阅读说明：本技术 用于去除蚀刻残余物的清洗液 (Cleaning solution for removing etching residues ) 是由 林建玮 蔡维哲 涂胜宏 黄右昕 何明哲 姜欣伶 曹恒光 于 2020-04-02 设计创作，主要内容包括：本发明提供一种用于去除蚀刻残余物的清洗液,其包括含氟化合物；其中,该含氟化合物选自：氟化盐、氟代烷、六氟硅酸、六氟硅酸盐、六氟磷酸、六氟磷酸盐、氟硼酸、氟硼酸盐、三氟甲磺酸、三氟甲磺酸盐、氟磺酸、氟磺酸盐、和以上任一组合。该清洗液可提高对由蚀刻氮化硅等含硅材料产生的含硅副产物的去除能力。(The invention provides a cleaning solution for removing etching residues, which comprises a fluorine-containing compound; wherein the fluorine-containing compound is selected from: fluoride salts, fluoroalkanes, hexafluorosilicic acid, hexafluorosilicate, hexafluorophosphoric acid, hexafluorophosphate salts, fluoroboric acid, fluoroborate salts, trifluoromethanesulfonic acid salts, fluorosulfonic acid salts, and any combination of the foregoing. The cleaning solution can improve the removal capability of silicon-containing by-products generated by etching silicon-containing materials such as silicon nitride.)

1. A cleaning solution for removing etching residues, which comprises a fluorine-containing compound;

wherein the fluorine-containing compound is selected from: fluoride salts, fluoroalkanes, hexafluorosilicic acid, hexafluorosilicate, hexafluorophosphoric acid, hexafluorophosphate salts, fluoroboric acid, fluoroborate salts, trifluoromethanesulfonic acid salts, fluorosulfonic acid salts, and any combination of the foregoing.

2. A cleaning solution for removing etching residues as claimed in claim 1, wherein the cleaning solution further comprises an additive; wherein the additive is selected from: silicon-containing compounds, halogen oxo acids, halogen acids, nitric acids, sulfuric acids, sulfurous acids, phosphoric acids, carbonic acids, cyanic acids, boric acids, organic acid salts, primary amines, secondary amines, tertiary amines, quaternary ammonium salts, alkyl sulfonates, alkyl sulfates, alkyl benzene sulfonates, alkyl phosphates, alkyl amine oxides, and any combination thereof.

3. A cleaning solution for removing etch residues as claimed in claim 2, wherein the silicon-containing compound has a structure represented by formula I:

wherein each R is independentlyA hydrogen atom, a hydroxyl group, an amine group, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkylamino group having 1 to 5 carbon atoms, a sulfonic acid group, a phosphoric acid group, a phosphono group, or a thiol group.

4. A cleaning solution for removing etch residues as claimed in claim 2, wherein the silicon-containing compound has a structure represented by formula II:

5. A cleaning solution for removing etching residues according to claim 2, wherein the additive is selected from: the quaternary ammonium salt, the alkyl sulfonate, the alkyl sulfate, the alkyl benzene sulfonate, the alkyl phosphate, the alkyl amine oxide, and any combination thereof.

6. The cleaning liquid for removing etching residues as claimed in any one of claims 1 to 5, wherein the fluorine-containing compound is the hexafluorosilicic acid, the hexafluorophosphoric acid, or the fluoroboric acid.

7. A cleaning solution for removing etching residues as claimed in claim 1, wherein the cleaning solution further comprises a solvent.

8. A cleaning solution for removing etching residues as claimed in any one of claims 2 to 5, wherein the cleaning solution further comprises a solvent.

9. The cleaning solution for removing etching residues as claimed in claim 7, wherein the concentration of the fluorine-containing compound is 0.1 to 40 wt% based on the total weight of the cleaning solution.

10. The cleaning solution for removing etching residues as claimed in claim 8, wherein the concentration of the fluorine-containing compound is 0.1 wt% to 40 wt%, and the concentration of the additive is 0.001 wt% to 30 wt%, based on the total weight of the cleaning solution.

