WO2010125664A1 - Peeling liquid and method for cleaning object - Google Patents

Peeling liquid and method for cleaning object Download PDF

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Publication number
WO2010125664A1
WO2010125664A1 PCT/JP2009/058454 JP2009058454W WO2010125664A1 WO 2010125664 A1 WO2010125664 A1 WO 2010125664A1 JP 2009058454 W JP2009058454 W JP 2009058454W WO 2010125664 A1 WO2010125664 A1 WO 2010125664A1
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WO
WIPO (PCT)
Prior art keywords
stripping solution
water
polycarboxylic acid
cleaning
liquid
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PCT/JP2009/058454
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French (fr)
Japanese (ja)
Inventor
充司 林田
映子 関
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アクアサイエンス株式会社
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Priority to PCT/JP2009/058454 priority Critical patent/WO2010125664A1/en
Priority to TW099113221A priority patent/TW201100534A/en
Publication of WO2010125664A1 publication Critical patent/WO2010125664A1/en

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    • 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
    • H01L21/02041—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
    • 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
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67011—Apparatus for manufacture or treatment
    • H01L21/67017—Apparatus for fluid treatment
    • H01L21/67063—Apparatus for fluid treatment for etching
    • H01L21/67075—Apparatus for fluid treatment for etching for wet etching
    • H01L21/6708—Apparatus for fluid treatment for etching for wet etching using mainly spraying means, e.g. nozzles

Definitions

  • the present invention relates to foreign matters adhering to an object to be cleaned, more specifically, unnecessary substances such as polymer residues adhering to the surface of an object such as a semiconductor, a hard disk, a liquid crystal display, a printed board, and a flat panel display in a dry etching process.
  • the present invention relates to a stripping solution and a cleaning method used for stripping and removing. More specifically, the present invention relates to a stripping solution and a cleaning method used for removing a sidewall polymer (sidewall protective film) on a side surface of a via hole formed after dry etching among the objects.
  • Patent Documents 1 and 2 disclose a stripping solution containing an organic amine compound, an anticorrosive, and an organic solvent, and Patent Document 3
  • a stripping solution containing ammonium fluoride, an anticorrosive, and a water-soluble organic solvent has been proposed.
  • these Patent Documents 1 to 3 aim to provide a stripping solution capable of treating an object under low temperature conditions.
  • the process is performed under high temperature conditions. There has been proposed a method of peeling off a polymer film or the like that has been sprayed and adhered to the surface of the object.
  • Patent Documents 4 and 5 it is possible to prevent the structure of the integrated circuit from being damaged or dissolved and to avoid dangers such as deleterious substances.
  • this method there is a problem that unnecessary objects such as polymer residues attached to the surface of the object in the dry etching process cannot be sufficiently removed.
  • any of the above-described conventional techniques is not suitable for cleaning polymer residues (sidewall protective films) remaining on the via hole side wall and the aluminum wiring side wall.
  • the via hole side wall and the aluminum wiring side wall are particularly difficult to clean, the use of strong chemicals or hard cleaning conditions (for example, spraying conditions) may damage the via hole and aluminum wiring.
  • spraying conditions for example, spraying conditions
  • the chemical is not used or the condition is mild, the adhering polymer residue is not sufficiently cleaned.
  • the method of Patent Document 4 since the sprayed material only flows along the surface of the polymer residue, it is difficult to remove the remaining polymer residue.
  • the present invention minimizes the influence on the environment without damaging or dissolving the structure of the integrated circuit, and in particular, without damaging the via hole and the aluminum wiring of the object to be cleaned, and the via hole side wall and the aluminum wiring. It is an object of the present invention to provide means for reliably peeling and removing the polymer residue adhering to the side wall.
  • the present inventor analyzed the composition of the sidewall protective film by Auger electron spectroscopy. As a result, 7 atom% Ti was detected for the via hole and 5 atom% Ti for the aluminum wiring. This Ti is considered to be derived from the barrier metal.
  • the inventors focused on the fact that Ti exhibits a corrosion behavior different from room temperature in an aqueous solution close to the boiling point, and examined chemical substances that act on Ti. As a result of finding that polycarboxylic acid (particularly oxalic acid) acts effectively, the present invention has been completed.
  • the present invention (1) substantially comprises an anticorrosive agent and a water-soluble organic solvent containing a chelate-forming polycarboxylic acid containing a carboxyl group and a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between the carboxyl groups. It is a stripping solution for removing a sidewall protective film for stripping a polymer residue of an object, which is made of an aqueous solution not contained in.
  • the present invention (2) is the stripping solution for removing a sidewall protective film of the invention (1), wherein the polycarboxylic acid is oxalic acid.
  • the present invention (3) is a method for cleaning an object including a step of injecting a multiphase fluid obtained by mixing liquid vapor and liquid.
  • the liquid vapor is water vapor;
  • the liquid is substantially free of anticorrosive and water-soluble organic solvent, including a chelatable polycarboxylic acid containing a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between the carboxyl group and the carboxyl group.
  • An object cleaning method characterized by being an aqueous solution.
  • the present invention (4) is the object cleaning method of the invention (3), wherein the polycarboxylic acid is oxalic acid.
  • Polycarboxylic acid means a carboxylic acid compound having two or more carboxyl groups.
  • the stripping liquid according to the present invention as a mixed phase fluid of water vapor and stripping liquid, heat can be applied in addition to the polymer removal effect by the stripping liquid according to the present invention.
  • the polycarboxylic acid has an effect of exhibiting particularly high detergency.
  • FIG. 1 is a schematic configuration diagram of a cleaning system S1 according to the best mode.
  • the stripping solution for removing the sidewall protective film according to the present invention comprises an aqueous solution containing a polycarboxylic acid and not containing an anticorrosive and a water-soluble organic solvent. Even with such a polycarboxylic acid aqueous solution, it is possible to sufficiently wash an object by a cleaning method using the stripping solution according to the present invention (for example, a cleaning method including a stripping solution spraying step). Become. That is, by ejecting a mixed phase fluid of a stripping solution and water vapor, unnecessary substances such as a resist are removed by a physical action in addition to a chemical action by the stripping solution.
  • the “object” to be cleaned in the present invention is an object (for example, a semiconductor substrate, an electronic device such as a semiconductor, a hard disk, a liquid crystal display, a printed board, or a flat panel display) to which a polymer residue is adhered in a dry etching process. Parts).
  • the present invention is suitable for stripping polymer residues.
  • the present invention is effective in removing polymer residues formed on the side walls of via holes and aluminum wiring, as in a semiconductor substrate after an etching process. In particular, it is effective for removal of polymer residues formed on via holes formed in an object containing titanium nitride and side walls of aluminum wiring.
  • the “polymer residue” is not particularly limited as long as it is a residue during dry etching, and is typically SiO 2 , Al 2 O 3 , TiO 2 and / or TiN. Among these, it is particularly preferable to use for removing residues containing TiN.
  • the stripping solution according to the best mode comprises an aqueous solution containing a polycarboxylic acid and substantially free of an anticorrosive and a water-soluble organic solvent.
  • the polycarboxylic acid used in the present invention is a polycarboxylic acid capable of forming a chelate containing a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between the carboxyl group and the carboxyl group.
  • can form a chelate means a polycarboxylic acid having a sterically close structure such that a carboxyl group can form a chelate with a metal atom, for example, a double bond such as fumaric acid.
  • a metal atom for example, a double bond such as fumaric acid.
  • steric chelate formation is not possible, such as a trans form of a polycarboxylic acid having a carbon chain having 2 carbon atoms, this concept does not apply.
