TW200536014A - SiN film selective etching solution and etching method - Google Patents

Abstract

There is provided a solution for selective etching of an SiN film, comprising hydrogen fluoride, an ether solvent and/or a fluorinated ether solvent optionally together with water.

Description

200536014 ⑴ IX. Description of the invention [Technical field to which the invention belongs] The present invention relates to a silicon nitride (SiN) film that can be selectively etched on a silicon (si) substrate, a compound semiconductor substrate, or a film formed on a glass substrate for liquid crystal display. The etching technology, in detail, can selectively etch a silicon nitride film in a silicon nitride film and a substrate containing a silicon nitride film. p [Prior art] Generally, in a semiconductor processing step, a step of selectively removing a certain material from other materials is often included. In semiconductor devices, in general, silicon nitride films formed by various CVD methods, and silicon oxide (S i) films formed by various c VD methods and thermal oxidation methods are used as insulating films. In various uses. In this processing step, it is often necessary to seek selective etching of the silicon nitride film. Examples of the etching method include a wet etching method and a dry etching method. In general, if it is desired to remove the film without damaging it, a wet etching method is used. Among them, a method of wet-etching a silicon nitride film (SiN), in general, a method using thermal phosphoric acid (Japanese Patent Application Laid-Open No. 9-4 5 660; Japanese Patent Application Laid-Open No. 2002-246378). The silicon nitride film can be etched at an etching rate of 100 A / min, and the etching rate of the silicon nitride film and the silicon oxide (Si0) film can be selected at a ratio of 100: 1. However, the thermal phosphoric acid needs 140 to 180. (: Processing at high temperature. At low temperatures below 100t, the silicon nitride film will hardly be etched. Also, P (phosphorus) will cause doubts about contamination of the clean room, so it is highly desirable to have alternative steps -4-200536014 χ: A method of removing a silicon nitride film by mixing a mixture of any of ethylene glycol, glycerol, and diethylene glycol with dilute fluoric acid is known " U.S. Patent No. 4 2 6 9 6 5 4). When using this mixture, it can be etched at low temperature (below 100 ° C). However, U.S. Patent No. 42 69 6 5 4 As shown in the comparative examples described below, alcohol and water have extremely low etching selection ratios, so they are not suitable for use as highly selective etching solutions (US Patent No. 36 0 7 48). [Summary of the Invention] The present invention The purpose is to provide a "selective etching of silicon nitride film with high selectivity", which can realize etching at low temperature (below 100 ° C), and before the silicon oxide film is not etched. Chemical solution "and" Method for highly selective etching of silicon nitride film ". In the present invention, for a silicon nitride film formed on a substrate, when a mixed solution containing hydrogen fluoride and an ether-based solvent, and if necessary, water may be further contained, nitrogen can be removed at a low temperature of φ 100 ° C or lower. A silicon film, a silicon (si) film, or a silicon (Si) substrate, especially a silicon oxide film, is characterized by selective etching. Specific contents of the present invention include, for example, the following etching solution and etching method. 1. An etching solution 'for selectively etching a silicon nitride film, which is characterized in that it contains hydrogen fluoride, an ether-based solvent and / or a fluorinated ether-based solvent' and may further contain water if necessary. 2. The etching solution as described in item 1 above, wherein the content of water is the quality of the etching solution. ¾ or less. -5-200536014 (3) 3. The etching solution as described in item 1 or 2 above, which contains substantially no water. 4. The etching solution according to any one of items 1 to 3 above, wherein the content of the ether-based solvent and / or the fluorinated ether-based solvent is 99.9 to 60% by mass, and the content of hydrogen fluoride (HF) is 0.1 to 30% by mass. %, Water content is 10% by mass or less. 5. The etching solution according to any one of items 1 to 3 above, wherein the content of the ether-based p solvent and / or the fluorinated ether-based solvent is 90 to 70% by mass, and the content of hydrogen fluoride (HF) is 10 to 30. % By mass, and the content of water is 10% by mass or less. 6. The etching solution according to any one of items 1 to 3 above, wherein the content of the ether-based solvent and / or the fluorinated ether-based solvent is 99.9 to 90% by mass, and the content of hydrogen fluoride (HF) is 0.1 to 10% by mass. %, The content of water is 3% by mass or less. 7. The etching solution according to any one of items 1 to 3 above, wherein the ether-based φ solvent and / or the fluorinated ether-based solvent are ethylene glycol diether-based solvents. 8. The etching solution as described in item 7 above, wherein the glycol diether-based solvent is a glycol dimethylfluorene (M ο η 0 g I y m e) -based solvent. 9. The etching solution according to item 7, wherein the ethylene glycol diether-based solvent is a triethylene glycol dimethyl ether (Triglyme) -based solvent. 10. The etching solution according to item 7 above, wherein the ethylene glycol diether-based solvent is a diethylene glycol dimethyl ether (Diglyme) -based solvent. 1 1. The etching solution according to item 7 above, wherein the glycol diether-based solvent is diethylene glycol diethyl ether. -6-200536014 (4) 12. The etching solution according to any one of items 1 to 3 above, wherein the ether-based solvent and / or the fluorinated ether-based solvent are perfluoroether-based solvents. 1 3. The etching solution according to any one of items 1 to 3 above, wherein the ether-based solvent and / or the fluorinated ether-based solvent are C4F90Ch3 and / or CF3CH2OCF2CHF2. 14. A method for selectively etching a nitrided nitride film, characterized in that a silicon nitride film and a substrate including a silicon oxide film are prepared by using the etching solution of any one of items 1 to 13 in A method for etching at a temperature below 1000 ° C. 15. The method according to the foregoing item 14, wherein the substrate is a semiconductor substrate or a glass substrate. 16. The method as described in item 14 or 15 above, wherein the etching temperature is 20 to 50 ° C. 17. The method as described in item 16 above, wherein the etching temperature is 20 to 300 ° C. In the description of the present invention, "ether-based solvents and / or fluorinated φ ether-based solvents" will be described only as ether-based solvents in the following. Examples of the ether-based solvent include ethylene glycol dimethyl ether (Monoglyme), diethylene glycol dimethyl ether (Diglyme), triethylene glycol dimethyl ether (Triglyme), and 1,2-diethoxyethyl Alkane, ι, 2-dipropoxyethane, dioxane, tetrahydrofuran and the like. In particular, it is an ether-based solvent represented by the following formula (1) or (2).

