TW201905191A - Washing method for vacuum evaporation mask and leaching composition - Google Patents

Abstract

Provided is a method for washing a mask for vacuum vapor deposition, the method comprising washing a mask by using a washing composition that contains at least one selected from N-methyl-2-pyrrolidinone and N,N-dimethylformamide, and then rinsing the washed mask by using a rinsing composition containing at least one type of a hydro fluoro ether selected from among HFE-347pc-f, HFE-254pc, HFE-356pcf, and HFE-449mec-f. According to this washing method, when rinsing off the washing composition during washing of the mask that has been used in a vacuum vapor deposition process in the manufacturing of an organic EL element, it is possible to wash the mask so as to be extremely clean without resulting in decomposition of an active ingredient.

Description

Cleaning method of mask for vacuum evaporation and leaching composition

The invention relates to a cleaning method and a shower composition for a mask for vacuum evaporation.

BACKGROUND OF THE INVENTION In recent years, a display device including a liquid crystal display device or an organic EL element has attracted attention as a flat panel display. The liquid crystal display device has low power consumption, but in order to obtain a bright picture, external lighting (backlight) is required. On the other hand, since a display device including an organic EL element is a self-luminous element, there is no need to provide a backlight like a liquid crystal display device. Therefore, a display device provided with an organic EL element has the characteristics of power saving, and also has the characteristics of high brightness and wide viewing angle.

The organic EL element has a functional layer between an anode and a cathode, and the functional layer includes a light emitting layer composed of an organic compound. As a method for forming such a functional layer, a vapor phase process (also referred to as a dry process) or a liquid phase process (also referred to as a wet process or a coating process) such as a vacuum evaporation method are known (for example, refer to Patent Documents 1 to 3). In the phase process, a solution in which the functional layer forming material is dissolved or dispersed in a solvent is used.

When forming a functional layer by vacuum evaporation, a mask is placed close to the substrate, and the cathode, hole injection layer, hole transport layer, light emitting layer, electron transport layer, anode and other layers are patterned through the mask. The vapor deposition mask used at this time, especially the vapor deposition mask used for the fine patterning of the RGB layer, is very high-precision, so it is difficult to manufacture, and the unit price is very high. However, when the pattern of the organic layer in the organic EL element is formed, if the same mask is used for vapor deposition multiple times, organic substances will accumulate and adhere to the mask, so the high-definition mask pattern cannot be transferred correctly. Onto the substrate. Therefore, in order to achieve a high-definition mask pattern, the expensive mask that has been used many times has to be discarded. From the perspective of production cost, it is one of the reasons that it is difficult to mass-produce.

At this point, various attempts have been made to reduce the cost of using masks repeatedly. Among them, a cleaning solution composition has been proposed in the literature for cleaning various types of substances attached to the masks during the vacuum evaporation step of manufacturing organic EL elements. Organic matter (for example, refer to Patent Document 4).

Patent Document 4 describes that a mask is washed with a washing liquid composition and then rinsed with a hydrofluoroether. However, the "Novec HFE7100" (C ₄ F ₉ OCH ₃ ) used as an eluent in Patent Document 4 is found in, for example, N-methyl-2-pyrrolidone or N, N-dimethylformamide. It decomposes in the presence of fluorine ions (for example, refer to Patent Document 5). Therefore, the surface of the mask cannot be cleaned by the above method.

Prior Art Literature Patent Literature Patent Literature 1: Japanese Patent Laid-Open No. 2002-110345 Patent Literature 2: Japanese Patent Laid-Open No. 2002-305079 Patent Literature 3: Japanese Patent Laid-Open No. 2002-313564 Patent Literature 4: Japanese Patent Laid-Open No. 2005- Patent Document No. 162947 Patent Document 5: Japanese Patent Publication No. 2009-518857

SUMMARY OF THE INVENTION Problems to be Solved by the Invention The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a cleaning method and a rinsing composition which are cleaned, for example, in a vacuum evaporation step when manufacturing an organic EL element. The mask method used, when the mask washed with the washing composition is rinsed with the eluent composition, the active ingredients of the eluent composition are not decomposed, and the mask can be cleaned extremely cleanly.