  • the polycarboxylic acid is not particularly limited as long as it satisfies the above conditions, and examples thereof include oxalic acid, malonic acid, maleic acid, citric acid, tartaric acid, and phthalic acid.
  • polycarboxylic acids such as oxalic acid and malonic acid, which contain a carbon chain having 0 or 1 carbon atoms between the carboxyl group and the carboxyl group, are preferable.
  • these polycarboxylic acids are used, a strong detergency can be exhibited.
  • oxalic acid exhibits high peelability at a low concentration. The reason is that the molecular weight is small and the degree of ionization is high.
  • the concentration of the polycarboxylic acid used is preferably 0.0015 to 0.12 mol / l, more preferably 0.0025 to 0.06 mol / l, and 0.0050 to 0.12 mol / l. Is more preferred.
  • a substance for adjusting pH may be added.
  • carbon dioxide, sulfuric acid, nitric acid, citric acid, oxalic acid, acetic acid and the like can be cited as substances for adjusting the pH in the lower direction.
  • ammonia, 2-aminoethanol, choline and the like can be cited as substances for adjusting the pH in the higher direction.
  • the pH of the stripping solution is preferably 2.0 to 6.0, more preferably 3.0 to 4.5, and even more preferably 3.3 to 3.7.
  • the pH is measured by a method defined in JIS Z8802.
  • the stripping solution according to the best mode is substantially free of an anticorrosive and a water-soluble organic solvent.
  • substantially not containing as used in the claims and the present specification means that the influence on the environment is not a problem, for example, 0.1 wt% or less based on the total mass of the liquid. Means content.
  • the water-soluble organic solvent include amides such as N, N-dimethylformamide and dimethylacetamide, alcohols such as ethanol, isopropyl alcohol, glycerin, ethylene glycol and diethylene glycol, diethylene glycol monomethyl ether and dipropylene glycol.
  • glycol ethers such as monomethyl ether, sulfoxides such as dimethyl sulfoxide, and organic nitriles such as acetonitrile, propionitrile, butyronitrile, isobutyronitrile, succinonitrile, benzonitrile, and adiponitrile.
  • organic nitriles such as acetonitrile, propionitrile, butyronitrile, isobutyronitrile, succinonitrile, benzonitrile, and adiponitrile.
  • the “anticorrosive” is not particularly limited as long as it is an anticorrosive used in a semiconductor process, and examples thereof include catechol, sorbitol, xylitol and the like.
  • the stripping solution has a problem of contamination of metals derived from raw materials (for example, Al, Cu, K, Mg, Na, Ti, Fe, Cr, Pt, Ni, Ca, Zn).
  • raw materials for example, Al, Cu, K, Mg, Na, Ti, Fe, Cr, Pt, Ni, Ca, Zn.
  • the raw materials are purified.
  • the amount of metal in the stripping solution has been reduced by contrivances such as. However, even with such a device, the amount of metal could be reduced only to the ppm order.
  • the concentration of polycarboxylic acid can be reduced while using only water as a solvent, it is possible to achieve a desired amount of metal (for example, nano-order).
  • the amount of contamination metal derived from polycarboxylic acid can be reduced to 1/10 or 1/100 by setting the dilution amount with water to 10 times or 100 times.
  • the object cleaning system S1 includes a nozzle 101, operation valves 102a and 102b, water flow meters 103a and 103b, stop valves 104a and 104c, a water pressurization tank 105 (which can be replaced by a water pump), a steam generator 106, and a water supply pipe 107a.
  • a nitrogen supply pipe 108 a pressure reducing valve 109, pressure-resistant pipes 110 to 112, a stage 113, a chamber 114, a pressure gauge 115, a heater 116, a chemical liquid tank 117, and a CO 2 supply pipe 118.
  • a processing object (for example, a semiconductor wafer) W is set on the stage 113.
  • each element will be described in detail.
  • the nozzle 101 is disposed so as to face the object W, and generates a two-fluid jet of water vapor and stripping solution or pure water. Then, a mixed phase flow of pure water supplied from the water pressurization tank 105 or the peeling liquid supplied from the chemical liquid tank 117 and the water vapor supplied from the water vapor generator 106 to the object W through the nozzle 101. As a result of the spraying, the object is cleaned. At this time, if the supply of pure water and stripping solution is stopped, a jet of only water vapor is obtained. It is also possible to stop the supply of water vapor and simply allow the stripping solution to flow down to the object W.
  • the water pressurization tank 105 pressurizes pure water supplied from the water supply pipe 107b to a predetermined value A 1 (MP), and supplies a predetermined flow rate B 1 (l / min) of the pressurized pure water to the pressure pipe. 110 is sent to the nozzle 101 in a high-pressure state (however, depending on the nozzle shape, it is possible to send pure water to the nozzle without pressurization).
  • the water flow meter 103 a measures the flow rate of pure water supplied from the water pressure tank 105 to the nozzle 101. The operator can check the flow rate with the water flow meter 103a and adjust it to a desired value using the operation valve 102a. In addition, the supply of pure water can be stopped or restarted by opening and closing the stop valve 104a.
  • nitrogen is supplied from the nitrogen supply pipe 108 to the water pressurization tank 105.
  • pure water is mixed with nitrogen, but it is obvious that only pure water may be supplied to the nozzle 101.
  • it is not limited to nitrogen gas, It can substitute also with inert gas like Ar gas.
  • the chemical liquid tank 117 pressurized CO 2 that is supplied from the CO 2 supply pipe 118 to a predetermined value, to dissolve the CO 2 stripping solution in the chemical liquid tank.
  • a predetermined flow rate B 2 (l / min) of the pressurized stripping solution is sent to the nozzle 101 through the pressure tube 112.
  • the water flow meter 103b measures the flow rate of the stripping solution supplied from the chemical solution tank 117 to the nozzle 101.
  • the operator can check the flow rate with the water flow meter 103b and adjust it to a desired value using the operation valve 102b. Further, since the heater 116 is provided, the temperature of the stripping solution can be easily adjusted.
  • the supply of the stripping solution can be stopped or restarted by opening and closing the stop valve 104c.
  • CO 2 from the CO 2 supply pipe 118 is configured to be supplied to the chemical liquid tank 117.
  • the configuration may be such that carbon dioxide can be blown through a transport pipe from the tank to the nozzle, or may be mixed with a substance that adjusts the pH.
  • you may adjust pH at the time of stripping solution manufacture. For example, after dissolving carbon dioxide, the stripping solution may be supplied from a container sealed with carbon dioxide.
  • the water vapor generator 106 heats the pure water supplied from the water supply pipe 107 a to a predetermined temperature D 1 (° C.) or higher to generate water vapor, and is supplied to the nozzle 101 in a high pressure state via the pressure resistant pipe 111. Send it out.
  • the pressure gauge 115 measures the pressure of water vapor supplied from the water vapor generator 106 to the nozzle 101. An operator can check the pressure with the pressure gauge 115 and adjust it to a desired value using the pressure reducing valve 109. In addition, the supply of water vapor can be stopped or restarted by opening and closing the stop valve 104b.
  • cleaning method which concerns on this invention includes the peeling liquid injection process which injects the multiphase flow which consists of peeling liquid and water vapor
  • the stripping solution spraying step is a step of spraying a fluid, which is a mixture of the stripping solution according to the best mode and water vapor, onto an object.
  • the stripping solution according to the best mode has an effect that the stripping solution has sufficient cleaning power and does not damage the semiconductor substrate by being sprayed onto the object by the method according to the spraying step. It demonstrates more suitably.
  • the method can be performed by, for example, the cleaning system S1 according to the best mode.