Rni.〇- (C2H4-O) n-R

200536014 (where Rm and Ri are the same or different C! To C4 lower alkyl group having a linear or branched chain, and η is an integer of 0 to 4)

Rni, Ri, G to C4 lower alkyl having straight or branched chain, such as methyl, ethyl, η-propyl, isopropyl, η-butyl, isobutyl, sec-butyl , Ter t-butyl, and the like, methyl, ethyl, η-propyl, and isopropyl are preferred, methyl or ethyl is more preferred, and methyl is particularly preferred. η is an integer of 0 to 4, preferably an integer of 1 to 3. Ether solvents such as (mono-, di ... tri-, tetra-) ethylene glycol dimethyl ether, (mono-, di-, tri-, tetra-) ethylene glycol diethyl ether, (mono-, Di-, tri-, tetra-) ethylene glycol di-n-propyl ether, (mono-, di-, tri-, tetra-) ethylene glycol diisopropyl ether, (mono-, di-, tri- , Tetra-) ethylene glycol di-n-butyl ether, (mono-, di-, tri-, tetra-) ethylene glycol diisobutyl ether, (mono-, di-, tri-, tetra-) ethyl Glycol disec-butyl ether, (mono-, di-, tri-, tetra-) glycol ditert-butyl ether and other glycol ether solvents, (mono-, di-, tri ... tetra- ) Propylene glycol dimethyl ether, (mono-, di-, tri- 'tetra-) propylene glycol diethyl ether, (mono-, di-, tri-, tetra-) propylene glycol di n-propyl ether, (mono- , Di-, tri-, tetra-) propylene glycol diisopropyl ether, (mono ... di-, tri-, tetra-) propylene glycol di-n "butyl ether, broad mono-, di-, tri-, tetra-) Propylene glycol diisobutyl ether, (mono-, di-, tri-, tetra-) propylene glycol disec-butyl ether, (mono-, di-, tri-, tetra-) propylene glycol di tert-butyl ether and other propylene glycol Ether solvents, or ethylene glycol / propylene glycol Polymers of lower alkyl ethers, etc. -8-200536014 (6) Fluorinated ether solvents refer to the solvents in which one or more hydrogen atoms are replaced by fluorine atoms in the above ether solvents. The fluorine atom may be Either the alkanol part or the alkether part may be introduced. A preferred fluorinated ether-based solvent is a fluorinated ether-based solvent represented by the following formula (1 f) or (2 f).

