KR20110021189A - Thinner composition which can reduce consumption of photoresists - Google Patents

Abstract

PURPOSE: A thinner composition which can reduce consumption of photoresists is provided to spread evenly photoresists on the whole surface of a substrate by firstly surface-treating the photoresists on the substrate before the photoresists is applied to the substrate. CONSTITUTION: A thinner composition which can reduce consumption of photoresists comprises, based on the total weight of the composition, 0.01-20 weight% of organic solvents which has a boiling point of 180°C or more and can perform hydrogen bond, 10-70 weight% of glycols which has a boiling point of 150°C or less and can perform hydrogen bond with organic solvents, and 10-89.99 weight% of esters.

Description

Thinner composition that can reduce the amount of photoresist used {THINNER COMPOSITION WHICH CAN REDUCE CONSUMPTION OF PHOTORESISTS}

The present invention relates to a thinner composition that can effectively remove the unnecessary photoresist applied to the edge portion or the back side of the substrate while reducing the amount of photoresist used for implementing the pattern.

Like a semiconductor integrated circuit, a fine circuit pattern is uniformly coated with a photoresist including a photosensitive compound and a solvent by a rotation coating method on a conductive metal film or an oxide film formed on a substrate, and then subjected to exposure, development, etching and peeling processes. It is manufactured through a method for implementing a desired microcircuit pattern. At this time, since the exposure process, which is a subsequent process, is implemented by exposing a desired pattern to the coating film using light having a short wavelength in the ultraviolet region, it is very sensitive to external and internal contamination. Therefore, undesired photoresist residues and other contaminants applied to the edges or backsides of the substrate in the application process may be fatal sources of contamination in the subsequent exposure process and must be removed. Thinners have been used in EBR (edge bead removing) processes to remove these contaminants.

On the other hand, in recent years, as the degree of integration of semiconductors has increased, photoresists using short-wavelength KrF and ArF (including ArF immersion) light sources have been applied. There has been a continuous need to reduce the amount of photoresist used.

Due to this requirement, RRC (reducing resist consumption) is applied to the surface of the substrate with thinner before applying the photoresist so that the photoresist can be evenly applied to the entire surface of the substrate even with a small amount of photoresist. The process has been applied. As the density of substrates (wafers) increases with the increase in the degree of integration, the importance of the RRC process is further increased. Therefore, development of thinners having high RRC efficiency while sufficiently proceeding with the existing EBR process is required.

Conventionally, single solvents such as ethyl cellosolve acetate (ECA), methylmethoxy propionate (MMP) and ethyl lactate (EL) are widely used as thinner compositions for removing photoresist. Although used, ethyl cellosolve acetate has been problematic in its use due to its harmfulness to the human body, and methyl methoxy propionate and ethyl lactate due to economic and performance limitations.

In order to solve this problem, a conventional method of mixing a single solvent has been developed. As a thinner composition in the form of such a mixture, a mixture of propylene glycol alkyl ether, butyl acetate and ethyl lactate, or butyl acetate, ethyl Mixtures of lactates and propylene glycol alkyl ether acetates (JP-A-7-128867); A mixture of propylene glycol alkyl ether propionate and methyl ethyl ketone or a mixture of propylene glycol alkyl ether propionate and butyl acetate (Japanese Patent Laid-Open No. 7-160008); Mixtures of propylene glycol alkyl ether acetates and propylene glycol alkyl ethers (US Pat. No. 4,983,490); And mixtures of ethyl lactate and propylene glycol alkyl ethers (US Pat. No. 4,886,728) and the like.

However, the above-described thinner composition in the form of a mixture also has a limit in reducing the amount of photoresist to the satisfaction of semiconductor device manufacturers.

Accordingly, an object of the present invention is to compensate for the disadvantages of the existing thinner composition, not only can dramatically reduce the amount of photoresist used for the pattern implementation, but also to achieve uniform application of the photoresist, It is to provide a thinner composition that can effectively remove unnecessary photoresist applied to the edge portion or the rear surface portion.

The present invention to achieve the above object,

Based on the total weight of the composition,

(1) 0.01 to 20% by weight of an organic solvent having a boiling point of 180 ° C. or higher and capable of hydrogen bonding;

(2) 10 to 70% by weight of glycols having a boiling point of 150 ° C. or lower capable of hydrogen bonding with the organic solvent, and

(3) Provides a thinner composition comprising 10 to 89.99% by weight of esters.