  • the temperature of the multiphase flow in the stripping solution jetting process is preferably 60 to 115 ° C, more preferably 80 to 113 ° C, and still more preferably 90 to 110 ° C. By setting the temperature at 60 ° C. or higher, the reaction rate is significantly increased.
  • the fluid temperature was defined as the temperature in a steady state after a thermocouple was installed on the wafer and the fluid was ejected for one minute with a predetermined distance between the objects.
  • the injection speed of the multiphase flow is preferably 60 m / s or more, more preferably 140 m / s or more, and further preferably 260 m / s. Although an upper limit is not specifically limited, It is 600 m / s or less.
  • the ejection speed is a value obtained by dividing the volume flow rate of the fluid by the cross-sectional area of the nozzle opening.
  • Stripping solution the flow rate is suitably 0.05 ⁇ 0.4dm 3 / min, 0.1 ⁇ 0.3dm 3 / min is more preferred, 0.1 ⁇ 0.2dm 3 / min is more preferred is there.
  • the mixing ratio of water vapor and stripping solution ([stripping solution volume] / [water vapor volume]) is preferably 0.00003 to 0.005, more preferably 0.00004 to 0.002, and 0.00005 to 0.0015 is more preferred.
  • the treatment time is preferably 25 to 180 seconds, more preferably 40 to 90 seconds, and even more preferably 50 to 70 seconds. Note that the numerical range is a value mainly indicating a limit value of a parameter that affects cleaning, and a combination of these can be easily selected and set according to the degree of required impact force.
  • Object to be cleaned a TiN film having a thickness of 100 ⁇ m was formed on a silicon wafer having a thickness of 0.625 mm, and a silicon oxide film having a thickness of 1000 ⁇ m (hereinafter referred to as an oxide film) was further formed thereon. . Lithograph and dry etching were performed, and a hole with an opening diameter of 1 ⁇ m was opened to the depth of the interface between TiN and the oxide film. The object was cleaned by the object cleaning system S1.
  • the conditions in the example are as follows. Residual polymer and hole damage were observed with a scanning electron microscope. At this time, 5 holes were observed per case.
  • the data of an Example and a comparative example are shown.

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Cleaning Or Drying Semiconductors (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)

Abstract

Disclosed is a peeling liquid that can reliably peel and remove a polymer residue deposited on a via hole side wall or an aluminum wiring side wall without damage to or dissolution of the structure of an integrated circuit while minimizing an influence on environment and particularly without damage to a via hole or an aluminum wiring as a cleaning object. The peeling liquid for side wall protective film removal for peeling a polymer residue as an object is an aqueous solution that comprises a chelate-forming polycarboxylic acid having a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between carboxyl groups and is substantially free from an anticorrosive agent and a water soluble organic solvent.

Description

剥離液及び対象物洗浄方法Stripping solution and object cleaning method
　本発明は、洗浄対象物上に付着した異物、より詳細には、半導体・ハードディスク・液晶ディスプレイ・プリント基板・フラットパネルディスプレイ等の対象物表面にドライエッチング工程で付着したポリマ残渣等の不要物を剥離して除去するために使用される剥離液及び洗浄方法に関する。より詳細には、前記対象物の中でも、ドライエッチング後に形成されるビアホール側面のサイドウォールポリマー（側壁保護膜）を除去するために使用される剥離液及び洗浄方法に関する。 The present invention relates to foreign matters adhering to an object to be cleaned, more specifically, unnecessary substances such as polymer residues adhering to the surface of an object such as a semiconductor, a hard disk, a liquid crystal display, a printed board, and a flat panel display in a dry etching process. The present invention relates to a stripping solution and a cleaning method used for stripping and removing. More specifically, the present invention relates to a stripping solution and a cleaning method used for removing a sidewall polymer (sidewall protective film) on a side surface of a via hole formed after dry etching among the objects.
　半導体、ハードディスク、液晶ディスプレイ、プリント基板又はフラットパネルディスプレイ等の対象物表面にエッチング工程で被着したポリマ残渣等の不要物は、当該工程後に剥離して除去される必要がある。ここで、レジスト膜の除去については、（１）プラズマ灰化、（２）化学薬品により除去する技術が用いられている。 Unnecessary substances such as polymer residues deposited on the surface of an object such as a semiconductor, a hard disk, a liquid crystal display, a printed board or a flat panel display in the etching process need to be peeled off and removed after the process. Here, with respect to the removal of the resist film, (1) plasma ashing and (2) a technique of removing with chemicals are used.
　しかしながら、（１）の技術では、僅かながらＳｉを損傷し、（２）の技術では、Ｓｉに加えて絶縁膜及び金属配線を溶解するという問題がある。近年の集積回路の高密度化に伴い、僅かでも集積回路の構造を損傷又は溶解することが許されなくなりつつある。 However, in the technique (1), Si is slightly damaged, and in the technique (2), there is a problem that the insulating film and the metal wiring are dissolved in addition to Si. With the recent increase in the density of integrated circuits, it is no longer allowed to damage or dissolve the structure of the integrated circuit.
　そこで、（２）の技術に関し、集積回路の構造を損傷又は溶解させない剥離液として、特許文献１及び２に、有機アミン系の化合物、防食剤及び有機溶剤を含有する剥離液や、特許文献３に、フッ化アンモニウム、防食剤及び水溶性有機溶剤を含有する剥離液が提案されている。また、これらの特許文献１～３においては、低温条件で対象物を処理可能な剥離液を提供することを目的としている。一方、高温条件での処理になるが、更に、集積回路の構造を損傷又は溶解させないようなマイルドな条件で対象物を洗浄する技術として、特許文献４や特許文献５に、水蒸気を対象物に噴射して当該対象物表面に付着した高分子膜等を剥離する手法が提案されている。 Therefore, regarding the technique of (2), as a stripping solution that does not damage or dissolve the structure of the integrated circuit, Patent Documents 1 and 2 disclose a stripping solution containing an organic amine compound, an anticorrosive, and an organic solvent, and Patent Document 3 In addition, a stripping solution containing ammonium fluoride, an anticorrosive, and a water-soluble organic solvent has been proposed. In addition, these Patent Documents 1 to 3 aim to provide a stripping solution capable of treating an object under low temperature conditions. On the other hand, as a technique for cleaning an object under mild conditions that do not damage or dissolve the structure of the integrated circuit, the process is performed under high temperature conditions. There has been proposed a method of peeling off a polymer film or the like that has been sprayed and adhered to the surface of the object.
特開平７－６４２９７号公報Japanese Patent Laid-Open No. 7-64297 特開平８－３３４９０５号公報JP-A-8-334905 特開平９－１９７６８１号公報JP-A-9-197681 特開２００４－３４９５７７号公報JP 2004-349577 A 特開２００５－１７５１７２号公報JP 2005-175172 A
　ここで、特許文献１～３に記載された剥離剤は、強アルカリ性又は強酸性であったり有機溶剤を含有しているため、劇物又は消防法の危険物に該当する例が多い。従って、これら剥離剤は、洗浄作業及び廃液処理の従事者が危険に曝される、環境に重篤な影響を与える危険性がある、等の問題を有している。 Here, since the release agents described in Patent Documents 1 to 3 are strongly alkaline or strongly acidic, or contain an organic solvent, there are many examples that fall under the category of dangerous substances or dangerous substances of the Fire Service Act. Therefore, these stripping agents have problems such as the risk of seriously affecting the environment, and the workers engaged in cleaning operations and waste liquid treatment are exposed to danger.