Rfm-O- (C 2 H m 1 F m 2 " 〇) nl-Rf, (If) or Rfm-0- (C3Hm3Fm4-〇) nl_Rfi (2f) (where Rfm and Rfi are the same or the same phase Different Ci to C4 lower alkyl groups with straight or branched chain, η 1 is an integer from 0 to 4, ill 1 + m2 = 4, m3 + m4 two 6, ml, m2, m3 and πα4 are each 0 or A positive integer. However, when m2 = 0 in the formula (If), at least one of Rfm and Rh contains a fluorine atom.

Rfm, Rf] is CpHqFr (p is an integer from 1 to 4, q + r = 2p + l φ 'and q and r are 0 or a positive integer), the lower level can be substituted by a fluorine atom with a straight or branched chain The alkyl group is preferably a perfluoroalkyl group such as a trifluoromethyl group or a pentafluoroethyl group. nl is an integer of 0 to 4, preferably an integer of 0 to 3. n2 is an integer of 0 to 4, preferably an integer of 0 to 3. Preferred fluorinated ether solvents are, for example, less toxic C4F90CH3 (trade name "HE-7100", manufactured by 3M Corporation) or CF3CH2OCF2CHF2 (trade name "HFE- 3 4 7pc-f", manufactured by Daikin Corporation). In particular, it is an ether-based solvent that is a constituent of a locally selected uranium etching solution. For example, 9-200536014 (7) It is best to use ethylene glycol dimethyl ether (Mono glyme). In addition, for example, polymer ether solvents such as triethylene glycol dimethyl ether (Trig 1 yme) have higher ignition points (100 ° C or higher), and are therefore preferable solvents in terms of safety. . Heretofore, although a method of selectively etching a silicon nitride film by using a mixed solution of an organic solvent and hydrofluoric acid (Patent Document 3) is used, this organic solvent is characterized by using a solvent having a hydroxyl group. Further, the organic solvent used as a raw material in the present invention is etherified with the aforementioned technique to have all oxygen atoms etherified to form an ether-based solvent / fluorinated ether-based solvent having no alcoholic or etheric hydroxyl group, and is different in characteristics. As shown in the comparative example in the description of the present invention, the presence of a hydroxyl group causes the disadvantage of reducing the selectivity of the silicon nitride film. The fluorinated alkyl group (Rfm, Rf!) In the above-mentioned fluorinated ether-based solvent, It is preferred to use a perfluoroalkyl group. An organic solvent containing a perfluoroalkyl group and an ether group bond is not flammable regardless of whether the alkanediol moiety is fluorinated or not, so it is preferable from the viewpoint of φ safety. The uranium etching solution 'is preferably a solvent mixed with the above-mentioned ether-based solvent, hydrogen fluoride (H F), or a dilute hydrofluoric acid. When a fluorinated ether-based solvent is mixed with hydrogen fluoride containing water in the middle ring, it is preferable to use it in combination with other ether-based solvents from the viewpoint of compatibility with water. The content of the ether-based solvent and / or the fluorinated ether-based solvent in the etching solution of the present invention is generally 99.9 to 60.0% by mass, preferably 99.9 to 70.0% by mass, and more preferably 9 9.9 to 80.0% by mass. The concentration of hydrogen fluoride (HF) contained in the mixed solution is used when the silicon nitride film is etched. -10- 200536014 (8) The local concentration (for example, 10 to 30% of the temporary amount, more preferably) It is preferably 0 to 20% by mass). When high selectivity is sought, it is preferable to use a low concentration (for example, 0.1 to 10% by mass, more preferably 0.1 to 5% by mass). The 'water in the etching solution of the present invention may contain any component form or may not be contained at all. The content of water is generally 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, most preferably 2% by mass or less, particularly preferably 1% by mass or less, and particularly 0.5% by mass. Mass% or less. The content of water may be 0 mass. The concentration of water contained in the etching solution is preferably lower when the silicon nitride film is etched at a higher level, and more preferably without water at all. In addition, when the water concentration is increased, the etch speed of the silicon nitride film and the silicon oxide film can be accelerated, but when the water concentration is increased too much, the etching speed of the silicon oxide film will be faster than that of the silicon nitride film. Faster. Therefore, in general, the selective adjustment can be made by adjusting the water concentration. When the etching speed is increased, the etching speed is increased, and it also tends to improve the etching selectivity of the silicon nitride film. Therefore, it is preferable to increase the etching temperature from the viewpoints of improving the etching speed and improving the selectivity of the silicon nitride film to the silicon nitride film. Moreover, when the temperature is too high, the blade-type treatment is difficult to form, and there are disadvantages in releasing hydrogen fluoride gas. The required etching speed ratio and etching speed can be adjusted by adjusting the temperature. The preferred etching temperature is below 100 ° C, preferably 20 to 80 01, more preferably 20 to 50 ° C, and most preferably 20 to 30 t. In the existing blade type device, it is extremely difficult to stabilize the high-temperature chemical solution -11- 200536014 (9) and to uniformly supply the wafer surface, in fact, it is extremely difficult to perform it at a temperature exceeding 100 ° C. Therefore, the temperature is preferably below 1000 ° C. In addition, regardless of the batch type, the blade type, etc., as the temperature approaches the room temperature, the heating time of the medicinal solution can be shortened, and the temperature can be easily controlled and managed. The uranium etching time is generally between 0.5 and 5 minutes, and more preferably between 0.1 and 2 minutes. The etching treatment method of the present invention is, for example, a method of coating a substrate to be treated, spraying an etchant, or immersing a substrate in an etchant. (Related film) The aforementioned silicon nitride film can be formed by various CVD methods such as plasma, heat, light, laser, and ion