11. A cleaning solution for removing etching residues as claimed in claim 1, wherein the cleaning solution has a removal rate of removing etching residues higher than 0.5 a/min.

12. A cleaning solution for removing etching residues as set forth in claim 1, wherein the cleaning solution has an etching rate of etching silicon oxide layer of less than 1.0 a/min.

Technical Field

The present invention relates to a cleaning solution for removing etching residues, and more particularly, to a cleaning solution for removing residues generated by etching silicon nitride.

Background

In semiconductor processing, silicon-containing materials such as silicon nitride (silicon nitride) are often used to form a protective layer for a silicon oxide layer (silicon oxide). For example, SiN as in FIG. 1_x/SiO₂a/Si wafer, wherein the silicon oxide layer 10 and the silicon nitride layer 20 (SiN)_xLayers) are deposited in a staggered arrangement on a silicon wafer 30 and formed with an aperture 40 through the silicon oxide layer 10 and the silicon nitride layer 20. For forming a specific pattern or structure, the SiN_x/SiO₂the/Si wafer is immersed in an etchant and the etchant typically begins etching silicon nitride layer 20 through the aperture 40.

Generally, phosphoric acid (H) is disclosed in U.S. Pat. No. 7,976,718₃PO₄) Are often used as etchants suitable for etching silicon nitride layers. The silicon nitride layer after etching generates silicon-containing by-products (Si (OH) as residues₄) And deposited on the silicon oxide layer. Since the residue interferes with subsequent processing, a cleaning composition is required to remove the residue. For example, U.S. patent No. 10,381,226 discloses the use of an aqueous solution of hydrofluoric acid (HF) as the cleaning composition. However, the cleaning composition also attacks the silicon oxide layer during cleaning, and the etching rate of the silicon oxide layer is too high, resulting in an underlayerThe silicon oxide layer is often damaged, which leads to a decrease in reliability of the resulting semiconductor device.

With the increasing demand for higher integration density of semiconductors, miniaturization of structures, and thinning of layer structures, the film thicknesses of the silicon oxide layer and the silicon nitride layer are increasingly reduced, and the pattern accuracy is also increasingly improved. In view of the above, there is an increasing need to develop a cleaning solution that can have a high selectivity between the etching residue and the silicon oxide during the cleaning process.

Disclosure of Invention

In view of the fact that conventional cleaning solutions cannot sufficiently remove silicon oxide and etching residues resulting from etching silicon-containing materials such as silicon nitride, silicon carbide (silicon carbide), silicon germanium (silicon-germanium), and the like, the present invention provides a cleaning solution having a high removal selectivity between the etching residues and silicon oxide.

To achieve the above objects, the present invention provides a cleaning solution for removing etching residues, comprising a fluorine-containing compound; wherein the fluorine-containing compound is selected from: fluoride salts (fluorosalt), fluoroalkanes (fluoroalkaine), hexafluorosilicic acid (HFSA, H for short)₂SiF₆) Hexafluorosilicate (hexafluorosilicate), hexafluorophosphoric acid (HPF)₆) Hexafluorophosphate (hexafluorophosphate), tetrafluoroboric acid (HBF)₄) Fluoroborate (tetrafluoroborate salt), trifluoromethanesulfonic acid (CF)₃SO₃H) Triflate (triflate), fluorosulfonic acid (HSO)₃F, which may also be referred to as fluorosulfuric acid), fluorosulfonate (fluorosulfate salt), and any combination of the above.

The cleaning solution of the present invention, by including a specific fluorine-containing compound, can improve the removal capability of the silicon-containing by-product (i.e., residue) generated by etching the silicon-containing material.

According to the invention, the residue may be orthosilicic acid (Si (OH)₄) Or any derivative thereof, e.g. a derivative of the aforementioned Si (OH)₄Oligomers formed, and in the presence of fluoride ions (F)^-) Si (OH) formed in the presence of₃F。

According to the present invention, the fluoride salt may comprise tetramethylammonium fluoride (TMAF for short), (CH)₃)₄NF), ammonium fluoride (NH)₄) F), ammonium hydrogen fluoride (NH)₄)HF₂) Sodium fluoride (NaF), calcium fluoride (CaF)₂) Magnesium fluoride (MgF)₂) Or any combination thereof.

