Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/69—Etching of wafers, substrates or parts of devices using masks for semiconductor materials
  • H10P50/691—Etching of wafers, substrates or parts of devices using masks for semiconductor materials for Group V materials or Group III-V materials
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K13/00—Etching, surface-brightening or pickling compositions
  • C09K13/04—Etching, surface-brightening or pickling compositions containing an inorganic acid
  • C09K13/06—Etching, surface-brightening or pickling compositions containing an inorganic acid with organic material
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/20—Dry etching; Plasma etching; Reactive-ion etching
  • H10P50/28—Dry etching; Plasma etching; Reactive-ion etching of insulating materials
  • H10P50/282—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of inorganic materials
  • H10P50/283—Dry etching; Plasma etching; Reactive-ion etching of insulating materials of inorganic materials by chemical means

Definitions

• the present disclosure relates to an etchant for silicon nitride films, an etching method using the same, and a method for manufacturing a semiconductor substrate.
• the SiN film is selectively etched from a substrate having a silicon nitride film (hereinafter also referred to as "SiN film”) and a silicon oxide film (hereinafter also referred to as "SiO 2 film”).
• SiN film silicon nitride film
• SiO 2 film silicon oxide film
• Patent Document 1 discloses an etching method containing at least one silane inorganic acid salt produced by reacting a first inorganic acid, a second inorganic acid and a silane compound with a solvent, and a solvent. have been proposed.
• Patent Document 2 proposes an etching composition containing an inorganic acid, a siloxane compound, an ammonium compound, and a solvent.
• Patent Document 3 proposes an etchant containing an organic phosphonic acid compound, phosphoric acid, and water.
• Patent Document 4 discloses ceria-coated inorganic oxide particles and an ethyleneoxy group.
• a polishing composition comprising a silicone-containing compound having at least one group of (EO) and a propyleneoxy group (PO) and a substituted ethylenediamine group, a nonionic organic molecule having at least two hydroxyl groups, and a solvent. is proposed.
• the present disclosure provides an etchant for removing a silicon nitride film from a substrate having a silicon nitride film and a silicon oxide film, the siloxane compound modified with a compound having an alkyleneoxy group; and water.
• the present disclosure in one aspect, relates to an etching method including removing a silicon nitride film from a substrate having a silicon nitride film and a silicon oxide film using an etchant of the present disclosure.
• the present disclosure includes, in one aspect, using an etchant of the present disclosure to remove a silicon nitride film from a substrate having a silicon nitride film and a silicon oxide film, the substrate being a substrate for use in semiconductors.
• the present invention relates to a method for manufacturing a semiconductor substrate.
• silica SiO 2
• an etchant capable of suppressing deposition and adhesion on the SiO 2 film even when the concentration of silica generated during the etching process is high (for example, 200 ppm).
• the present disclosure provides an etchant that can suppress deposition and adhesion of silica generated during an etching process to a silicon oxide film, an etching method using the same, and a method for manufacturing a semiconductor substrate.
• an etchant capable of suppressing deposition and adhesion of silica generated during an etching process to a silicon oxide film.
• the present disclosure provides an etchant for removing a silicon nitride film from a substrate having a silicon nitride film and a silicon oxide film, the siloxane compound modified with a compound having an alkyleneoxy group. , phosphoric acid, and water (hereinafter also referred to as “etching solution of the present disclosure”). According to the etching solution of the present disclosure, it is possible to suppress deposition and adhesion of silica generated during the etching process to the silicon oxide film.
• a siloxane compound modified with a compound having an alkyleneoxy group for example, a siloxane compound represented by formula (II) is adsorbed on the Si(OH) 4 , silica or SiO2 film surface generated during the etching process. do.
• a siloxane compound represented by formula (II) when it is adsorbed on the SiO2 film surface, it suppresses the deposition and adhesion of silica by a protective film action, and when it adheres to silica, it suppresses the adhesion of silica by repulsion with the siloxane compound adsorbed on the SiO2 film surface. Conceivable.
• the present disclosure need not be construed as being limited to these mechanisms.
