US20050139233A1 - Cleaning solution and method of cleaning a semiconductor device using the same - Google Patents
Cleaning solution and method of cleaning a semiconductor device using the same Download PDFInfo
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- US20050139233A1 US20050139233A1 US11/070,645 US7064505A US2005139233A1 US 20050139233 A1 US20050139233 A1 US 20050139233A1 US 7064505 A US7064505 A US 7064505A US 2005139233 A1 US2005139233 A1 US 2005139233A1
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- 238000004140 cleaning Methods 0.000 title claims abstract description 147
- 238000000034 method Methods 0.000 title abstract description 50
- 239000004065 semiconductor Substances 0.000 title abstract description 30
- 229920000642 polymer Polymers 0.000 claims abstract description 85
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 78
- 239000001257 hydrogen Substances 0.000 claims abstract description 53
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 53
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 52
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 51
- 229960002050 hydrofluoric acid Drugs 0.000 claims abstract description 51
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 239000008367 deionised water Substances 0.000 claims description 19
- 229910021641 deionized water Inorganic materials 0.000 claims description 19
- 239000000758 substrate Substances 0.000 abstract description 69
- 229910052751 metal Inorganic materials 0.000 abstract description 24
- 239000002184 metal Substances 0.000 abstract description 24
- 239000000243 solution Substances 0.000 description 141
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 108
- 229910052721 tungsten Inorganic materials 0.000 description 108
- 239000010937 tungsten Substances 0.000 description 108
- 230000008569 process Effects 0.000 description 32
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 19
- 229920005591 polysilicon Polymers 0.000 description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 18
- 239000001301 oxygen Substances 0.000 description 18
- 229910052760 oxygen Inorganic materials 0.000 description 18
- 239000012535 impurity Substances 0.000 description 16
- 238000005530 etching Methods 0.000 description 14
- 150000004767 nitrides Chemical class 0.000 description 14
- 239000011229 interlayer Substances 0.000 description 12
- 229920002120 photoresistant polymer Polymers 0.000 description 7
- 238000004380 ashing Methods 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 125000006850 spacer group Chemical group 0.000 description 4
- WQJQOUPTWCFRMM-UHFFFAOYSA-N tungsten disilicide Chemical compound [Si]#[W]#[Si] WQJQOUPTWCFRMM-UHFFFAOYSA-N 0.000 description 4
- 229910021342 tungsten silicide Inorganic materials 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 230000004888 barrier function Effects 0.000 description 3
- 238000001312 dry etching Methods 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- 230000010354 integration Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052814 silicon oxide Inorganic materials 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- 238000002955 isolation Methods 0.000 description 2
- 229920000620 organic polymer Polymers 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000005368 silicate glass Substances 0.000 description 2
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 2
- AVXURJPOCDRRFD-UHFFFAOYSA-N Hydroxylamine Chemical compound ON AVXURJPOCDRRFD-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000003190 augmentative effect Effects 0.000 description 1
- VEFXTGTZJOWDOF-UHFFFAOYSA-N benzene;hydrate Chemical compound O.C1=CC=CC=C1 VEFXTGTZJOWDOF-UHFFFAOYSA-N 0.000 description 1
- LPTWEDZIPSKWDG-UHFFFAOYSA-N benzenesulfonic acid;dodecane Chemical compound OS(=O)(=O)C1=CC=CC=C1.CCCCCCCCCCCC LPTWEDZIPSKWDG-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
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- 238000005260 corrosion Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 238000009751 slip forming Methods 0.000 description 1
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Images
Classifications
-
- 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
-
- 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
- H01L21/02041—Cleaning
- H01L21/02057—Cleaning during device manufacture
- H01L21/02068—Cleaning during device manufacture during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers
- H01L21/02071—Cleaning during device manufacture during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers the processing being a delineation, e.g. RIE, of conductive layers
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D9/00—Chemical paint or ink removers
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/39—Organic or inorganic per-compounds
- C11D3/3947—Liquid compositions
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/02—Inorganic compounds
- C11D7/04—Water-soluble compounds
- C11D7/08—Acids
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/50—Solvents
- C11D7/5004—Organic solvents
- C11D7/5018—Halogenated solvents
-
- 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
- H01L21/02041—Cleaning
- H01L21/02057—Cleaning during device manufacture
- H01L21/0206—Cleaning during device manufacture during, before or after processing of insulating layers
- H01L21/02063—Cleaning during device manufacture during, before or after processing of insulating layers the processing being the formation of vias or contact holes
-
- 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 at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System 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
- H01L21/31127—Etching organic layers
- H01L21/31133—Etching organic layers by chemical means
-
- C11D2111/22—
Definitions
- This disclosure relates to a cleaning solution and a method of cleaning a semiconductor device using the same, and more particularly to a cleaning solution for completely removing various polymers attached to a tungsten wiring of a semiconductor device and a method of cleaning a semiconductor device using the same.
- semiconductor devices have been greatly improved as information processing apparatus such as a computers are rapidly developed.
- the semiconductor device is required to have rapid response speed and large storage capacity so that a semiconductor manufacturing process is developed to improve integration density and reliability of the semiconductor device.
- a cell of the semiconductor device should be reduced.
- all the patterns formed on a substrate have reduced dimensions and processing margins are also decreased.
- the semiconductor device may not have adequate electrical insulation and refresh characteristics.
- sizes of the patterns are greatly reduced and multi-layered wirings are demanded according as the semiconductor device has high integration density.
- a metal having a relative low electrical resistance is used for metal wirings of the semiconductor device instead of a metal having high electrical resistance.
- tungsten silicide rather than tungsten, is employed for the metal wiring of the semiconductor device to be used as a gate electrode or a bit line of a volatile or non-volatile memory device.
- a dry etch process for etching a metal and an ashing process for removing a photoresist pattern are also frequently performed.
- impurities are generated from a dry etch gas, the photoresist pattern, an oxide film, and a tungsten film and the impurities are attached to a sidewall of the metal wiring.
- the impurities may increase electrical resistance of a semiconductor device or may cause an electrical short between adjacent metal wirings when the impurities remain on the metal wiring. Thus, these impurities should be removed from the metal wiring.
- Japanese Patent Laid Open Publication No. 10-779366 discloses a method of removing impurities remaining on a substrate using a cleaning solution including about 24 percent by weight of sulfuric acid, about 5 percent by weight of aqueous hydrogen peroxide solution, about 0.02 percent by weight of hydrogen fluoride, about 0.075 percent by weight of N-dodecyl benzene sulfonic acid and water.
- the impurities on the substrate are removed by immersing the substrate into the cleaning solution for about 10 minutes and rinsing the substrate using deionized water for about 7 minutes.
- Korean Patent Laid Open Publication No. 2000-61342 discloses a method of removing polymers remaining on a substrate by successively using a cleaning solution of sulfuric acid (H 2 SO 4 ) and aqueous hydrogen peroxide solution (H 2 O 2 ), a cleaning solution of hydrogen fluoric acid (HF) and water (H 2 O), and an SCl cleaning solution.
- the polymers are generated after a dry etch process for forming a tungsten silicide wiring on the substrate.
- an organic stripper including hydroxylamine is generally used in a cleaning process for removing impurities generated after a process of etching a tungsten wiring because the organic stripper may not cause damages of the tungsten wiring and an underlying film.
- the organic stripper may not completely remove the impurities remaining on a substrate.
- the organic stripper may not effectively remove oxygen-containing polymers (polymeric oxides) generated during etching of the tungsten wiring so that the impurities are not completely removed from the substrate.
- the impurities attached to the tungsten wiring are adequately removed from the tungsten wiring for more than about 20 minutes, the time required for removing the impurities may be too long when the impurities are removed using the organic stripper.
- the improved organic stripper additionally includes fluorine-containing chemicals like HF or NHF4, an organic solvent, and a corrosion inhibitor.
- the organic solvent can prevent a metal wiring from being damaged due to the fluorine-containing chemicals.
- the improved organic stripper may not effectively remove polymers generated during etching the metal wiring and the improved organic stripper is very expensive.
- the improved organic stripper may excessively etch some underlying films to such an extent that the improved organic stripper can hardly be employed for a semiconductor manufacturing process.
- Embodiments of the invention address these and other disadvantages of the conventional art.
- embodiments of the invention provide a cleaning solution that can effectively remove various polymers attached to tungsten wiring without damage to the tungsten wiring and an underlying film. Additionally, the time required for removing the polymers can be greatly reduced, improving the throughput of the semiconductor device.
- FIG. 1 is a graph illustrating the etch rate of a tungsten wiring relative to the amount of sulfuric acid contained in a cleaning solution according to embodiments of the invention.
- FIG. 2 is a graph illustrating the etch rate of an oxide film relative to the amount of sulfuric acid contained in a cleaning solution according to embodiments of the invention.