　一方、特許文献４、５に開示された手法によると、集積回路の構造を損傷又は溶解させることの防止や、劇物等の危険回避はできる。しかし、当該手法では、対象物表面にドライエッチング工程で付着したポリマ残渣等の不要物を十分に剥離除去できないという問題がある。 On the other hand, according to the methods disclosed in Patent Documents 4 and 5, it is possible to prevent the structure of the integrated circuit from being damaged or dissolved and to avoid dangers such as deleterious substances. However, in this method, there is a problem that unnecessary objects such as polymer residues attached to the surface of the object in the dry etching process cannot be sufficiently removed.
　特に、前述したいずれの従来技術も、ビアホール側壁やアルミニウム配線側壁に残留したポリマ残渣（側壁保護膜）の洗浄には不向きである。ビアホール側壁やアルミニウム配線側壁は特に洗浄し難い位置にあるため、強力な薬剤を使用したりハードな洗浄条件（例えば噴射条件）にするとビアホールやアルミニウム配線が損傷してしまう一方、特許文献４等のように薬剤を使用しなかったり条件をマイルドにすると付着したポリマ残渣の洗浄が不十分となる。例えば、特許文献４の手法では、噴射物は当該ポリマ残渣表面に沿って流れるにすぎないため、残留したポリマ残渣を取り除くことが困難であった。 In particular, any of the above-described conventional techniques is not suitable for cleaning polymer residues (sidewall protective films) remaining on the via hole side wall and the aluminum wiring side wall. Since the via hole side wall and the aluminum wiring side wall are particularly difficult to clean, the use of strong chemicals or hard cleaning conditions (for example, spraying conditions) may damage the via hole and aluminum wiring. Thus, when the chemical is not used or the condition is mild, the adhering polymer residue is not sufficiently cleaned. For example, in the method of Patent Document 4, since the sprayed material only flows along the surface of the polymer residue, it is difficult to remove the remaining polymer residue.
　そこで、本発明は、集積回路の構造を損傷又は溶解すること無くかつ環境への影響を最小限にとどめると共に、特に、洗浄対象物のビアホールやアルミニウム配線を損傷すること無く、ビアホール側壁やアルミニウム配線側壁に付着したポリマ残渣を確実に剥離して除去する手段を提供することを目的とする。 Therefore, the present invention minimizes the influence on the environment without damaging or dissolving the structure of the integrated circuit, and in particular, without damaging the via hole and the aluminum wiring of the object to be cleaned, and the via hole side wall and the aluminum wiring. It is an object of the present invention to provide means for reliably peeling and removing the polymer residue adhering to the side wall.
　本発明者は、側壁保護膜の組成をオージェ電子分光測定により分析を行なった。その結果、ビアホールについて７ａｔｏｍ％、アルミニウム配線については５ａｔｏｍ％のＴｉがそれぞれ検出された。尚、このＴｉはバリアメタルに由来すると考えられる。発明者は、Ｔｉは沸点に近い水溶液では、室温と異なった腐食挙動を示すことに着目し、当該Ｔｉに作用する化学物質を検討した。そして、ポリカルボン酸（特に、シュウ酸）が有効に作用することを見出した結果、本発明を完成させた。 The present inventor analyzed the composition of the sidewall protective film by Auger electron spectroscopy. As a result, 7 atom% Ti was detected for the via hole and 5 atom% Ti for the aluminum wiring. This Ti is considered to be derived from the barrier metal. The inventors focused on the fact that Ti exhibits a corrosion behavior different from room temperature in an aqueous solution close to the boiling point, and examined chemical substances that act on Ti. As a result of finding that polycarboxylic acid (particularly oxalic acid) acts effectively, the present invention has been completed.
　本発明（１）は、カルボキシル基とカルボキシル基の間に炭素数０～２の飽和又は不飽和の炭素鎖を含むキレート形成可能なポリカルボン酸を含む、防食剤及び水溶性有機溶媒を実質的に含有しない水溶液からなる、対象物のポリマ残渣を剥離するための側壁保護膜除去用剥離液である。 The present invention (1) substantially comprises an anticorrosive agent and a water-soluble organic solvent containing a chelate-forming polycarboxylic acid containing a carboxyl group and a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between the carboxyl groups. It is a stripping solution for removing a sidewall protective film for stripping a polymer residue of an object, which is made of an aqueous solution not contained in.
　本発明（２）は、前記ポリカルボン酸が、シュウ酸である、前記発明（１）の側壁保護膜除去用剥離液である。 The present invention (2) is the stripping solution for removing a sidewall protective film of the invention (1), wherein the polycarboxylic acid is oxalic acid.
　本発明（３）は、液体蒸気と液体とを混合してなる混相流体を噴射する工程を含む、対象物を洗浄する方法において、
　前記液体蒸気が、水蒸気であり、
　前記液体が、カルボキシル基とカルボキシル基の間に炭素数０～２の飽和又は不飽和の炭素鎖を含むキレート形成可能なポリカルボン酸を含む、防食剤及び水溶性有機溶媒を実質的に含有しない水溶液であることを特徴とする、対象物洗浄方法である。 The present invention (3) is a method for cleaning an object including a step of injecting a multiphase fluid obtained by mixing liquid vapor and liquid.
The liquid vapor is water vapor;
The liquid is substantially free of anticorrosive and water-soluble organic solvent, including a chelatable polycarboxylic acid containing a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between the carboxyl group and the carboxyl group. An object cleaning method characterized by being an aqueous solution.
　本発明（４）は、前記ポリカルボン酸が、シュウ酸である、前記発明（３）の対象物洗浄方法である。 The present invention (4) is the object cleaning method of the invention (3), wherein the polycarboxylic acid is oxalic acid.
　ここで、本明細書で用いる各用語の説明をする。「ポリカルボン酸」とは、二以上のカルボキシル基を有するカルボン酸化合物を意味する。 Here, each term used in this specification is explained. “Polycarboxylic acid” means a carboxylic acid compound having two or more carboxyl groups.
　本発明（１）、（３）によれば、低濃度であっても、ビアホールやアルミニウム配線に形成された側壁保護膜等、ドライエッチング後のポリマを十分に剥離することが可能になるという効果を奏する。 According to the present invention (1) and (3), it is possible to sufficiently peel off a polymer after dry etching, such as a sidewall protective film formed in a via hole or an aluminum wiring, even at a low concentration. Play.
　本発明（２）よれば、ポリカルボン酸の中でも、特に高い洗浄力を発揮するという効果を奏する。 According to the present invention (2), among polycarboxylic acids, there is an effect of exhibiting particularly high detergency.
　本発明（３）によれば、水蒸気と剥離液の混相流体として、本発明に係る剥離液を使用することにより、本発明に係る剥離液によるポリマの除去効果に加えて、熱を加えることが可能である上に、更に、混相流体の物理的な剥離力を活用することが可能となるため、特に高い洗浄力を発揮するという効果を奏する。 According to the present invention (3), by using the stripping liquid according to the present invention as a mixed phase fluid of water vapor and stripping liquid, heat can be applied in addition to the polymer removal effect by the stripping liquid according to the present invention. In addition to this, it is possible to utilize the physical separation force of the mixed phase fluid, so that the effect of exhibiting a particularly high detergency is achieved.
　本発明（４）よれば、ポリカルボン酸の中でも、特に高い洗浄力を発揮するという効果を奏する。 According to the present invention (4), the polycarboxylic acid has an effect of exhibiting particularly high detergency.
図１は、本最良形態に係る洗浄システムＳ１の概略構成図である。FIG. 1 is a schematic configuration diagram of a cleaning system S1 according to the best mode.
