JP2007234825A - Cleaning method of substrate processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the cleaning method of a substrate processing apparatus which can remove an unwanted extraneous matter of the target more easily and securely, and can prevent the damage of the target itself. <P>SOLUTION: A target 11 is put in an acid-proof container 31, nitrohydrofluoric acid-based water solution is inpoured, physical stimulation by ultrasonic wave is applied to the acid-proof container using an ultrasonic wave generator 30, the unwanted extraneous matter is oxidized by the action of nitric acid to float them from the target 11 by the action of hydrofluoric acid, the process to separate the floated unwanted extraneous matter from the target by the stimulation of the ultrasonic wave is carried out at the same time in the same water solution, and the unwanted extraneous matter is removed more easily and securely. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for removing a metal compound attached to a metal target of a substrate processing apparatus, and particularly to a method for removing only a refractory metal compound that is difficult to remove from a refractory metal target.

  Currently, a substrate processing apparatus using a metal target is used when a metal component-containing film is formed on a substrate by manufacturing a semiconductor or the like. As a substrate processing apparatus capable of forming a film with particularly good embedding properties, halogen radicals are used to halogenate a metal and reduce it again to deposit the metal (see Patent Document 1), or nitrogen is added to the halogenated metal. There is a metal-containing film creation apparatus that deposits as a metal nitride film by acting a contained gas plasma (see Patent Document 2).

  For example, when forming a metal film using this apparatus, a metal (M) target is provided in the chamber, a halogen gas is supplied, an induction plasma is generated to generate a halogen gas plasma, and a halogen radical is generated. A precursor of a metal component and a halogen gas component contained in the target is generated by etching the target with the halogen radical, and the precursor is reduced with the halogen radical on the substrate at a temperature lower than that of the target, and the metal component is the substrate. Adsorb to the surface.

This series of reactions is represented by the following formula when halogen is chlorine.
(1) Plasma dissociation reaction; Cl ₂ → 2Cl ^*
(2) Etching reaction; M + Cl ^* → MCl (g)
(3) Adsorption reaction to the substrate; MC1 (g) → MC1 (ad)
(4) Film formation reaction; MCl (ad) + Cl ^* → M + Cl ₂ ↑
In the formula, Cl ^* represents a chlorine radical, (g) represents a gas state, and (ad) represents an adsorption state. For the metal M, a substance (such as copper) that forms a high vapor pressure halide is used.

  By utilizing this series of reaction formulas, the reaction can be reversed in some cases, and etching opposite to film formation can be performed.

  Since the metal target used in the substrate processing apparatus is likely to adhere to undesired substances, it is often cleaned as necessary. In particular, in an apparatus for producing a metal-containing film by reacting a halogen radical with a metal target, the metal halide tends to adhere to the metal target, and it is necessary to remove the metal halide.

  Until now, various methods have been used for cleaning a metal target of a substrate processing apparatus. Among these, wet cleaning using an acid can be cited as a method for easily removing a large amount of metal compound from a metal target.

JP 2003-147534 A Japanese Patent Laid-Open No. 2003-247071

  However, so far, it is possible to remove only unwanted substances without excessively dissolving the metal target using an acid solution, and it is also possible to remove the refractory metal compound firmly attached to the refractory metal target. No cleaning method that can handle various metal targets has been reported.

  In view of the above situation, the present invention can remove only undesirable substances without excessively dissolving the metal target, and can also remove refractory metal compounds firmly attached to the refractory metal target. It is an object of the present invention to provide a cleaning method for a substrate processing apparatus using an acid solution that can be applied to the metal target.

  In order to achieve the above object, a cleaning method for a substrate processing apparatus of the present invention according to claim 1 uses a hydrofluoric acid-based aqueous solution containing hydrofluoric acid, nitric acid, and water, and applies a physical stimulus to the substrate processing apparatus. It is characterized by performing cleaning.

  In the present invention according to claim 1, the unwanted deposits are oxidized by the action of nitric acid, floated from the substrate processing apparatus by the action of hydrofluoric acid, and the floated unwanted deposits are separated from the substrate processing apparatus by physical stimulation. By simultaneously performing the steps in the same aqueous solution, it is possible to more easily and reliably remove unwanted deposits.

