TWI781168B - Cleaning method and rinsing composition of mask for vacuum evaporation - Google Patents

Abstract

The object of the present invention is a cleaning method, which is a method of cleaning a mask for vacuum evaporation. The method is to clean the mask with a cleaning composition, and then rinse the cleaned mask with a rinsing composition. The aforementioned The cleaning composition contains at least one selected from N-methyl-2-pyrrolidone and N,N-dimethylformamide, and the aforementioned rinse composition contains selected from HFE-347pc-f, HFE- At least one hydrofluoroether selected from 254pc, HFE-356pcf and HFE-449mec-f. With this cleaning method, when cleaning the mask used in the vacuum deposition step in the manufacture of organic EL elements, the mask can be cleaned without decomposing active ingredients when rinsing the cleaning composition very clean.

Description

Cleaning Method and Rinse Composition of Vacuum Evaporation Mask

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

Background of the Invention In recent years, in terms of flat panel displays, display devices including liquid crystal display devices or organic EL elements have attracted attention. Liquid crystal display devices have low power consumption, but require external lighting (backlight) in order to obtain a bright screen. In contrast, a display device including an organic EL element does not require a backlight like a liquid crystal display device because the organic EL element is a self-luminous element. Therefore, the display device equipped with organic EL elements has the characteristics of power saving, and at the same time has the characteristics of high brightness and wide viewing angle.

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

When forming the functional layer by vacuum evaporation, the 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 quite high-definition, so it is difficult to manufacture, and the unit price is very high. However, when forming the pattern of the organic layer in the organic EL element, if the same mask is used for vapor deposition multiple times, organic matter will accumulate and adhere to the mask, so it becomes impossible to accurately transfer the high-definition mask pattern onto the substrate. Therefore, in order to realize 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 actually one of the reasons why mass production is difficult.

Therefore, in order to repeatedly use the mask to reduce the cost, various attempts have been made. Among them, there is a document that proposes a cleaning solution composition for cleaning various substances attached to the mask during the vacuum evaporation step of manufacturing organic EL elements. Organic matter (for example, refer to Patent Document 4).

Patent Document 4 discloses that after cleaning the mask with a cleaning solution composition, it is rinsed with hydrofluoroether. However, the "Novec HFE7100" (C ₄ F ₉ OCH ₃ ) used as the eluent in Patent Document 4, for example, will It decomposes in the presence to generate fluoride ions (for example, refer to Patent Document 5). Therefore, the surface of the mask cannot be cleaned by the above method.

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

Summary of the Invention Problems to be Solved by the Invention The present invention was made to solve the above-mentioned problems. Its object is to provide a cleaning method and a rinsing composition. The method of masking used, when the mask cleaned by the cleaning composition is rinsed with the rinsing composition, the mask can be cleaned extremely clean without decomposing the active ingredients of the rinsing composition.

Means for Solving the Problems The cleaning method of the embodiment is a method of cleaning a mask for vacuum evaporation, which is characterized in that the mask is cleaned with a cleaning composition, and then rinsed with a rinsing composition. mask, the aforementioned cleaning composition contains at least one selected from N-methyl-2-pyrrolidone (NMP) and N,N-dimethylformamide (DMF), and the aforementioned rinsing 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 at least one hydrofluoroether among CF ₃ CHFCF ₂ -O-CH ₂ CF ₃ (HFE-449mec-f).

In the cleaning method of the embodiment, the content ratio of the hydrofluoroether in the rinse 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 rinse composition preferably contains CF ₃ CH ₂ -O-CF ₂ CHF ₂ .

In the cleaning method of the embodiment, both cleaning and rinsing of the mask are preferably carried out at a temperature above 10°C and below 40°C, and preferably both are carried out at a temperature above 20°C and below 30°C.

In the cleaning method of the embodiment, vacuum vapor deposition is preferably performed when manufacturing a low-molecular-weight organic EL device.