発明を実施するための最良形態BEST MODE FOR CARRYING OUT THE INVENTION
　本発明に係る側壁保護膜除去用剥離液は、ポリカルボン酸を含む、防食剤及び水溶性有機溶媒を含有しない水溶液からなる。このようなポリカルボン酸水溶液であっても、本発明に係る、当該剥離液を用いた洗浄方法（例えば、剥離液噴射工程からなる洗浄方法）により、対象物を十分に洗浄することが可能となる。即ち、剥離液と水蒸気の混相流体を噴射することにより、剥離液による化学的な作用に加えて、物理的な作用によりレジスト等の不用物を除去する。ここで、本発明において洗浄対象となる「対象物」は、ドライエッチング工程でポリマ残渣が付着した対象物（例えば、半導体、ハードディスク、液晶ディスプレイ、プリント基板又はフラットパネルディスプレイ等の、半導体基板や電子部品）である。本発明は、ポリマ残渣を剥離するのに好適である。更に、本発明は、エッチング工程後の半導体基板のように、ビアホール、アルミニウム配線の側壁に形成されているポリマ残渣の除去に有効である。特に、窒化チタンが含まれる対象物に形成されたビアホール、アルミニウム配線の側壁に形成されているポリマ残渣の除去に有効である。以下、まず本発明に係る剥離液の構成と、当該剥離液を用いた洗浄方法を実施可能な装置構成を説明し、続いて洗浄方法について詳述することとする。また、「ポリマ残渣」は、ドライエッチング時の残渣であれば特に限定されず、典型的には、ＳｉＯ２、Ａｌ２Ｏ３、ＴｉＯ２及び／又はＴｉＮである。これらの中でも特に、ＴｉＮが含まれる残渣除去に使用することが好適である。 The stripping solution for removing the sidewall protective film according to the present invention comprises an aqueous solution containing a polycarboxylic acid and not containing an anticorrosive and a water-soluble organic solvent. Even with such a polycarboxylic acid aqueous solution, it is possible to sufficiently wash an object by a cleaning method using the stripping solution according to the present invention (for example, a cleaning method including a stripping solution spraying step). Become. That is, by ejecting a mixed phase fluid of a stripping solution and water vapor, unnecessary substances such as a resist are removed by a physical action in addition to a chemical action by the stripping solution. Here, the “object” to be cleaned in the present invention is an object (for example, a semiconductor substrate, an electronic device such as a semiconductor, a hard disk, a liquid crystal display, a printed board, or a flat panel display) to which a polymer residue is adhered in a dry etching process. Parts). The present invention is suitable for stripping polymer residues. Furthermore, the present invention is effective in removing polymer residues formed on the side walls of via holes and aluminum wiring, as in a semiconductor substrate after an etching process. In particular, it is effective for removal of polymer residues formed on via holes formed in an object containing titanium nitride and side walls of aluminum wiring. Hereinafter, first, the configuration of the stripping solution according to the present invention and the configuration of an apparatus capable of performing the cleaning method using the stripping solution will be described, and then the cleaning method will be described in detail. The “polymer residue” is not particularly limited as long as it is a residue during dry etching, and is typically SiO 2 , Al 2 O 3 , TiO 2 and / or TiN. Among these, it is particularly preferable to use for removing residues containing TiN.
《剥離液》
　まずは、本最良形態に係る剥離液の構成から説明する。本最良形態に係る剥離液は、ポリカルボン酸を含む、防食剤及び水溶性有機溶媒を実質的に含有しない水溶液からなる。ここで、本発明において使用するポリカルボン酸は、カルボキシル基とカルボキシル基の間に炭素数０～２の飽和又は不飽和の炭素鎖を含むキレート形成可能なポリカルボン酸である。ここで「キレート形成可能な」とは、カルボキシル基が金属原子とキレート形成可能な程度に立体的に近い構造を有しているポリカルボン酸を意味し、例えば、フマル酸等の二重結合を有する炭素数２の炭素鎖を有するポリカルボン酸のトランス体等、立体的にキレート形成不可能である場合は当該概念に当てはまらない。ポリカルボン酸は、前記条件を満たしていれば特に限定されないが、例えば、シュウ酸、マロン酸、マレイン酸、クエン酸、酒石酸、フタル酸等が挙げられる。これらの中でも、シュウ酸、マロン酸等のカルボキシル基とカルボキシル基の間に炭素数０又は１の炭素鎖が含まれるポリカルボン酸であることが好適である。これらのポリカルボン酸を用いた場合には強い洗浄力を発揮することが可能となる。また、更に、これらの中でも、特にシュウ酸が、低濃度で高い剥離性を示す。分子量が小さいことと電離度が高いことが理由と考えられる。ここで、使用するポリカルボン酸の濃度は、０．００１５～０．１２ｍｏｌ／ｌが好適であり、０．００２５～０．０６ｍｏｌ／ｌがより好適であり、０．００５０～０．１２ｍｏｌ／ｌが更に好適である。 <Release liquid>
First, the configuration of the stripping solution according to the best mode will be described. The stripping solution according to the best mode comprises an aqueous solution containing a polycarboxylic acid and substantially free of an anticorrosive and a water-soluble organic solvent. Here, the polycarboxylic acid used in the present invention is a polycarboxylic acid capable of forming a chelate containing a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between the carboxyl group and the carboxyl group. Here, “can form a chelate” means a polycarboxylic acid having a sterically close structure such that a carboxyl group can form a chelate with a metal atom, for example, a double bond such as fumaric acid. In the case where steric chelate formation is not possible, such as a trans form of a polycarboxylic acid having a carbon chain having 2 carbon atoms, this concept does not apply. The polycarboxylic acid is not particularly limited as long as it satisfies the above conditions, and examples thereof include oxalic acid, malonic acid, maleic acid, citric acid, tartaric acid, and phthalic acid. Among these, polycarboxylic acids such as oxalic acid and malonic acid, which contain a carbon chain having 0 or 1 carbon atoms between the carboxyl group and the carboxyl group, are preferable. When these polycarboxylic acids are used, a strong detergency can be exhibited. Furthermore, among these, oxalic acid exhibits high peelability at a low concentration. The reason is that the molecular weight is small and the degree of ionization is high. Here, the concentration of the polycarboxylic acid used is preferably 0.0015 to 0.12 mol / l, more preferably 0.0025 to 0.06 mol / l, and 0.0050 to 0.12 mol / l. Is more preferred.
　本最良形態に係る剥離液の性能を向上させるために、ｐＨを調整する物質を加えてもよい。ここで、ｐＨを低い方向へ調整するための物質として、二酸化炭素、硫酸、硝酸、クエン酸、シュウ酸、酢酸等が挙げられる。また、ｐＨを高い方向へ調整するための物質として、アンモニア、２－アミノエタノール、コリン等が挙げられる。ここで、剥離液のｐＨは、２.０～６.０が好適であり、３.０～４.５がより好適であり、３.３～３.７が更に好適である。ここで、ｐＨは、ＪＩＳ　Ｚ８８０２に既定されている方法により測定する。 In order to improve the performance of the stripping solution according to the best mode, a substance for adjusting pH may be added. Here, carbon dioxide, sulfuric acid, nitric acid, citric acid, oxalic acid, acetic acid and the like can be cited as substances for adjusting the pH in the lower direction. In addition, ammonia, 2-aminoethanol, choline and the like can be cited as substances for adjusting the pH in the higher direction. Here, the pH of the stripping solution is preferably 2.0 to 6.0, more preferably 3.0 to 4.5, and even more preferably 3.3 to 3.7. Here, the pH is measured by a method defined in JIS Z8802.