  According to a second aspect of the present invention, there is provided a cleaning method for a substrate processing apparatus according to the first aspect of the present invention, wherein the substrate processing apparatus is cleaned by jet spraying, boiling, or physical stimulation by ultrasonic waves. It is characterized by performing cleaning.

  In the present invention according to claim 2, by applying physical stimulation by jet spraying, boiling, or ultrasonic waves, it becomes possible to more easily separate undesired substances, and effective cleaning can be performed.

  According to a third aspect of the present invention, there is provided a substrate processing apparatus cleaning method according to the first or second aspect, wherein the metal target of the substrate processing apparatus is cleaned.

  According to the third aspect of the present invention, effective metal target cleaning can be performed.

  According to a fourth aspect of the present invention, there is provided a substrate processing apparatus cleaning method according to any one of the first to third aspects, wherein the refractory metal target of the substrate processing apparatus is cleaned. Features.

  According to the fourth aspect of the present invention, effective refractory metal target cleaning can be performed.

  A cleaning method for a substrate processing apparatus according to a fifth aspect of the present invention is the cleaning method for a substrate processing apparatus according to any one of the first to fourth aspects, wherein a halogen radical is allowed to act on the metal, the metal component and the halogen The precursor is deposited, the precursor is deposited, and the deposited precursor is reduced by halogen radicals to clean a substrate processing apparatus that performs substrate processing.

  In the present invention according to claim 5, it is possible to effectively remove unwanted deposits composed of halides in particular.

  A cleaning method for a substrate processing apparatus according to a sixth aspect of the present invention is the cleaning method for a substrate processing apparatus according to the third or fourth aspect, wherein a halogen radical is allowed to act on the metal, and the precursor of the metal component and the halogen. And depositing the precursor, and reducing only the undesired deposits attached to the metal target from the metal target of the substrate processing apparatus that performs substrate processing by reducing the deposited precursor with halogen radicals. Features.

  In this invention which concerns on Claim 6, the unwanted deposit which consists of a halide especially can be effectively removed from a metal target.

  A cleaning method for a substrate processing apparatus of the present invention according to claim 7 is the cleaning method for a substrate processing apparatus according to claim 6, wherein only the chloride or nitride adhering to the metal target is removed from the metal target. It is characterized by.

  In the present invention according to claim 7, only the chloride or nitride adhering to the metal target can be effectively removed from the metal target.

  A cleaning method for a substrate processing apparatus according to an eighth aspect of the present invention is the cleaning method for a substrate processing apparatus according to the sixth aspect, wherein only unwanted deposits attached to the refractory metal target from the refractory metal target are removed. It is characterized by removing.

  In the present invention according to claim 8, only the unwanted deposits attached to the refractory metal target can be effectively removed from the refractory metal target.

  A cleaning method for a substrate processing apparatus according to a ninth aspect of the present invention is the cleaning method for a substrate processing apparatus according to the eighth aspect, wherein only a chloride or nitride attached to the refractory metal target from the refractory metal target is used. It is characterized by removing.

  In the present invention according to claim 9, only the chloride or nitride adhering to the refractory metal target can be effectively removed from the refractory metal target.

  A cleaning method for a substrate processing apparatus according to a tenth aspect of the present invention is the cleaning method for a substrate processing apparatus according to any one of the first to ninth aspects, wherein the hydrofluoric acid aqueous solution is hydrofluoric acid: nitric acid: water = It is characterized in that x: 3: 6 (0 <x ≦ 1) and hydrofluoric acid: hydrofluoric acid aqueous solution = y: 10 (0 <y ≦ 1).

  In the present invention according to claim 10, by performing cleaning using an acid solution mixed at a weight ratio of nitric acid: water = 1: 2, appropriate oxidation is performed while preventing excessive oxidation due to excessive nitric acid. Only the undesired material can be removed from the substrate processing apparatus. In addition, since hydrofluoric acid provides a sufficient effect with 10 W% of the hydrofluoric acid-based aqueous solution, excessive use of hydrofluoric acid can be prevented by mixing the hydrofluoric acid with a ratio not exceeding 10 W% of the hydrofluoric acid-based aqueous solution. can do.