- FIG. 3 is a graph illustrating the etch rate of a tungsten wiring relative to the amount of aqueous hydrogen peroxide solution contained in a cleaning solution according to embodiments of the invention.
- FIG. 4 is a graph illustrating the etch rate of an oxide film relative to the amount of aqueous hydrogen peroxide solution contained in a cleaning solution according to embodiments of the invention.
- FIG. 5 is a graph illustrating the etch rate of an oxide film relative to the cleaning time using an embodiment of the invention.
- FIG. 6A is an electron microscope photograph illustrating a structure including a tungsten wiring cleaned using a conventional cleaning method.
- FIG. 6B is an electron microscope photograph illustrating a structure including a tungsten wiring cleaned in accordance with an embodiment of the invention.
- FIGS. 7A to 7 D are cross-sectional diagrams illustrating a method of forming a transistor of a semiconductor device according to an embodiment of the invention.
- FIGS. 8A to 8 E are cross-sectional diagrams illustrating a method of forming a bit line of a semiconductor device according to another embodiment of the invention.
- a cleaning solution according to embodiments of the invention includes sulfuric acid (H 2 SO 4 ), aqueous hydrogen peroxide solution (H 2 O 2 ), deionized water (H 2 O), and hydrogen fluoric acid (HF) solution.
- the hydrogen fluoric solution is prepared by diluting hydrogen fluoric acid with deionized water.
- the cleaning solution efficiently removes various polymers remaining on a metal wiring formed on a substrate without damages of the metal wiring and an underlying film after a dry etch process is performed to form the metal wiring.
- the cleaning solution has the following characteristics.
- the cleaning solution can prevent damage to a tungsten wiring under an adequately controlled condition even though the sulfuric acid and the aqueous hydrogen peroxide solution contained in the cleaning solution may corrode the tungsten wiring.
- the cleaning solution can completely remove various polymers including metallic components and oxygen-containing components generated during dry etching the tungsten wiring.
- the cleaning solution can adequately etch oxygen-containing polymers while simultaneously preventing the lifting of the tungsten wiring due to en excessive etch of an underlying oxide film.
- the cleaning solution can prevent an increase in the aspect ratio of the tungsten wiring and the generation of a void in an interlayer dielectric film by reducing the etching of the interlayer dielectric film.
- cleaning solutions according to embodiments of the invention preferably include about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution, and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution. Therefore, the cleaning solution can effectively remove the polymers generated during a formation of a structure including a tungsten wiring.
- the cleaning solution preferably includes about 1 to about 10 percent by weight of sulfuric acid. If the cleaning solution includes less than about 1 percent by weight of sulfuric acid, the cleaning solution will not cause damage to a tungsten film pattern and an oxide film pattern formed on a substrate. However, the cleaning solution will not easily remove the polymers including metallic by-products and oxides generated during the etching of the tungsten film. When the cleaning solution includes more than about 10 percent by weight of sulfuric acid, although the cleaning solution can easily remove metallic polymers and oxygen-containing polymers generated during a formation of the tungsten film pattern, the cleaning solution may cause damage to the tungsten film pattern and the oxide film pattern.
- the cleaning solution preferably includes about 1 to about 10 percent by weight, and more preferably, about 3 to about 8 percent by weight of sulfuric acid.
- an etched amount of the tungsten film pattern can be controlled in accordance with the amount of the sulfuric acid contained in the cleaning solution. Additionally, the sulfuric acid serves as a catalyst that augments the potential of hydrogen (pH) of the cleaning solution to more rapidly dissolve the hydrogen fluoric acid. Hence, the oxygen-containing polymers are more easily removed from the tungsten film pattern.
- the cleaning solution preferably includes about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution.
- the cleaning solution includes less than about 0.5 percent of by weight of aqueous hydrogen peroxide solution, the metallic polymers and the oxygen-containing polymers are not easily removed although the cleaning solution will not cause damage to the tungsten film pattern and the oxide film pattern.
- the cleaning solution includes more than 5 percent by weight of aqueous hydrogen peroxide solution, the cleaning solution may cause the damages of the tungsten film pattern and the oxide film pattern although the cleaning solution will easily remove the metallic polymers and the oxygen-containing polymers. Therefore, the cleaning solution preferably includes about 0.5 to about 5, and more preferably about 1 to about 3 percent by weight of aqueous hydrogen peroxide solution.
- the aqueous hydrogen peroxide solution has a concentration of about 25 to about 30 percent.
- the amount of hydrogen fluoric acid solution contained in the cleaning solution varies in accordance with the concentration of the hydrogen fluoric acid after dilution with deionized water.
- the hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid. In this case, the hydrogen fluoric acid solution has a concentration of about 50 percent.
- the cleaning solution preferably includes about 85 to about 95 percent by weight of hydrogen fluoric acid solution.
- the cleaning solution may not remove the oxygen-containing polymers.
- the cleaning solution may cause damage to the tungsten film pattern and the oxide film pattern although the cleaning solution can easily remove the oxygen-containing polymers and the metallic polymers.
- the cleaning solution preferably includes a hydrogen fluoric acid solution of about 85 to about 95 percent by weight.
- the hydrogen fluoric acid has a concentration of 50 percent and the hydrogen fluoric acid solution includes about 0.1 to about 2 ml of hydrogen fluoric acid and about 1,000 ml of deionized water.
- FIG. 1 is a graph illustrating an etch rate of a tungsten wiring relative to the amount of sulfuric acid contained in a cleaning solution according embodiments of the invention.
- the etch rate of the tungsten wiring increases from about 70 to about 330 ⁇ /min as the amount of sulfuric acid contained in the cleaning solution is augmented from about 1 to about 10 percent by weight.
- a substrate including the tungsten wiring was immersed in the cleaning solution having a temperature of about 25° C. for about 10 minutes.
- the amount of the sulfuric acid contained in the cleaning solution was more than about 5 percent by weight, the etch rate of the tungsten wiring rapidly increased.
- the amount of the sulfuric acid contained in the cleaning solution is preferably no more than about 5 percent by weight.
- FIG. 2 is a graph illustrating an etch rate of an oxide film relative to the amount of sulfuric acid contained a cleaning solution according to embodiments of the invention.
- the etch rate of the oxide film increases from about 150 to about 300 ⁇ /min as the amount of sulfuric acid contained in the cleaning solution increases from about 1 to about 10 percent by weight.
- a substrate including the oxide wiring was immersed in the cleaning solution having a temperature of about 25° C. for about 10 minutes.
- the sulfuric acid cannot directly etch the oxide film
- the sulfuric acid serves as a catalyst that can more rapidly dissociate hydrogen fluoric acid contained in the cleaning solution because the acidity of the cleaning solution increases in accordance with an increase of the amount of sulfuric acid contained in the cleaning solution.
- the hydrogen fluoric acid is dissociated, it can more easily etch the oxide film and oxygen-containing polymers.
- FIG. 3 is a graph illustrating an etch rate of a tungsten wiring relative to the amount of aqueous hydrogen peroxide solution contained in a cleaning solution according to embodiments of the invention.
- the etch rate of the tungsten wiring increases from about 50 to about 90 ⁇ /min as the amount of the aqueous hydrogen peroxide solution contained in the cleaning solution increases from about 2.5 to about 5 percent by weight at a temperature of about 25° C. Additionally, at a temperature of about 32.5° C., as the amount of the aqueous hydrogen peroxide solution contained in the cleaning solution increases from about 2.5 to about 5 percent by weight, the etch rate of the tungsten wiring increases from about 120 to about 200 ⁇ /min. Here, the substrate including the tungsten wiring was immersed in the cleaning solution for about 10 minutes.
- a temperature variation of the cleaning solution has a greater effect on the etch rate of the tungsten wiring than the amount of the aqueous hydrogen peroxide solution or the sulfuric acid. Accordingly, in order to more easily control the etch rate of the tungsten wiring, the temperature of the cleaning solution is preferably maintained at about 25° C. while the amounts of the aqueous hydrogen peroxide solution and the sulfuric acid are selectively adjusted.
- FIG. 4 is a graph illustrating an etch rate of an oxide film relative to the amount of aqueous hydrogen peroxide solution contained a cleaning solution according to embodiments of the invention.
- the etch rate of the oxide film increases from about 150 to about 170 ⁇ /min as the amount of the aqueous hydrogen peroxide solution contained in the cleaning solution increases from about 2.5 to about 5 percent by weight.
- the etch rate of the oxide film increases from about 180 to about 210 ⁇ /min. In this case, a substrate including the oxide film was immersed in the cleaning solution for about 10 minutes.
- the etch rate of the oxide film gradually increases because the aqueous hydrogen peroxide solution does not directly etch the oxide film but serves as a catalyst for etching the oxide film.