The method for solving the problem The cleaning method of the embodiment is a method for cleaning a mask for vacuum evaporation, which is characterized in that the mask is washed with a cleaning composition, and then the rinsed composition is rinsed. The mask, the washing composition contains at least one selected from the group consisting of N-methyl-2-pyrrolidone (NMP) and N, N-dimethylformamide (DMF), and the washing composition contains Selected from CF ₃ CH ₂ -O-CF ₂ CHF ₂ (HFE-347pc-f), CHF ₂ CF ₂ -O-CH ₃ (HFE-254pc), CHF ₂ -O-CH ₂ CF ₂ CHF ₂ (HFE- 356pcf) and _{CF 3 CHFCF 2 -O-CH 2} CF 3 (HFE-449mec-f) in the at least one hydrofluoroether.

In the cleaning method according to the embodiment, the content ratio of the hydrofluoroether in the eluent composition is preferably 80% by mass or more and 100% by mass or less.

In the cleaning method of the embodiment, the cleaning composition preferably contains N-methyl-2-pyrrolidone.

In the cleaning method of the embodiment, the eluent composition preferably contains CF ₃ CH ₂ -O-CF ₂ CHF ₂ .

In the cleaning method according to the embodiment, it is preferable that both the washing and rinsing of the mask are performed at a temperature of 10 ° C. or higher and 40 ° C. or lower, and both are preferably performed at a temperature of 20 ° C. or higher and 30 ° C. or lower.

In the cleaning method of the embodiment, the vacuum evaporation is preferably performed when a low-molecular-type organic EL device is manufactured.

In the cleaning method according to the embodiment, the mask after the shower composition is rinsed is preferably dried.

The eluent composition of the embodiment is a person who rinses a mask for vacuum evaporation washed with the cleaning composition, and the cleaning composition contains a member selected from the group consisting of N-methyl-2-pyrrolidone and N, N- At least one of dimethylformamide; the above-mentioned eluent composition is characterized in that it contains a member selected from the group consisting of CF ₃ CH ₂ -O-CF ₂ CHF ₂ , CHF ₂ CF ₂ -O-CH ₃ , and CHF ₂ -O -CH ₂ CF ₂ CHF ₂ and CF ₃ CHFCF ₂ -O-CH ₂ CF ₃ at least one kind of hydrofluoroether.

The content ratio of the hydrofluoroether in the rinse composition of the embodiment is preferably 80% by mass or more and 100% by mass or less.

In this specification, the abbreviation of the compound may be noted in parentheses after the compound name, and the abbreviation may be used to replace the compound name if necessary. In addition, the symbol "~" in this specification indicates the range from the value carried in front of it to the value carried behind.

Advantageous Effects of Invention According to the cleaning method and the rinsing composition of this embodiment, when the mask used in the vacuum evaporation step at the time of manufacturing the organic EL element is cleaned, the rinsing composition is used to rinse the rinsing composition In the case of a clean mask, the mask can be cleaned extremely cleanly without accompanying decomposition of the active ingredients of the eluent composition.

Embodiments for Carrying Out the Invention Embodiments of the present invention will be described in detail below with reference to the drawings. The cleaning method according to this embodiment is a method for cleaning a mask used in, for example, a vacuum vapor deposition step when manufacturing an organic EL element, and includes a cleaning step, a rinsing step, and a drying step. In the cleaning method of this embodiment, the mask is washed with the cleaning composition in the cleaning step, and the cleaning composition contains a member selected from the group consisting of N-methyl-2-pyrrolidone and N, N-di At least one of methylformamide. Next, in the rinsing step, the mask washed with the washing composition is rinsed with the washing composition, and the washing composition contains a member selected from the group consisting of HFE-347pc-f, HFE-254pc, HFE-356pcf, and HFE. -449mec-f at least one type of hydrofluoroether. Then, if necessary, a drying step is performed to dry the mask.

