CN112111280A - Selective etching solution for silicon oxide and application and use method thereof - Google Patents
Selective etching solution for silicon oxide and application and use method thereof Download PDFInfo
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- CN112111280A CN112111280A CN202010875704.9A CN202010875704A CN112111280A CN 112111280 A CN112111280 A CN 112111280A CN 202010875704 A CN202010875704 A CN 202010875704A CN 112111280 A CN112111280 A CN 112111280A
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- 238000005530 etching Methods 0.000 title claims abstract description 129
- 229910052814 silicon oxide Inorganic materials 0.000 title claims abstract description 93
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 90
- 238000000034 method Methods 0.000 title claims abstract description 40
- WPPDFTBPZNZZRP-UHFFFAOYSA-N aluminum copper Chemical compound [Al].[Cu] WPPDFTBPZNZZRP-UHFFFAOYSA-N 0.000 claims abstract description 37
- 230000007797 corrosion Effects 0.000 claims abstract description 37
- 238000005260 corrosion Methods 0.000 claims abstract description 37
- 229910000881 Cu alloy Inorganic materials 0.000 claims abstract description 36
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 31
- 229910052751 metal Inorganic materials 0.000 claims abstract description 23
- 239000002184 metal Substances 0.000 claims abstract description 23
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000001039 wet etching Methods 0.000 claims abstract description 17
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims abstract description 11
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 11
- 239000003112 inhibitor Substances 0.000 claims abstract description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 9
- 239000004094 surface-active agent Substances 0.000 claims abstract description 8
- RILZRCJGXSFXNE-UHFFFAOYSA-N 2-[4-(trifluoromethoxy)phenyl]ethanol Chemical compound OCCC1=CC=C(OC(F)(F)F)C=C1 RILZRCJGXSFXNE-UHFFFAOYSA-N 0.000 claims abstract description 6
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 claims abstract description 6
- 239000002736 nonionic surfactant Substances 0.000 claims description 7
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical group [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 6
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims description 6
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims description 6
- 239000001099 ammonium carbonate Substances 0.000 claims description 6
- 238000001035 drying Methods 0.000 claims description 6
- 238000005406 washing Methods 0.000 claims description 6
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims description 3
- 150000008431 aliphatic amides Chemical group 0.000 claims description 2
- 239000010410 layer Substances 0.000 abstract description 35
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 abstract description 27
- 230000008569 process Effects 0.000 abstract description 24
- 229910021420 polycrystalline silicon Inorganic materials 0.000 abstract description 19
- 229920005591 polysilicon Polymers 0.000 abstract description 14
- 238000011065 in-situ storage Methods 0.000 abstract description 11
- 239000007788 liquid Substances 0.000 abstract description 10
- 239000011241 protective layer Substances 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 7
- 230000008021 deposition Effects 0.000 abstract description 5
- 239000003814 drug Substances 0.000 abstract description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 4
- 230000005764 inhibitory process Effects 0.000 abstract description 3
- 239000000203 mixture Substances 0.000 abstract description 3
- 235000012431 wafers Nutrition 0.000 description 34
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 14
- 239000002253 acid Substances 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 5
- 238000000151 deposition Methods 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 235000019864 coconut oil Nutrition 0.000 description 4
- 239000003240 coconut oil Substances 0.000 description 4
- 235000014113 dietary fatty acids Nutrition 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 239000000194 fatty acid Substances 0.000 description 4
- 229930195729 fatty acid Natural products 0.000 description 4
- 150000004665 fatty acids Chemical class 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000001133 acceleration Effects 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000005034 decoration Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- -1 fluorine ions Chemical class 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000001259 photo etching Methods 0.000 description 2
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K13/00—Etching, surface-brightening or pickling compositions
- C09K13/04—Etching, surface-brightening or pickling compositions containing an inorganic acid
- C09K13/10—Etching, surface-brightening or pickling compositions containing an inorganic acid containing a boron compound
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/311—Etching the insulating layers by chemical or physical means
- H01L21/31105—Etching inorganic layers
- H01L21/31111—Etching inorganic layers by chemical means
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- General Chemical & Material Sciences (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Weting (AREA)
- Internal Circuitry In Semiconductor Integrated Circuit Devices (AREA)
Abstract
The invention relates to a selective etching solution for silicon oxide and an application and a using method thereof. The composition of the selective etching solution for silicon oxide is as follows: 60-80% of phosphoric acid, 1-3% of nitric acid, 8-12% of acetic acid, 1-3% of fluoroboric acid, 0-1% of surfactant, 0-1% of corrosion inhibitor and the balance of water. Among them, the corrosion inhibitor is preferably soluble bicarbonate. Compared with the prior art, the etching solution has moderate corrosion to silicon oxide, greatly reduces the corrosion to polysilicon, has little corrosion to silicon nitride, has a certain corrosion inhibition effect on aluminum metal, has the advantages of higher safety factor, convenience in liquid medicine treatment and control of a client and the like, and is particularly suitable for etching a silicon oxide thin layer generated by in-situ deposition of a wafer which takes a silicon nitride medium protective layer and an aluminum-copper alloy as a metal layer in the wet etching process of the aluminum-copper alloy.