- the temperature of the cleaning solution is maintained at about 25° C. while the amounts of sulfuric acid and aqueous hydrogen peroxide solution contained in the cleaning solution are selectively adjusted in order to easily control the etch rate of the oxide film.
- the temperature of the cleaning solution and the amounts of etchant and catalyst are advantageously controlled to achieve pertinent etching of a metal wiring or an insulation film.
- a cleaning solution is provided in a cleaning bath.
- the cleaning solution includes about 5 percent by weight of sulfuric acid, about 2.5 percent by weight of aqueous hydrogen peroxide solution and about 92.5 percent by weight of hydrogen fluoric acid solution.
- the hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid.
- the hydrogen fluoric acid has a concentration of about 50 percent.
- the tungsten wiring includes, for example, tungsten patterns.
- the organic and metallic polymers are exposed.
- the organic and metallic polymers are removed by the aqueous hydrogen peroxide solution and sulfuric acid contained in the cleaning solution without damage to the tungsten wiring.
- the cleaning solution When a temperature of the cleaning solution is below about 20° C., the time required for completely removing the polymers from the sidewall of the tungsten wiring is greatly increased. To the contrary, when the cleaning solution has a temperature above about 30° C., damage to the tungsten wiring and an underlying layer may be caused even though the polymers may be rapidly removed from the tungsten wiring. Accordingly, the cleaning solution preferably has a temperature of about 25° C. to remove the polymers from the tungsten wiring.
- FIG. 5 is a graph illustrating the etch rate of an oxide film relative to the cleaning time using a cleaning solution according to an embodiment of the invention.
- the etched amount of the oxide film formed beneath the tungsten wiring was observed by varying the cleaning time of the tungsten wiring so that the etch rate was measured in order to identify an advantageous cleaning time for the tungsten wiring.
- the polymers could be more completely removed from the tungsten wiring as the cleaning time increased, however, the underlying oxide film was excessively etched during removal of the polymers. That is, when the cleaning time increased from about 1 to about 10 minutes, the etch rate of the oxide film increased from about 30 to about 200 ⁇ .
- a process for cleaning the tungsten wiring is preferably executed with a cleaning time of below about 9 minutes.
- the substrate including the tungsten wiring is taken out of the cleaning solution. Then, the substrate is rinsed using deionized water to remove the cleaning solution remaining on the substrate.
- the substrate is taken out of the cleaning solution, most polymers are dissolved in the cleaning solution or detached from the tungsten wiring so that most polymers are removed from the substrate or bond strengths between the polymers and the tungsten wiring are greatly reduced. Therefore, the polymers are cleaned from the substrate and the tungsten wiring when the rinsing process is performed on the substrate.
- the substrate is dried to remove the remaining deionized water.
- the polymers can be effectively removed from the tungsten wiring without damage to the tungsten wiring.
- FIG. 6A is an electron microscope photograph illustrating a structure including a tungsten wiring that was cleaned using a conventional cleaning method.
- FIG. 6B is an electron microscope photograph illustrating a structure including a tungsten wiring cleaned employing a cleaning method according to an embodiment of the invention.
- oxygen-containing polymers are not sufficiently removed from the tungsten wiring and also damage of the tungsten wiring (region A) was caused when the tungsten wiring was cleaned using the conventional method.
- FIG. 6B when the tungsten wiring is cleaned according to an-embodiment of the invention, the polymers generated during etching of the tungsten wiring and during ashing of a photoresist pattern were completely removed from the tungsten wiring. Also, damage to the tungsten wiring and the underlying oxide film are not nearly as severe.
- FIGS. 7A to 7 D are cross-sectional diagrams illustrating a method of forming a transistor of a semiconductor device according to an embodiment of the invention.
- an isolation process such as a shallow trench isolation (STI) process or a local oxidation of silicon (LOCOS) is performed on a substrate 100 to define an active region and a field region 100 b.
- STI shallow trench isolation
- LOC local oxidation of silicon
- the active and field regions 100 b are defined using the STI process.
- the substrate 100 is partially etched to form a trench at a portion of the substrate 100 corresponding to the field region 100 b.
- the silicon oxide film is etched using a chemical mechanical polishing (CMP) process, thereby forming a filed oxide film in the trench to define the field region 100 b.
- CMP chemical mechanical polishing
- gate electrodes 110 are formed on the substrate 100 .
- the gate electrodes 110 include gate oxide film patterns 102 a, first polysilicon film pattern 104 a, first tungsten film patterns 106 a, and first nitride film patterns 108 a, respectively.
- a gate oxide film 102 having a thickness of about 50 to about 100 ⁇ is formed on the substrate 100 .
- a first polysilicon film 104 doped with N-type impurities is formed on the gate oxide film 102 to a thickness of about 1,000 to about 1,500 ⁇ .
- a first tungsten film 106 is formed on the first polysilicon film 104 in order to reduce a resistance of the gate electrode 110 .
- a first tungsten silicide film can be formed on the first polysilicon film 104 instead of the first tungsten film 106 .
- a first nitride film 108 is formed on the tungsten film 106 .
- a barrier layer can be formed between the first polysilicon film 104 and the first tungsten film 106 so as to easily form the first tungsten film 106 .
- a photoresist pattern (not shown) is formed on the first nitride film 108 to define a layout of the gate electrodes 110 , the first nitride film 108 , the first tungsten film 106 , the first polysilicon film 104 , and the gate oxide film 102 are successively etched using the photoresist film as an etching mask, thereby forming the gate oxide film patterns 102 a, the first polysilicon film patterns 104 a, the first tungsten film patterns 106 a, and the first nitride film patterns 108 a.
- the gate electrodes 110 serve as word lines for a semiconductor device that is formed on the substrate 100 .
- the photoresist pattern is removed via a plasma ashing process and a stripping process using sulfuric acid.
- the gate electrodes 110 are formed using the etching process, a great quantity of polymers (P) is attached to sidewalls of the gate electrodes 110 .
- the polymers (P) are generated during the etching of the photoresist pattern, the first nitride film 108 , the first tungsten film 106 , the first polysilicon film 104 , and the gate oxide film 102 .
- the polymers (P) may increase the electrical resistance of the transistor including the first tungsten film patterns 106 a so they should be removed from the gate electrodes 110 .
- a cleaning bath including a cleaning solution is provided.
- the cleaning solution includes about 5 to about 7 percent by weight of sulfuric acid, about 2.5 percent by weight of aqueous hydrogen peroxide solution and about 90.5 to about 92.5 percent by weight of hydrogen fluoric acid solution.
- the hydrogen fluoric acid solution includes about 0.1 to about 2 ml of hydrogen fluoric acid and about 1,000 ml of deionized water wherein the hydrogen fluoric acid has a concentration of about 50 percent.
- the substrate 100 including the polymers (P) attached thereto is immersed in the cleaning solution having a temperature of about 20 to about 30° C. for about 1 to about 9 minutes so that the polymers (P) are removed from the gate electrodes 110 .
- the polymers (P) include organic polymers, metallic polymers, and oxygen-containing polymers.
- the organic and metallic polymers are first attached on the sidewalls of the gate electrodes 110 when the tungsten film patterns 106 a are formed.
- the oxygen-containing polymers are attached to the metallic polymers and the sidewalls of the first tungsten film patterns 106 a when the gate film patterns 102 a are formed.
- the substrate 100 including the gate electrodes 110 is immersed in the cleaning solution bath.
- the oxygen-containing polymers are first removed from the sidewalls of the gate electrodes 110 using the hydrogen fluoric acid included in the cleaning solution.
- the organic polymers and the metallic polymers are exposed.
- the organic and metallic polymers are removed from the gate electrodes 110 using the aqueous hydrogen peroxide solution and the sulfuric acid contained in the cleaning solution without damage to the first tungsten film patterns 106 a.
- the cleaning solution has a temperature of below about 20° C.
- the time required for removing the polymers (P) attached to the gate electrodes 110 is greatly increased.
- the cleaning solution has a temperature of above about 30° C.
- the gate electrodes 110 and the gate oxide film patterns may be damaged although the polymers (P) are rapidly removed from the gate electrodes 110 . Therefore, the cleaning solution advantageously has a temperature of about 25° C.
- the substrate 100 including the gate electrodes 110 is taken out of the cleaning solution, the substrate 100 is rinsed using deionized water to remove the remaining cleaning solution.
- the substrate 100 is taken out of the cleaning solution, most polymers (P) are dissolved by components contained in the cleaning solution and removed from the gate electrodes 110 , the polymers (P) are detached from the gate electrodes 110 , or the adhesion strength between the gate electrodes 110 and the polymers (P) is greatly reduced. Hence, the polymers (P) remaining on the substrate 100 are completely removed during the rinsing process using deionized water.
- a dry process is performed on the rinsed substrate 100 to remove the deionized water remaining on the substrate 100 .