In the cleaning method of the embodiment, it is preferable to dry the mask after being rinsed with the rinse composition.

The rinsing composition of the embodiment is a mask for rinsing the vacuum evaporation that has been cleaned by the cleaning composition, and the aforementioned cleaning composition contains N-methyl-2-pyrrolidone and N,N- _At least one _{of dimethylformamide ;} the _{aforementioned rinsing composition} is characterized in that: it _contains - at least one hydrofluoroether selected from CH ₂ CF ₂ CHF ₂ and CF ₃ CHFCF ₂ -O—CH ₂ CF ₃ .

The content ratio of the aforementioned hydrofluoroether in the rinsing composition of the embodiment is preferably not less than 80% by mass and not more than 100% by mass.

Also, in this specification, the abbreviation of the compound may be indicated in parentheses after the compound name, and the abbreviation may be used instead of the compound name as necessary. In addition, the symbol "~" in this specification indicates the range from above the numerical value stated before it to below the numerical value stated behind it.

Effects of the Invention With the cleaning method and the rinse composition of this embodiment, when cleaning, for example, the mask used in the vacuum deposition step during the manufacture of an organic EL element, the rinse composition is rinsed with the rinse composition. When cleaning the mask, the effective ingredients of the rinse composition will not be decomposed, and the mask can be cleaned extremely clean.

Embodiments for Carrying Out the Invention The embodiments of the present invention will be described in detail below with reference to the drawings. The cleaning method of this embodiment is a method of cleaning, for example, a mask used in a vacuum deposition step in the manufacture of an organic EL device, and includes a cleaning step, a rinsing step, and a drying step. In the cleaning method of this embodiment, the mask is cleaned with a cleaning composition in the cleaning step, and the cleaning composition contains N-methyl-2-pyrrolidone and N,N-di At least one kind of methyl formamide. Next, in the washing step, the mask washed by the washing composition is rinsed with the washing composition, and the washing composition contains HFE-347pc-f, HFE-254pc, HFE-356pcf and HFE - at least one hydrofluoroether from 449mec-f. An optional drying step is then performed to dry the mask.

In the cleaning method of this embodiment, the above-mentioned specific hydrofluoroether contained in the rinsing composition is even N-methyl-2-pyrrolidone or N,N-dimethylformyl in the cleaning composition It is also not easily decomposed in the presence of amines. Therefore, when the cleaning composition remains on the mask after cleaning, the above-mentioned specific hydrofluoroether in the rinse composition will not be decomposed by the cleaning composition, and fluoride ions will not be generated. Therefore, the surface of the mask can be cleaned extremely clean.

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

Referring to the manufacturing method of the organic EL display device, referring to FIG. 1 and FIG. 2, the steps of vacuum evaporation using a mask will be outlined. TFT (Thin Film Transistor) and transparent electrodes are formed on the glass substrate, and a hole transport layer is further formed. The glass substrate 1 formed with TFT, transparent electrode and hole transport layer is carried into the vacuum chamber with the treated surface of the glass substrate 1 facing down. In the vacuum chamber, light-emitting layers corresponding to the respective primary colors R, G, and B as a color display device are formed on the glass substrate 1 . This step is carried out in individual vacuum chambers corresponding to 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 luminescent layer corresponding to the primary color R, a vacuum chamber for forming a luminescent layer corresponding to the primary color G, and a vacuum chamber for forming a luminescent layer corresponding to the primary color B. vacuum chamber.