Description
Technical Field
The invention relates to an etching solution, a preparation method and an application field thereof, in particular to an etching solution which can selectively etch a thin silicon oxide layer generated in the process of wet etching of aluminum-copper alloy on a wafer, and an application and a use method thereof.
Background
The wafers are used as carriers for the production of integrated circuits for the production of silicon chips for silicon semiconductor integrated circuits. The silicon chip gathers circuit elements such as transistors, diodes, resistors, capacitors and the like on a wafer to form a complete logic circuit, so as to achieve the functions of control, calculation, memory and the like, thereby meeting the function of processing various things of a user. In the process of processing a wafer into a CPU chip, after an N well or a P well is generated through etching to form a gate circuit of a CPU, a dielectric layer needs to be grown again, then a layer of polycrystalline silicon with the thickness generally being hundreds of nanometers is deposited, then a photoresist substance is coated, the photolithography and the etching are repeated to obtain a groove structure containing the polycrystalline silicon and the dielectric, and the groove structure is repeatedly used for multiple times to form the core of the CPU; and a metal layer is filled in the middle of each several layers to be used as a conductor. The dielectric protective layer is a silicon nitride layer with the thickness of tens of nanometers generally, and the reduction of the isolation capability caused by over-etching can be reduced. The metal layer can be an aluminum-copper alloy metal layer and consists of 97 percent of aluminum and 3 percent of copper; is a good and cheap substitute for the expensive copper metal layer.
In the process of processing a CPU chip, particularly in the process of processing an aluminum-copper alloy metal layer on a wafer, a wet etching technology or a dry etching technology is generally used, wherein the wet etching technology adopts a chemical reagent, and a photoetching pattern is formed on the surface of a metal film by a photoetching method to be used as a shield, so that the metal film is patterned; compared with the dry etching technology, the method is more beneficial in economic efficiency. In the prior art, the etching solution for the aluminum-copper alloy is mainly prepared by uniformly stirring and filtering phosphoric acid, nitric acid and acetic acid, has a good etching effect on the aluminum-copper alloy, but a thin silicon oxide layer with the thickness of only a few nanometers is generated on the surface of a polycrystalline silicon substrate in the wet etching process, so that the performance of a chip is influenced. It is therefore necessary to remove the thin layer of silicon oxide deposited in situ during the wet etching of the aluminum-copper alloy on the wafer.
The silicon oxide etching liquid is a mixture of hydrofluoric acid and ammonium fluoride, which has good etching effect on silicon oxide, but for a wafer deposited with a silicon nitride medium protective layer, the etching rate of the silicon oxide etching liquid system on silicon nitride is too fast and far exceeds that of the silicon nitride etching liquid system
The silicon nitride etch ceiling requirement of (a); etch rate of polysilicon in waferIs also very fast, exceed
The upper limit requirement for polysilicon etching. Therefore, the existing silicon oxide etching liquid formula system is not suitable for the etching process requirement of the silicon oxide thin layer generated by in-situ deposition in the process of wet etching of the aluminum-copper alloy on the wafer. Therefore, it is necessary to study how to etch a thin silicon oxide layer generated in situ during the wet etching process of aluminum-copper alloy on a wafer, and develop an etching solution system that can selectively etch the silicon oxide layer and has weak corrosion to polysilicon, especially silicon nitride layer.
Disclosure of Invention
The first purpose of the invention is to overcome the defect of the prior art that the silicon oxide etching solution has high corrosivity on polysilicon, particularly silicon nitride layer, and provide a selective silicon oxide etching solution which can corrode silicon oxide at a proper speed, has reduced corrosivity on polysilicon, particularly has low corrosion on silicon nitride layer, can realize selective corrosion on silicon oxide, and is more suitable for the practical use of the etching production line for depositing aluminum-copper metal wire wafers.
A second object of the present invention is to provide an application of a selective etchant for silicon oxide.
It is a further object of the present invention to provide a method for using a selective etchant for silicon oxide.