- various polymers can be completely removed from the gate electrodes without the damages of the gate oxide film patterns 102 and the first tungsten film patterns 106 a.
- nitride spacers 112 are formed on the sidewalls of the gate electrodes 110 . Impurities are implanted into portions of the substrate 100 between the gate electrodes 110 using the gate electrodes 110 as masks, thereby forming source/drain regions 114 a and 114 b between the gate electrodes 110 . Thus, transistor structures including the gate electrodes 110 , the spacers 112 , and the source/drain regions 114 a and 114 b are formed on the substrate 100 .
- the source regions 114 a of the transistor structures correspond to contact regions of capacitors and the drain regions 114 b of the transistor structures correspond to contact regions of bit lines.
- FIGS. 8A to 8 E are cross-sectional diagrams illustrating a method of forming a bit line of a semiconductor device according to another embodiment of the invention.
- the processes for forming transistor structures are identical to those of the embodiment described in FIGS. 7A-7D .
- a first oxide film is formed on the substrate 100 where the transistor structures are formed.
- the first oxide film is etched using an etch back process or a CMP process until upper faces of the transistor structures are exposed.
- a first interlayer dielectric film 120 is formed on the substrate 100 to cover the transistor structures.
- the first interlayer dielectric film 120 includes boro-phosphor silicate glass (BPSG), undoped silicate glass (USG), or silicon oxide.
- a portion of the first interlayer dielectric film 120 is anisotropically etched to form a contact hole 122 using the mask pattern as an etching mask.
- the contact hole 122 exposes the drain region 114 a of the transistor structure.
- the contact hole 122 is formed as a self-aligned contact by the spacer 120 in order to ensure a process margin.
- a conductive material like tungsten is formed on the first interlayer dielectric film 120 to fill up the contact hole 122 , and a portion of the conductive material on the first interlayer dielectrics is etched using a CMP process. Hence, a conductive plug 124 is formed in the contact hole 122 . The conductive plug 124 is electrically connected to the drain region 114 b of the transistor structure.
- a bit line 132 is formed on the first interlayer dielectric film 120 where the conductive plug 124 is formed.
- a second polysilicon film 126 , a second tungsten film 128 , and a second nitride film 130 are successively formed on the first interlayer dielectric film 120 in which the conductive plug 124 is formed.
- a second tungsten silicide film can be formed on the second polysilicon film 126 instead of the second tungsten film 128 .
- a barrier layer can be formed between the second polysilicon film 126 and the second tungsten film 128 so as to easily form the second tungsten film 128 on the second polysilicon film 126 .
- the second nitride film 130 , the second tungsten film 128 , and the second polysilicon film 126 are successively etched using a mask pattern (not shown) and a dry etch process to form the bit line 132 including a second nitride film pattern 130 a, a second tungsten film pattern 128 a, and the second polysilicon film pattern 126 a.
- the bit line 132 is positioned on the conductive plug 124 .
- a large quantity of polymers (P) adhere to a sidewall of the bit line 132 .
- the polymers (P) are generated during etching of the second nitride film 130 , the second tungsten film 128 , the second polysilicon film 126 , and the mask pattern.
- the polymers (P) may increase the electrical resistance of the bit line 132 including the second tungsten film pattern 128 a. Therefore, the polymers (P) should be completely removed from the sidewall of the bit line 132 .
- a bath receiving a cleaning solution is prepared.
- the cleaning solution includes about 5 percent by weight of sulfuric acid, about 2.5 percent by weight of aqueous hydrogen peroxide solution, and about 92.5 percent by weight of hydrogen fluoric acid solution.
- the hydrogen fluoric acid solution has about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid.
- the hydrogen fluoric acid has a concentration of about 50 percent.
- the substrate 100 having the resultant structure to which the polymers (P) are attached is immersed in the cleaning solution, which has a temperature of about 20 to about 30° C., for about 1 to about 9 minutes.
- the polymers (P) are removed from the bit line 132 .
- a process for removing the polymers (P) is performed under conditions identical to those of the embodiment described in FIGS. 7A-7D .
- the substrate 100 is taken out of the cleaning solution, the substrate 100 is rinsed using deionized water to remove the cleaning solution remaining on the substrate 100 .
- the substrate 100 is the dried to remove the remaining deionized water on the substrate. Consequently, the polymers (P) are completely removed from the sidewall of the bit line 132 without damage to the first interlayer dielectric film 120 or the second tungsten film pattern 128 a.
- a silicon nitride film having a uniform thickness is continuously formed on the first interlayer dielectric film 120 and on the bit line 132 , and then the silicon nitride film is etched using an etch back process to form a spacer 134 on the sidewall of the bit line.
- a bit line structure including the bit line 132 and the spacer 134 is completed.
- a semiconductor device including the bit line structure can have improved electrical characteristics because the bit line structure can has a second tungsten film pattern 128 a that is damage-free.
- various polymers attached to metal patterns can be easily removed without damage to the metal patterns or the underlying oxide film.
- a throughput of a semiconductor device can be improved by reducing the time required for removing the polymers.
- Embodiments of the invention provide a cleaning solution for removing a polymer that includes about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution, and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution.
- the hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid, wherein the hydrogen fluoric acid has a concentration of about 45 to about 55 percent, and preferably about 50 percent.
- Embodiments of the invention also provide a method of cleaning a semiconductor device. After a cleaning solution is prepared, polymers attached to a metal wiring formed on a substrate are removed.
- the cleaning solution includes about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution.
- the polymers are removed by immersing (or dipping) the substrate into the cleaning solution after a dry etching process is performed to form the metal wiring on the substrate. Then, the substrate is rinsed to remove the remaining cleaning solution and the substrate is dried.
- the cleaning solution has a temperature of about 20 to about 30° C. and the substrate is immersed in the cleaning solution for about 1 to about 9 minutes.
- a method of forming a structure of a semiconductor device A substrate is provided.
- the substrate includes a polysilicon film, a tungsten film, and a nitride film successively formed thereon.
- a mask pattern is formed on the nitride film and structure is formed on the substrate.
- the structure includes a nitride film pattern, a tungsten film pattern, and a polysilicon film pattern formed by dry etching the polysilicon film, the tungsten film, and the nitride film.
- polymers attached to a sidewall of the structure formed on the substrate are removed.
- the polymers are removed by immersing the substrate into the cleaning solution including about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution, and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution.
- the hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid, wherein the hydrogen fluoric acid has a concentration of about 45 to about 55 percent, and preferably about 50 percent.
- the substrate is rinsed to remove the cleaning solution and dried.
- a barrier layer is formed between the polysilicon film and the tungsten film.
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Abstract
In a cleaning solution and a method of cleaning a semiconductor substrate, the cleaning solution includes about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution, and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution. Various polymers attached to a metal wiring formed on a substrate are removed by immersing the substrate into the cleaning solution. The substrate is rinsed to remove the cleaning solution remaining on the substrate. Thus, the polymers can be completely removed without damage to the metal wiring and an underlying oxide film.
Description
- This application is a divisional of U.S. patent application Ser. No. 10/671,245, filed on Sep. 24, 2003, now pending, which is claims priority from Korean Patent Application 2002-80610, filed on Dec. 17, 2002, the contents of which are herein incorporated by reference in their entirety.
- 1. Field of the Invention
- This disclosure relates to a cleaning solution and a method of cleaning a semiconductor device using the same, and more particularly to a cleaning solution for completely removing various polymers attached to a tungsten wiring of a semiconductor device and a method of cleaning a semiconductor device using the same.
- 2. Description of the Related Art
- Recently, semiconductor devices have been greatly improved as information processing apparatus such as a computers are rapidly developed. The semiconductor device is required to have rapid response speed and large storage capacity so that a semiconductor manufacturing process is developed to improve integration density and reliability of the semiconductor device.
- To accomplish high integration density of a semiconductor device, a cell of the semiconductor device should be reduced. In accordance with reduction of the size of the cell, all the patterns formed on a substrate have reduced dimensions and processing margins are also decreased. Hence, the semiconductor device may not have adequate electrical insulation and refresh characteristics. Also, sizes of the patterns are greatly reduced and multi-layered wirings are demanded according as the semiconductor device has high integration density.
- As design rules for semiconductor devices are reduced, a metal having a relative low electrical resistance is used for metal wirings of the semiconductor device instead of a metal having high electrical resistance. For example, tungsten silicide, rather than tungsten, is employed for the metal wiring of the semiconductor device to be used as a gate electrode or a bit line of a volatile or non-volatile memory device.
- As processes of forming a metal wiring and a contact hole for multi-layered metal wirings are more frequently employed in a semiconductor manufacturing process, a dry etch process for etching a metal and an ashing process for removing a photoresist pattern are also frequently performed. When the metal wiring is formed using the dry etch and ashing processes, impurities are generated from a dry etch gas, the photoresist pattern, an oxide film, and a tungsten film and the impurities are attached to a sidewall of the metal wiring. The impurities may increase electrical resistance of a semiconductor device or may cause an electrical short between adjacent metal wirings when the impurities remain on the metal wiring. Thus, these impurities should be removed from the metal wiring.
