JP6266680B2 - Cleaning method and cleaning liquid - Google Patents

Description

  The present invention relates to a method for cleaning an article and a cleaning liquid used in the method.

  In the surface cleaning of electronic materials such as semiconductor wafer plates for semiconductors, there is known a method of cleaning while decomposing ozone by irradiating ultraviolet rays using ozone water (see Patent Documents 1 to 4). In such a method, for example, a resist film formed on the surface of an electronic material can be peeled off by strong oxidizing power of hydroxyl radicals (also referred to as OH radicals) generated when ozone is decomposed.

  In addition, a method using microbubbles is known as a method for cleaning the surface of an electronic material by generating OH radicals without performing ultraviolet irradiation (see Non-Patent Document 1 and Non-Patent Document 2). In the method, ozone or air microbubbles are generated in water, and a large amount of OH radicals are generated when the bubbles disappear, thereby obtaining a high cleaning effect. According to these methods, it is known that removal is very difficult by a combination of ozone microbubbles, 5% tetramethylammonium hydroxide (hereinafter sometimes referred to as TMAH) and air microbubbles. “A resist partially transformed into amorphous carbon by high-concentration ion implantation treatment (the amorphous carbon portion of the resist is sometimes referred to as crest. Hereinafter, the resist is also referred to as a surface crested resist. .) ”Can also be removed.

  Furthermore, in order to decompose and remove organic compounds adhering to solid surfaces such as wafers and TOC decomposition in ultrapure water, maintain the concentration of OH radicals generated at locations away from the point of use for several minutes. There is also known a method of supplying cleaning to a use point (see Patent Document 5). In Patent Document 5, ozone, hydrogen peroxide, and at least one additive selected from the group consisting of a water-soluble organic substance, an inorganic acid, a salt of the inorganic acid, and hydrazine are dissolved in pure water. And generating a hydroxyl radical-containing water, a transfer step of transferring the generated hydroxyl radical-containing water to a point of use, and a supplying step of supplying the hydroxyl radical-containing water after transfer at the point of use. A method for supplying hydroxyl radical-containing water is disclosed.

  However, in the case of using ozone water, measures for suppressing exposure of the human body to ozone are required. In addition, it is difficult to supply a stable concentration of ozone water with a normal ozone generator, and furthermore, since the lifetime of OH radicals is extremely short, it is difficult to control the dissolved ozone concentration at the point of use. Further, in order to generate microbubbles, a microbubble generator is required, and not only the cleaning apparatus is increased in size, but also the control and maintenance of these apparatuses becomes complicated.

  As a method of generating OH radicals without using ozone or microbubbles, a method of irradiating hydrogen peroxide, nitric acid or nitrous acid with ultraviolet rays is known. Hydrogen peroxide absorbs ultraviolet rays having a wavelength of 290 nm or less and generates OH radicals. In addition, nitrate ions directly generate OH radicals when irradiated with ultraviolet rays having a wavelength of 240 nm or less (see Non-Patent Documents 3 and 4). The generation of OH radicals from nitrate ions is considered to go through reduction from nitrate ions to nitrite ions, and from the viewpoint of binding energy, OH radicals from nitrite ions are generated more than OH radicals directly from nitrate ions. It is advantageous to generate radicals. In the generation of OH radicals by irradiating nitrite ions with ultraviolet rays, OH radicals can be generated even with longer wavelength ultraviolet rays.

  An example of cleaning the surface of an electronic material by irradiating an aqueous solution of hydrogen peroxide that does not contain ozone with ultraviolet rays is a mixture of hydrogen peroxide water, alkaline solution such as volatile ammonia solution, and pure water. A method is known in which a cleaning liquid is used to irradiate the cleaning liquid with ultraviolet rays to form an irradiation cleaning liquid, and the substrate is cleaned with the irradiation cleaning liquid immediately after the ultraviolet irradiation is completed (see Patent Document 6).