According to the present invention, the fluoroalkane may comprise carbon tetrafluoride (CF)₄) Difluoromethane (CH)₂F₂) 1,1,1-trifluoroethane (1,1,1-trifluoroethane, C)₂H₃F₃) Or any combination thereof.

According to the present invention, the hexafluorosilicate may contain sodium fluorosilicate (Na)₂(SiF₆) Potassium fluosilicate (K), potassium fluosilicate (K)₂(SiF₆) Calcium fluorosilicate (Ca (SiF)), (Ca)₆) Or any combination thereof.

According to the present invention, the hexafluorophosphate salt may comprise sodium hexafluorophosphate (NaPF)₆) Potassium hexafluorophosphate (KPF)₆) Magnesium hexafluorophosphate (Mg (PF)₆)₂) Or any combination thereof.

According to the invention, the fluoroborate may comprise sodium tetrafluoroborate (NaBF)₄) Potassium tetrafluoroborate (KBF)₄) Silver tetrafluoroborate (AgBF)₄) Or any combination thereof.

According to the invention, the triflate salt may comprise sodium triflate (CF)₃NaO₃S), potassium trifluoromethanesulfonate (CF)₃KO₃S) or a combination thereof.

According to the present invention, the fluorosulfonate salt may comprise sodium fluorosulfonate (NaSO)₃F) Potassium fluorosulfonate (KSO)₃F) Ammonium fluorosulfonate (NH)₄SO₃F) Or any combination thereof.

Preferably, the cleaning solution is present in the form of a solution. Therefore, the cleaning solution further includes a solvent, for example, the solvent is water, so the cleaning solution is in the form of an aqueous solution, but not limited thereto.

Preferably, the fluorine-containing compound has a concentration of 0.1 weight percent (wt%) to 40 wt%, based on the total weight of the cleaning solution. More preferably, the concentration of the fluorine-containing compound is 0.3 wt% to 38 wt%. In some embodiments, the concentration of the fluorine-containing compound can be 0.15 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%, 0.9 wt%, 1.1 wt%, 1.3 wt%, 1.5 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%, 2.5 wt%, 2.6 wt%, 2.7 wt%, 2.8 wt%, 2.9 wt%, 3.0 wt%, 3.2 wt%, 3.5 wt%, 3.7 wt%, 3.9 wt%, 4.0 wt%, 4.2 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.5 wt%, 7.0 wt%, 8.2 wt%, 8.5 wt%, 9.0 wt%, 9.2 wt%, 9.5 wt%, 10.0 wt%, 10.5 wt%, 11.5 wt%, 6.5 wt%, 7.0 wt%, 8.2 wt%, 8.5 wt%, 9.0 wt%, 9.2 wt%, 9.5 wt%, 9.0 wt%, 9.5 wt%, 10.0 wt%, 11 wt%, 15 wt%, 27.5 wt%, 16.30 wt%, 16.5 wt%, 16.25 wt%, 16.5 wt%, 16.

Preferably, the concentration of the fluoride salt in the cleaning solution is 0.1 wt% to 30 wt%. More preferably, the concentration of the fluoride salt in the cleaning solution is 0.3 wt% to 25 wt%. Specifically, in the cleaning liquid, the concentration of the ammonium fluoride is 0.1 wt% to 30 wt%. More preferably, the concentration of the ammonium fluoride in the cleaning solution is 1 wt% to 25 wt%.

Preferably, the concentration of the fluoroalkane in the cleaning solution is 0.01 wt% to 10 wt%. More preferably, the concentration of the fluorinated alkane in the cleaning solution is 0.05 wt% to 8 wt%.

Preferably, the concentration of the HFSA in the cleaning solution is 0.1 wt% to 25 wt%. More preferably, the concentration of the HFSA in the cleaning solution is 0.1 wt% to 20 wt%. Specifically, the concentration of the HFSA in the cleaning liquid is 1.0 wt% to 12 wt%.