- Japanese Patent Laid Open Publication No. 10-779366 discloses a method of removing impurities remaining on a substrate using a cleaning solution including about 24 percent by weight of sulfuric acid, about 5 percent by weight of aqueous hydrogen peroxide solution, about 0.02 percent by weight of hydrogen fluoride, about 0.075 percent by weight of N-dodecyl benzene sulfonic acid and water. The impurities on the substrate are removed by immersing the substrate into the cleaning solution for about 10 minutes and rinsing the substrate using deionized water for about 7 minutes.
- Korean Patent Laid Open Publication No. 2000-61342 discloses a method of removing polymers remaining on a substrate by successively using a cleaning solution of sulfuric acid (H2SO4) and aqueous hydrogen peroxide solution (H2O2), a cleaning solution of hydrogen fluoric acid (HF) and water (H2O), and an SCl cleaning solution. The polymers are generated after a dry etch process for forming a tungsten silicide wiring on the substrate.
- Meanwhile, an organic stripper including hydroxylamine is generally used in a cleaning process for removing impurities generated after a process of etching a tungsten wiring because the organic stripper may not cause damages of the tungsten wiring and an underlying film. However, the organic stripper may not completely remove the impurities remaining on a substrate. The organic stripper may not effectively remove oxygen-containing polymers (polymeric oxides) generated during etching of the tungsten wiring so that the impurities are not completely removed from the substrate. Additionally, because the impurities attached to the tungsten wiring are adequately removed from the tungsten wiring for more than about 20 minutes, the time required for removing the impurities may be too long when the impurities are removed using the organic stripper.
- To solve the above-mentioned problems, an improved organic stripper has been developed. The improved organic stripper additionally includes fluorine-containing chemicals like HF or NHF4, an organic solvent, and a corrosion inhibitor. The organic solvent can prevent a metal wiring from being damaged due to the fluorine-containing chemicals. However, the improved organic stripper may not effectively remove polymers generated during etching the metal wiring and the improved organic stripper is very expensive. Also, the improved organic stripper may excessively etch some underlying films to such an extent that the improved organic stripper can hardly be employed for a semiconductor manufacturing process.
- Embodiments of the invention address these and other disadvantages of the conventional art.
- Among other advantages, embodiments of the invention provide a cleaning solution that can effectively remove various polymers attached to tungsten wiring without damage to the tungsten wiring and an underlying film. Additionally, the time required for removing the polymers can be greatly reduced, improving the throughput of the semiconductor device.
- The above and other advantages of the invention will become readily apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings.
-
FIG. 1 is a graph illustrating the etch rate of a tungsten wiring relative to the amount of sulfuric acid contained in a cleaning solution according to embodiments of the invention. -
FIG. 2 is a graph illustrating the etch rate of an oxide film relative to the amount of sulfuric acid contained in a cleaning solution according to embodiments of the invention. -
FIG. 3 is a graph illustrating the etch rate of a tungsten wiring relative to the amount of aqueous hydrogen peroxide solution contained in a cleaning solution according to embodiments of the invention. -
FIG. 4 is a graph illustrating the etch rate of an oxide film relative to the amount of aqueous hydrogen peroxide solution contained in a cleaning solution according to embodiments of the invention. -
FIG. 5 is a graph illustrating the etch rate of an oxide film relative to the cleaning time using an embodiment of the invention. -
FIG. 6A is an electron microscope photograph illustrating a structure including a tungsten wiring cleaned using a conventional cleaning method. -
FIG. 6B is an electron microscope photograph illustrating a structure including a tungsten wiring cleaned in accordance with an embodiment of the invention. -
FIGS. 7A to 7D are cross-sectional diagrams illustrating a method of forming a transistor of a semiconductor device according to an embodiment of the invention. -
FIGS. 8A to 8E are cross-sectional diagrams illustrating a method of forming a bit line of a semiconductor device according to another embodiment of the invention. - Hereinafter, the preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In the following drawings, like reference numerals identify similar or identical elements.
- Cleaning Solution
- A cleaning solution according to embodiments of the invention includes sulfuric acid (H2SO4), aqueous hydrogen peroxide solution (H2O2), deionized water (H2O), and hydrogen fluoric acid (HF) solution. The hydrogen fluoric solution is prepared by diluting hydrogen fluoric acid with deionized water. The cleaning solution efficiently removes various polymers remaining on a metal wiring formed on a substrate without damages of the metal wiring and an underlying film after a dry etch process is performed to form the metal wiring.
- In particular, the cleaning solution has the following characteristics.
- The cleaning solution can prevent damage to a tungsten wiring under an adequately controlled condition even though the sulfuric acid and the aqueous hydrogen peroxide solution contained in the cleaning solution may corrode the tungsten wiring.
- The cleaning solution can completely remove various polymers including metallic components and oxygen-containing components generated during dry etching the tungsten wiring.
- The cleaning solution can adequately etch oxygen-containing polymers while simultaneously preventing the lifting of the tungsten wiring due to en excessive etch of an underlying oxide film. In addition, the cleaning solution can prevent an increase in the aspect ratio of the tungsten wiring and the generation of a void in an interlayer dielectric film by reducing the etching of the interlayer dielectric film.
- To meet the above-mentioned characteristics, cleaning solutions according to embodiments of the invention preferably include about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution, and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution. Therefore, the cleaning solution can effectively remove the polymers generated during a formation of a structure including a tungsten wiring.
- The cleaning solution preferably includes about 1 to about 10 percent by weight of sulfuric acid. If the cleaning solution includes less than about 1 percent by weight of sulfuric acid, the cleaning solution will not cause damage to a tungsten film pattern and an oxide film pattern formed on a substrate. However, the cleaning solution will not easily remove the polymers including metallic by-products and oxides generated during the etching of the tungsten film. When the cleaning solution includes more than about 10 percent by weight of sulfuric acid, although the cleaning solution can easily remove metallic polymers and oxygen-containing polymers generated during a formation of the tungsten film pattern, the cleaning solution may cause damage to the tungsten film pattern and the oxide film pattern. The cleaning solution preferably includes about 1 to about 10 percent by weight, and more preferably, about 3 to about 8 percent by weight of sulfuric acid.
- Because sulfuric acid can easily corrode the tungsten film pattern, an etched amount of the tungsten film pattern can be controlled in accordance with the amount of the sulfuric acid contained in the cleaning solution. Additionally, the sulfuric acid serves as a catalyst that augments the potential of hydrogen (pH) of the cleaning solution to more rapidly dissolve the hydrogen fluoric acid. Hence, the oxygen-containing polymers are more easily removed from the tungsten film pattern.
- The cleaning solution preferably includes about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution. When the cleaning solution includes less than about 0.5 percent of by weight of aqueous hydrogen peroxide solution, the metallic polymers and the oxygen-containing polymers are not easily removed although the cleaning solution will not cause damage to the tungsten film pattern and the oxide film pattern. In the case where the cleaning solution includes more than 5 percent by weight of aqueous hydrogen peroxide solution, the cleaning solution may cause the damages of the tungsten film pattern and the oxide film pattern although the cleaning solution will easily remove the metallic polymers and the oxygen-containing polymers. Therefore, the cleaning solution preferably includes about 0.5 to about 5, and more preferably about 1 to about 3 percent by weight of aqueous hydrogen peroxide solution. Here, the aqueous hydrogen peroxide solution has a concentration of about 25 to about 30 percent.
- The amount of hydrogen fluoric acid solution contained in the cleaning solution varies in accordance with the concentration of the hydrogen fluoric acid after dilution with deionized water. The hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid. In this case, the hydrogen fluoric acid solution has a concentration of about 50 percent. The cleaning solution preferably includes about 85 to about 95 percent by weight of hydrogen fluoric acid solution.
- When the cleaning solution includes less than about 85 percent by weight of hydrogen fluoric acid solution or the amount of hydrogen fluoric acid contained in the hydrogen fluoric acid solution is less than 0.1 ml, the cleaning solution may not remove the oxygen-containing polymers.
- When the cleaning solution includes more than 95 percent by weight of hydrogen fluoric acid solution or the amount of hydrogen fluoric acid contained in the hydrogen fluoric acid solution is more than 2 ml, the cleaning solution may cause damage to the tungsten film pattern and the oxide film pattern although the cleaning solution can easily remove the oxygen-containing polymers and the metallic polymers.
- Thus, the cleaning solution preferably includes a hydrogen fluoric acid solution of about 85 to about 95 percent by weight. Here, the hydrogen fluoric acid has a concentration of 50 percent and the hydrogen fluoric acid solution includes about 0.1 to about 2 ml of hydrogen fluoric acid and about 1,000 ml of deionized water.