  On the other hand, a cleaning method using the oxidizing power of hydrogen peroxide is also known. For example, a cleaning solution obtained by mixing a hydrogen peroxide solution added with a chelating agent, a basic chemical solution such as ammonia or TMAH, and water. A method of cleaning a trench having a high aspect ratio by a BOSCH process using high-density plasma is known (see Patent Document 7). In this method, cleaning is performed by a lift-off mechanism in which the substrate surface is oxidized by the oxidizing power of hydrogen peroxide and the formed oxide layer is dissolved with a basic chemical solution. Since the cleaning liquid does not contain ozone and is not irradiated with ultraviolet rays, it is considered that there is almost no contribution of OH radicals.

Japanese Patent No. 3016301 Japanese Patent No. 4513122 JP 2008-166404 A Japanese Patent No. 3034720 International Publication No. 2010/140581 Pamphlet Japanese Patent No. 3125753 Japanese Patent No. 5278492 Japanese Patent No. 5591305

M. Takahashi, H. Ishikawa, T. Asano, and H. Horibe, Effect of Microbubbles on Ozonized Water for Photoresist Removal, Journal of Physical Chemistry C 116,12578-12583, (2012) FY2010 Strategic Substrate Technology Advancement Support Project “Development of Environmentally Friendly Semiconductor Wafer Cleaning Equipment Using Micro-Nano Bubbles” Research Results Report, March 2013, Contractor Kanto Bureau of Economy, Trade and Industry, Contractor Hitachinaka Techno Center Co., Ltd. Bull. Korean Chem. Soc. 2011, Vol. 32, No. 8, 3039-3044. Techneau, D2.4.1.1, 1-27. https://dspace.wul.waseda.ac.jp/dspace/handle/2065/5349, Sota Nakagawa “Process for Decomposing Trace Organic Substances in Wastewater by Enhanced Oxidation” p10, Table 1.5

According to the method described in Patent Document 5, it is claimed that organic contamination, particle contamination, and metal contamination can be removed with a relatively low concentration chemical solution.
However, since the lifetime of the OH radical is extremely short, even if the substrate is cleaned immediately after the cleaning liquid is irradiated with ultraviolet rays, the OH radical concentration is drastically lowered. Therefore, there remains a question about the detergency of contaminants that are very difficult to remove, such as resists whose surfaces are highly crested by high concentration ion implantation (surface crested resist). Even if the method described in Patent Document 5 is used to extend the lifetime of OH radicals, the OH radical concentration over time is unavoidably reduced although there is a difference in degree. The need to use salt and the like also arises.

  Therefore, an object of the present invention is to provide a cleaning method that can perform cleaning with a high OH radical concentration that can remove a surface crested resist using a cleaning liquid that does not use ozone or microbubbles.

  The inventors of the present invention are cleaning liquids that do not contain ozone or metal ions, while irradiating ultraviolet rays with high intensity in a state where a cleaning liquid that generates OH radicals by ultraviolet irradiation is held on the surface of the surface to be cleaned. The inventors have conceived that the cleaning is performed for a predetermined time, and obtained the knowledge that the higher the energy of ultraviolet rays to be irradiated (the shorter the wavelength of ultraviolet rays), the higher the generation efficiency of OH radicals, and the present invention has been completed.

The first aspect of the present invention is: (a) a cleaning agent comprising hydrogen peroxide, quaternary ammonium hydroxide, and water and not containing ozone and metal ions is attached to the surface of the surface to be cleaned. And (b) irradiating the cleaning liquid adhered and held on the surface of the surface to be cleaned with an ultraviolet ray having a wavelength of 200 nm or more and 250 nm or less from an ultraviolet light source. ), The ultraviolet light irradiation time: t (unit: second) and / or the light emission output of the ultraviolet light source: P (unit: mW) is controlled to be held on the surface of the surface to be cleaned within the irradiation time. Cleaning of an object to be cleaned, characterized in that an integrated dose I (unit: mJ / cm ² ) of ultraviolet rays irradiated to the cleaning liquid is not less than a predetermined integrated dose I ₀ set in advance. Is the method.

  In the method of the first aspect of the present invention, an ultraviolet light source having an ultraviolet light emitting diode (hereinafter sometimes referred to as “UV-LED”) that emits ultraviolet light having a peak in a wavelength region of 200 nm to 250 nm as the ultraviolet light source. The light emission output P of the ultraviolet light source is preferably controlled by controlling the forward current flowing through the ultraviolet light emitting diode.