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

Each vacuum chamber is equipped with a mask corresponding to any primary color of R, G, and B and having only a part of the opening corresponding to the transparent electrode (anode) 11 as a mask 20, and the transparent electrode (anode) 11 is used for Makes a predetermined primary color glow. 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 of the light-emitting layer (organic EL material) is heated and evaporated from the evaporation source (source) 30 arranged under the holding table 24, and the material is evaporated on the glass through the opening of the mask. Substrate 1 surface. FIG. 2 schematically shows how the light-emitting layer is formed through the mask 20 . As shown in FIG. 2 , each transparent electrode (anode) 11 is covered with a mask 20 in each vacuum chamber except for the formation area of the transparent electrode corresponding to the primary color. Then, the organic EL material corresponding to the primary color is heated and vaporized in the vapor deposition source 30 , and evaporated and formed on the glass substrate 1 (which is exactly the hole transport layer) through the opening 20 h of the mask 20 . In addition, the material of the mask can be, for example, stainless steel such as SUS, Ni single body, Ni alloy (such as Fe—Ni alloy, Mg—Ni alloy), or semiconductor such as silicon.

唑基)酚]鋅(II)(Zn-PBO)、紅螢烯、二甲基喹吖酮、N,N’-二甲基喹吖酮(DMQ)、4-(二氰基亞甲基)-2-甲基-6-[2-(2,3,6,7-四氫-1H,5H-苯并[ij]喹

-9-基)乙烯基]-4H-哌喃(DCM2)等。電子輸送材料可舉如Alq₃ 、2,9-二甲基-4,7-二苯基-1,10-啡啉(BCP)、2-苯基-5-(4-聯苯基)-1,3,4-

二唑(PBD)、噻咯(silole)衍生物等。In this vapor deposition step, various organic substances composed of vapor deposition materials adhere to the mask. Examples of vapor deposition materials include hole injection materials, hole transport materials, and electron transport materials used in the production of organic EL elements, in addition to the above-mentioned organic EL materials. Hole injection materials can be exemplified as copper phthalocyanine (CuPC), poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) composite (PEDOT/PSS), 4,4' ,4”-refer to [phenyl (m-tolyl) amino] triphenylamine (m-MTDATA), etc. The hole transport materials can be exemplified as triphenylamine (TPD), diphenyl naphthalene diamine (α-NPD ), ginseng (4-carbazol-9-ylphenyl) amine (TCTA), etc. Organic EL materials include bistyrylbenzene derivatives, ginseng (8-hydroxyquinoline) aluminum (Alq ₃ ), bis [2-(2-Benzo

Azolyl)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]quinone

-9-yl) vinyl] -4H-pyran (DCM2) and so on. Electron transport materials such as Alq ₃ , 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 2-phenyl-5-(4-biphenyl)- 1,3,4-

Diazole (PBD), silole (silole) derivatives, etc.

In the cleaning step of the cleaning method of this embodiment, the organic matter adhering to the mask is cleaned with a cleaning composition, and the cleaning composition contains N-methyl-2-pyrrolidone and N , at least one of N-dimethylformamide. The cleaning method includes a method of immersing the mask in a cleaning composition, a method of spraying the cleaning composition on the mask with a jet of water, and the like. In addition, when cleaning the mask, it can also be cleaned with ultrasonic waves, thereby improving the dissolving ability and shortening the cleaning time. From the viewpoint of detergency, the detergency composition used in the detergency step preferably contains N-methyl-2-pyrrolidone.

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

The cleaning composition may contain components other than N-methyl-2-pyrrolidone and N,N-dimethylformamide within the range that does not impair the effect of the present embodiment. Such components can be exemplified by, but 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, cyclo Unsaturated hydrocarbons such as hexene; methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, secondary butanol, tertiary butanol and other alcohols; dimethyl ether, ethyl methyl Ether, diethyl ether, diisopropyl ether, methyl-tertiary butyl ether, tetrafluoroethanol and other ethers; acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, methyl Isobutyl ketone, cyclopentanone, cyclohexanone and other ketones; 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 - Chlorocarbons such as dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene, tetrachloroethylene, 1,2-dichloropropane; 1,1,1,3,3-pentafluorobutane, 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-Nafluorohexane, 1,1,1,2,2,3,3,4,4,5,5,6,6-Tridecafluorohexane, 1,1,1,2,2,3,3,4,4,5,5,6,6-Tridecafluorooctane and other HFCs (hydrofluorocarbons); decafluorobutane, dodecafluoropentane , Tetrafluorohexane, hexadecane fluoroheptane, octadecadecafluorooctane and other PFCs (perfluorocarbons); dichloropentafluoropropane, 1,1-dichloro-1-fluoroethane, 1-chloro- HCFC (hydrochlorofluorocarbons) such as 1,1-difluoroethane, 2,2-dichloro-1,1,1-trifluoroethane, etc. Moreover, these components may be contained individually, and may contain multiple types.