-
FIG. 1 is a graph illustrating an etch rate of a tungsten wiring relative to the amount of sulfuric acid contained in a cleaning solution according embodiments of the invention. - Referring to
FIG. 1 , the etch rate of the tungsten wiring increases from about 70 to about 330 Å/min as the amount of sulfuric acid contained in the cleaning solution is augmented from about 1 to about 10 percent by weight. Here, a substrate including the tungsten wiring was immersed in the cleaning solution having a temperature of about 25° C. for about 10 minutes. - When the amount of the sulfuric acid contained in the cleaning solution was more than about 5 percent by weight, the etch rate of the tungsten wiring rapidly increased. In order to easily control the etch rate of the tungsten wiring, the amount of the sulfuric acid contained in the cleaning solution is preferably no more than about 5 percent by weight.
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FIG. 2 is a graph illustrating an etch rate of an oxide film relative to the amount of sulfuric acid contained a cleaning solution according to embodiments of the invention. - Referring to
FIG. 2 , the etch rate of the oxide film increases from about 150 to about 300 Å/min as the amount of sulfuric acid contained in the cleaning solution increases from about 1 to about 10 percent by weight. In this case, a substrate including the oxide wiring was immersed in the cleaning solution having a temperature of about 25° C. for about 10 minutes. - Although the sulfuric acid cannot directly etch the oxide film, the sulfuric acid serves as a catalyst that can more rapidly dissociate hydrogen fluoric acid contained in the cleaning solution because the acidity of the cleaning solution increases in accordance with an increase of the amount of sulfuric acid contained in the cleaning solution. When the hydrogen fluoric acid is dissociated, it can more easily etch the oxide film and oxygen-containing polymers.
-
FIG. 3 is a graph illustrating an etch rate of a tungsten wiring relative to the amount of aqueous hydrogen peroxide solution contained in a cleaning solution according to embodiments of the invention. - Referring to
FIG. 3 , the etch rate of the tungsten wiring increases from about 50 to about 90 Å/min as the amount of the aqueous hydrogen peroxide solution contained in the cleaning solution increases from about 2.5 to about 5 percent by weight at a temperature of about 25° C. Additionally, at a temperature of about 32.5° C., as the amount of the aqueous hydrogen peroxide solution contained in the cleaning solution increases from about 2.5 to about 5 percent by weight, the etch rate of the tungsten wiring increases from about 120 to about 200 Å/min. Here, the substrate including the tungsten wiring was immersed in the cleaning solution for about 10 minutes. - As described above, a temperature variation of the cleaning solution has a greater effect on the etch rate of the tungsten wiring than the amount of the aqueous hydrogen peroxide solution or the sulfuric acid. Accordingly, in order to more easily control the etch rate of the tungsten wiring, the temperature of the cleaning solution is preferably maintained at about 25° C. while the amounts of the aqueous hydrogen peroxide solution and the sulfuric acid are selectively adjusted.
-
FIG. 4 is a graph illustrating an etch rate of an oxide film relative to the amount of aqueous hydrogen peroxide solution contained a cleaning solution according to embodiments of the invention. - Referring to
FIG. 4 , at a temperature of about 25° C., the etch rate of the oxide film increases from about 150 to about 170 Å/min as the amount of the aqueous hydrogen peroxide solution contained in the cleaning solution increases from about 2.5 to about 5 percent by weight. In addition, at a temperature of about 32.5° C., as the amount of the aqueous hydrogen peroxide solution contained in the cleaning solution increases from about 2.5 to about 5 percent by weight, the etch rate of the oxide film increases from about 180 to about 210 Å/min. In this case, a substrate including the oxide film was immersed in the cleaning solution for about 10 minutes. - When the amount of aqueous hydrogen peroxide solution contained in the cleaning solution increases, the etch rate of the oxide film gradually increases because the aqueous hydrogen peroxide solution does not directly etch the oxide film but serves as a catalyst for etching the oxide film.
- Because the etch rate of the oxide film is more proportional to the temperature of the cleaning solution than the amount of the aqueous hydrogen peroxide solution contained in the cleaning solution, the temperature of the cleaning solution is maintained at about 25° C. while the amounts of sulfuric acid and aqueous hydrogen peroxide solution contained in the cleaning solution are selectively adjusted in order to easily control the etch rate of the oxide film.
- According to embodiments of the invention, because the etch rates of the tungsten wiring and the oxide film vary greatly in accordance with the temperature of the cleaning solution and the amounts of the sulfuric acid and the aqueous hydrogen peroxide solution contained in the cleaning solution, the temperature of the cleaning solution and the amounts of etchant and catalyst are advantageously controlled to achieve pertinent etching of a metal wiring or an insulation film.
- Method for Cleaning a Tungsten Wiring
- In a process for cleaning polymers that remain on a tungsten wiring, a cleaning solution is provided in a cleaning bath. The cleaning solution includes about 5 percent by weight of sulfuric acid, about 2.5 percent by weight of aqueous hydrogen peroxide solution and about 92.5 percent by weight of hydrogen fluoric acid solution. Here, the hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid. The hydrogen fluoric acid has a concentration of about 50 percent.
- After a dry etch process is performed on a substrate that includes an oxide film and the tungsten wiring, the substrate is immersed in the cleaning solution. In this case, organic, metallic, and oxygen-containing polymers adhere to the tungsten wiring and the oxide film. The oxygen-containing polymers positioned on an outer sidewall of the tungsten wiring are first removed with the hydrogen fluoric acid contained in the cleaning solution. The tungsten wiring includes, for example, tungsten patterns.
- When the oxygen-containing polymers are removed, the organic and metallic polymers are exposed. The organic and metallic polymers are removed by the aqueous hydrogen peroxide solution and sulfuric acid contained in the cleaning solution without damage to the tungsten wiring.
- When a temperature of the cleaning solution is below about 20° C., the time required for completely removing the polymers from the sidewall of the tungsten wiring is greatly increased. To the contrary, when the cleaning solution has a temperature above about 30° C., damage to the tungsten wiring and an underlying layer may be caused even though the polymers may be rapidly removed from the tungsten wiring. Accordingly, the cleaning solution preferably has a temperature of about 25° C. to remove the polymers from the tungsten wiring.
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FIG. 5 is a graph illustrating the etch rate of an oxide film relative to the cleaning time using a cleaning solution according to an embodiment of the invention. InFIG. 5 , when the tungsten wiring including the polymers was cleaned, the etched amount of the oxide film formed beneath the tungsten wiring was observed by varying the cleaning time of the tungsten wiring so that the etch rate was measured in order to identify an advantageous cleaning time for the tungsten wiring. - Referring to
FIG. 5 , the polymers could be more completely removed from the tungsten wiring as the cleaning time increased, however, the underlying oxide film was excessively etched during removal of the polymers. That is, when the cleaning time increased from about 1 to about 10 minutes, the etch rate of the oxide film increased from about 30 to about 200 Å. Thus, a process for cleaning the tungsten wiring is preferably executed with a cleaning time of below about 9 minutes. - After the process for cleaning the tungsten wiring is accomplished, the substrate including the tungsten wiring is taken out of the cleaning solution. Then, the substrate is rinsed using deionized water to remove the cleaning solution remaining on the substrate. When the substrate is taken out of the cleaning solution, most polymers are dissolved in the cleaning solution or detached from the tungsten wiring so that most polymers are removed from the substrate or bond strengths between the polymers and the tungsten wiring are greatly reduced. Therefore, the polymers are cleaned from the substrate and the tungsten wiring when the rinsing process is performed on the substrate.
- The substrate is dried to remove the remaining deionized water.
- According to the method for cleaning the tungsten wiring, the polymers can be effectively removed from the tungsten wiring without damage to the tungsten wiring.
-
FIG. 6A is an electron microscope photograph illustrating a structure including a tungsten wiring that was cleaned using a conventional cleaning method.FIG. 6B is an electron microscope photograph illustrating a structure including a tungsten wiring cleaned employing a cleaning method according to an embodiment of the invention. - Referring to
FIG. 6A , oxygen-containing polymers are not sufficiently removed from the tungsten wiring and also damage of the tungsten wiring (region A) was caused when the tungsten wiring was cleaned using the conventional method. As shown inFIG. 6B , however, when the tungsten wiring is cleaned according to an-embodiment of the invention, the polymers generated during etching of the tungsten wiring and during ashing of a photoresist pattern were completely removed from the tungsten wiring. Also, damage to the tungsten wiring and the underlying oxide film are not nearly as severe. - Hereinafter, a method of forming a structure of a semiconductor device will be described with reference to the accompanying drawings.