  The substrate processing apparatus cleaning method of the present invention uses a hydrofluoric acid aqueous solution containing hydrofluoric acid, nitric acid, and water, and cleans the substrate processing apparatus by applying a physical stimulus, thereby removing undesired deposits in nitric acid. Oxidized by the action of hydrofluoric acid, floated from the substrate processing apparatus by the action of hydrofluoric acid, and separated from the substrate processing apparatus by physical stimulation at the same time in the same aqueous solution. In addition, it is possible to remove unwanted deposits, and it is possible to remove only unwanted substances from the substrate processing apparatus without excessively dissolving the substrate processing apparatus itself.

(First embodiment)
The present invention relates to a cleaning method for a substrate processing apparatus, and in this embodiment, a halogen radical is allowed to act on a refractory metal to generate a precursor of a refractory metal component and a halogen gas component. The substrate is transported onto a substrate and reduced again on the substrate to be a target of a substrate processing apparatus for producing a refractory metal film.

  Specifically, the refractory metal film is prepared by providing a target made of a refractory metal (M) in a vacuum chamber, supplying a halogen gas, generating induction plasma, generating a halogen radical, A precursor of a refractory metal component and a halogen gas component is generated by etching the target with radicals, and the precursor is reduced with a halogen radical on a substrate having a temperature lower than that of the target. It is made to adsorb to.

This series of reactions is represented by the following formula when halogen is chlorine.
(1) Plasma dissociation reaction; Cl ₂ → 2Cl ^*
(2) Etching reaction; M + Cl ^* → MCl (g)
(3) Adsorption reaction to the substrate; MC1 (g) → MC1 (ad)
(4) Film formation reaction; MCl (ad) + Cl ^* → M + Cl ₂ ↑
In the formula, Cl ^* represents a chlorine radical, (g) represents a gas state, and (ad) represents an adsorption state. For the refractory metal M, a substance (such as tantalum) that forms a high vapor pressure halide is used.

  FIG. 1 is a schematic cross-sectional view of a substrate processing apparatus that performs substrate processing using this series of reactions.

  A support base 2 is provided near the bottom of the chamber 1 formed in a cylindrical shape, and a substrate 3 is placed on the support base 2. The substrate 3 is controlled to a predetermined temperature by a temperature control means 6 provided with a heater 4 and a refrigerant flow means 5 provided on the support base 2.

  The upper surface of the chamber 1 is an opening, and the opening is closed by the ceiling plate 7. Above the ceiling plate 7 is provided a plasma antenna 8 for converting the inside of the chamber 1 into plasma. The plasma antenna 8 is connected to a matching unit 9 and a high frequency power source 10 to be supplied with high frequency. Plasma generating means for generating induction plasma is constituted by the plasma antenna 8, the matching unit 9, and the high frequency power source 10. A target 11 made of a refractory metal is supported on an annular member 12 on the substrate 3 in the chamber 1 and supplied with a refractory metal as a raw material. The target 11 (metal target) has a shape in which the long portion 21 is supported by the ring portion 20 as shown in FIG.

  Above the target 11, a gas supply nozzle 14 is provided as a halogen gas supply means for supplying a halogen gas 13 into the chamber 1. A halogen gas 13 is sent to the nozzle 14 via a flow rate controller 15 whose flow rate and pressure are controlled.

  The gas supplied into the apparatus is exhausted from the exhaust port 16 and maintained at a predetermined pressure by the vacuum apparatus 17.

  A halogen gas 13 is supplied into the chamber 1 maintained at a predetermined pressure, plasma is generated to generate halogen radicals, the target 11 made of a refractory metal is etched by the halogen radicals, and a refractory metal component and a halogen are then generated. And the precursor is adsorbed on the substrate 3, and the precursor is reduced on the substrate 3, whereby only the refractory metal component is deposited.

  In the film formation of a refractory metal using the halogen radical, a chloride of the target component may adhere to the target 11, and if the amount of adhesion is large, it needs to be removed together with other unwanted deposits.