Preferably, the concentration of the hexafluorosilicate in the cleaning liquid is 0.1 to 25 wt%. More preferably, the concentration of the hexafluorosilicate in the cleaning liquid is 0.1 to 20 wt%.

Preferably, in the cleaning liquid, the HPF₆Is 0.05 wt% to 10 wt%. More preferably, in the cleaning solution, the HPF₆Is 0.1 to 5 wt%.

Preferably, the concentration of the hexafluorophosphate salt in the cleaning liquid is 0.05 wt% to 10 wt%. More preferably, the concentration of the hexafluorophosphate salt in the cleaning solution is 0.1 wt% to 5 wt%.

Preferably, in the cleaning solution, the HBF₄Is 0.1 to 20 wt%. More preferably, in the cleaning solution, the HBF₄Is 0.8 to 15 wt%.

Preferably, the concentration of the fluoroborate in the cleaning liquid is 0.1 wt% to 20 wt%. More preferably, the concentration of the fluoroborate in the cleaning liquid is 0.8 wt% to 15 wt%.

Preferably, the concentration of the trifluoromethanesulfonic acid in the cleaning solution is 0.05 wt% to 10 wt%. More preferably, the concentration of the trifluoromethanesulfonic acid in the cleaning solution is 0.1 wt% to 5 wt%.

Preferably, the concentration of the triflate in the cleaning solution is 0.05 wt% to 10 wt%. More preferably, the concentration of the triflate in the cleaning solution is 0.1 wt% to 5 wt%.

Preferably, the concentration of the fluorosulfonic acid in the cleaning solution is 0.05 wt% to 10 wt%. More preferably, the concentration of the fluorosulfonic acid in the cleaning solution is 0.1 wt% to 5 wt%.

Preferably, the concentration of the fluorosulfonate salt in the cleaning solution is 0.05 wt% to 10 wt%. More preferably, the concentration of the fluorosulfonate salt in the cleaning solution is 0.1 wt% to 5 wt%.

By using different types of fluorine-containing compounds simultaneously, the removal rate of the cleaning solution for removing etching residues generated by etching silicon nitride can be regulated. Preferably, the fluorine-containing compound may simultaneously contain a combination of hexafluorosilicic acid and ammonium fluoride, or a combination of fluoroboric acid and ammonium fluoride.

In some embodiments, the cleaning fluid may comprise more than two of the fluoride salts of the same type, such as sodium fluoride and ammonium fluoride.

In some embodiments, the cleaning fluid consists essentially of the fluorochemical and water.

In order to improve the performance of the cleaning solution, the cleaning solution may preferably further comprise additives. The additive may be, but is not limited to, a silicon-containing compound, a halogen oxyacid (halogen oxyacid), a halogen acid (halogen acid), a nitric acid (HNO)₃) Sulfuric acid (H)₂SO₄) Sulfurous acid (H)₂SO₃) Phosphoric acid (H)₃PO₄) Carbonic acid (H)₂CO₃) Cyanic acid (NCOH), boric acid (H)₃BO₃) Organic acids, salts of organic acids, primary amines (primary amines), secondary amines (secondary amines), tertiary amines (tertiary amines), quaternary ammonium salts (quaternary ammonium salts), alkyl sulfonates (alkyl sulfates), alkyl sulfates (alkyl sulfates), alkyl benzene sulfonates (alkyl benzene sulfonates), alkyl phosphates (alkyl phosphate salts), alkyl amine oxides (tertiary amine oxides), and any combination thereof.

According to the present invention, when the additive can be used as a surfactant such as the alkylsulfonate or the alkylsulfate, it can adjust the surface tension of the cleaning solution. According to the present invention, when the additive can be used as an acid source such as the oxyhalogen acid or the hydrohalogen acid, it can adjust the compatibility of the surfactant and the cleaning solution.

Preferably, the additive is selected from: the quaternary ammonium salt, the alkyl sulfonate, the alkyl sulfate, the alkyl benzene sulfonate, the alkyl phosphate, the alkyl amine oxide, and any combination thereof.