-
FIGS. 7A to 7D are cross-sectional diagrams illustrating a method of forming a transistor of a semiconductor device according to an embodiment of the invention. - Referring to
FIG. 7A , an isolation process such as a shallow trench isolation (STI) process or a local oxidation of silicon (LOCOS) is performed on asubstrate 100 to define an active region and afield region 100 b. Preferably, the active andfield regions 100 b are defined using the STI process. - Particularly, the
substrate 100 is partially etched to form a trench at a portion of thesubstrate 100 corresponding to thefield region 100 b. After a silicon oxide film is formed on thesubstrate 100 and fills up the trench, the silicon oxide film is etched using a chemical mechanical polishing (CMP) process, thereby forming a filed oxide film in the trench to define thefield region 100 b. - Referring to
FIG. 7B , after impurities are selectively implanted into portions of thesubstrate 100 to from a P-type well and an N-type well on thesubstrate 100,gate electrodes 110 are formed on thesubstrate 100. Thegate electrodes 110 include gateoxide film patterns 102 a, firstpolysilicon film pattern 104 a, firsttungsten film patterns 106 a, and firstnitride film patterns 108 a, respectively. - Particularly, a
gate oxide film 102 having a thickness of about 50 to about 100 Å is formed on thesubstrate 100. Afirst polysilicon film 104 doped with N-type impurities is formed on thegate oxide film 102 to a thickness of about 1,000 to about 1,500 Å. Afirst tungsten film 106 is formed on thefirst polysilicon film 104 in order to reduce a resistance of thegate electrode 110. Alternatively, a first tungsten silicide film can be formed on thefirst polysilicon film 104 instead of thefirst tungsten film 106. Afirst nitride film 108 is formed on thetungsten film 106. Alternatively, a barrier layer can be formed between thefirst polysilicon film 104 and thefirst tungsten film 106 so as to easily form thefirst tungsten film 106. After a photoresist pattern (not shown) is formed on thefirst nitride film 108 to define a layout of thegate electrodes 110, thefirst nitride film 108, thefirst tungsten film 106, thefirst polysilicon film 104, and thegate oxide film 102 are successively etched using the photoresist film as an etching mask, thereby forming the gateoxide film patterns 102 a, the firstpolysilicon film patterns 104 a, the firsttungsten film patterns 106 a, and the firstnitride film patterns 108 a. As a result, thegate electrodes 110 serve as word lines for a semiconductor device that is formed on thesubstrate 100. The photoresist pattern is removed via a plasma ashing process and a stripping process using sulfuric acid. - When the
gate electrodes 110 are formed using the etching process, a great quantity of polymers (P) is attached to sidewalls of thegate electrodes 110. The polymers (P) are generated during the etching of the photoresist pattern, thefirst nitride film 108, thefirst tungsten film 106, thefirst polysilicon film 104, and thegate oxide film 102. The polymers (P) may increase the electrical resistance of the transistor including the firsttungsten film patterns 106 a so they should be removed from thegate electrodes 110. - Referring to
FIG. 7C , in order to remove the polymers (P) attached to the sidewalls of thegate electrodes 110 including the firsttungsten film patterns 106 a, a cleaning bath including a cleaning solution is provided. The cleaning solution includes about 5 to about 7 percent by weight of sulfuric acid, about 2.5 percent by weight of aqueous hydrogen peroxide solution and about 90.5 to about 92.5 percent by weight of hydrogen fluoric acid solution. In this case, the hydrogen fluoric acid solution includes about 0.1 to about 2 ml of hydrogen fluoric acid and about 1,000 ml of deionized water wherein the hydrogen fluoric acid has a concentration of about 50 percent. - The
substrate 100 including the polymers (P) attached thereto is immersed in the cleaning solution having a temperature of about 20 to about 30° C. for about 1 to about 9 minutes so that the polymers (P) are removed from thegate electrodes 110. - In particular, the polymers (P) include organic polymers, metallic polymers, and oxygen-containing polymers. The organic and metallic polymers are first attached on the sidewalls of the
gate electrodes 110 when thetungsten film patterns 106 a are formed. The oxygen-containing polymers are attached to the metallic polymers and the sidewalls of the firsttungsten film patterns 106 a when thegate film patterns 102 a are formed. - To remove these polymers (P), the
substrate 100 including thegate electrodes 110 is immersed in the cleaning solution bath. The oxygen-containing polymers are first removed from the sidewalls of thegate electrodes 110 using the hydrogen fluoric acid included in the cleaning solution. - When the oxygen-containing polymers are removed, the organic polymers and the metallic polymers are exposed. The organic and metallic polymers are removed from the
gate electrodes 110 using the aqueous hydrogen peroxide solution and the sulfuric acid contained in the cleaning solution without damage to the firsttungsten film patterns 106 a. - In cases where the cleaning solution has a temperature of below about 20° C., the time required for removing the polymers (P) attached to the
gate electrodes 110 is greatly increased. On the other hand, when the cleaning solution has a temperature of above about 30° C., thegate electrodes 110 and the gate oxide film patterns may be damaged although the polymers (P) are rapidly removed from thegate electrodes 110. Therefore, the cleaning solution advantageously has a temperature of about 25° C. - After the
substrate 100 including thegate electrodes 110 is taken out of the cleaning solution, thesubstrate 100 is rinsed using deionized water to remove the remaining cleaning solution. When thesubstrate 100 is taken out of the cleaning solution, most polymers (P) are dissolved by components contained in the cleaning solution and removed from thegate electrodes 110, the polymers (P) are detached from thegate electrodes 110, or the adhesion strength between thegate electrodes 110 and the polymers (P) is greatly reduced. Hence, the polymers (P) remaining on thesubstrate 100 are completely removed during the rinsing process using deionized water. - Then, a dry process is performed on the rinsed
substrate 100 to remove the deionized water remaining on thesubstrate 100. In this case, various polymers can be completely removed from the gate electrodes without the damages of the gateoxide film patterns 102 and the firsttungsten film patterns 106 a. - Referring to
FIG. 7D ,nitride spacers 112 are formed on the sidewalls of thegate electrodes 110. Impurities are implanted into portions of thesubstrate 100 between thegate electrodes 110 using thegate electrodes 110 as masks, thereby forming source/drain regions gate electrodes 110. Thus, transistor structures including thegate electrodes 110, thespacers 112, and the source/drain regions substrate 100. - In this embodiment, the
source regions 114 a of the transistor structures correspond to contact regions of capacitors and thedrain regions 114 b of the transistor structures correspond to contact regions of bit lines. -
FIGS. 8A to 8E are cross-sectional diagrams illustrating a method of forming a bit line of a semiconductor device according to another embodiment of the invention. In this embodiment, the processes for forming transistor structures are identical to those of the embodiment described inFIGS. 7A-7D . - Referring to
FIG. 8A , a first oxide film is formed on thesubstrate 100 where the transistor structures are formed. The first oxide film is etched using an etch back process or a CMP process until upper faces of the transistor structures are exposed. Thus, a firstinterlayer dielectric film 120 is formed on thesubstrate 100 to cover the transistor structures. The firstinterlayer dielectric film 120 includes boro-phosphor silicate glass (BPSG), undoped silicate glass (USG), or silicon oxide. - After a mask pattern (not shown) is formed on the first
interlayer dielectric film 120, a portion of the firstinterlayer dielectric film 120 is anisotropically etched to form acontact hole 122 using the mask pattern as an etching mask. Thecontact hole 122 exposes thedrain region 114 a of the transistor structure. Thecontact hole 122 is formed as a self-aligned contact by thespacer 120 in order to ensure a process margin. - Referring to
FIG. 8B , a conductive material like tungsten is formed on the firstinterlayer dielectric film 120 to fill up thecontact hole 122, and a portion of the conductive material on the first interlayer dielectrics is etched using a CMP process. Hence, aconductive plug 124 is formed in thecontact hole 122. Theconductive plug 124 is electrically connected to thedrain region 114 b of the transistor structure. - Referring to
FIG. 8C , abit line 132 is formed on the firstinterlayer dielectric film 120 where theconductive plug 124 is formed. In a process of forming thebit line 132, asecond polysilicon film 126, asecond tungsten film 128, and asecond nitride film 130 are successively formed on the firstinterlayer dielectric film 120 in which theconductive plug 124 is formed. Alternatively, a second tungsten silicide film can be formed on thesecond polysilicon film 126 instead of thesecond tungsten film 128. In addition, a barrier layer can be formed between thesecond polysilicon film 126 and thesecond tungsten film 128 so as to easily form thesecond tungsten film 128 on thesecond polysilicon film 126. - Referring to
FIG. 8D , thesecond nitride film 130, thesecond tungsten film 128, and thesecond polysilicon film 126 are successively etched using a mask pattern (not shown) and a dry etch process to form thebit line 132 including a secondnitride film pattern 130 a, a secondtungsten film pattern 128 a, and the secondpolysilicon film pattern 126 a. Thebit line 132 is positioned on theconductive plug 124. When the dry etch process is accomplished, a large quantity of polymers (P) adhere to a sidewall of thebit line 132. The polymers (P) are generated during etching of thesecond nitride film 130, thesecond tungsten film 128, thesecond polysilicon film 126, and the mask pattern. The polymers (P) may increase the electrical resistance of thebit line 132 including the secondtungsten film pattern 128 a. Therefore, the polymers (P) should be completely removed from the sidewall of thebit line 132. - Referring to
FIG. 8E , in order to remove the polymers (P) attached to the sidewall of thebit line 132 having the secondtungsten film pattern 128 a, a bath receiving a cleaning solution is prepared. The cleaning solution includes about 5 percent by weight of sulfuric acid, about 2.5 percent by weight of aqueous hydrogen peroxide solution, and about 92.5 percent by weight of hydrogen fluoric acid solution. In this case, the hydrogen fluoric acid solution has about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid. The hydrogen fluoric acid has a concentration of about 50 percent. - The
substrate 100 having the resultant structure to which the polymers (P) are attached is immersed in the cleaning solution, which has a temperature of about 20 to about 30° C., for about 1 to about 9 minutes. Thus, the polymers (P) are removed from thebit line 132. Here, a process for removing the polymers (P) is performed under conditions identical to those of the embodiment described inFIGS. 7A-7D . - After the
substrate 100 is taken out of the cleaning solution, thesubstrate 100 is rinsed using deionized water to remove the cleaning solution remaining on thesubstrate 100. - The
substrate 100 is the dried to remove the remaining deionized water on the substrate. Consequently, the polymers (P) are completely removed from the sidewall of thebit line 132 without damage to the firstinterlayer dielectric film 120 or the secondtungsten film pattern 128 a. - A silicon nitride film having a uniform thickness is continuously formed on the first
interlayer dielectric film 120 and on thebit line 132, and then the silicon nitride film is etched using an etch back process to form aspacer 134 on the sidewall of the bit line. Thus, a bit line structure including thebit line 132 and thespacer 134 is completed. In this embodiment, a semiconductor device including the bit line structure can have improved electrical characteristics because the bit line structure can has a secondtungsten film pattern 128 a that is damage-free. - According to embodiments of the invention, various polymers attached to metal patterns can be easily removed without damage to the metal patterns or the underlying oxide film. In addition, a throughput of a semiconductor device can be improved by reducing the time required for removing the polymers.