In order to achieve the first object of the present invention, the technical solution of the present invention is a selective etching solution for silicon oxide, which comprises the following components by weight: 60-80% of phosphoric acid, 1-3% of nitric acid, 8-12% of acetic acid, 1-3% of fluoroboric acid, 0-1% of surfactant, 0-1% of corrosion inhibitor and the balance of water.
The former process is aluminum copper alloy etching, and a proper silicon oxide etchant is searched under the system; the inventor selects the product of the fluoboric acid specially as a silicon oxide etching agent to be added into a system of phosphoric acid, nitric acid and acetic acid, overcomes the defect that the etching rate of fluorine ions such as the traditional hydrofluoric acid to silicon and silicon nitride is too high, and the added fluoboric acid is added into waterCan be slowly hydrolyzed in the solution to generate hydroxyl fluoboric acid (HBF)3OH) and has moderate corrosion to silicon oxide at normal temperature, the corrosion to polysilicon is greatly reduced at normal temperature, the corrosion to silicon nitride is very little, and the low-concentration fluoboric acid has certain corrosion inhibition effect on aluminum metal, so that the requirement of the etching process of the silicon oxide thin layer generated by in-situ deposition of the wafer which takes the silicon nitride medium protective layer and the aluminum-copper alloy as the metal layer in the aluminum-copper alloy wet etching process is met.
Adjusting the surface tension of the liquid medicine to increase the wettability of the liquid medicine, preferably, the selective etching liquid of the silicon oxide contains 0.1-1% of surfactant; the surfactant is a nonionic surfactant. Further preferably, the nonionic surfactant is an aliphatic amide nonionic surfactant. Still more preferably, the nonionic surfactant is coconut oil fatty acid diethanolamide.
The etching process of the etching solution is a heat release process, the temperature is locally gathered to a certain high temperature, and hydroxyl fluoboric acid formed by hydrolyzing fluoboric acid in a system is heated and decomposed to form hydrofluoric acid for accelerating the corrosion of polysilicon, particularly silicon nitride. In order to reduce the corrosion to the polysilicon and improve the corrosion selectivity to the silicon oxide, the selective etching solution for the silicon oxide preferably contains 0.1-1% of a corrosion inhibitor. Further preferably, the corrosion inhibitor is a soluble bicarbonate. Here, the decomposition temperature of bicarbonate is lower than the boiling point of water, and the decomposition absorbs heat, consuming the heat generated by etching, lowering the system temperature, and further suppressing the acceleration of corrosion of polysilicon, particularly silicon nitride, due to the heat release from corrosion. Even more preferably, the bicarbonate is ammonium bicarbonate. The ammonium bicarbonate can be decomposed by heating above 36 to absorb the corrosion heat, thereby effectively inhibiting the corrosion acceleration of the polysilicon, especially the silicon nitride due to the corrosion heat release, and not introducing other metal ions.
Preferably, the etching selectivity of the selective etching solution, i.e., the etching rate of silicon oxide
Etch Rate of silicon nitride
Is 25 or more.
In order to achieve the second object of the present invention, the present invention provides an application of the above selective etching solution for silicon oxide, wherein the selective etching solution for silicon oxide is used for selectively etching a silicon oxide layer generated in a wet etching process of an aluminum-copper alloy on a wafer.
In order to achieve the third object of the present invention, the present invention provides a method for using the above selective etchant for silicon oxide, the method comprising:
(a) etching the wafer deposited with the aluminum-copper alloy by using a metal etching solution;
(b) placing the etched wafer in the selective etching solution of the silicon oxide for 1-30s, and keeping the temperature of the selective etching solution of the silicon oxide at 20-35 ℃;
(c) and washing and drying the wafer.
Preferably, in the step (b), the silicon oxide selective etchant is maintained at a temperature of 25 ℃.
Compared with the prior art, the method has the advantages that the fluoboric acid product is used as the silicon oxide etching agent, and is added with phosphoric acid, nitric acid and acetic acid, so that the silicon oxide etching agent has moderate corrosivity on silicon oxide, the corrosivity on polysilicon is greatly reduced, the corrosivity on silicon nitride is very little, and aluminum metal has a certain corrosion inhibition effect, so that the etching process requirement of a silicon oxide thin layer generated by in-situ deposition of a wafer which takes a silicon nitride medium protective layer and an aluminum-copper alloy as a metal layer in the aluminum-copper alloy wet etching process is met. Besides the requirement of an etching process is met, fluoride ions in the selective etching solution are not easy to ionize, the safety coefficient of a human body is higher, the etching solution system is similar to the main formula of the etching solution used in the previous etching of the aluminum-copper alloy, the liquid medicine of a client side is convenient to treat and control, wafers do not need to be washed and dried after the etching of the aluminum-copper alloy, the waiting time between the steps of etching of the aluminum-copper alloy and etching of silicon oxide is reduced, and the contact reaction of metal wires and air is effectively prevented. Particularly, the corrosion inhibitor is selected to inhibit fluoboric acid from generating hydrofluoric acid due to corrosion heat, further inhibit the corrosion acceleration of polycrystalline silicon, particularly silicon nitride due to corrosion heat release in the corrosion process of the etching solution, and is favorable for ensuring the selective corrosion of the etching solution to silicon oxide. The selective etching solution is suitable for etching a silicon oxide thin layer generated by in-situ deposition of a wafer which takes a silicon nitride dielectric protective layer and an aluminum-copper alloy as a metal layer in the aluminum-copper alloy wet etching process.