beam. Commonly used methods such as plasma CVD method, thermal CVD low pressure CVD (LP-CVD) method and so on. The aforementioned silicon oxide film includes a silicon substrate, a silicon dioxide film by thermal hardening and thermal oxidation, and a silicon oxide film prepared by various CVD methods such as plasma, heat, light, laser, and ion beam, nitric acid, sulfuric acid, etc. Silicon oxide film obtained by chemical reaction, silicon substrate, natural oxide film of silicon film, TEOS film, etc. The silicon oxide film does not include a film doped with impurities such as BPSG, BSG, and AsSG containing boron (B), phosphorus (P), and arsenic (As). In the etching solution of the present invention, the etching selection ratio between the silicon nitride film of the LP-CVD method and the silicon oxide film of the thermal oxidation method [(etching speed of the silicon nitride film) / (etching speed of the silicon oxide film)] is generally It is 1.3 or more, preferably 1.5 or more, more preferably 2.0 or more, most preferably 2.5 or more, and particularly preferably 3 or more. The etching solution of the present invention is not only a choice of silicon nitride film for silicon oxide film. -12- 200536014 (10) Selective etching, but also selective etching of silicon nitride film or silicon substrate. The selectivity of the etching solution of the present invention for a silicon film or a silicon substrate is shown below. The etching selection ratio of silicon film to silicon substrate [(etching speed of silicon nitride film) / (etching speed of silicon film)] is generally 10 or more, preferably 100 or more, and more preferably, the silicon film is not completely Etcher is preferred, and the etching selection ratio [(etching speed of silicon nitride film) / (etching speed of silicon substrate)] of silicon film and silicon substrate is generally 10 or more, preferably 100 or more, and more preferably It is preferable that the sand substrate is not touched at all. (Related substrate) In the present invention, a silicon nitride film and a silicon oxide film are, for example, a semiconductor substrate, a glass substrate for display such as a liquid crystal display, a silicon substrate, a SiC substrate, a compound semiconductor substrate such as GaAs, InP, or GaP. (Production method of etching solution) • A method for producing an anhydrous etching solution obtained by using the above-mentioned hydrogen fluoride and an ether-based solvent and / or a fluorinated ether-based solvent, such as absorbing hydrogen fluoride gas in the ether-based solvent and / or the fluorinated ether-based solvent Method and method of maintaining hydrogen fluoride below 20 ° C and mixing with liquid. It can use any method. The aqueous etching solution may be a mixture of hydrogen fluoride and an ether-based solvent and / or a fluorinated ether-based solvent to make an etching solution, or a mixed solution of the hydrogen fluoride and an ether-based solvent and / or a fluorinated ether-based solvent prepared as described above. It is also possible to add water. Generally speaking, 'the etching solution of the present invention is prepared without mixing hydrogen fluoride with an ether-based solvent-13- 200536014 (11) (Other components) Cangworm M liquid' contains hydrogen fluoride, or a hydrogen fluoride acid and an ether-based solvent and / Or a mixture of fluorinated ether-based solvents, it can also be mixed with other surfactants, honeying agents, corrosion inhibitors, etc. However, it is preferable that the addition amount of other ingredients is suppressed to 10% by mass or less. According to the content of the present invention, a nitrided sand film formed on an oxide sand film can be etched on a substrate such as a semiconductor substrate, a glass substrate, or the like at a low temperature and below 100 °. [Embodiment] Hereinafter, the present invention will be described in detail using examples and comparative examples. However, the present invention is not limited by the following examples. Examples 1 to 4 and Comparative Examples 1 to 2 are formed by a low-temperature (LP) CVD CVD method of a silicon nitride film 2 ′ formed on a silicon substrate and a thermal oxidation method formed on a silicon substrate In the 2000a silicon oxide film, an etching test was performed using the etching method of the present invention. The etching rate is obtained from the difference in film thickness before and after etching, and the etching time, and the etching rate ratio (selection ratio) is derived. The film thickness was measured using an elliptical symmetry method. The conditions vary depending on the various brewing systems, cereals, gasification gas concentration, and water concentration. Table 1 shows the etching rates of the etching solution of the present invention obtained using hydrogen fluoride and an ether-based solvent, and a mixed solution composed of a hydroxyl group-added solvent and hydrogen fluoride described in Patent Document 3. It is the same hydrogen fluoride concentration (mass%), phase -14- 200536014 (12) etching characteristics under the same temperature conditions. As shown in Table 1, the number of hydroxyl groups varies with 2-1 (ethylene glycol-ethylene glycol monobutyl ether-ethylene glycol dimethyl ether / Comparative Example 2-Comparative Example 1-Example 4). As the etching rate selectivity changes, the effect of improvement is shown. The mixed solution of ether solvents and hydrogen fluoride, as reported in the current literature, shows a more optimized effect than the mixed solution of organic solvents and hydrogen fluoride. Example: Structure of a solvent mixed with hydrogen fluoride. Hydrogen fluoride concentration 20mass ° / 〇Temperature 60 ° C. Hydrogen fluoride concentration 25] nass% temperature 50 ° C. min) Etching speed ratio (SiN / SiO) SiN SiO SiO SiN Example 1 Diethylene glycol diethyl ether C2H5-0- (C2H4-0) rC2H5 81 20 4.1 Example 2 Diethylene glycol dimethyl ether CHr0 -(C2H4-0) rCH3 111 25 4.4 73 18 4.1 Example 3 Triethylene glycol dimethyl ether CH3-0- (C2H4_0) 3-CH3 80 18 4.4 Example 4 ethylene glycol dimethyl ether CHr0-C2H4 -0-CH3 73 8 9.1 75 18 4.2 Comparative Example 1 Ethylene diether monomethyl ether CH3-O-C2H4-OH 137 99 1.4 Comparative Example 2 Ethylene glycol HO-C2H4-OH 252 402 0.6 186 482 0.4