• the etching solution of the present disclosure in one or more embodiments, can be prepared by blending a siloxane compound modified with a compound having an alkyleneoxy group, phosphoric acid, water, and optionally optional ingredients. That is, in one or more embodiments, the etching solution of the present disclosure is obtained by blending a siloxane compound modified with a compound having an alkyleneoxy group, phosphoric acid, and water.
• “composed of” means that optional components can be blended as necessary in addition to the siloxane compound modified with a compound having an alkyleneoxy group, phosphoric acid, and water.
• the compounding amount of each component in the etching solution can be read as the content in the etching solution.
• the etching solution of the present disclosure contains a siloxane compound modified with a compound having an alkyleneoxy group.
• the etching solution of the present disclosure contains a siloxane compound modified with a compound having an alkyleneoxy group.
• the siloxane compound modified with the compound having an alkyleneoxy group may be used singly or in combination of two or more.
• the alkyleneoxy group include at least one selected from an ethyleneoxy group (EO) and a propyleneoxy group (PO), and EO is preferred from the viewpoint of suppressing precipitation and adhesion of silica to the SiO 2 film.
• the siloxane compound modified with a compound having an alkyleneoxy group in the present disclosure is a siloxane compound having a structure represented by the following formula (I) from the viewpoint of suppressing the deposition and adhesion of silica to the SiO 2 film.
• a siloxane compound represented by the following formula (II) is preferred, and more preferred.
• R is an alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an anionic group.
• t is 1 or more and 50 or less, and r is 1 or more and 30 or less.
• R is an alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an anionic group.
• t/(s+t) ⁇ 100 is 4 or more, and r is 1 or more and 30 or less.
• the anionic group includes, for example, a phosphonic acid group, a sulfate group, a carboxylic acid group or a phosphoric acid group (--O--PO--(OH) 2 ).
• R in the formulas (I) and ( II ) is an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or An anionic group is preferred, a methyl group, a methoxy group or a phosphate group is more preferred, and a phosphate group is even more preferred.
• t / (s + t) ⁇ 100 is 4 or more, preferably 7 or more, more preferably 10 or more, and 15 or more, from the viewpoint of suppressing deposition and adhesion of silica to the SiO 2 film. is more preferably 20 or more, more preferably 30 or more, still more preferably 40 or more, and preferably 100 or less, more preferably 80 or less, even more preferably 70 or less, and even more preferably 60 or less. From the same point of view, t/(s+t) ⁇ 100 is preferably 4 or more and 100 or less, more preferably 7 or more and 100 or less.
• t is preferably 1 or more and 50 or less, more preferably 1 or more and 30 or less, from the same viewpoint.
• r is 1 or more and 30 or less, preferably 1 or more and 25 or less, more preferably 3 or more and 20 or less, from the same viewpoint.
• the HLB of the siloxane compound modified with the compound having an alkyleneoxy group is preferably 4 or more, more preferably 5 or more, and even more preferably 10 or more from the viewpoint of suppressing deposition and adhesion of silica to the SiO 2 film.
• HLB is Davis, J. T.; Proc. Intern. Congr. Surface Activity, 2nd, London, 1, 426 (1957). It is a value defined by "sum of radix numbers - sum of radix numbers of lipophilic groups".
• siloxane compound modified with a compound having an alkyleneoxy group examples include PEG-7 dimethicone phosphate (HLB: 14.6), PEG-3 dimethicone (HLB: 4.5), PEG-10 dimethicone (HLB : 4.5 or 14) and trisiloxane ethoxylate (HLB: 5.4).
• the amount of the siloxane compound modified with the compound having an alkyleneoxy group in the etching solution of the present disclosure is preferably 0.03% by mass or more from the viewpoint of suppressing deposition and adhesion of silica to the SiO 2 film, and 0.03% by mass or more. 04% by mass or more is more preferable, and 0.05% by mass or more is still more preferable, and from the same viewpoint, 0.2% by mass or less is preferable, 0.15% by mass or less is more preferable, and 0.1% by mass or less is preferable. is more preferred.
• the amount of the siloxane compound modified with the compound having an alkyleneoxy group in the etching solution of the present disclosure is preferably 0.03% by mass or more and 0.2% by mass or less, and 0.04% by mass or more. 0.15% by mass or less is more preferable, and 0.05% by mass or more and 0.1% by mass or less is even more preferable.