Detailed Description
The following describes the present invention in further detail with reference to examples and comparative examples. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and the protection scope of the present invention is not limited thereby.
Example 1
A selective etching solution for silicon oxide, which comprises the following components by weight: 70% of phosphoric acid, 2% of nitric acid, 10% of acetic acid, 2% of fluoroboric acid and the balance of water. The selective etching solution of silicon oxide can be used for the selective etching of a silicon oxide layer generated in situ in the wet etching process of aluminum-copper alloy on a wafer by using a silicon nitride dielectric protective layer and an aluminum-copper alloy as a metal layer. The method for using the silicon oxide selective etching solution comprises the following steps:
(a) etching the wafer deposited with the aluminum-copper alloy by using a metal etching solution;
(b) placing the etched wafer in the selective etching solution of the silicon oxide for 1-30s, and keeping the temperature of the selective etching solution of the silicon oxide at 20 ℃;
(c) and washing and drying the wafer.
Example 2
A selective etching solution for silicon oxide, which comprises the following components by weight: 60% of phosphoric acid, 3% of nitric acid, 12% of acetic acid, 3% of fluoboric acid, 1% of coconut oil fatty acid diethanolamide, 1% of ammonium bicarbonate and the balance of water. The selective etching solution of silicon oxide can be used for the selective etching of a silicon oxide layer generated in situ in the wet etching process of aluminum-copper alloy on a wafer by using a silicon nitride dielectric protective layer and an aluminum-copper alloy as a metal layer. The method for using the silicon oxide selective etching solution comprises the following steps:
(a) etching the wafer deposited with the aluminum-copper alloy by using a metal etching solution;
(b) placing the etched wafer in the selective etching solution of the silicon oxide for 1-30s, and keeping the temperature of the selective etching solution of the silicon oxide at 35 ℃;
(c) and washing and drying the wafer.
Example 3
A selective etching solution for silicon oxide, which comprises the following components by weight: 80% of phosphoric acid, 1% of nitric acid, 8% of acetic acid, 1% of fluoboric acid, 0.1% of coconut oil fatty acid diethanolamide, 0.1% of ammonium bicarbonate and the balance of water. The selective etching solution of silicon oxide can be used for the selective etching of a silicon oxide layer generated in situ in the wet etching process of aluminum-copper alloy on a wafer by using a silicon nitride dielectric protective layer and an aluminum-copper alloy as a metal layer. The method for using the silicon oxide selective etching solution comprises the following steps:
(a) etching the wafer deposited with the aluminum-copper alloy by using a metal etching solution;
(b) placing the etched wafer in the selective etching solution of the silicon oxide for 1-30s, and keeping the temperature of the selective etching solution of the silicon oxide at 25 ℃;
(c) and washing and drying the wafer.
Example 4
A selective etching solution for silicon oxide, which comprises the following components by weight: 70% of phosphoric acid, 2% of nitric acid, 10% of acetic acid, 2% of fluoboric acid, 0.3% of coconut oil fatty acid diethanolamide, 0.2% of ammonium bicarbonate and the balance of water. The selective etching solution of silicon oxide can be used for the selective etching of a silicon oxide layer generated in situ in the wet etching process of aluminum-copper alloy on a wafer by using a silicon nitride dielectric protective layer and an aluminum-copper alloy as a metal layer. The method for using the silicon oxide selective etching solution comprises the following steps:
(a) etching the wafer deposited with the aluminum-copper alloy by using a metal etching solution;
(b) placing the etched wafer in the selective etching solution of the silicon oxide for 1-30s, and keeping the temperature of the selective etching solution of the silicon oxide at 25 ℃;
(c) and washing and drying the wafer.
Comparative example 1
Unlike example 1, comparative example 1 replaces fluoroboric acid with hydrofluoric acid; the etching solution of comparative example 1 had the following composition by weight: 70% of phosphoric acid, 2% of nitric acid, 10% of acetic acid, 2% of hydrofluoric acid and the balance of water.