Preferably, the concentration of the additive is 0.001 wt% to 30 wt%, based on the total weight of the cleaning solution; more preferably, the concentration of the additive is 0.003 to 27 wt%; even more preferably, the concentration of the additive is 0.005 wt% to 1.0 wt%. In some embodiments, the concentration of the additive is 0.0015 wt%, 0.002 wt%, 0.004 wt%, 0.005 wt%, 0.006 wt%, 0.0065 wt%, 0.007 wt%, 0.0075 wt%, 0.008 wt%, 0.0085 wt%, 0.009 wt%, 0.0095 wt%, 0.01 wt%, 0.011 wt%, 0.012 wt%, 0.013 wt%, 0.015 wt%, 0.017 wt%, 0.019 wt%, 0.02 wt%, 0.021 wt%, 0.022 wt%, 0.023 wt%, 0.024 wt%, 0.025 wt%, 0.026 wt%, 0.028 wt%, 0.03 wt%, 0.032 wt%, 0.035 wt%, 0.037 wt%, 0.039 wt%, 0.04 wt%, 0.045 wt%, 0.055 wt%, 0.065 wt%, 0.07 wt%, 0.085 wt%, 0.080.080.085 wt%, 0.085 wt%, 0.7 wt%, 0.09 wt%, 0.15 wt%, 0.7 wt%, 0.9 wt%, 0.15 wt%, 0.10 wt%, 0.9 wt%, 0.8 wt%, 0.15 wt%, 0.8 wt%, 0.9 wt%, 0.8wt, 22.5 wt%, 24.0 wt%, 25.0 wt%, 26.6 wt%, 27.5 wt%, 28.8 wt%, or 29.5 wt%.

According to the present invention, the silicon-containing compound may be represented by the structure shown in formula (I) or formula (II), but is not limited thereto.

In the formulae (I) and (II), each R is independently a hydrogen atom, a hydroxyl group, an amine group, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, an alkynyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms (alkoxy group), an alkylamino group having 1 to 5 carbon atoms (alkyl amino group), a sulfonic acid group (sulfonate group), a phosphoric acid group (phosphate group), a phosphono group (phosphono group), or a thiol group (thiol group). Each R may be the same or different from each other.

In formula (II), n is an integer equal to or greater than 0 and equal to or less than 10.

Specifically, the silicon-containing compound may be 3-Aminopropyltriethoxysilane (APTES), N- (2-aminoethyl) -3-aminopropyltrimethoxysilane (N- [3- (trimethylosyl) propyl ] ethylenediamine), or aminopropylsilsesquioxane (e.g., WSA-7011, a commercial product sold by GELEST, Inc.).

Preferably, the concentration of the silicon-containing compound in the cleaning liquid is 0.005 wt% to 10 wt% based on the total weight of the cleaning liquid. More preferably, the concentration of the silicon-containing compound in the cleaning liquid is 0.005 wt% to 8 wt%.

According to the present invention, the halogen oxyacid may be, but is not limited to, perchloric acid (HClO)₄) Bromic acid (HBrO)₃) Iodic acid (HIO)₃) Or any combination thereof.

Preferably, the concentration of the halogen oxygen acid in the cleaning liquid is 0.005 wt% to 10 wt%. More preferably, the concentration of the halogen oxo acid in the cleaning liquid is 0.005 wt% to 8 wt%.

According to the present invention, the halogen acid may be, but is not limited to, hydrochloric acid (HCl), hydrofluoric acid, or a combination thereof.

Preferably, the concentration of the halogen acid in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the halogen acid in the cleaning solution is 0.005 wt% to 5 wt%. Preferably, the concentration of hydrofluoric acid in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of hydrofluoric acid in the cleaning solution is 0.005 wt% to 5 wt%.

According to the present invention, the organic acid may be, but is not limited to, an organic acid having a carbon number of 1 to 10; for example, the organic acid may be acetic acid (CH)₃COOH), oxalic acid (H)₂C₂O₄) Octanoic acid (O-acid, C)₈H₁₆O₂) Hexanoic acid (C)₆H₁₂O₂) Or any combination thereof.