　本最良形態に係る剥離液は、防食剤及び水溶性有機溶媒を実質的に含有しない。ここで、本特許請求の範囲及び本明細書にいう「実質的に含有しない」とは、環境への影響が問題にならない程度の、例えば、液の全質量を基準として０.１ｗｔ％以下の含有量であることを意味する。尚、水溶性有機溶媒としては、例えば、Ｎ，Ｎ－ジメチルホルムアミド、ジメチルアセトアミド等のアミド類や、エタノール、イソプロピルアルコール、グリセリン、エチレングリコール、ジエチレングリコール等のアルコール類や、ジエチレングリコールモノメチルエーテル、ジプロピレングリコールモノメチルエーテル等のグリコールエーテル類や、ジメチルスルホキシド等のスルホキシド類や、アセトニトリル、プロピオニトリル、ブチロニトリル、イソブチロニトリル、スクシノニトリル、ベンゾニトリル、アジポニトリル等の有機ニトリル類等、が挙げられる。「防食剤」としては、半導体プロセスにおいて使用される防食剤であれば特に限定されず、例えば、カテコール、ソルビトール、キシリトール等が挙げられる。 The stripping solution according to the best mode is substantially free of an anticorrosive and a water-soluble organic solvent. Here, “substantially not containing” as used in the claims and the present specification means that the influence on the environment is not a problem, for example, 0.1 wt% or less based on the total mass of the liquid. Means content. Examples of the water-soluble organic solvent include amides such as N, N-dimethylformamide and dimethylacetamide, alcohols such as ethanol, isopropyl alcohol, glycerin, ethylene glycol and diethylene glycol, diethylene glycol monomethyl ether and dipropylene glycol. Examples include glycol ethers such as monomethyl ether, sulfoxides such as dimethyl sulfoxide, and organic nitriles such as acetonitrile, propionitrile, butyronitrile, isobutyronitrile, succinonitrile, benzonitrile, and adiponitrile. The “anticorrosive” is not particularly limited as long as it is an anticorrosive used in a semiconductor process, and examples thereof include catechol, sorbitol, xylitol and the like.
　以上のような剥離液構成とすることで、本発明の主効果である、ビアホールに付着したポリマ残渣の剥離効果に加え、以下で述べるような副次的効果をも奏することが可能となる。剥離液には原料由来の金属（例えば、Ａｌ、Ｃｕ、Ｋ、Ｍｇ、Ｎａ、Ｔｉ、Ｆｅ、Ｃｒ、Ｐｔ、Ｎｉ、Ｃａ、Ｚｎ）汚染の問題があり、従来技術においては、原料を精製する等といった工夫をして剥離液中の金属量の低減を図ってきた。しかしながら、そのような工夫によってもせいぜいｐｐｍオーダーまでしか金属量を低減することができなかった。他方、本発明では、溶媒を水のみとした上でのポリカルボン酸の低濃度化を実現できたため、所望オーダーの金属量（例えばナノオーダー）とすることが可能となる。具体的には、水での希釈量を１０倍、１００倍とすることで、ポリカルボン酸由来の汚染金属量を１／１０、１／１００とすることが可能となる。 By adopting the stripping solution configuration as described above, in addition to the stripping effect of the polymer residue adhering to the via hole, which is the main effect of the present invention, the following secondary effects can be achieved. The stripping solution has a problem of contamination of metals derived from raw materials (for example, Al, Cu, K, Mg, Na, Ti, Fe, Cr, Pt, Ni, Ca, Zn). In the prior art, the raw materials are purified. The amount of metal in the stripping solution has been reduced by contrivances such as. However, even with such a device, the amount of metal could be reduced only to the ppm order. On the other hand, in the present invention, since the concentration of polycarboxylic acid can be reduced while using only water as a solvent, it is possible to achieve a desired amount of metal (for example, nano-order). Specifically, the amount of contamination metal derived from polycarboxylic acid can be reduced to 1/10 or 1/100 by setting the dilution amount with water to 10 times or 100 times.
《装置構成》
　続いて、本発明に係る洗浄方法に用いる装置について説明する。図１を参照しながら、本最良形態に係る対象物洗浄システムＳ１について詳述する。洗浄システムＳ１は、ノズル１０１、操作バルブ１０２ａ～ｂ、水流量計１０３ａ～ｂ、ストップバルブ１０４ａ～ｃ、水加圧タンク１０５（水圧送ポンプでも代替できる）、水蒸気発生器１０６、水供給管１０７ａ～ｂ、窒素供給管１０８、減圧弁１０９、耐圧管１１０～１１２、ステージ１１３、チャンバ１１４、圧力計１１５、ヒータ１１６、薬液タンク１１７、ＣＯ２供給管１１８で構成されている。ステージ１１３上には処理対象物（例えば半導体ウエハ）Ｗがセットされている。以下、各要素について詳述する。 "Device configuration"
Subsequently, an apparatus used for the cleaning method according to the present invention will be described. The object cleaning system S1 according to the best mode will be described in detail with reference to FIG. The cleaning system S1 includes a nozzle 101, operation valves 102a and 102b, water flow meters 103a and 103b, stop valves 104a and 104c, a water pressurization tank 105 (which can be replaced by a water pump), a steam generator 106, and a water supply pipe 107a. And b, a nitrogen supply pipe 108, a pressure reducing valve 109, pressure-resistant pipes 110 to 112, a stage 113, a chamber 114, a pressure gauge 115, a heater 116, a chemical liquid tank 117, and a CO 2 supply pipe 118. A processing object (for example, a semiconductor wafer) W is set on the stage 113. Hereinafter, each element will be described in detail.
　まず、ノズル１０１は、対象物Ｗに対向するように配置されており、水蒸気と、剥離液又は純水の２流体噴流を発生する。そして、当該ノズル１０１を介して、水加圧タンク１０５から供給された純水又は薬液タンク１１７から供給された剥離液と、水蒸気発生器１０６から供給された水蒸気との混相流が対象物Ｗに吹き付けられる結果、対象物の洗浄処理が行われる。この際、純水及び剥離液の供給を止めれば水蒸気のみの噴流となる。また、水蒸気の供給を止めて、剥離液を対象物Ｗに対して単に流下することも可能である。 First, the nozzle 101 is disposed so as to face the object W, and generates a two-fluid jet of water vapor and stripping solution or pure water. Then, a mixed phase flow of pure water supplied from the water pressurization tank 105 or the peeling liquid supplied from the chemical liquid tank 117 and the water vapor supplied from the water vapor generator 106 to the object W through the nozzle 101. As a result of the spraying, the object is cleaned. At this time, if the supply of pure water and stripping solution is stopped, a jet of only water vapor is obtained. It is also possible to stop the supply of water vapor and simply allow the stripping solution to flow down to the object W.
　水加圧タンク１０５は、水供給管１０７ｂから供給される純水を所定値Ａ１（ＭＰ）に加圧し、加圧した純水のうち所定の流量Ｂ１（ｌ／ｍｉｎ）を、耐圧管１１０を介して高圧状態でノズル１０１に送り出す（但し、ノズル形状によっては、加圧しないで純水をノズルに送り出すことが可能）。水流量計１０３ａは、水加圧タンク１０５からノズル１０１に供給される純水の流量を計測する。作業員は、水流量計１０３ａで当該流量を確認し、操作バルブ１０２ａを用いて所望の値に調整することができる。また、ストップバルブ１０４ａを開閉することにより、純水の供給を停止したり、再開したりすることもできる。 The water pressurization tank 105 pressurizes pure water supplied from the water supply pipe 107b to a predetermined value A 1 (MP), and supplies a predetermined flow rate B 1 (l / min) of the pressurized pure water to the pressure pipe. 110 is sent to the nozzle 101 in a high-pressure state (however, depending on the nozzle shape, it is possible to send pure water to the nozzle without pressurization). The water flow meter 103 a measures the flow rate of pure water supplied from the water pressure tank 105 to the nozzle 101. The operator can check the flow rate with the water flow meter 103a and adjust it to a desired value using the operation valve 102a. In addition, the supply of pure water can be stopped or restarted by opening and closing the stop valve 104a.
