e) a polyethylene oxide condensate.

4. The thinner composition of claim 1 , which comprises

a) 10 to 90 parts by weight of a propylene glycol monoalkyl ether;

b) 10 to 70 parts by weight of an alkyl ethanoate;

c) 1 to 70 parts by weight of a cycloketone; and

d) 0.001 to 1 part by weight of a fluorinated acrylic copolymer.

5. The thinner composition of claim 1 , which comprises

a) 10 to 90 parts by weight of a propylene glycol monoalkyl ether;

b) 10 to 70 parts by weight of an alkyl ethanoate;

c) 1 to 70 parts by weight of a cycloketone; and e) 0.001 to 1 part by weight of a polyethylene oxide condensate.

6. The thinner composition of claim 1, which comprises

a) 10 to 90 parts by weight of a propylene glycol monoalkyl ether;

b) 10 to 70 parts by weight of an alkyl ethanoate;

c) 1 to 70 parts by weight of a cycloketone;

d) 0.001 to 1 part by weight of a fluorinated acrylic copolymer; and

e) 0.001 to 1 part by weight of a polyethylene oxide condensate.

7. The thinner composition of claim 1 , wherein the propylene glycol monoalkyl

ether is at least one selected from the group consisting of propylene glycol monomethyl

ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, and

propylene glycol monobutyl ether.

8. The thinner composition of claim 1 , wherein the alkyl ethanoate is at least

one selected from the group consisting of methyl ethanoate, ethyl ethanoate, isopropyl

ethanoate, n-propyl ethanoate, and butyl ethanoate.

9. The thinner composition of claim 1, wherein the cycloketone is at least one

selected from the group consisting of cyclopentanone, cyclohexanone, and

cycloheptanone.

10. The thinner composition of claim 3, wherein the fluorinated acrylic copolymer has a weight-average molecular weight ranging from 3000 to 10,000.

11. The thinner composition of claim 3, wherein the polyethylene oxide condensate is a condensation product of an alkyl phenol having a linear or branched alkyl group having 6 to 12 carbon atoms and 5 to 25 moles of ethylene oxide per 1 mole of the alkyl phenol.