  The present embodiment relates to a cleaning method for removing undesired deposits including a refractory metal chloride from the target of the substrate processing apparatus shown in FIGS. 1 and 2. This embodiment will be described in detail below.

  FIG. 3 is a schematic view of an apparatus used when the target of the substrate processing apparatus shown in FIGS. 1 and 2 is cleaned using ultrasonic waves. An acid-resistant container 31 made of Teflon (registered trademark) is placed on the ultrasonic generator 30, and a Teflon (registered trademark) mesh-like support base 32 is installed in the acid-resistant container 31, and the target is placed on the mesh-like support base 32. 11 is placed. A hydrofluoric acid-based aqueous solution 33 is injected into the acid resistant container 31, and ultrasonic waves are generated using the ultrasonic generator 30. The hydrofluoric acid aqueous solution 33 is a mixture of hydrofluoric acid: nitric acid: water = 1: 3: 6 in a weight ratio.

  The target 11 is immersed in the hydrofluoric acid aqueous solution 33 shown in FIG. 3 and ultrasonic waves are generated to remove refractory metal chloride, which is a chloride of the target 11 component, from the target 11. As a result, the steps of oxidizing the unwanted deposits by the action of nitric acid, floating from the target 11 by the action of hydrofluoric acid, and separating the floated unwanted deposits from the target 11 by ultrasonic stimulation are simultaneously performed in the same aqueous solution. It is possible to remove unwanted deposits more easily and reliably. Moreover, by using the hydrofluoric acid aqueous solution 33 mixed at a weight ratio of hydrofluoric acid: nitric acid: water = 1: 3: 6, it is possible to perform appropriate oxidation while preventing excessive oxidation due to excessive nitric acid, Only unwanted material can be removed from the target. Furthermore, since sufficient effect can be obtained with 10 W% of the hydrofluoric acid aqueous solution 33, hydrofluoric acid is mixed at a ratio not exceeding 10 W% of the hydrofluoric acid aqueous solution 33, so that excessive use of hydrofluoric acid is possible. Can be prevented.

  In the present embodiment, the ultrasonic generator 30 is used to provide physical stimulation. However, a heater (not shown) may be used in place of the ultrasonic generator 30 and boiling may be performed by applying heat. Desired deposits can be separated from the target. Further, the material of the acid resistant container 31 is not limited to Teflon (registered trademark) as long as it is resistant to hydrofluoric acid, and the shape is not limited. Similarly, the reticulated support base 32 may have a non-reticulated shape, and is not limited to Teflon (registered trademark) as long as the material is resistant to hydrofluoric acid. Moreover, the mesh support 32 may not be used.

  The object to be cleaned is not limited to the refractory metal target 11 of the substrate processing apparatus using halogen radicals, and the material of the object may be an insulating part such as quartz or a metal part other than the target 11. Even if the object to be cleaned is dissolved in the hydrofluoric acid-based aqueous solution 33, if the immersion in the hydrofluoric acid-based aqueous solution 33 is performed for a short time and then water-washing is performed instantaneously, the cleaning method of the present invention is used. Undesired deposits such as chloride can be easily removed. Further, the shape of the cleaning object is not limited, and a plurality of parts may be cleaned together or individually.

  Another acid such as acetic acid may be added to the hydrofluoric acid aqueous solution 33. In that case, the mixing ratio of acid and water is used under conditions suitable for the object and situation. Undesirable deposits to be removed are not limited to chloride, but include nitride and other materials. Further, a trap for removing the solid matter of the unwanted deposits that have been removed, and a system for effectively reusing or safely discarding the solution after cleaning may be provided.

  In the apparatus of FIG. 1, a nitrogen-containing gas supply means (not shown) and, if necessary, a nitrogen-containing gas plasma generating means (not shown) are added below the target 11 to generate a nitrogen-containing gas plasma below the target 11. Thus, a metal nitride film can be formed on the substrate 3. That is, metal nitride (MN) is generated on the substrate 3 by causing MCl (g) generated by the etching reaction shown in the formula (2) in the vicinity of the target 11 in FIG. It is possible to create a metal nitride film. In forming the metal nitride film, it may be necessary to remove undesired nitride adhering to the substrate processing apparatus. The cleaning method for a substrate processing apparatus of the present invention shown in the present embodiment is also effective for such nitride cleaning.