　尚、本形態においては、窒素供給管１０８から窒素が水加圧タンク１０５に供給されるように構成されている。本最良形態では純水に窒素を混合したが、純水のみをノズル１０１に供給してもよいことは明らかである。また、窒素ガスに限定されず、Ａｒガスのような不活性ガスでも代替可能である。 In this embodiment, nitrogen is supplied from the nitrogen supply pipe 108 to the water pressurization tank 105. In this best mode, pure water is mixed with nitrogen, but it is obvious that only pure water may be supplied to the nozzle 101. Moreover, it is not limited to nitrogen gas, It can substitute also with inert gas like Ar gas.
　続いて、薬液タンク１１７は、ＣＯ２供給管１１８から供給されるＣＯ２を所定値に加圧し、薬液タンク内の剥離液にＣＯ２を溶解させる。次に、加圧した剥離液のうち所定の流量Ｂ２（ｌ／ｍｉｎ）を、耐圧管１１２を介してノズル１０１に送り出す。水流量計１０３ｂは、薬液タンク１１７からノズル１０１に供給される剥離液の流量を計測する。作業員は、水流量計１０３ｂで当該流量を確認し、操作バルブ１０２ｂを用いて所望の値に調整することができる。更に、ヒータ１１６が設けられているため、剥離液の温度を容易に調節できる。また、ストップバルブ１０４ｃを開閉することにより、剥離液の供給を停止したり、再開したりすることもできる。 Subsequently, the chemical liquid tank 117, pressurized CO 2 that is supplied from the CO 2 supply pipe 118 to a predetermined value, to dissolve the CO 2 stripping solution in the chemical liquid tank. Next, a predetermined flow rate B 2 (l / min) of the pressurized stripping solution is sent to the nozzle 101 through the pressure tube 112. The water flow meter 103b measures the flow rate of the stripping solution supplied from the chemical solution tank 117 to the nozzle 101. The operator can check the flow rate with the water flow meter 103b and adjust it to a desired value using the operation valve 102b. Further, since the heater 116 is provided, the temperature of the stripping solution can be easily adjusted. In addition, the supply of the stripping solution can be stopped or restarted by opening and closing the stop valve 104c.
　尚、本形態においては、ＣＯ２供給管１１８からＣＯ２が薬液タンク１１７に供給されるように構成されている。このように、薬液タンク中の剥離液にＣＯ２を供給可能に構成することにより、対象物に供給する剥離液中に含まれるＣＯ２の濃度を適宜調整することが可能となる。また、当該構成でなくとも、タンクからノズルまでの輸送管で二酸化炭素を吹き込み可能なように構成したり、ｐＨを調整する物質と混合可能に構成してもよい。その他、当該混合手段を有していなくとも、剥離液製造時にｐＨを調整してもよい。例えば、二酸化炭素を溶解させた後、二酸化炭素で封入した容器から剥離液を供給してもよい。 In the present embodiment, CO 2 from the CO 2 supply pipe 118 is configured to be supplied to the chemical liquid tank 117. In this manner, by configuring so that CO 2 can be supplied to the stripping solution in the chemical tank, it is possible to appropriately adjust the concentration of CO 2 contained in the stripping solution supplied to the object. In addition, the configuration may be such that carbon dioxide can be blown through a transport pipe from the tank to the nozzle, or may be mixed with a substance that adjusts the pH. In addition, even if it does not have the said mixing means, you may adjust pH at the time of stripping solution manufacture. For example, after dissolving carbon dioxide, the stripping solution may be supplied from a container sealed with carbon dioxide.
　次に、水蒸気発生器１０６は、水供給管１０７ａから供給される純水を所定温度Ｄ１（℃）以上に加温して水蒸気を発生し、耐圧管１１１を介して高圧状態でノズル１０１に送り出す。圧力計１１５は、水蒸気発生器１０６からノズル１０１に供給される水蒸気の圧力を計測する。作業員は、圧力計１１５で当該圧力を確認し、減圧弁１０９を用いて所望の値に調整することができる。また、ストップバルブ１０４ｂを開閉することにより、水蒸気の供給を停止したり、再開したりすることもできる。 Next, the water vapor generator 106 heats the pure water supplied from the water supply pipe 107 a to a predetermined temperature D 1 (° C.) or higher to generate water vapor, and is supplied to the nozzle 101 in a high pressure state via the pressure resistant pipe 111. Send it out. The pressure gauge 115 measures the pressure of water vapor supplied from the water vapor generator 106 to the nozzle 101. An operator can check the pressure with the pressure gauge 115 and adjust it to a desired value using the pressure reducing valve 109. In addition, the supply of water vapor can be stopped or restarted by opening and closing the stop valve 104b.
《洗浄方法》
　本発明に係る対象物洗浄方法は、剥離液と水蒸気とからなる混相流を対象物表面に対して噴射する剥離液噴射工程を含む。剥離液噴射工程は、本最良形態に係る剥離液と水蒸気とを混合した流体を対象物に噴射する工程である。本最良形態に係る剥離液は、当該噴射工程に係る方法で対象物に噴射されることにより、当該剥離液であっても十分な洗浄力を有し、且つ、半導体基板を損傷しないという効果をより好適に発揮する。特に、従来、剥離し難いとされていたプラズマエッチング後のビアホール側面に付着したポリマ残渣であっても、好適に剥離する能力を有する。当該方法は、例えば、本最良形態に係る洗浄システムＳ１により、実施可能である。ここで、剥離液噴射工程の各種条件について説明する。剥離液噴射工程における混相流の温度は、６０～１１５℃が好適であり、８０～１１３℃がより好適であり、９０～１１０℃が更に好適である。６０℃以上とすることにより、著しく反応速度が上がる。流体温度は、熱電対をウエハに設置し、所定の対象物間距離だけ離して１分間流体を噴射した後の定常状態の温度を流体温度とした。混相流の噴射速度は、６０ｍ／ｓ以上が好適であり、１４０ｍ／ｓ以上がより好適であり、２６０ｍ／ｓが更に好適である。上限は特に限定されないが、６００ｍ／ｓ以下である。噴射速度は、流体の体積流量をノズル口の断面積で除した値とする。剥離液流量は、０．０５～０．４ｄｍ３／ｍｉｎが好適であり、０．１～０．３ｄｍ３／ｍｉｎがより好適であり、０．１～０．２ｄｍ３／ｍｉｎが更に好適である。水蒸気と剥離液の混合比（［剥離液体積］／［水蒸気体積］）は、０．００００３～０．００５が好適であり、０．００００４～０．００２がより好適であり、０．００００５～０．００１５が更に好適である。処理時間は、２５～１８０秒が好適であり、４０～９０秒がより好適であり、５０～７０秒が更に好適である。尚、当該数値範囲は主に洗浄に影響するパラメータの限界値を示した値であり、これらの組合せは必要となる衝撃力の度合いに応じて容易に選択し設定することが可能である。 《Cleaning method》
The object washing | cleaning method which concerns on this invention includes the peeling liquid injection process which injects the multiphase flow which consists of peeling liquid and water vapor | steam with respect to the target object surface. The stripping solution spraying step is a step of spraying a fluid, which is a mixture of the stripping solution according to the best mode and water vapor, onto an object. The stripping solution according to the best mode has an effect that the stripping solution has sufficient cleaning power and does not damage the semiconductor substrate by being sprayed onto the object by the method according to the spraying step. It demonstrates more suitably. In particular, even polymer residues adhering to the side surface of a via hole after plasma etching, which has been conventionally considered difficult to peel off, have the ability to peel off suitably. The method can be performed by, for example, the cleaning system S1 according to the best mode. Here, the various conditions of a peeling liquid injection process are demonstrated. The temperature of the multiphase flow in the stripping solution jetting process is preferably 60 to 115 ° C, more preferably 80 to 113 ° C, and still more preferably 90 to 110 ° C. By setting the temperature at 60 ° C. or higher, the reaction rate is significantly increased. The fluid temperature was defined as the temperature in a steady state after a thermocouple was installed on the wafer and the fluid was ejected for one minute with a predetermined distance between the objects. The injection speed of the multiphase flow is preferably 60 m / s or more, more preferably 140 m / s or more, and further preferably 260 m / s. Although an upper limit is not specifically limited, It is 600 m / s or less. The ejection speed is a value obtained by dividing the volume flow rate of the fluid by the cross-sectional area of the nozzle opening. Stripping solution the flow rate is suitably 0.05 ~ 0.4dm 3 / min, 0.1 ~ 0.3dm 3 / min is more preferred, 0.1 ~ 0.2dm 3 / min is more preferred is there. The mixing ratio of water vapor and stripping solution ([stripping solution volume] / [water vapor volume]) is preferably 0.00003 to 0.005, more preferably 0.00004 to 0.002, and 0.00005 to 0.0015 is more preferred. The treatment time is preferably 25 to 180 seconds, more preferably 40 to 90 seconds, and even more preferably 50 to 70 seconds. Note that the numerical range is a value mainly indicating a limit value of a parameter that affects cleaning, and a combination of these can be easily selected and set according to the degree of required impact force.