Test Example 1 In Table 2, the etching rates of the silicon nitride film of the LP-CVD method and the silicon oxide film of the thermal oxidation method are described with respect to the water concentration in a solvent obtained with hydrogen fluoride and ethylene glycol dimethyl ether. Compared with selection. It shows a tendency to increase the etching speed of the silicon nitride film and the silicon oxide film when the water concentration is increased, and it tends to decrease the selective etching property of the silicon nitride film. Therefore, although hydrogen fluoride can be used as a dilute hydrofluoric acid containing water, the use of anhydrous hydrogen fluoride that does not contain water can exhibit higher selective etching properties than dilute hydrofluoric acid. -15- 200536014 (13) In addition, the effect of increasing the etching rate caused by increasing the water concentration in the chemical solution has a greater effect on the silicon oxide film than on the silicon nitride film. Therefore, it is possible to adjust the moisture concentration so that the silicon oxide film and the silicon nitride film are etched at a constant speed. Table 2 shows the etching speed and speed of the silicon nitride film of the LP-CVD method and the silicon oxide film of the thermal oxidation method relative to the water concentration in the mixed solution of hydrogen fluoride and ethylene glycol dimethyl ether at 60 ° C. Choose the corresponding relationship. Table 2 Composition ratio Uranium etching speed (A / min) Etching speed ratio HF (mass%) Water (mass%) SiN SiO SiN / SiO 2 0% 0.0% 7 1 8 9.1 2 0% 0.5% 96 20 4.7 2 0% 1.0% 127 3 1 4.1 2 0% 3.0% 1 7 1 83 2.1 2 0% 5.0% 1 74 9 1 1 .9 20% 10.0% 353 450 0.8 2 0% 2 0.0% 456 1108 0.4 Test Example 2 (About hydrogen fluoride Concentration) The ratio of etching speed to etching speed when changing the concentration of hydrogen fluoride contained in the mixed liquid is shown in Table 3. When seeking high-speed etching, it is better to use high-concentration -16- 200536014 (14) degrees. When seeking high selectivity, it is better to use low concentration. Table 3 Etching speed of LP-CVD silicon nitride film and thermal oxidation silicon oxide film in a mixed solution of hydrogen fluoride and ethylene glycol dimethyl ether Correspondence between speed selection ratio and hydrogen fluoride concentration and temperature