- Embodiments of the invention will now be described in a non-limiting way.
- Embodiments of the invention provide a cleaning solution for removing a polymer that includes about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution, and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution. The hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid, wherein the hydrogen fluoric acid has a concentration of about 45 to about 55 percent, and preferably about 50 percent.
- Embodiments of the invention also provide a method of cleaning a semiconductor device. After a cleaning solution is prepared, polymers attached to a metal wiring formed on a substrate are removed. The cleaning solution includes about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution. The polymers are removed by immersing (or dipping) the substrate into the cleaning solution after a dry etching process is performed to form the metal wiring on the substrate. Then, the substrate is rinsed to remove the remaining cleaning solution and the substrate is dried. In this case, the cleaning solution has a temperature of about 20 to about 30° C. and the substrate is immersed in the cleaning solution for about 1 to about 9 minutes.
- In accordance with another embodiment of the invention, there is provides a method of forming a structure of a semiconductor device. A substrate is provided. The substrate includes a polysilicon film, a tungsten film, and a nitride film successively formed thereon. Subsequently, a mask pattern is formed on the nitride film and structure is formed on the substrate. The structure includes a nitride film pattern, a tungsten film pattern, and a polysilicon film pattern formed by dry etching the polysilicon film, the tungsten film, and the nitride film. After the mask pattern is removed, polymers attached to a sidewall of the structure formed on the substrate are removed. The polymers are removed by immersing the substrate into the cleaning solution including about 1 to about 10 percent by weight of sulfuric acid, about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution, and about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution. In this case, the hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid, wherein the hydrogen fluoric acid has a concentration of about 45 to about 55 percent, and preferably about 50 percent. Then, the substrate is rinsed to remove the cleaning solution and dried. Alternatively, a barrier layer is formed between the polysilicon film and the tungsten film.
- Having described several exemplary embodiments of the invention, it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made to the particular embodiments of the invention disclosed that are nevertheless within the scope and the spirit of the invention as outlined by the appended claims.
Claims (2)
1. A cleaning solution for removing a polymer comprising:
about 1 to about 10 percent by weight of sulfuric acid;
about 0.5 to about 5 percent by weight of aqueous hydrogen peroxide solution; and
about 85 to about 98.5 percent by weight of hydrogen fluoric acid solution.
2. The cleaning solution of claim 1 , wherein the hydrogen fluoric acid solution includes about 1,000 ml of deionized water and about 0.1 to about 2 ml of hydrogen fluoric acid, wherein the hydrogen fluoric acid has a concentration of about 45 to about 55 percent.
Priority Applications (1)
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US11/070,645 US20050139233A1 (en) | 2002-12-17 | 2005-03-02 | Cleaning solution and method of cleaning a semiconductor device using the same |
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KR10-2002-0080610A KR100505044B1 (en) | 2002-12-17 | 2002-12-17 | Cleaning Solution and Method of Cleaning semiconductor device |
KR2002-80610 | 2002-12-17 | ||
US10/671,245 US6875706B2 (en) | 2002-12-17 | 2003-09-24 | Cleaning solution and method of cleaning a semiconductor device using the same |
US11/070,645 US20050139233A1 (en) | 2002-12-17 | 2005-03-02 | Cleaning solution and method of cleaning a semiconductor device using the same |
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US11/070,645 Abandoned US20050139233A1 (en) | 2002-12-17 | 2005-03-02 | Cleaning solution and method of cleaning a semiconductor device using the same |
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Cited By (3)
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US20100267225A1 (en) * | 2009-04-15 | 2010-10-21 | Lee Hyo-San | Method of manufacturing semiconductor device |
US8759183B2 (en) | 2012-01-03 | 2014-06-24 | Samsung Electronics Co., Ltd. | Methods of forming semiconductor devices using electrolyzed sulfuric acid (ESA) |
CN111029887A (en) * | 2019-12-19 | 2020-04-17 | 北京航天控制仪器研究所 | Device and method for stripping polyimide copper-clad wire coating layer |
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TWI229917B (en) * | 2003-09-09 | 2005-03-21 | Nanya Technology Corp | Interconnect process and method for removing silicide |
KR100795364B1 (en) * | 2004-02-10 | 2008-01-17 | 삼성전자주식회사 | Composition for cleaning a semiconductor substrate, method of cleaning and method for manufacturing a conductive structure using the same |
US7387927B2 (en) * | 2004-09-10 | 2008-06-17 | Intel Corporation | Reducing oxidation under a high K gate dielectric |
KR100778851B1 (en) * | 2005-12-28 | 2007-11-22 | 동부일렉트로닉스 주식회사 | Method For Fabricating Metal-Insulator-Metal Capacitor In Semiconductor Device |
US7579282B2 (en) * | 2006-01-13 | 2009-08-25 | Freescale Semiconductor, Inc. | Method for removing metal foot during high-k dielectric/metal gate etching |
KR100721207B1 (en) * | 2006-05-18 | 2007-05-23 | 주식회사 하이닉스반도체 | Method of removing the ion implanted photoresist |
US20080011322A1 (en) * | 2006-07-11 | 2008-01-17 | Frank Weber | Cleaning systems and methods |
KR100758125B1 (en) * | 2006-12-27 | 2007-09-13 | 동부일렉트로닉스 주식회사 | Method for removing the metal polymer generated during the semiconductor fabricating process |
DE102007030957A1 (en) * | 2007-07-04 | 2009-01-08 | Siltronic Ag | Method for cleaning a semiconductor wafer with a cleaning solution |
US8314022B1 (en) * | 2011-05-20 | 2012-11-20 | Intermolecular, Inc. | Method for etching gate stack |
US20130099330A1 (en) * | 2011-10-25 | 2013-04-25 | Intermolecular, Inc. | Controllable Undercut Etching of Tin Metal Gate Using DSP+ |
US20140179112A1 (en) * | 2012-12-26 | 2014-06-26 | Globalfoundries | High Productivity Combinatorial Techniques for Titanium Nitride Etching |
WO2014205285A1 (en) * | 2013-06-20 | 2014-12-24 | Dow Corning Corporation | Method of removing silicone resin from a substrate |
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US6875706B2 (en) | 2005-04-05 |
KR20040054050A (en) | 2004-06-25 |
KR100505044B1 (en) | 2005-07-29 |
US20040115909A1 (en) | 2004-06-17 |
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