The thinner composition according to the present invention is first surface-treated on a substrate before the photoresist is applied to the substrate during the semiconductor device manufacturing process so that the photoresist may be evenly applied on the entire surface of the substrate even when a small amount of the photoresist is used. Process cost and productivity can be improved, and unnecessary photoresist applied to the edge or backside of the substrate can be removed quickly and effectively. That is, when the thinner composition of the present invention is used, an RRC process and an EBR process may be efficiently performed when manufacturing a semiconductor device.

A method of reducing the amount of photoresist used by spraying a thinner composition onto a stationary substrate and then rotating and then spraying a photoresist onto the substrate is a reducing resist consumption (RRC) process. A portion of the rotated thinner component remains on the surface of the substrate without volatilization, thereby facilitating the application of the photoresist, thereby improving the RRC performance. In other words, the surface of the substrate is thinly coated with an organic solvent thinner so that the photoresist, which is an organic material, is efficiently applied to the substrate. On the other hand, in order to obtain the desired performance in the edge bead removing (EBR) process that effectively removes unnecessary photoresist applied to the edge or backside of the substrate, the thinner must satisfy both excellent dissolving ability and volatilization of the photoresist at the same time. In order to maximize the RRC performance, simply increasing the boiling point of the thinner component causes the thinner to penetrate into the inside of the photoresist-coated substrate in the EBR process, causing swelling of the applied film, thereby contaminating the lens during the exposure process. The gap between the lens and the substrate becomes impossible.

Therefore, the thinner composition according to the present invention is based on the total weight of the composition, (1) 0.01 to 20% by weight of a high boiling point organic solvent capable of hydrogen bonding at 180 ° C. or more, and (2) easily hydrogen-bonded with the organic solvent. 10 to 70% by weight of glycols having a boiling point of 150 ° C. or less, and (3) 10 to 89.99% by weight of esters having excellent solubility in photoresist and having an appropriate volatility.

In the present invention, most of the thinner composition applied to the substrate is volatilized while the substrate is rotated to apply the photoresist, and the remaining thinner component is evenly distributed on the entire surface of the substrate. At this time, a high electronegativity of the high boiling organic solvent (for example, oxygen) and -OH groups of glycols form hydrogen bonds, so that a small amount of the high boiling organic solvent component and glycols remain on the surface of the substrate simultaneously. Help spread. In addition, since only a small amount of the thinner composition does not significantly affect the volatilization of the entire thinner, it is possible to effectively remove the unwanted portion of the photoresist due to its excellent dissolving ability and volatility. In order to hydrogen bond with glycols, elements such as N, O, F, etc., which have strong electronegativity, must be present in the organic solvent. Should be able to form Therefore, the organic solvent used in the present invention preferably has a hydroxyl group (-OH), an ether group (-O-) or an ester group (-COO-), in which case the electrical of the oxygen element (O) in the bond Because of its high negativeness, organic solvents can facilitate hydrogen bonding with H elements of glycols.

The high boiling point organic solvent component should have a boiling point of 180 ° C. or higher and is used in an amount of 0.01 to 20% by weight, preferably 1 to 10% by weight, based on the total weight of the composition. If the boiling point does not become 180 ° C or higher, the amount of residue remaining on the substrate is so small that the RRC effect is inferior. In addition, if the high boiling point organic solvent component is less than 0.01% by weight, the amount of residual on the substrate is too small to reduce the RRC effect. If the high boiling point organic solvent component is more than 20% by weight, the overall volatility of the thinner composition is reduced, which affects the thickness of the photoresist, which is undesirable. The thinner is not sufficiently dried during the EBR process, causing the thinner to penetrate the inside of the substrate to which the photoresist is applied, causing swelling of the applied film or the tailing phenomenon caused by the swelling of the swollen portion by rotation. This results in contamination of the lens in the exposure process or inability to adjust the gap between the lens and the substrate.

As the high boiling organic solvent used in the present invention, alkylene glycols, dialkylene glycol alkyl ethers or gamma butyrolactone are preferable. Alkylene glycols, dialkylene glycol alkyl ethers, and gamma butyrolactone contain oxygen atoms with strong electronegations in their molecular structure, and glycols with a boiling point of 150 ° C or less are easily hydrogen-bonded. At the same time, it remains and increases the RRC efficiency by forming thin films evenly without significantly affecting the volatility of the entire thinner.

More specific examples of the high-boiling organic solvent used in the present invention include alkyl such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol having a weight average molecular weight of 400 or less, polypropylene glycol having a weight average molecular weight of 400 or less Lene glycols; Dialkylene glycol alkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and dipropylene glycol monomethyl ether; Gamma butyrolactone; And mixtures thereof.