In the cleaning method of this embodiment, the specific hydrofluoroether contained in the eluent composition may be N-methyl-2-pyrrolidone or N, N-dimethylformamidine in the eluent composition. It is not easily decomposed in the presence of amines. Therefore, when the washing composition remains on the mask after washing, the above-mentioned specific hydrofluoroether in the washing composition will not be decomposed by the washing composition, and fluorine ions will not be generated. Therefore, the mask surface can be cleaned extremely cleanly.

The mask to be cleaned in the cleaning method of the present embodiment is a substance used in a vacuum vapor deposition step in the manufacturing process of an organic EL display device described below, for example.

In the following, a method for manufacturing an organic EL display device is described with reference to FIGS. 1 and 2. A TFT (thin film transistor) and a transparent electrode are formed on a glass substrate, and a hole transporting layer is further formed. The glass substrate 1 on which the TFT, the transparent electrode, and the hole transport layer are formed is carried into the vacuum chamber with the processed surface of the glass substrate 1 facing downward. A light-emitting layer corresponding to each of the primary colors R, G, and B as a color display device is formed on a glass substrate 1 in a vacuum chamber. This step is performed in a separate vacuum chamber corresponding to each of the primary colors R, G, and B as a color display device. That is, the glass substrate 1 is sequentially transferred to a vacuum chamber for forming a light-emitting layer corresponding to the primary color R, a vacuum chamber for forming a light-emitting layer corresponding to the primary color G, and a vacuum chamber for forming a light-emitting layer corresponding to the primary color B. Vacuum chamber.

In the aspect shown in FIG. 1, a mask 20 which is opened in accordance with the shape of the light emitting layer is arranged in each vacuum chamber in advance. The mask 20 is fixed by a mask frame 21 arranged on a holding table 24.

Each vacuum chamber is provided with a mask corresponding to any one of the primary colors of R, G, and B, and only a part of the opening corresponding to the transparent electrode (anode) 11 is used as the mask 20, and the transparent electrode (anode) 11 is used The predetermined primary colors are made to emit light. Thereby, in each vacuum chamber, the light emitting layers corresponding to the respective primary colors can be formed at respective predetermined positions.

In FIG. 1, the material (organic EL material) of the light-emitting layer is heated and evaporated from an evaporation source 30 disposed below the holding table 24, and the material is vapor-deposited to the glass through the opening of the mask. The surface of the substrate 1. FIG. 2 schematically shows the formation state of the light-emitting layer through the mask 20. As shown in FIG. 2, each transparent electrode (anode) 11 is covered with a mask 20 outside the formation area of the transparent electrode corresponding to the primary color in each vacuum chamber. In addition, the organic EL material corresponding to the primary color is heated and vaporized in the evaporation source 30, and is formed on the glass substrate 1 (the hole transporting layer thereof accurately) through the opening 20h of the mask 20. In addition, the material of the mask may include stainless steel such as SUS, Ni monomer, Ni alloy (such as Fe-Ni alloy, Mg-Ni alloy), or semiconductor such as silicon.

In this vapor deposition step, various organic substances composed of a vapor deposition material are attached to the mask. In addition to the above-mentioned organic EL materials, the vapor deposition materials include hole injection materials, hole transport materials, and electron transport materials used in the manufacture of organic EL elements. Hole injection materials such as copper phthalocyanine (CuPC), poly (3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) composites (PEDOT / PSS), 4,4 ' , 4 ”-p- [phenyl (m-tolyl) amino] triphenylamine (m-MTDATA), etc. Electrode transporting materials can be triphenylamines (TPD), diphenyl naphthalenediamine (α-NPD) ), Ginseng (4-carbazole-9-ylphenyl) amine (TCTA), etc. Organic EL materials can be exemplified by bisstyrylbenzene derivatives, ginseng (8-hydroxyquinoline) aluminum (Alq ₃ ), bis [2- (2-benzo Oxazolyl) phenol] zinc (II) (Zn-PBO), rubrene, dimethylquinacridone, N, N'-dimethylquinacridone (DMQ), 4- (dicyanomethylene) ) -2-methyl-6- [2- (2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quine -9-yl) vinyl] -4H-piran (DCM2) and the like. Examples of the electron transporting material include Alq ₃ , 2,9-dimethyl-4,7-diphenyl-1,10-morpholine (BCP), 2-phenyl-5- (4-biphenyl)- 1,3,4- Diazole (PBD), silole derivatives and the like.