Preferably, the concentration of the organic acid in the cleaning liquid is 0.005 wt% to 10 wt%. More preferably, the concentration of the organic acid in the cleaning liquid is 0.005 wt% to 5 wt%. Preferably, the concentration of acetic acid in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of acetic acid in the cleaning solution is 0.005 wt% to 5 wt%. Preferably, the concentration of octanoic acid in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of octanoic acid in the cleaning solution is 0.005 wt% to 5 wt%.

According to the present invention, the organic acid salt may be, but is not limited to, an organic acid salt having a carbon number of 1 to 12; for example, the organic phaseThe acid salt can be sodium formate (HCOONa), potassium propionate (CH)₃CH₂CO₂K) Calcium caproate (Ca (C)₆H₁₁O₂)₂) Sodium heptanoate or any combination thereof.

Preferably, the concentration of the organic acid salt in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the organic acid salt in the cleaning solution is 0.005 wt% to 5 wt%.

According to the present invention, the primary amine may be, but is not limited to, a primary amine having a carbon number of 4 to 16; for example, the primary amine may be n-butylamine (CH)₃(CH₂)₃NH₂) N-pentylamine (CH)₃(CH₂)₄NH₂) N-hexylamine (CH)₃(CH₂)₅NH₂) N-heptylamine (CH)₃(CH₂)₆NH₂) N-octylamine (CH)₃(CH₂)₇NH₂) Or n-decylamine (CH)₃(CH₂)₉NH₂)。

Preferably, the concentration of the primary amine in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the primary amine in the cleaning solution is 0.005 wt% to 5 wt%.

According to the present invention, the secondary amine may be, but is not limited to, a secondary amine having a carbon number of 4 to 24; for example, the secondary amine may be dihexylamine ([ CH ]₃(CH₂)₅]₂NH), dioctylamine ([ CH ]₃(CH₂)₇]₂NH) or didecylamine ([ CH ]₃(CH₂)₉]₂NH)。

Preferably, the concentration of the secondary amine in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the secondary amine in the cleaning solution is 0.005 wt% to 5 wt%.

According to the present invention, the tertiary amine may be, but is not limited to, a tertiary amine having a carbon number of 4 to 32; for example, the tertiary amine may be tripentylamine ([ CH ]₃(CH₂)₄]₃N), trihexylamine ([ CH ]₃(CH₂)₅]₃N) or trioctylamine ([ CH ]₃(CH₂)₆]₃N)。

Preferably, the concentration of the tertiary amine in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the tertiary amine in the cleaning solution is 0.005 wt% to 5 wt%.

According to the present invention, the quaternary ammonium salt may be, but is not limited to, a quaternary ammonium salt having a carbon number of 4 to 40; for example, the quaternary ammonium salt may be cetyltrimethylammonium bromide (CTAB), dodecyltrimethylammonium bromide (dodecyl-trimethyl-ammonium bromide) or cetyltrimethylammonium chloride (hexaecyl-trimethyl-ammonium chloride).

Preferably, the concentration of the quaternary ammonium salt in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the quaternary ammonium salt in the cleaning solution is 0.005 wt% to 5 wt%. Preferably, the concentration of CTAB in the cleaning liquid is 0.005 wt% to 10 wt%. More preferably, the concentration of CTAB in the cleaning liquid is 0.005 wt% to 5 wt%.

According to the present invention, the alkylsulfonic acid salt may be, but is not limited to, an alkylsulfonic acid salt having a carbon number of 4 to 16; for example, the alkyl sulfonate may be sodium dodecyl sulfate (CH 1-dodecanesulfonate)₃(CH₂)₁₁SO₃Na) or sodium 1-heptanesulfonate (C)₇H₁₅O₃SNa)。

Preferably, the concentration of the alkylsulfonate in the cleaning solution is from 0.005 wt% to 10 wt%. More preferably, the concentration of the alkylsulfonate in the cleaning solution is from 0.005 wt% to 5 wt%.