When the cleaning composition contains components other than N-methyl-2-pyrrolidone and N,N-dimethylformamide, the content ratio is preferably 20% by mass or less, preferably 5% by mass or less, 2% by mass or less is more preferable. Components other than N-methyl-2-pyrrolidone and N,N-dimethylformamide contained in the cleansing composition may be the above-mentioned components that do not have a cleansing effect. In addition, if the cleaning composition contains water, the water may adhere to the surface of the mask, causing water spots and reducing the cleaning power of the solvent composition. Therefore, the water content in the cleaning composition is preferably 5% by mass or less, and 3 mass % or less is preferable, and 1 mass % or less is more preferable. Preferably, the cleansing composition does not contain water.

The time for the cleaning step depends on the size of the mask or the type and amount of attached organic matter, for example, 5 to 15 minutes. The temperature of the cleaning composition in the cleaning step does not need to be adjusted, but can be at room temperature, preferably 10-40°C, and more preferably 20-30°C. In this way, using a cleaning composition containing at least one kind selected from N-methyl-2-pyrrolidone and N,N-dimethylformamide, cleaning within the above temperature range can It has excellent cleaning properties and does not cause mask deformation or strain due to heat during cleaning.

Also, in the cleaning step, one or two or more organic substances adhering to the surfaces of various masks can be sufficiently removed only with the above-mentioned cleaning composition. Therefore, cleaning tanks with different types of cleaning solutions are not required, and as a result, the cleaning process can be made very simple.

In addition, the cleaning composition may be reused by distilling the used cleaning liquid composition. When the cleaning composition contains components other than N-methyl-2-pyrrolidone and N,N-dimethylformamide, the used cleaning liquid composition can also be distilled and the recovered liquid The composition is adjusted before use.

The rinsing step of the cleaning method of this embodiment is to use the rinsing composition to rinse the mask cleaned by the rinsing composition. In this specification, rinsing means to remove the cleaning composition adhering to the mask after cleaning with the cleaning composition.

The method of rinsing the mask after cleaning includes, for example, a method of immersing the mask after cleaning in a rinse composition, a method of rinsing the mask after cleaning with a rinse composition, and the like. Both methods can easily remove the cleaning composition attached to the surface of the mask after cleaning, and the surface of the mask can be rinsed extremely clean. The time for the washing step depends on the size of the mask, for example, 5 to 15 minutes. The temperature of the rinsing composition in the rinsing step does not need to be adjusted, it can be at room temperature, preferably 10-40°C, and more preferably 20-30°C. In this way, rinsing can be performed at a lower temperature, so the mask will not be deformed, strained, etc. due to heat.

The rinse composition contains at least one hydrofluoroether selected from HFE-347pc-f, HFE-254pc, HFE-356pcf and HFE-449mec-f as an active ingredient. The boiling points of HFE-347pc-f, HFE-254pc, HFE-356pcf and HFE-449mec-f are all as low as below 74°C. They have good drying properties and are easy to evaporate at room temperature. Also, even if it is boiled to become a vapor, it is less likely to have adverse effects on parts that are easily affected by heat, such as resin parts. As the rinsing composition, one kind of the above-mentioned hydrofluoroethers may be used alone, or two or more kinds may be used in combination.