• the siloxane compound modified with the compound having an alkyleneoxy group is a combination of two or more
• the blending amount of the siloxane compound modified with the compound having an alkyleneoxy group refers to the total blending amount thereof.
• the amount of the siloxane compound modified with the compound having an alkyleneoxy group in the etching solution of the present disclosure is from the viewpoint of improving the etching rate ratio of the silicon nitride film to the silicon oxide film (SiN / SiO 2 selection rate ratio). , preferably 0.01% by mass or more, more preferably 0.02% by mass or more, still more preferably 0.03% by mass or more, and from the same viewpoint, preferably 0.2% by mass or less, 0.1% by mass % or less is more preferable, 0.08 mass % or less is still more preferable, and 0.05 mass % or less is even more preferable.
• the amount of the siloxane compound modified with the compound having an alkyleneoxy group in the etching solution of the present disclosure is preferably 0.01% by mass or more and 0.2% by mass or less, and 0.02% by mass or more. 0.1 mass % or less is more preferable, 0.03 mass % or more and 0.08 mass % or less is still more preferable, and 0.03 mass % or more and 0.05 mass % or less is still more preferable.
• the amount of phosphoric acid in the etching solution of the present disclosure is 50% by mass or more from the viewpoint of improving the etching rate ratio of a silicon nitride film to a silicon oxide film (hereinafter also referred to as “SiN/ SiO2 selection rate ratio”). is preferable, 70% by mass or more is more preferable, 80% by mass or more is still more preferable, and from the same viewpoint, 95% by mass or less is preferable, 90% by mass or less is more preferable, and 85% by mass or less is even more preferable.
• the amount of phosphoric acid in the etching solution of the present disclosure is preferably 50% by mass or more and 95% by mass or less, more preferably 70% by mass or more and 90% by mass or less, and 80% by mass or more and 85% by mass or less. More preferred.
• water contained in the etching solution of the present disclosure examples include distilled water, ion-exchanged water, pure water, and ultrapure water.
• the amount of water in the etching solution of the present disclosure is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 7% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less.
• 20% by mass or less is more preferable.
• the etching solution of the present disclosure further contains or blends a high temperature stabilizer from the viewpoint of suppressing filter clogging in cyclic use while maintaining the SiN/SiO 2 selection rate ratio. It can be anything.
• the high temperature stabilizer includes at least one selected from sulfonic acid compounds, maleic acid and oxalic acid. Examples of sulfonic acid compounds include p-toluenesulfonic acid and benzenesulfonic acid.
• the etching solution of the present disclosure from the viewpoint of improving the SiN / SiO 2 selection rate ratio and / or from the viewpoint of further suppressing the deposition and adhesion of silica to the SiO 2 film, It may further contain or be blended with an acid compound.
• organic phosphonic acid compounds include phosphoric acid polymers such as polyvinyl phosphonic acid (PVPA), alkyl phosphonic acid, and the like, from the viewpoint of improving the SiN/SiO 2 selective rate ratio and suppressing the precipitation and adhesion of silica to the SiO 2 film.
• PVPA polyvinyl phosphonic acid
• alkyl phosphonic acid alkyl phosphonic acid
• the etching solution of the present disclosure further contains or blends a nonionic surfactant from the viewpoint of further suppressing the deposition and adhesion of silica to the SiO 2 film.
• a nonionic surfactant from the viewpoint of further suppressing the deposition and adhesion of silica to the SiO 2 film.
• nonionic surfactants include polyoxyalkylene alkyl ethers from the viewpoint of suppressing deposition and adhesion of silica to SiO2 films. At least one selected from oxypropylene lauryl myristyl ether can be mentioned.
• the etching solution of the present disclosure may further contain or be blended with other components as long as the effects of the present disclosure are not impaired.
• Other components include acids other than phosphoric acid, chelating agents, surfactants other than the nonionic surfactants described above, solubilizers, antiseptics, rust inhibitors, bactericides, antibacterial agents, antioxidants, and the like. mentioned.