According to the present invention, the alkyl sulfate may be, but is not limited to, an alkyl sulfate having a carbon number of 4 to 16; for example, the alkyl sulfate may be sodium dodecyl sulfate (CH)₃(CH₂)₁₁OSO₃Na, SDS for short) or sodium octyl sulfate (CH)₃(CH₂)₇OSO₃Na)。

Preferably, the concentration of the alkyl sulfate in the cleaning liquid is 0.005 wt% to 10 wt%. More preferably, the concentration of the alkyl sulfate in the cleaning liquid is 0.005 wt% to 5 wt%. Preferably, the concentration of SDS in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of SDS in the cleaning solution is 0.005 wt% to 5 wt%.

According to the present invention, the alkylbenzene sulfonate may be, but is not limited to, alkylbenzene sulfonates having an alkyl group with a carbon number of 4 to 16; for example, the alkylbenzene sulfonate can be sodium dodecylbenzenesulfonate (CH)₃(CH₂)₁₁C₆H₄SO₃Na, SDBS for short).

Preferably, the concentration of the alkylbenzene sulfonate in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the alkylbenzene sulfonate in the cleaning solution is from 0.005 wt% to 5 wt%.

According to the present invention, the alkyl phosphate may be, but is not limited to, alkyl phosphate having a carbon number of 4 to 16; the alkyl phosphate may be, for example, sodium monododecyl phosphate (sodium monododecyl phosphate) or potassium monolauryl phosphate (MLPK).

Preferably, the concentration of the alkyl phosphate in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the alkyl phosphate in the cleaning solution is 0.005 wt% to 5 wt%. Preferably, the concentration of MLPK in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of MLPK in the cleaning solution is 0.005 wt% to 5 wt%.

According to the present invention, the alkylamine oxide may be, but is not limited to, alkylamine oxide having a carbon number of 3 to 26; for example, the alkylamine oxide can be dodecyl dimethyl amine oxide (LDAO).

Preferably, the concentration of the alkylamine oxide in the cleaning solution is 0.005 wt% to 10 wt%. More preferably, the concentration of the alkylamine oxide in the cleaning solution is from 0.005 wt% to 5 wt%.

In the cleaning solution, combinations of different types of additives may be used simultaneously. Preferably, the additive may be a combination of the halogen acid and the quaternary ammonium salt, a combination of the halogen acid and the alkyl sulfate salt, a combination of the halogen acid and the alkyl sulfonate salt, a combination of the halogen acid and the alkyl benzene sulfonate salt, or a combination of the halogen acid and the alkyl phosphate salt. Specifically, the additive may be a combination of HF and SDS, a combination of HF and n-octylamine (n-octylamine), or a combination of HF and octanoic acid (O-acid).

According to the invention, the pH value (pH value) of the cleaning solution is 0 to 8. In some embodiments, the pH of the cleaning solution is 0 to 3. In other embodiments, the pH of the cleaning solution is 6.5 to 7.8. More specifically, the pH of the cleaning solution may be 0.1, 0.3, 0.5, 0.75, 1.0, 1.3, 1.5, 1.7, 1.9, 2.2, 2.6, 3.0, 3.5, 4.0, 4.4, 4.9, 5.2, 5.5, 6.0, 6.5, 6.8, 7.2, 7.5, 7.8, or 7.9.

Specifically, when the fluorine-containing compound includes ammonium fluoride, it is preferable that the cleaning liquid has a pH of 6.5 to 7.8. When the fluorine-containing compound comprises HFSA and HBF₄And/or HPF₆Preferably, the cleaning solution has a pH of 0 to 3. More preferably, when the fluorine-containing compound comprises HFSA, HBF₄And/or HPF₆Preferably, the pH of the cleaning solution is 0 to 1.25.

Preferably, when said SiN is_x/SiO₂After the Si wafer is subjected to an etching procedure, deionized water with the temperature of 10-90 ℃ can be used for cleaning the etched SiN_x/SiO₂Drying the/Si wafer with nitrogen, and etching the SiN_x/SiO₂the/Si wafer is immersed in the aforementioned cleaning solution.