HFE-347pc-f has zero ozone depletion potential and low global warming potential. The boiling point of HFE-347pc-f is 56°C. For example, HFE-347pc-f can be used to react 2,2,2-trifluoroethanol with tetrafluoroethylene in the presence of an aprotic polar solvent and catalyst (alkali metal alkoxide or alkali metal hydroxide). method (refer to International Publication No. 2004/108644) to manufacture. Commercially available products of HFE-347pc-f include "ASAHIKLIN (registered trademark) AE-3000" (manufactured by Asahi Glass Co., Ltd.).

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

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

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

N-methyl-2-pyrrolidone and N,N-dimethylformamide in the cleaning composition have excellent solubility for any hydrofluoroether in the washing composition. Therefore, the cleaning composition can be very easily removed by the rinsing composition. In addition, the above-mentioned hydrofluoroether is not decomposed by either N-methyl-2-pyrrolidone or N,N-dimethylformamide contained in the cleaning composition. Therefore, no fluorine ions will remain on the surface of the mask after rinsing, and the mask can be cleaned very cleanly.

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

For example, hydrofluoroethers like methyl-perfluoro-n-butyl ether (C ₄ F ₉ OCH ₃ , HFE-449sl) have CF ₃ -groups with strong electron attraction, and CF ₃ -groups bonded The carbon system exhibits an electron-deficient state. When the carbon bonded to the CF ₃ -group is bonded to an atom or atomic group that is easily separated, such as a halogen atom, it will be affected by N-methyl-2-pyrrolidone or N,N-dimethylformamide become easily decomposed by nucleophilic attack. On the contrary, the hydrofluoroether in the rinsing composition used in this embodiment does not have a CF ₃ -group, or even if it has a CF ₃ -group, the carbon bonded by CF ₃ - will not be bonded to an atom that is easily detached or atomic groups. Therefore, it is not easy to cause charge shift in the molecule, and it is not easy to be nucleophilic attack from N-methyl-2-pyrrolidone or N,N-dimethylformamide.

The rinse composition used in the cleaning method of this embodiment preferably contains HFE-347pc-f from the viewpoint of sufficient removal of the cleaning composition and excellent drying properties.

The content ratio of the hydrofluoroether in the rinsing composition used in the cleaning method of this embodiment is preferably 80 to 100 mass % from the viewpoint of sufficient rinsing of the mask, and 95 to 100 mass % is better than Good, more preferably 98~100% by mass. When the rinsing composition contains two or more kinds of the above-mentioned hydrofluoroethers, the total content ratio thereof is preferably within the above-mentioned ideal range from the viewpoint of sufficient rinsing of the mask.

The rinse composition may contain components other than the above-mentioned hydrofluoroethers without impairing the effects of the present invention. Components other than the above-mentioned hydrofluoroether include, but are not limited to, the same components as the components other than N-methyl-2-pyrrolidone and N,N-dimethylformamide in the above-mentioned cleaning composition. Wait. Moreover, these components may be contained individually, and may contain multiple types.

When the rinsing composition contains components other than the above-mentioned hydrofluoroether, the content of the component is preferably 20% by mass or less, preferably 5% by mass or less, more preferably 2% by mass or less.

As mentioned above, if the cleaning composition contains water, the water may adhere to the surface of the mask and cause water spots. When the rinsing composition contains at least one alcohol selected from methyl alcohol, ethyl alcohol, n-propanol, and isopropanol, even if the rinsing composition contains water, the water can be dissolved and removed, so it is suitable . When the rinsing composition contains the above-mentioned alcohol, the alcohol content ratio in the rinsing composition is preferably 10% by mass or less, preferably 1 to 8% by mass, more preferably 2 to 5% by mass, from the viewpoint of sufficient water removal. good.

In the drying step of the cleaning method of this embodiment, the mask after the rinsing is dried in the rinsing step. As the drying method, a method of drying the rinsed mask by natural drying, a method of drying by air blowing, a method of drying by reducing pressure, and the like can be used. Among them, a method of drying the mask under reduced pressure is preferable from the viewpoint of drying the mask more efficiently.