The glycol component should have a boiling point of 150 ° C. or less and is used in an amount of 10 to 70% by weight, preferably 20 to 50% by weight, based on the total weight of the composition. The -OH groups of glycols form hydrogen bonds with atoms having high boiling point electronegativity and remain at the same time with the high boiling point organic solvent component to help the photoresist spread well. When the content of glycols having a boiling point of 150 ° C. or less is less than 10% by weight, the remaining components in the RRC process almost leave only the high boiling point components, resulting in poor volatilization, thereby preventing the formation of a uniform thin film. Problems with poor sex occurs. In addition, when the content of glycol is more than 70% by weight, the ability to melt the photoresist is excellent, but the straightness of the EBR-treated cross section may be deteriorated.

Specific examples of the glycols used in the present invention include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Glycol monopropyl ether, propylene glycol monobutyl ether, and mixtures thereof. Among them, propylene glycol monomethyl ether having excellent solubility in polymers is preferably used.

The ester component is frequently used as a solvent of the photoresist because it has excellent solubility in the photoresist. Preferred EBR performance can be obtained by using at least one ester having excellent solubility in photoresist and having an appropriate volatility. The ester component is used in an amount of 10 to 89.99% by weight, preferably 20 to 60% by weight, based on the total weight of the composition. If the content of the esters is less than 10% by weight, the EBR performance is poor, and it is not preferable.

Specific examples of the esters used in the present invention include propylene glycol monomethyl ether acetate, ethyl ethoxy propionate, propylene glycol monomethyl ether propionate, ethylene glycol diacetate, ethyl lactate, butyl lactate, methyl 2- Hydroxyisobutyrate, and mixtures thereof.

The thinner composition of the present invention may further include a surfactant in addition to the above-described components. At this time, the surfactant is preferably a nonionic surfactant, and may be used in an amount of about 10 to 500 ppm. The addition of a surfactant can achieve the effect of improving the EBR properties.

When the thinner composition of the present invention including the above-mentioned components is used in an RRC process in a semiconductor device manufacturing process, the thinner composition may be applied to a substrate in a conventional manner prior to the application of the photoresist, for example, in the center of the fixed substrate. After spraying the composition, the substrate may be rotated to allow the sprayed thinner composition to spread over the entire surface of the substrate, where the spraying amount may be in the range of 1 to 5 cc.

In addition, when the thinner composition of the present invention is used in an EBR process during a semiconductor device manufacturing process, the substrate is rotated while spraying the thinner composition onto the EBR section of the photoresist-coated substrate to remove the photoresist in the EBR section for an additional time. The substrate can be rotated to dry.

As described above, the thinner composition according to the present invention is first surface-treated on the substrate before the photoresist is applied to the substrate during the semiconductor device manufacturing process so that the photoresist can be evenly applied on the entire surface of the substrate even when a small amount of photoresist is used. By reducing the amount of resist used, process cost and productivity can be improved, and unnecessary photoresist applied to the edge or backside of the substrate can be removed quickly and effectively. That is, when the thinner composition of the present invention is used, an RRC process and an EBR process may be efficiently performed when manufacturing a semiconductor device.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated more concretely based on an Example. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

Examples 1-10 and Comparative Examples 1-4: Preparation of Thinner Composition

The thinner compositions of Examples 1 to 10 and Comparative Examples 1 to 4 were prepared by mixing the corresponding amounts of the components as shown in Table 1 below. If necessary, an additional 10 to 50 ppm of nonionic surfactant may be included in the compositions of Examples 1 to 10 to further improve the EBR properties.

MDG: diethylene glycol monomethyl ether, DPM: dipropylene glycol monomethyl ether, PEG200: polyethylene glycol having a weight average molecular weight of 200, PGBE: propylene glycol monobutyl ether, PGME: propylene glycol monomethyl ether, EGEE: ethylene glycol monoethyl Ether, EL: ethyl lactate, HBM: methyl 2-hydroxyisobutyrate, PGMEA: propylene glycol monomethyl ether acetate, EEP: ethyl ethoxy propionate

Test Example 1: Evaluation of RRC (reducing resist consumption) performance

In order to evaluate the RRC performance of each of the thinner compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 4, an RRC process under application conditions as shown in Table 2 was performed, and the evaluation results are shown in Table 3 below. It was.

step Time (sec) Substrate Rotational Speed (RPM) Spray material One 4 0 2 One 0 Thinner composition 3 0.1 1000 4 One 4000 Photoresist 5 One 100 6 25 2000