Etching speed (A / min) Touching speed ratio SiN SiO SiN / SiO HF concentration (mass%) 10% 15% 20% 25% 10% 15% 20% 25% 10% 15% 20% 25% Temperature (° c ) 30 11 1.5 7.1 40 6.2 11 23 0.5 1 3.1 12 11 7.4 50 75 18 4.2 56 50 150 6 35 8.3 4.3 60 22 42 73 1.5 η 8 15 14 9.1 65 140 13 10.8 70 80 5.1 16 80 71 3.1 23 (Related Etching temperature) Table 3 is a correspondence table between the etching speed and the etching speed selection ratio with respect to the etching temperature. When the temperature of the mixed solution of hydrogen fluoride and ethylene glycol dimethyl ether is increased at a temperature of -17-200536014 (15), the silicon nitride film and the oxide will tend to exhibit a high etching rate ratio. Therefore, 1 adjusts the etching rate and selection ratio. In hydrogen fluoride and ethylenedi I, an etching rate of 7 lA / min was obtained at a temperature of 80 ° C and a concentration of hydrogen fluoride of 10 m a. The selectivity of the present invention is 4 lines for nitrogen compared to the conventional etching solution. Etching speed of evening film. In addition, Ϊ adjusts the mixed solution of dimethyl ether with the etching temperature; at s%, the silicon nitride film can be 2 3. Therefore, it is known that the silicon film has a higher selection ratio than