In the method of drying by spraying air, for example, dry air at 10 to 40° C., more preferably 20 to 30° C., is blown to dry. In this way, it can be dried at a lower temperature, so the mask will not be deformed, strained, etc. due to heat.

The pressure at which the mask is dried by decompression is used. Since the decompression takes time, the smaller the decompression degree, the better. However, if the adhesion amount of the rinse composition on the mask is small, it can be dried during the decompression process, so it can be set appropriately according to the size of the mask or the adhesion amount of the rinse composition on the mask. For example, it should be set at The vapor pressure of the rinsing composition is above 20°C and below 101.3kPa. For example, when the rinsing composition is composed of HFE-347pc-f, the pressure should be reduced to 25~101.3kPa in the drying step.

According to the cleaning method of the embodiment described above, by using the specific hydrofluoroether as the rinse composition, the hydrofluoroether will not be affected by the N-formazan in the cleaning composition attached to the mask during cleaning. Both base-2-pyrrolidone and N,N-dimethylformamide can be decomposed without generating fluoride ions. Therefore, the mask can be washed extremely clean. The cleaning method of this embodiment is effective as a mask cleaning method in the manufacture of organic EL elements by the vacuum deposition method, and is suitable for use in the vacuum deposition step in the manufacture of low-molecular-weight EL devices. Example

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 decomposing property of the rinse composition by NMP and DMF after heating for a predetermined time was investigated. After adding 5% by mass of NMP or DMF to HFE-347pc-f (manufactured by Asahi Glass Co., Ltd., AE-3000), and adding 5% by mass of NMP or DMF to HFE-449sl (manufactured by 3M Corporation, Novec7100), the Take out the sample solution. Each reagent was left to stand in a thermostat at 55°C for 3 days. The fluoride ion concentration in each solvent sample liquid after leaving still was measured with the fluorine ion meter (DKK-TOA company make, IM-55G, fluorine ion electrode: DKK-TOA company make, F-2021). In addition, the detection limit of the fluoride ion concentration was set at 0.5 ppm. The results are listed in Table 1.

[Table 1]

(Experimental Example 2) In this experimental example, as an accelerated test, the decomposing property of the rinse composition by NMP after heating and refluxing the sample solution containing HFE-347pc-f or HFE-449sl and NMP was tested. Put 250 g of a sample solution obtained by adding 5% by mass of NMP to the same HFE-347pc-f (manufactured by Asahi Glass Co., Ltd., AE-3000) as above in a flask, heat it to boiling with a heater, and conduct 4 hours reflow. Thereafter, 175 g of distillate was collected in 80 minutes, and the pH, fluoride ion concentration, and acid content of the remaining bottom raffinate were measured. The results are listed in Table 2.

Also, 250 g of a sample solution obtained by adding 5% by mass of NMP to the same HFE-449sl (manufactured by 3M Corporation, Novec 7100) as above was put into a flask, heated with a heater to boil, and then refluxed for 4 hours. Thereafter, 175 g of distillate was collected in 80 minutes, and the pH, fluoride ion concentration, and acid content of the remaining bottom raffinate were measured. In addition, pH measurement was carried out with a pH meter (manufactured by DKK-TOA, HM-25R, electrode: DKK-TOA, GST-5741C), and fluoride ion concentration was measured with a fluoride meter (manufactured by DKK-TOA, IM -55G, fluorine ion electrode: DKK-TOA company make, F-2021), acid content measurement was carried out by titration using phenol peptide as an indicator. The detection limits of fluoride ion concentration and acid content are both set to 0.5ppm. The results are listed in Table 2.

[Table 2]

It can be seen from Table 1 and Table 2 that even after 3 days of heating or 80 minutes of heating and reflux, HFE-347pc-f in the rinse composition was not decomposed by NMP or DMF, and fluoride ions were not produced, but relatively, HFE-449sl is decomposed by NMP or DMF to produce fluoride ions.