(Second Embodiment)
Also in the present embodiment, as in the first embodiment, a halogen radical is allowed to act on a refractory metal, a precursor of a metal component and a halogen gas component is generated, and the precursor is transported onto the substrate. The target 11 of the substrate processing apparatus shown in FIG. 1 and FIG. In the film formation using halogen, the chloride of the target component may adhere to the target, and when the amount of adhesion is large, it needs to be removed together with other unwanted deposits.

  Hereinafter, a cleaning method for a substrate processing apparatus according to the second embodiment will be described in detail with reference to the drawings.

  FIG. 4 shows a schematic view of a cleaning apparatus when cleaning the substrate processing apparatus using jet spray. A reticulated support base 32 made of Teflon (registered trademark) is installed in the acid resistant container 31, and the target 11 is placed on the reticulated support base. A hydrofluoric acid aqueous solution 33 is jet sprayed onto the target 11 using the movable jet spray nozzle 34. The hydrofluoric acid aqueous solution 33 is a mixture of hydrofluoric acid: nitric acid: water = 1: 3: 6 in a weight ratio.

  A hydrofluoric acid aqueous solution 33 is jet sprayed onto the target 11 to remove from the target 11 refractory metal chloride, which is a chloride of the target 11 component. As a result, the step of oxidizing the unwanted deposits by the action of nitric acid, floating the target deposits 11 by the action of hydrofluoric acid, and separating the floated unwanted deposits from the target 11 by jet spray stimulation is performed simultaneously. It is possible to easily and reliably remove unwanted deposits. Moreover, by using the hydrofluoric acid aqueous solution 33 mixed at a weight ratio of hydrofluoric acid: nitric acid: water = 1: 3: 6, it is possible to perform appropriate oxidation while preventing excessive oxidation due to excessive nitric acid, Only unwanted materials can be removed from the target 11. Furthermore, since sufficient effect can be obtained with 10 W% of the hydrofluoric acid aqueous solution 33, hydrofluoric acid is mixed at a ratio not exceeding 10 W% of the hydrofluoric acid aqueous solution 33, so that excessive use of hydrofluoric acid is possible. Can be prevented. The hydrofluoric acid aqueous solution may be used by heating.

  The material of the acid resistant container 31 is not limited to Teflon (registered trademark) as long as it is resistant to hydrofluoric acid, and the shape is not limited. Similarly, the reticulated support base 32 may have a non-reticulated shape, and is not limited to Teflon (registered trademark) as long as the material is resistant to hydrofluoric acid. Moreover, the mesh support 32 may not be used.

  The object to be cleaned is not limited to the refractory metal target 11 of the substrate processing apparatus using halogen radicals, and the material of the object may be an insulating part such as quartz or a metal part other than the target 11. Even if the object to be cleaned is dissolved in the hydrofluoric acid aqueous solution 33, the cleaning method of the present invention can be used as long as the jet spraying of the hydrofluoric acid aqueous solution 33 is performed for a short time and then the water is instantly washed. Undesired deposits such as chloride can be easily removed. Further, the shape of the cleaning object is not limited, and a plurality of parts may be cleaned together or individually.

  Another acid such as acetic acid may be added to the hydrofluoric acid aqueous solution. In that case, the mixing ratio of acid and water is used under conditions suitable for the object and situation. Undesirable deposits to be removed are not limited to chloride, but include nitride and other materials. Further, a trap for removing the solid matter of the unwanted deposits that have been removed, and a system for effectively reusing or safely discarding the solution after cleaning may be provided.