  Further, it is preferable that the temperature of the object to be cleaned or the temperature of the cleaning liquid at the time of irradiation with the ultraviolet light is 50 ° C. or higher and 80 ° C. or lower.

Furthermore, in the method of the first aspect of the present invention, for each cleaning basic condition comprising a combination of the type of the object to be cleaned, the temperature of the object to be cleaned or the temperature of the cleaning liquid at the time of ultraviolet irradiation, and the type of the cleaning agent, The light emission intensity P of the light source is set to a predetermined light emission intensity P ₀ , the irradiation time t is changed, the steps (a) and (b) are repeated, and the shortest irradiation time t _{min at} which a sufficient cleaning effect is obtained is determined. The integrated dose calculated as the product of the light emission intensity P ₀ and the shortest irradiation time t _min is preferably the predetermined integrated dose I ₀ when cleaning is performed under the same cleaning basic conditions.

As shown in Non-Patent Documents 1 and 2, the detergency for the surface crested resist depends on the OH radical concentration and is promoted by the coexistence of a quaternary ammonium hydroxide such as TMAH. Therefore, the shortest irradiation time t _min can be determined even for an object to be cleaned to which a substance that is difficult to remove such as a surface crested resist adheres. At this time, whether or not a sufficient cleaning effect has been obtained can be easily determined by observing the surface of the object to be cleaned with an electron microscope or analyzing a cleaning liquid.

Furthermore, when the effective optical path length is defined as the thickness at which the irradiance of the transmitted ultraviolet light is 0.01 mW / cm ² when the ultraviolet light emitted from the ultraviolet light source passes through the layer made of the cleaning agent, In the step (a), the surface of the surface to be cleaned is covered so that the cleaning agent covers the entire surface of the surface to be cleaned, and the thickness of the layer of the cleaning agent covering the surface to be cleaned is equal to or less than the effective optical path length. It is preferable that the cleaning agent is attached to and held on the substrate and that the light source and the cleaning agent are not contacted with each other in the step (b).

  The second aspect of the present invention is a cleaning agent used in the method of the first aspect of the present invention, which contains hydrogen peroxide, quaternary ammonium hydroxide, and water, and does not contain ozone and metal ions. It is a cleaning agent characterized by this.

  The cleaning agent of the second aspect of the present invention preferably further comprises a water-soluble organic solvent or further comprises a chelating agent.

The third aspect of the present invention is a method for manufacturing a semiconductor wafer having a structure made of a low-k material and an ion implantation region, wherein the number of atoms per unit area is 1 × 10 ¹⁴ atoms / cm ² or more and 1 × 10 ¹⁷ atoms. A method for producing a semiconductor wafer comprising a step of removing a photoresist layer exposed to ion implantation of / cm ² or less by the cleaning method of the first aspect of the present invention.

  In this specification, the “low-k material” means an insulator material having a relative dielectric constant of less than 3.5.

  According to the cleaning method of the first aspect of the present invention, since the ultraviolet rays are irradiated throughout the cleaning, new OH radicals are constantly generated even if the lifetime of the OH radicals is short, so that a high cleaning effect can be obtained. Can do. Furthermore, since an ozone generator and a microbubble generator are not required, the apparatus can be made compact by using a UV-LED as an ultraviolet light source, and operation and maintenance are facilitated.

  Further, for example, according to the cleaning method of the first aspect of the present invention in which the distance d (unit: cm) between the object to be cleaned and the ultraviolet light source and / or the light emission output P (unit: mW) of the ultraviolet light source is controlled. For example, effective cleaning can be performed in a short time such as several minutes, and the applicability to a single wafer cleaning apparatus is also high.

  Conventionally, the surface-crested resist has been generally removed using a solution-based cleaning agent after ashing. However, the ashing process is not suitable for manufacturing a semiconductor wafer having a highly miniaturized pattern because it may damage a low-k material used as an interlayer insulating film in manufacturing the semiconductor wafer. According to the cleaning method of the first aspect of the present invention, the surface crested resist can be removed only by wet cleaning without passing through such an ashing process that causes damage to the low-k material. Therefore, the cleaning method of the first aspect of the present invention can be particularly preferably employed as a cleaning step in a manufacturing process of a semiconductor wafer having a highly miniaturized pattern.