In the washing step of the washing method according to this embodiment, the organic matter attached to the mask is washed with a washing composition containing a member selected from the group consisting of N-methyl-2-pyrrolidone and N , At least one of N-dimethylformamide. The cleaning method includes a method of immersing the mask in the cleaning composition, and a method of spraying and cleaning the composition on the mask using a jet of water. In addition, when the mask is washed, ultrasonic washing can be used together, thereby improving the dissolving ability and shortening the washing time. From the standpoint of detergency, the detergency composition used in the detergency step preferably contains N-methyl-2-pyrrolidone.

From the viewpoint that the mask can be sufficiently washed, the content ratio of N-methyl-2-pyrrolidone or N, N-dimethylformamide in the cleaning composition used in the cleaning step is preferably 80 to 100% by mass, more preferably 95 to 100% by mass, and more preferably 98 to 100% by mass. When the cleaning composition contains both N-methyl-2-pyrrolidone and N, N-dimethylformamide, from the viewpoint that the mask can be sufficiently washed, these total content ratios should be within the above-mentioned ideals. Within range.

The cleaning composition may contain components other than N-methyl-2-pyrrolidone and N, N-dimethylformamide within a range that does not impair the effects of this embodiment. Examples of such ingredients include, but are not limited to: heptane, hexane, heptane, octane, nonane, cyclobutane, cyclopentane, cyclohexane, cyclohexane and other saturated hydrocarbons; 1 -Butene, 2-butene, 2-methylpropene, 1-pentene, 2-pentene, 1-butyne, 2-butyne, pentyne, cyclopropene, cyclobutene, cyclopentene, ring Unsaturated hydrocarbons such as hexene; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, secondary butanol, tertiary butanol; dimethyl ether, ethyl methyl Ethers such as ether, diethyl ether, diisopropyl ether, methyl-tertiary butyl ether, tetrafluoroethanol; acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl Ketones such as isobutyl ketone, cyclopentanone, cyclohexanone; methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl butyrate, ethyl butyrate, Esters such as γ-butyrolactone; amines such as monomethylamine, dimethylamine, and trimethylamine; dichloromethane, 1,1-dichloroethane, 1,2-dichloroethane, 1,1,2 -Trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, 1,1-dichloroethylene, cis -1,2-dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene, tetrachloroethylene, 1,2-dichloropropane and other chlorocarbons; 1,1,1,3,3-penta Fluorobutane, 1,1,1,2,2,3,4,5,5,5-decafluoropentane, 1,1,2,2,3,3,4-heptafluorocyclopentane, 1 , 1,1,2,2,3,3,4,4-nonafluorohexane, 1,1,1,2,2,3,3,4,4,5,5,6,6--13 HFC (hydrofluorocarbon) such as fluorohexane, 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecanefluorooctane; decafluorobutane, ten PFCs (perfluorocarbons) such as difluoropentane, tetrafluorofluorohexane, hexafluorofluoroheptane, and octafluorooctane; dichloropentafluoropropane, 1,1-dichloro-1-fluoroethane, HCFCs (hydrochlorofluorocarbons) such as 1-chloro-1,1-difluoroethane and 2,2-dichloro-1,1,1-trifluoroethane. These components may be contained alone or in combination.

When the cleaning composition contains components other than N-methyl-2-pyrrolidone and N, N-dimethylformamidine, these content ratios are preferably 20% by mass or less, and preferably 5% by mass or less. It is more preferably 2% by mass or less. Components other than N-methyl-2-pyrrolidone and N, N-dimethylformamidine contained in the cleaning composition may be components that do not have a cleaning effect among the above. In addition, if the cleaning composition contains water, the water may adhere to the surface of the mask, which may cause water spots and reduce the cleaning power of the solvent composition. Therefore, the water content in the cleaning composition should be 5% by mass or less, and 3 mass% or less is preferable, and 1 mass% or less is more preferable. The cleaning composition is preferably free of water.