The etching solutions of examples 1 to 4 and comparative example 1 were compared in their etching effects on silicon oxide, polysilicon and silicon nitride, and the results are shown in tables 1 and 2. The etching conditions used for the evaluation of the etching effect were: the etching temperature is 25 ℃, the flow rate of the liquid medicine is 14.2L/min, and the rotating speed of the machine is 40 rpm.
TABLE 1
TABLE 2
As can be seen from tables 1 and 2, the selective etching solutions for silicon oxide of examples 1 to 4 etched silicon oxide with substantially no corrosion of silicon nitride and much less corrosion of polysilicon than hydrofluoric acid instead of fluoroboric acid.
The etching rates of the silicon oxide selective etching solutions of examples 1-4 on silicon oxide under the test conditions
And etching rate of silicon nitride
Ratio of (i.e. etching rate of silicon oxide)
Etch rate to silicon nitride
Are all above 25, and the etching rate to the silicon nitride is less than
Has a lower etching rate than polysilicon
Has an etching rate greater than that of silicon oxide
Particularly, after the surfactant and the corrosion inhibitor are added, the etching selectivity is further improved, and the uniformity of the etching rate is better.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. The selective etching solution for silicon oxide is characterized by comprising the following components in parts by weight: 60-80% of phosphoric acid, 1-3% of nitric acid, 8-12% of acetic acid, 1-3% of fluoroboric acid, 0-1% of surfactant, 0-1% of corrosion inhibitor and the balance of water.
2. The selective etching solution for silicon oxide according to claim 1, wherein the selective etching solution for silicon oxide contains 0.1 to 1% of a surfactant; the surfactant is a nonionic surfactant.
3. The selective etching solution for silicon oxide according to claim 2, wherein the nonionic surfactant is an aliphatic amide nonionic surfactant.
4. The silicon oxide selective etching solution of claim 1, wherein the silicon oxide selective etching solution contains 0.1 to 1% of a corrosion inhibitor.
5. The selective etching solution for silicon oxide according to claim 4, wherein the corrosion inhibitor is a soluble bicarbonate.
6. The selective etching solution for silicon oxide according to claim 5, wherein the hydrogen carbonate is ammonium hydrogen carbonate.
7. The silicon oxide selective etching solution according to any one of claims 1 to 6, wherein an etching selectivity of the selective etching solution, that is, an etching rate of silicon oxide
Etch Rate of silicon nitride
Is 25 or more.
8. Use of the silicon oxide-selective etching solution according to claims 1 to 7 for the selective etching of a silicon oxide layer formed during the wet etching of an aluminum-copper alloy on a wafer.
9. A method for using the silicon oxide selective etching solution according to claims 1 to 7, comprising the steps of:
(a) etching the wafer deposited with the aluminum-copper alloy by using a metal etching solution;
(b) placing the etched wafer in the selective etching solution of silicon oxide of claims 1-7 for 1-30s, and keeping the temperature of the selective etching solution of silicon oxide at 20-35 ℃;
(c) and washing and drying the wafer.
10. The method for using the silicon oxide-selective etching solution according to claim 9, wherein the silicon oxide-selective etching solution is maintained at a temperature of 25 ℃ in the step (b).
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115181569A (en) * | 2022-07-07 | 2022-10-14 | 湖北兴福电子材料有限公司 | Selective etching solution for silicon oxide |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4230522A (en) * | 1978-12-26 | 1980-10-28 | Rockwell International Corporation | PNAF Etchant for aluminum and silicon |
| CN101393867A (en) * | 2007-09-21 | 2009-03-25 | 大日本网屏制造株式会社 | Substrate processing apparatus |
| CN109706455A (en) * | 2019-02-18 | 2019-05-03 | 湖北兴福电子材料有限公司 | A kind of aluminium etching solution and preparation method thereof of high etch rates and selection ratio |
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2020
- 2020-08-27 CN CN202010875704.9A patent/CN112111280A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4230522A (en) * | 1978-12-26 | 1980-10-28 | Rockwell International Corporation | PNAF Etchant for aluminum and silicon |
| CN101393867A (en) * | 2007-09-21 | 2009-03-25 | 大日本网屏制造株式会社 | Substrate processing apparatus |
| CN109706455A (en) * | 2019-02-18 | 2019-05-03 | 湖北兴福电子材料有限公司 | A kind of aluminium etching solution and preparation method thereof of high etch rates and selection ratio |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115181569A (en) * | 2022-07-07 | 2022-10-14 | 湖北兴福电子材料有限公司 | Selective etching solution for silicon oxide |
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