Referring to the application conditions of the RRC process with reference to Table 2, the thinner spray nozzle was moved for 4 seconds to the center of the 8 inch silicon substrate to spray the thinner composition as a first step. As a second step, 2 cc of the thinner composition was sprayed onto the substrate for 1 second. In the third step, the substrate was rotated to spread the thinner composition onto the wafer for a relatively short 0.1 second. In the fourth step, the photoresist sprayed on the substrate was applied to the entire surface by rotating the substrate to a relatively fast 4000 RPM while spraying the photoresist for 1 second. In the fifth step, the applied photoresist was stabilized by reducing the substrate rotation speed to 100 RPM for 1 second. Subsequently, in the sixth step, the substrate was rotated at an arbitrary rotation speed for 25 seconds to control the thickness of the photoresist coating layer. As the photoresist, TM 600 (manufacturer: TOK, viscosity: 24 cP) was used in the above experimental conditions.

RRC performance evaluation was performed by measuring the minimum amount that photoresist could be evenly applied to the front surface on an 8 inch substrate. The smaller the minimum amount of photoresist, the better the RRC performance, especially 0.50cc or less is preferable. In addition, staining was observed after application of the photoresist to visually confirm the coating uniformity of the photoresist, and when the staining occurred, it was determined that the coating uniformity was inferior.

As can be seen from Table 3, the thinner composition of Examples 1 to 10 according to the present invention showed a significantly superior RRC performance compared to the existing thinner composition of Comparative Examples 1 to 4, thereby minimizing the amount of photoresist used to process costs It can be predicted that the cost savings and the productivity can be improved.

Test Example 2: EBR (edge bead removing) performance evaluation

In order to evaluate the EBR performance of each of the thinner compositions prepared in Examples 1 to 10 and Comparative Examples 1 to 4, EBR was applied under the same conditions as shown in Table 4 after the photoresist was applied in the same manner as in Test Example 1. The process was carried out and the evaluation results are shown in Table 5 below. The EBR process rotates the substrate while spraying the thinner composition on the unnecessary photoresist applied to the edge or the rear surface of the substrate, that is, the photoresist of the EBR section, and then removes the photoresist of the EBR section, and then further removes the substrate for a predetermined time. It progressed by rotating and drying. EBR process also used the same rotary applicator as used in Test Example 1.

After evaluating the EBR performance, the result of observing the photoresist in the EBR section after removing the photoresist was confirmed that the profile of the removed part was formed cleanly with a certain line and the residue of the photoresist in the removed part through the optical microscope. Is shown in Table 5 below.

From Table 5, it can be seen that the thinner composition of Examples 1 to 10 according to the present invention shows excellent EBR performance compared to the existing thinner composition of Comparative Examples 2 to 4.

Claims (8)

Based on the total weight of the composition, (1) 0.01 to 20% by weight of an organic solvent having a boiling point of 180 ° C. or higher and capable of hydrogen bonding; (2) 10 to 70% by weight of glycols having a boiling point of 150 ° C. or lower capable of hydrogen bonding with the organic solvent, and (3) A thinner composition comprising 10 to 89.99 wt% of esters. The method of claim 1, Thinner composition, characterized in that the organic solvent has a hydroxyl group, an ether group or an ester group. The method of claim 1, The organic solvent is ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol with a weight average molecular weight of 400 or less, polypropylene glycol with a weight average molecular weight of 400 or less, diethylene glycol monomethyl ether, diethylene glycol monoethyl A thinner composition, characterized in that it is selected from the group consisting of ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, gamma butyrolactone, and mixtures thereof. The method of claim 1, The glycols are ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl Thinner composition, characterized in that it is selected from the group consisting of ethers, and mixtures thereof. The method of claim 1, The esters are propylene glycol monomethyl ether acetate, ethyl ethoxy propionate, propylene glycol monomethyl ether propionate, ethylene glycol diacetate, ethyl lactate, butyl lactate, methyl 2-hydroxyisobutyrate, and these Thinner composition, characterized in that selected from the group consisting of. The method of claim 1, Thinner composition, characterized in that the composition further comprises a surfactant in an amount of 10 to 500 ppm. The method of claim 1, A thinner composition, wherein the composition is used in a process of reducing the amount of photoresist used by spraying a thinner composition onto a substrate and then rotating the coating and then rotating and spraying the photoresist onto the substrate. The method of claim 1, The composition is used for the process of removing the unnecessary photoresist applied to the edge part or the back part of a board | substrate.