The time for performing the washing step depends on the size of the mask or the type and amount of organic matter attached, such as 5-15 minutes. The temperature of the cleaning composition in the washing step does not need to be adjusted, and normal temperature is sufficient, preferably 10 to 40 ° C, and more preferably 20 to 30 ° C. In this way, a cleaning composition containing at least one selected from the group consisting of N-methyl-2-pyrrolidone and N, N-dimethylformamidine is used for washing in the above-mentioned temperature range. It has excellent detergency, and mask deformation and strain will not occur due to heat during washing.

In the washing step, one or two or more kinds of organic substances adhering to the surfaces of various masks can be sufficiently removed by using only the washing composition. Therefore, there is no need to use different cleaning tanks for cleaning liquids. As a result, the cleaning process can be simplified.

In addition, the cleaning composition may be used by distilling the used cleaning solution composition. When the cleaning composition contains components other than N-methyl-2-pyrrolidone and N, N-dimethylformamide, the used cleaning liquid composition may be distilled and the recovered liquid Use the composition after adjusting it.

The rinsing step of the cleaning method of this embodiment is a mask that is rinsed with the rinsing composition and washed with the rinsing composition. In this specification, leaching means removing the washing composition attached to the mask after washing the washing composition.

The method of washing and washing the mask may include a method of immersing the washed mask in the washing composition, and a method of washing and washing the mask with the washing composition. Both methods can easily remove the cleaning composition attached to the mask surface after washing, and the mask surface can be rinsed extremely cleanly. The time for performing the leaching step depends on the size of the mask, such as 5-15 minutes. In the leaching step, the temperature of the leaching composition of the bell does not need to be adjusted, and it is normal temperature, preferably 10 to 40 ° C, and more preferably 20 to 30 ° C. In this way, rinsing can be performed at a relatively low temperature, so that the mask is not deformed or deformed by heat.

The eluent composition contains, as an active ingredient, at least one hydrofluoroether selected from HFE-347pc-f, HFE-254pc, HFE-356pcf, and HFE-449mec-f. The boiling points of HFE-347pc-f, HFE-254pc, HFE-356pcf and HFE-449mec-f are all lower than 74 ° C. They have good drying properties and are easy to evaporate at room temperature. In addition, even if it is boiled and turned into a vapor, it is not easy to adversely affect parts that are easily affected by heat such as resin parts. The eluent composition may be used singly or in combination of two or more kinds.

HFE-347pc-f has zero ozone destruction potential and small global warming potential. HFE-347pc-f has a boiling point of 56 ° C. HFE-347pc-f can be used, for example, to react 2,2,2-trifluoroethanol with tetrafluoroethylene in the presence of aprotic polar solvents and catalysts (alkali metal alkoxides or alkali metal hydroxides). Method (refer to International Publication No. 2004/108644). A commercially available product of HFE-347pc-f is, for example, "ASAHIKLIN (registered trademark) AE-3000" (manufactured by Asahi Glass Co., Ltd.).

HFE-254pc has zero ozone destruction potential and small global warming potential. HFE-254pc has a boiling point of 37 ° C. HFE-254pc can be produced, for example, by adding tetrafluoroethylene to methanol in the presence of a strong base (such as potassium hydroxide).

HFE-356pcf has zero ozone destruction potential and small global warming potential. HFE-356pcf has a boiling point of 74 ° C. HFE-356pcf can be produced, for example, by adding tetrafluoropropanol (TFPO) in the presence of a strong base (such as potassium hydroxide) and adding chlorodifluoromethane (HCFC-22).

HFE-449mec-f has zero ozone destruction potential and small global warming potential. HFE-449mec-f has a boiling point of 73 ° C. For example, HFE-449mec-f can be a method of reacting 2,2,2-trifluoroethanol with hexafluoropropylene in the presence of an aprotic polar solvent and a catalyst (alkali metal alkoxide or alkali metal hydroxide). (Refer to Japanese Patent Application Laid-Open No. 9-263559).