• a step of blending a siloxane compound modified with a compound having an alkyleneoxy group, phosphoric acid, water, and optionally the optional components described above (hereinafter, also referred to as a “blending step”) (hereinafter also referred to as "etching liquid manufacturing method of the present disclosure”).
• "blending” includes mixing the siloxane compound modified with the compound having an alkyleneoxy group, phosphoric acid, water, and optionally the optional components described above simultaneously or in order. The order of mixing may not be particularly limited.
• the blending can be performed using a mixer such as a homomixer, a homogenizer, an ultrasonic disperser, and a wet ball mill.
• the pH of the etching solution of the present disclosure is preferably 0.1 or more, more preferably 0.2 or more, still more preferably 0.3 or more, and 2 or less. It is preferably 1.5 or less, more preferably 1 or less. From the same point of view, the pH of the etching solution of the present disclosure is preferably 0.1 or more and 2 or less, more preferably 0.2 or more and 1.5 or less, and even more preferably 0.3 or more and 1 or less.
• the pH of the etching solution is the value of the etching solution at 25° C. when used, and can be measured using a pH meter, specifically by the method described in the Examples.
• the etching solution of the present disclosure in one or more embodiments, is for use in etching at an etching temperature of 110°C or higher and 250°C or lower.
• the etchant of the present disclosure may be stored and supplied in a concentrated state to the extent that its stability is not impaired. In this case, it is preferable in that manufacturing and transportation costs can be reduced.
• This concentrated solution can be used in the etching process after being appropriately diluted with water, an aqueous solution of phosphoric acid, or the like, if necessary.
• the dilution ratio is preferably 5 to 100 times.
• the present disclosure relates to a kit for manufacturing the etching solution of the present disclosure (hereinafter also referred to as "kit of the present disclosure").
• kit of the present disclosure includes, for example, a solution containing a siloxane compound modified with a compound having an alkyleneoxy group (first liquid) and a solution containing phosphoric acid (second liquid) in a state in which they are not mixed with each other. , a kit (two-liquid etchant) in which these are mixed at the time of use. After the first liquid and the second liquid are mixed, they may be diluted with water or an aqueous solution of phosphoric acid, if necessary.
• the first liquid or the second liquid may contain all or part of the water used to prepare the etching liquid.
• the phosphoric acid contained in the second liquid may be the total amount of the phosphoric acid used for preparing the etching liquid, or may be a part thereof.
• the first liquid and the second liquid may each contain the optional components described above, if necessary. According to the kit of the present disclosure, it is possible to obtain an etchant capable of suppressing deposition and adhesion of silica generated during the etching process to the SiO 2 film.
• a substrate to be processed that is etched using the etchant of the present disclosure is, in one or more embodiments, a substrate having a silicon nitride film and a silicon oxide film.
• the substrate having silicon nitride films and silicon oxide films may be a substrate having a three-dimensional structure in which a plurality of silicon nitride films and a plurality of silicon oxide films are alternately laminated. Examples of substrates include substrates for use in semiconductors, substrates for use in flat panel displays, and the like.
• silicon nitride films include nitride films formed by low-pressure chemical vapor deposition (LPCVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), and the like.
• silicon oxide films include oxide films formed by a thermal oxidation method, an LPCVD method, a PECVD method, an ALD method, or the like.
• the etching solution of the present disclosure can be suitably used for manufacturing a three-dimensional semiconductor device such as a three-dimensional NAND flash memory.
• the etchant of the present disclosure can be used to etch a substrate having a three-dimensional structure in which a plurality of silicon nitride films and a plurality of silicon oxide films are alternately laminated.
• an etching method including a step of removing a silicon nitride film from a substrate having a silicon nitride film and a silicon oxide film (hereinafter also referred to as an “etching step”) using an etchant of the present disclosure. (hereinafter also referred to as “etching method of the present disclosure”).
• etching method of the present disclosure By using the etching method of the present disclosure, it is possible to suppress the precipitation and adhesion of silica generated during the etching process to the SiO 2 film, so that the productivity of semiconductor substrates with improved quality can be improved. can be played.
• the etching method and conditions in the etching step can be the same as those in the etching step in the method for manufacturing a semiconductor substrate of the present disclosure, which will be described later.