(Example) The cleanability of a metal mask when using HFE-347pc-f as a rinse composition was investigated. A metal (SUS) sheet with a low-molecular-weight organic EL material attached was immersed in NMP at room temperature (25° C.) for 1 minute. Then, the metal piece was immersed in HFE-347pc-f (manufactured by Asahi Glass Co., Ltd., AE-3000) at room temperature (25° C.) for 1 minute, rinsed, and then taken out. Allow the metal sheet to dry naturally, then immerse it in pure water, and measure the extracted fluoride ion with a fluoride ion meter (manufactured by DKK-TOA, IM-55G, fluoride electrode: DKK-TOA, F-2021) concentration. In addition, the detection limit of the fluoride ion concentration was set at 0.5 ppm. The results are listed in Table 3. The case where the fluoride ion was detected was expressed as "detected", and the case where it was not detected was expressed as "not detected".

(Comparative example) The detergency of a metal mask when HFE-449sl was used as a rinse composition was investigated. Immerse the metal (SUS) sheet with the low-molecular-weight organic EL material in NMP at room temperature (25°C) for 1 minute, and then immerse it in HFE-449sl (manufactured by 3M Company, Novec 7100) at room temperature (25°C) For 1 minute, rinse and take out. The metal piece was allowed to dry naturally, then immersed in pure water, and checked for the presence or absence of extracted fluoride ions. The results are listed in Table 3.

[table 3]

It can be seen from Table 3 that the mask can be cleaned by using HFE-347pc-f as the rinse composition. 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‧‧‧shroud 20h‧‧‧opening 21‧‧‧mask frame 24‧‧‧holder 30‧‧‧evaporation source

FIG. 1 is an explanatory diagram of a method of manufacturing an organic EL display device. FIG. 2 is a diagram schematically showing the formation state of the light-emitting layer through a mask.

1‧‧‧Glass substrate

20‧‧‧Masking

21‧‧‧Mask frame

24‧‧‧Holding table

30‧‧‧Evaporation source

Claims (8)

A cleaning method, which is a method for cleaning a mask for vacuum evaporation, is characterized in that the mask is cleaned with a cleaning composition, and then the mask after cleaning is rinsed with a rinsing composition. The clean composition contains at least one selected from N-methyl-2-pyrrolidone and N,N-dimethylformamide, and the aforementioned rinsing composition contains at least one selected from CF ₃ CH ₂ -O-CF ₂ At least one 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 ; and, the aforementioned hydrofluoro The content ratio of ether in the aforementioned rinsing composition is 80% by mass or more and 100% by mass or less. The cleaning method according to claim 1, wherein the cleaning composition contains N-methyl-2-pyrrolidone. The cleaning method according to claim 1, wherein the rinsing composition contains CF ₃ CH ₂ -O-CF ₂ CHF ₂ . The cleaning method according to any one of claims 1 to 3, wherein both the cleaning and rinsing of the mask are carried out at a temperature above 10°C and below 40°C. The cleaning method according to any one of claims 1 to 3, wherein both the cleaning and rinsing of the mask are carried out at a temperature above 20°C and below 30°C. The cleaning method according to any one of claims 1 to 3, wherein the aforementioned vacuum evaporation is carried out during the manufacture of low-molecular-weight organic EL elements. As the cleaning method of any one of claims 1 to 3, its The mask rinsed with the aforementioned rinse composition was allowed to dry. A rinsing composition, which is a mask for vacuum evaporation cleaned by rinsing the cleaning composition, and the cleaning composition contains N-methyl-2-pyrrolidone and N,N-dimethyl At least one of methyl formamides; the aforementioned washing composition is characterized in that: it contains selected from CF ₃ CH ₂ -O-CF ₂ 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 at least one hydrofluoroether; and, the content ratio of the aforementioned hydrofluoroether in the aforementioned rinsing composition is 80% by mass or more and 100% by mass %the following.

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