N-methyl-2-pyrrolidone and N, N-dimethylformamide in the cleaning composition have excellent solubility to any hydrofluoroether in the eluent composition. Therefore, the washing composition can be extremely easily removed by the rinsing composition. The hydrofluoroether is not decomposed by any of N-methyl-2-pyrrolidone and N, N-dimethylformamide contained in the cleaning composition. Therefore, no fluoride ions remain on the surface of the mask after washing, and the mask can be cleaned extremely cleanly.

Here, the reason why the hydrofluoroether used in the eluent composition is not decomposed by the N-methyl-2-pyrrolidone and N, N-dimethylformamide in the cleaning composition is presumed as follows.

For example, like methyl - perfluoro -n- butyl ether _{(C 4 F 9 OCH 3,} HFE-449sl) of a strong electron withdrawing CF ₃ - hydrofluoroether groups, bonded with a CF ₃ - group The carbon system is in a state of insufficient electrons. On the other hand, when a carbon atom having a CF ₃ -group is bonded to an easily detachable atom or an atomic group such as a halogen atom, it is subjected to N-methyl-2-pyrrolidone or N, N-dimethylformamide. It becomes easy to break down by nucleophilic attack. In contrast, the hydrofluoroether in the eluent composition used in this embodiment does not have a CF ₃ -group, or even if it has a CF ₃ -group, CF ₃ -bonded carbons do not have atoms that are easily detached. Or radicals. Therefore, it is not easy to cause a charge shift in the molecule, and it is not easy to be subjected to nucleophilic attack from N-methyl-2-pyrrolidone or N, N-dimethylformamide.

From the viewpoint that the cleaning composition can be sufficiently removed and the drying property is excellent, it is preferable that the shower composition used in the cleaning method of the present embodiment contains HFE-347pc-f.

The content ratio of the above-mentioned hydrofluoroether in the eluent composition used in the washing method of the present embodiment is preferably 80 to 100% by mass, and 95 to 100% by mass from the viewpoint of sufficient elutriation mask. Good, 98 ~ 100% by mass is better. When the eluent composition contains two or more kinds of the above-mentioned hydrofluoroethers, the total content ratio is preferably within the above-mentioned ideal range from the viewpoint that the mask can be sufficiently rinsed.

The eluent composition may contain components other than the above-mentioned hydrofluoroether without impairing the effect of the present invention. The components other than the hydrofluoroether may be the same as the components other than N-methyl-2-pyrrolidone and N, N-dimethylformamide in the cleaning composition, but are not limited thereto. Wait. These components may be contained alone or in combination.

When the eluent composition contains a component other than the above hydrofluoroether, the content ratio of the component is preferably 20% by mass or less, more preferably 5% by mass or less, and even more preferably 2% by mass or less.

As described above, if moisture is contained in the cleaning composition, the moisture may adhere to the surface of the mask and water spots may occur. When the eluent composition contains at least one alcohol selected from the group consisting of methyl alcohol, ethyl alcohol, n-propanol, and isopropanol, it is suitable to dissolve and remove the water even if the cleaning composition contains water, so it is suitable. . When the eluent composition contains the above-mentioned alcohol, the alcohol content ratio in the eluent composition is preferably 10% by mass or less, more preferably from 1 to 8% by mass, and more preferably from 2 to 5% by mass, from the viewpoint of sufficient water removal. good.

In the drying step of the washing method of this embodiment, the mask after the washing is dried in the washing step. Examples of the drying method include a method of drying the mask after rinsing by natural drying, a method of drying by air jet, and a method of drying by reducing pressure. Among them, from the viewpoint of making the mask more effective to dry, a method of drying under reduced pressure is suitable.

In the method of drying by air jet, for example, it is preferable to blow dry air at 10-40 ° C and more preferably 20-30 ° C to dry it. In this way, it can be dried at a relatively low temperature, so that the mask is not deformed or deformed by heat.