  In the apparatus of FIG. 1, a nitrogen-containing gas supply means (not shown) and, if necessary, a nitrogen-containing gas plasma generating means (not shown) are added below the target 11 to generate a nitrogen-containing gas plasma below the target 11. Thus, a metal nitride film can be formed on the substrate 3. That is, metal nitride (MN) is generated on the substrate 3 by causing MCl (g) generated by the etching reaction shown in the formula (2) in the vicinity of the target 11 in FIG. It is possible to create a metal nitride film. In forming the metal nitride film, it may be necessary to remove undesired nitride adhering to the substrate processing apparatus. The cleaning method for a substrate processing apparatus of the present invention shown in the present embodiment is also effective for such nitride cleaning.

It is the cross-sectional schematic of the substrate processing apparatus using the target used as the object of the cleaning which concerns on 1st Embodiment and 2nd Embodiment of this invention. It is the schematic of the target of the substrate processing apparatus cleaned by 1st Embodiment and 2nd Embodiment of this invention. 1 is a schematic cross-sectional view of a cleaning apparatus for a substrate processing apparatus according to a first embodiment of the present invention. It is the cross-sectional schematic of the apparatus for cleaning of the substrate processing apparatus which concerns on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chamber 2 Support stand 3 Substrate 4 Heater 5 Refrigerant distribution means 6 Temperature control means 7 Ceiling board 8 Plasma antenna 9 Matching device 10 High frequency power supply 11 Target 12 Ring member 13 Halogen gas 14 Nozzle 15 Flow rate controller 16 Exhaust port 17 Vacuum apparatus 20 Ring part 21 Long part 30 Ultrasonic generator 31 Acid resistant container 32 Reticulated support base 33 Hydrofluoric acid aqueous solution 34 Movable jet spray nozzle

Claims (10)

  A method for cleaning a substrate processing apparatus, comprising using a hydrofluoric acid aqueous solution containing hydrofluoric acid, nitric acid, and water, and applying physical stimulation to clean the substrate processing apparatus. In the cleaning method of the substrate processing apparatus according to claim 1,
A cleaning method for a substrate processing apparatus, wherein the substrate processing apparatus is cleaned by applying a physical stimulus by jet spraying, boiling, or ultrasonic waves. In the cleaning method of the substrate processing apparatus according to claim 1 or 2,
A cleaning method for a substrate processing apparatus, comprising: cleaning a metal target of the substrate processing apparatus. In the cleaning method of the substrate processing apparatus in any one of Claims 1-3,
A cleaning method for a substrate processing apparatus, comprising: cleaning a refractory metal target of the substrate processing apparatus. In the cleaning method of the substrate processing apparatus in any one of Claims 1-4,
A halogen radical is allowed to act on a metal to generate a precursor of a metal component and a halogen, and the precursor is deposited, and at the same time, the deposited precursor is reduced by the halogen radical to clean a substrate processing apparatus that performs substrate processing. A cleaning method for a substrate processing apparatus, comprising: In the cleaning method of the substrate processing apparatus of Claim 3 or 4,
A metal target of a substrate processing apparatus that causes a halogen radical to act on a metal, generates a precursor of a metal component and a halogen, deposits the precursor, and reduces the deposited precursor with the halogen radical to perform substrate processing. A method for cleaning a substrate processing apparatus, wherein only unwanted deposits adhered to a metal target are removed from the substrate. In the cleaning method of the substrate processing apparatus according to claim 6,
A cleaning method for a substrate processing apparatus, wherein only a chloride or nitride adhering to a metal target is removed from the metal target. In the cleaning method of the substrate processing apparatus according to claim 6,
A cleaning method for a substrate processing apparatus, wherein only unwanted deposits attached to a refractory metal target are removed from the refractory metal target. In the cleaning method of the substrate processing apparatus according to claim 8,
A cleaning method for a substrate processing apparatus, wherein only a chloride or nitride adhering to a refractory metal target is removed from the refractory metal target. In the cleaning method of the substrate processing apparatus in any one of Claims 1-9,
A hydrofluoric acid aqueous solution is mixed at a weight ratio of hydrofluoric acid: nitric acid: water = x: 3: 6 (0 <x ≦ 1) and hydrofluoric acid: hydrofluoric acid aqueous solution = y: 10 (0 <y ≦ 1). A cleaning method for a substrate processing apparatus, wherein the substrate processing apparatus is an aqueous solution.

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