-18-

Claims (1)

200536014 十 X. Scope of patent application 1 · An etching solution for selective etching of silicon nitride film, its special hydrogen fluoride, ether-based solvent and / or fluorinated ether-based solvent, and water is necessary. 2. The hungry etching solution according to item 1 of the patent application scope, wherein it is 10% by mass or less of the etching solution. 3. If the etching solution of item 1 or 2 of the patent application scope does not contain water. 4. If the corrosion of any one of items 1-3 of the scope of the patent application, the content of the ether-based solvent and / or the fluorinated ether-based solvent is 99.9 blue%, and the content of hydrogen fluoride (HF) is 0.1 to 30% by mass, It is 10% by mass or less. 5. If the erosion of any one of items 1 to 3 in the scope of the patent application, the content of the ether-based solvent and / or the fluorinated ether-based solvent is 90 to ° / 0, and the content of hydrogen fluoride (HF) is 10 to 30% by mass and 10% by mass of water. 6. In the erosion of any one of items 1 to 3 of the scope of patent application, the content of the ether-based solvent and / or the fluorinated ether-based solvent is 99.9 3%, and the content of hydrogen fluoride (HF) is 0.1 to 10% by mass, It is 3% by mass or less. 7. If the erosion of any one of items 1 to 3 in the scope of the patent application, the ether-based solvent and / or the fluorinated ether-based solvent is a glycol diether 8 Among them, the ether-based solvent is ethylene glycol dimethyl ether (Monoglyme) -based solvent | Characterized as the content of water that can be rehydrated when it is contained, its content is 60 g of water, and its content is 70 mass It is a engraving liquid, which has a large content of 90 mass water, and its solvent. Glycol Di 200536014 (2) 9. The etching solution according to item 7 of the scope of patent application, wherein the glycol diether-based solvent is a triethylene glycol dimethyl ether (Trig lyme) -based solvent. 10. The etching solution according to item 7 in the scope of the patent application, wherein the ethylene glycol diether-based solvent is a diethylene glycol dimethyl ether (Diglyme) -based solvent. 1 1 · The etching solution according to item 7 in the scope of patent application, wherein the glycol diether-based solvent is diethylene glycol diethyl ether. 1 2. The etching solution according to any one of claims 1 to 3, wherein the ether-based solvent and / or the fluorinated ether-based solvent are perfluoroether-based solvents. 1 3. The etching solution according to any one of claims 1 to 3, wherein the ether-based solvent and / or the fluorinated ether-based solvent are C4F9OCH3 and / or CF3CH2OCF2CHF2. 14. A method for selectively etching a silicon nitride film, characterized in that the silicon nitride film and a substrate including the silicon oxide film are etched using an etching solution according to any one of claims 1 to 13 in the patent application range. Method for etching at a temperature below 1 00 ° c. 15. The method according to item 14 of the scope of patent application, wherein the substrate is a semiconductor substrate or a glass substrate. 16. The method according to item 14 or 15 of the scope of patent application, wherein the temperature of the worm is 20 to 50 ° C. 17. The method according to item 16 of the patent application scope, wherein the etching temperature is 20 to 30 ° C. -20- 200536014 ts Wu Ming said the single abbreviation number, and Fu Wu t: the table is the fixed figure of the table, the table is the fixed chart, the table is the table, the table, and the table. If there is no case for the most revealing tense style: this style