The pressure at which the mask is dried by decompression reduces the degree of decompression as it takes time. However, if the adhesion amount of the eluent composition on the mask is small, it can be dried in the decompression process, so it can be appropriately set according to the size of the mask or the adhesion amount of the eluent composition on the mask. For example, it should be set at The eluent composition is in a range of 20 ° C. vapor pressure or higher and 101.3 kPa or lower. For example, when the eluent composition is composed of HFE-347pc-f, the pressure in the drying step should be reduced to a pressure of 25 to 101.3 kPa.

According to the cleaning method of the embodiment described above, by using a specific hydrofluoroether as the eluent composition, the hydrofluoroether does not suffer from N-formaldehyde in the cleaning composition attached to the mask during washing. Ethyl-2-pyrrolidone and N, N-dimethylformamide are decomposed without generating fluoride ions. Therefore, the mask can be cleaned extremely cleanly. The cleaning method of this embodiment can be effectively used as a mask cleaning method when manufacturing an organic EL element by a vacuum deposition method, and is suitably used in a vacuum deposition step when manufacturing a low-molecular EL element. Examples

Next, experimental examples and examples will be described. The present invention is not limited by these experimental examples and examples.

(Experimental Example 1) In this experimental example, the decomposability of the eluent composition due to NMP and DMF after a predetermined heating time was investigated. After adding 5 mass% of NMP or DMF to HFE-347pc-f (manufactured by Asahi Glass Co., Ltd., AE-3000), and also adding 5 mass% of NMP or DMF to HFE-449sl (3M company, Novec7100), do Take out the sample solution. Each reagent was allowed to stand in a constant temperature bath at 55 ° C for 3 days. The fluoride ion concentration in each solvent sample solution after standing was measured with a fluoride ion meter (IM-55G, manufactured by DKK-TOA Co., fluoride ion electrode: F-2021, manufactured by DKK-TOA Co., Ltd.). The detection limit of the fluoride ion concentration was set to 0.5 ppm. The results are shown in Table 1.

[Table 1]

(Experimental Example 2) In this experimental example, as an accelerated test system, the decomposability of the eluent composition after heating and refluxing a sample solution containing HFE-347pc-f or HFE-449sl and NMP due to NMP was tested. 250 g of a sample solution prepared by adding 5 mass% of NMP to the same HFE-347pc-f (manufactured by Asahi Glass Co., Ltd., AE-3000) was placed in a flask, and heated to a boiling state with a heater, followed by 4 hours. Reflux. Then, 175 g of a distillate was taken in 80 minutes, and the pH, fluoride ion concentration, and acid content of the remaining bottom liquid were measured. The results are shown in Table 2.

In addition, 250 g of a sample solution prepared by adding 5 mass% of NMP to the same HFE-449sl (manufactured by 3M, Novec 7100) was placed in a flask, heated by a heater to boil, and then refluxed for 4 hours. Then, 175 g of a distillate was taken in 80 minutes, and the pH, fluoride ion concentration, and acid content of the remaining bottom liquid were measured. The pH measurement was performed with a pH meter (manufactured by DKK-TOA, HM-25R, electrode: DKK-TOA company, GST-5741C), and the fluoride ion concentration was measured by a fluoride ion meter (manufactured by DKK-TOA, IM -55G, fluoride ion electrode: manufactured by DKK-TOA Co., Ltd., F-2021), and the acid content was measured by titration using phenol peptide as an indicator. The detection limits of fluoride ion concentration and acid content were both set at 0.5 ppm. The results are shown in Table 2.

[Table 2]

As can be seen from Tables 1 and 2, even after 3 days of heating or 80 minutes of heating and refluxing, HFE-347pc-f in the eluent composition was not decomposed by NMP or DMF, and fluoride ions were not generated, but relatively, HFE-449sl is decomposed by NMP or DMF, which generates fluoride ions.