　洗浄対象の対象物：厚さ０.６２５ｍｍのシリコンウエハ上に、厚さ１００μｍのＴｉＮの膜を形成し、さらにその上に厚さ１０００μｍのシリコン酸化膜（以後、酸化膜と記述）を形成した。リソグラフ、ドライエッチングを行い、開口径１μｍの穴を、ＴｉＮと酸化膜の界面の深さまで開けた。
　対象物洗浄システムＳ１により、対象物を洗浄した。当該実施例における条件は以下のとおりである。ポリマの残存及びホールの損傷は走査型電子顕微鏡により観察した。このとき、１例につき５つのホールの観察を行った。以下、実施例及び比較例のデータを示す。尚、表中の洗浄結果の“○”、“△”、“×”の評価方法は以下の通りである。前述の観察した５つのホール全てにおいてポリマが除去されていた例を“○”、１つ～４つのホールでポリマが残存していた例を“△”、５つのホール全てにポリマが残存していた例を“×”とした。 Object to be cleaned: a TiN film having a thickness of 100 μm was formed on a silicon wafer having a thickness of 0.625 mm, and a silicon oxide film having a thickness of 1000 μm (hereinafter referred to as an oxide film) was further formed thereon. . Lithograph and dry etching were performed, and a hole with an opening diameter of 1 μm was opened to the depth of the interface between TiN and the oxide film.
The object was cleaned by the object cleaning system S1. The conditions in the example are as follows. Residual polymer and hole damage were observed with a scanning electron microscope. At this time, 5 holes were observed per case. Hereafter, the data of an Example and a comparative example are shown. The evaluation methods for “◯”, “Δ”, and “×” of the cleaning results in the table are as follows. The example in which the polymer was removed in all the five holes observed above is “◯”, the example in which the polymer was left in one to four holes “△”, and the polymer was left in all five holes. An example is “×”.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Ｓ１～３：対象物洗浄システム
Ｗ：対象物
１００：噴射洗浄部
１０１：ノズル
１０２ａ～ｂ：操作バルブ
１０３ａ～ｂ：水流量計
１０４ａ～ｃ：ストップバルブ
１０５：水加圧タンク
１０６：水蒸気発生器
１０７ａ～ｂ：水供給管
１０８：窒素供給管
１０９：減圧弁
１１０～１１２：耐圧管
１１３：ステージ
１１４：チャンバ
１１５：圧力計
１１６：ヒータ
１１７：薬液タンク
１１８：ＣＯ２供給管 S1-3: Object cleaning system W: Object 100: Jet cleaning unit 101: Nozzle 102a-b: Operation valve 103a-b: Water flow meter 104a-c: Stop valve 105: Water pressurization tank 106: Steam generator 107a-b: water supply pipe 108: nitrogen supply pipe 109: pressure reducing valve 110-112: pressure-resistant pipe 113: stage 114: chamber 115: pressure gauge 116: heater 117: chemical tank 118: CO 2 supply pipe

Claims (4)

  1. 　カルボキシル基とカルボキシル基の間に炭素数０～２の飽和又は不飽和の炭素鎖を含むキレート形成可能なポリカルボン酸を含む、防食剤及び水溶性有機溶媒を実質的に含有しない水溶液からなる、対象物のポリマ残渣を剥離するための側壁保護膜除去用剥離液。 Comprising an aqueous solution substantially free of an anticorrosive and a water-soluble organic solvent, comprising a chelate-forming polycarboxylic acid containing a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between the carboxyl group and the carboxyl group, A stripping solution for removing a sidewall protective film for stripping a polymer residue of an object.
  2. 　前記ポリカルボン酸が、シュウ酸である、請求項１記載の側壁保護膜除去用剥離液。 The stripping solution for removing the sidewall protective film according to claim 1, wherein the polycarboxylic acid is oxalic acid.
  3. 　液体蒸気と液体とを混合してなる混相流体を噴射する工程を含む、対象物を洗浄する方法において、
    　前記液体蒸気が、水蒸気であり、
    　前記液体が、カルボキシル基とカルボキシル基の間に炭素数０～２の飽和又は不飽和の炭素鎖を含むキレート形成可能なポリカルボン酸を含む、防食剤及び水溶性有機溶媒を実質的に含有しない水溶液であることを特徴とする、対象物洗浄方法。     In a method for cleaning an object, including a step of injecting a multiphase fluid obtained by mixing liquid vapor and liquid,
    The liquid vapor is water vapor;
    The liquid is substantially free of anticorrosive and water-soluble organic solvent, including a chelatable polycarboxylic acid containing a saturated or unsaturated carbon chain having 0 to 2 carbon atoms between the carboxyl group and the carboxyl group. A method for cleaning an object, which is an aqueous solution.
  4. 　前記ポリカルボン酸が、シュウ酸である、請求項３記載の対象物洗浄方法。 The method for cleaning an object according to claim 3, wherein the polycarboxylic acid is oxalic acid.
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JP2003332288A (en) * 2002-05-10 2003-11-21 Lam Research Kk Water feeding method and water feeding apparatus
JP2004140196A (en) * 2002-10-17 2004-05-13 Nec Electronics Corp Manufacturing method of semiconductor device and substrate washing equipment
JP2004349577A (en) * 2003-05-23 2004-12-09 Aqua Science Kk Object processing device and object processing method
JP2005522027A (en) * 2002-03-25 2005-07-21 アドバンスド．テクノロジー．マテリアルス．インコーポレイテッド PH buffer composition for semiconductor substrate cleaning

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JP2005522027A (en) * 2002-03-25 2005-07-21 アドバンスド．テクノロジー．マテリアルス．インコーポレイテッド PH buffer composition for semiconductor substrate cleaning
JP2003332288A (en) * 2002-05-10 2003-11-21 Lam Research Kk Water feeding method and water feeding apparatus
JP2004140196A (en) * 2002-10-17 2004-05-13 Nec Electronics Corp Manufacturing method of semiconductor device and substrate washing equipment
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