Preferably, the etched SiN_x/SiO₂The Si wafer is immersed in the aforementioned cleaning solution at a temperature of 10 ℃ to 80 ℃. More preferably, the etched SiN_x/SiO₂The Si wafer is immersed in the aforementioned cleaning solution at a temperature of 10 ℃ to 40 ℃.

Preferably, the etched SiN_x/SiO₂the/Si wafer is immersed in the cleaning solution for 1 minute to 180 minutes. More preferably, the etched SiN_x/SiO₂the/Si wafer is immersed in the cleaning solution for 20 to 40 minutes.

According to the invention, the cleaning liquid has a viscosity of more than 0.5A/minRemoval rate of the etching residue. Preferably, the cleaning liquid has a removal rate of removing the etching residues higher than that of the cleaning liquidMore preferably, the cleaning solution has a removal rate of removing the etching residues higher than that of the etching residuesEven more preferably, the cleaning solution has a removal rate of the etching residues higher than that of the etching residues

According to the invention, the cleaning liquid has a viscosity lower than that of the cleaning liquid

The etch rate of etching the silicon oxide layer. Preferably, the cleaning liquid has an etching rate of etching the silicon oxide layer lower than that of

More preferably, the cleaning liquid has an etching rate of etching the silicon oxide layer lower than that of

Still more preferably, the cleaning liquid has an etching rate of etching the silicon oxide layer lower than

According to the invention, the cleaning liquid has a removal selectivity between etching residues (i.e. residues generated by etching silicon nitride) and silicon oxide higher than 5. Preferably, the cleaning liquid has a removal selectivity between the etching residue and the silicon oxide of more than 10. More preferably, the cleaning solution has a removal selectivity between the etching residue and the silicon oxide of higher than 12. Even more preferably, the cleaning fluid has a removal selectivity between the etching residues and the silicon oxide of higher than 15.

Drawings

FIG. 1 is SiN_x/SiO₂Schematic cross-sectional view of a/Si wafer.

FIG. 2 is a schematic flow chart of etching and cleaning etching residues according to an embodiment of the present invention.

Detailed Description

Hereinafter, those skilled in the art can easily understand the advantages and effects of the present invention from the following examples. Therefore, it is to be understood that the description set forth herein is intended merely to illustrate preferred embodiments and not to limit the scope of the invention, which can be modified and varied to practice or apply the teachings of the present invention without departing from the spirit and scope thereof.

Preparation example:

as shown in FIG. 2, all have a thickness ofAnd a silicon nitride layer 20' having a thickness of

The silicon wafer (thermal oxide wafer) chips 10'. The silicon wafer fragment 10' comprises a silicon layer and a silicon oxide layer on the silicon layer. The silicon nitride layer 20 'and the oxidized silicon wafer fragment 10' have the same shape and size. Attaching two pieces of sealing tapes 40 to two opposite edges of the oxidized silicon wafer fragments 10', respectively, and nitriding the silicon wafer fragmentsA silicon layer 20 'overlies and adheres to the oxidized silicon wafer fragment 10', thereby forming a bilayer structure 1. Therefore, there is a space between the silicon nitride layer 20 'and the silicon wafer fragment 10' coated with an oxide layer, and the distance of the space is the thickness of the sealing tape 40, 80 micrometers (μm).

Firstly, the double-layer structure 1 is soaked in an etching solution 50 with the temperature of 155 ℃ for 20 minutes; the etching solution 50 contains 85 vol% phosphoric acid. During the etching process, the silicon nitride layer 20 ' of the bilayer structure 1 is etched, and thus, the etching residues 201 generated by etching the silicon nitride layer 20 ' are continuously deposited on the surface of the silicon wafer fragment 10 ' until the etching residues 201 accumulate to a thickness of

Then, washing the etched double-layer structure 1 by deionized water at room temperature; the silicon nitride layer 20 'and the two pieces of sealing tape 40 were removed, thereby obtaining a test sample 1'. The thickness of the test sample 1' was measured with an ellipsometer (ellipsometer).