(Example) The cleanability of a metal mask when HFE-347pc-f was used as the eluent composition was investigated. A metal (SUS) sheet to which the low-molecular-type organic EL material was attached was immersed in NMP at room temperature (25 ° C) for 1 minute. Then, the metal sheet was immersed in HFE-347pc-f (Asahi Glass Co., Ltd., AE-3000) at room temperature (25 ° C) for 1 minute, rinsed, and taken out. After the metal piece was naturally dried, it was immersed in pure water, and the fluoride ion (DKK-TOA company, IM-55G, fluoride ion electrode: DKK-TOA company, F-2021) was used to measure the extracted fluoride ion. concentration. The detection limit of the fluoride ion concentration was set to 0.5 ppm. The results are listed in Table 3. A case where fluoride ion is detected is described as "detected", and a case where no fluorine ion is detected is described as "not detected".

(Comparative example) The cleanability of a metal mask when HFE-449sl was used as a eluent composition was investigated. A metal (SUS) sheet with a low-molecular organic EL material attached was immersed in NMP at room temperature (25 ° C) for 1 minute, and then immersed in HFE-449sl (manufactured by 3M, Novec7100) at room temperature (25 ° C). After 1 minute, rinse and remove. After the metal piece was naturally dried, it was immersed in pure water, and the presence or absence of extracted fluoride ions was investigated. The results are shown in Table 3.

[table 3]

As can be seen from Table 3, by using HFE-347pc-f as the eluent composition, the mask can be cleaned. In contrast, when HFE-449sl was used, fluorine ions adhered to the surface of the mask, and it was found that the mask could not be cleaned.

1‧‧‧ glass substrate

11‧‧‧ transparent electrode

20‧‧‧Mask

20h‧‧‧Opening

21‧‧‧Mask frame

24‧‧‧ holding table

30‧‧‧Evaporation source

FIG. 1 is an explanatory diagram of a manufacturing method of an organic EL display device. FIG. 2 is a schematic diagram showing a state where a light emitting layer is formed through a mask.

Claims (10)

A washing method is a washing method of a mask for vacuum evaporation, characterized in that the mask is washed with a washing composition, and the mask after washing is rinsed with a washing composition, and the washing is performed. The net composition contains at least one selected from the group consisting of N-methyl-2-pyrrolidone and N, N-dimethylformamide. The eluent composition contains a composition selected from CF ₃ CH ₂ -O-CF _2. At least one type of hydrofluoroether among CHF ₂ , CHF ₂ CF ₂ -O-CH ₃ , CHF ₂ -O-CH ₂ CF ₂ CHF ₂ and CF ₃ CHFCF ₂ -O-CH ₂ CF ₃ . The cleaning method according to claim 1, wherein the content ratio of the hydrofluoroether in the eluent composition is 80% by mass or more and 100% by mass or less. The cleaning method according to claim 1 or 2, wherein the cleaning composition contains N-methyl-2-pyrrolidone. The washing method according to any one of claims 1 to 3, wherein the eluent composition contains CF ₃ CH ₂ -O-CF ₂ CHF ₂ . The cleaning method according to any one of claims 1 to 4, wherein the washing and rinsing of the aforementioned mask are performed at a temperature of 10 ° C or higher and 40 ° C or lower. The cleaning method according to any one of claims 1 to 5, wherein the washing and rinsing of the aforementioned mask are performed at a temperature above 20 ° C and below 30 ° C. The cleaning method according to any one of claims 1 to 6, wherein the vacuum evaporation is performed when a low-molecular-type organic EL element is manufactured. The cleaning method according to any one of claims 1 to 7, which dries the mask after being rinsed by the aforementioned rinse composition. A rinse composition is a mask for vacuum evaporation washed by a rinse composition, and the rinse composition contains a material selected from N-methyl-2-pyrrolidone and N, N-dimethylformate. At least one of methylformamide; the above-mentioned eluent composition is characterized in that it contains a compound selected from the group consisting of CF ₃ CH ₂ -O-CF ₂ CHF ₂ , CHF ₂ CF ₂ -O-CH ₃ , and CHF ₂ -O-CH ₂ CF ₂ CHF ₂ and CF ₃ CHFCF ₂ -O-CH ₂ CF ₃ is at least one kind of hydrofluoroether. The rinse composition according to claim 9, wherein a content ratio of the hydrofluoroether in the rinse composition is 80% by mass or more and 100% by mass or less.