• the present disclosure includes a step (etching step) of removing a silicon nitride film from a substrate having a silicon nitride film and a silicon oxide film using the etchant of the present disclosure, and the substrate is used for a semiconductor.
• the present invention relates to a method for manufacturing a semiconductor substrate (hereinafter, also referred to as a "semiconductor substrate manufacturing method of the present disclosure"), which is a substrate for a semiconductor substrate. According to the semiconductor substrate manufacturing method of the present disclosure, it is possible to suppress the precipitation and adhesion of silica generated during the etching process to the SiO 2 film, so that it is possible to efficiently manufacture semiconductor substrates with improved quality. can be
• examples of the etching treatment method include immersion etching and single-wafer etching.
• the etching temperature of the etchant is preferably 110° C. or higher, more preferably 120° C. or higher, still more preferably 140° C. or higher, and even more preferably 150° C. or higher, from the viewpoint of improving the SiN/SiO 2 selection rate ratio.
• 250° C. or lower is preferred
• 230° C. or lower is more preferred
• 200° C. or lower is even more preferred
• 180° C. or lower is even more preferred.
• the etching temperature of the etchant is preferably 110° C. or higher and 250° C. or lower, more preferably 120° C. or higher and 230° C. or lower, still more preferably 140° C. or higher and 200° C. or lower, even more preferably 150° C. or higher and 180° C. or lower. .
• the etching time can be set to, for example, preferably 30 minutes or longer, more preferably 60 minutes or longer, and preferably 270 minutes or shorter, more preferably 180 minutes or shorter.
• the etching rate of the silicon nitride film is preferably 40 ⁇ /minute or more, more preferably 50 ⁇ /minute or more, and still more preferably 60 ⁇ /minute or more, from the viewpoint of productivity improvement.
• the etching rate of the silicon oxide film is preferably 1 ⁇ /minute or less, more preferably 0.5 ⁇ /minute or less, and still more preferably 0.3 ⁇ /minute or less, from the viewpoint of improving productivity.
• the SiN/SiO 2 selection rate ratio is preferably 150 or more, more preferably 200 or more, and even more preferably 300 or more, from the viewpoint of improving productivity.
• the pH value of the etching solution at 25° C. is a value measured using a pH meter (manufactured by Toa DKK Co., Ltd.), and is a value one minute after the electrode of the pH meter is immersed in the etching solution.
• etching solution [etching rate and selection rate ratio] Colloidal silica (PL-1, manufactured by Fuso Chemical Industry Co., Ltd.) was added to the etching solution prepared for each composition (Examples 1 to 7 and Comparative Examples 1 to 4) so that the Si concentration was 200 ppm, and a silicon nitride film ( A 1 cm ⁇ 1 cm silicon nitride film wafer whose thickness (SiN film) was measured was immersed and etched at 160° C. to 170° C. for 90 minutes. Then, after cooling and washing with water, the thickness of the silicon nitride film was measured again, and the difference was taken as the etching amount.
• PL-1 manufactured by Fuso Chemical Industry Co., Ltd.
• An optical interference type film thickness measuring device (“Random Ace VM-100” manufactured by SCREEN Co.) was used to measure the film thickness. Also, LP-TEOS of 1.5 cm ⁇ 1 cm was used as a silicon oxide film (SiO 2 film), and the etching amount of the silicon oxide film was obtained under the same conditions as the silicon nitride film. Then, the etching rate of the silicon nitride film, the etching rate of the silicon oxide film, and the selection rate ratio were calculated from the following equations. Table 1 shows the calculation results. In addition, from the value of the etching rate of the silicon oxide film, the effect of suppressing the deposition and adhesion of silica to the silicon oxide film can be evaluated.
• Silicon nitride film (SiN film) etching rate ( ⁇ /min) silicon nitride film etching amount ( ⁇ )/90 (min)
• Etching rate of silicon oxide film (SiO 2 film) ( ⁇ /min) silicon oxide film etching amount ( ⁇ )/90 (min)
• Selective speed ratio silicon nitride film etching speed/silicon oxide film etching speed
• the etchant of the present disclosure is useful in methods of manufacturing semiconductor substrates for high density or high integration.

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