  The cleaning liquid of the second aspect of the present invention can be preferably used as the cleaning liquid in the cleaning method of the first aspect of the present invention.

  According to the semiconductor wafer manufacturing method of the third aspect of the present invention, the removal of the photoresist layer (surface crested resist) exposed to high dose ion implantation is performed by the cleaning method of the first aspect of the present invention. -Eliminates ashing process that causes damage to materials. Therefore, the semiconductor wafer manufacturing method of the third aspect of the present invention can be preferably used for manufacturing a semiconductor wafer having a highly miniaturized pattern.

It is a longitudinal cross-sectional view which illustrates typically the washing | cleaning apparatus 100 which can perform suitably the washing | cleaning method of this invention. FIG. 6 is a longitudinal sectional view schematically illustrating another posture of the cleaning device 100. It is a longitudinal cross-sectional view which illustrates typically other washing | cleaning apparatus 100 'which can perform suitably the washing | cleaning method of this invention. It is an EE arrow line view of FIG. It is a FF arrow line view of FIG. It is the cross-sectional view and longitudinal cross-sectional view of the rod-shaped light source 110 in the ultraviolet light source (ultraviolet light emitting module) 30 '. It is a cross-sectional view of an ultraviolet light source (ultraviolet light emitting module) 30 '. It is a side view of ultraviolet light source (ultraviolet light emitting module) 30 '. It is a longitudinal cross-sectional view which illustrates typically further another washing | cleaning apparatus 100 '' which can perform suitably the washing | cleaning method of this invention.

The cleaning method of the first aspect of the present invention comprises (a) a hydrogen peroxide, a quaternary ammonium hydroxide, and water, and a cleaning agent that does not contain ozone and metal ions is applied to the surface to be cleaned. And (b) irradiating the cleaning liquid attached and held on the surface of the surface to be cleaned with ultraviolet light having a wavelength of 200 nm or more and 250 nm or less. In b), the irradiation time of ultraviolet rays: t (unit: second) and / or the light emission output of the ultraviolet light source: P (unit: mW) is controlled to be held on the surface of the surface to be cleaned within the irradiation time. The integrated irradiation dose I (unit: mJ / cm ² ) of ultraviolet rays applied to the cleaning liquid is set to be equal to or greater than a predetermined integrated irradiation dose I ₀ .

Here, the object to be cleaned means an article having a substance to be removed by cleaning on its surface. For example, a semiconductor silicon wafer, a wafer on which a device pattern is formed, a photomask, an electronic substrate such as a liquid crystal glass substrate, etc. Materials can be mentioned. Since OH radicals have a high effect of decomposing and removing organic substances, the present invention is particularly effective for removing a photoresist film. Examples of the photoresist film include a resist for forming a pattern in a semiconductor manufacturing process, a resist for manufacturing a photomask used for pattern transfer, a resist for forming a pattern, a solder resist, and a resist for a printing plate in a manufacturing process of a wiring board. . Because the merit of adopting the method of the present invention is great, the object to be cleaned has a structure made of a low-k material such as an interlayer insulating film structure used in a damascene method and the like, and has a unit per unit area. Photoresist exposed to ion implantation of 1 × 10 ¹⁴ atoms / cm ² or more and 1 × 10 ¹⁷ atoms / cm ² or less, particularly 1 × 10 ¹⁵ atoms / cm ² or more and 1 × 10 ¹⁷ atoms / cm ² or less as the number of atoms It is preferable to use a semiconductor wafer having a layer (such a resist layer is usually made of a surface-crested resist) on the surface, particularly a semiconductor wafer having a minimum wiring pitch of 20 nm to 40 nm.

  The cleaning agent used in the present invention contains hydrogen peroxide, quaternary ammonium hydroxide, and water, and does not contain ozone and metal ions. Here, “does not contain ozone and metal ions” means that these components are not actively added as a cleaning agent component before contacting with the object to be cleaned and / or before performing ultraviolet irradiation. However, inevitable contamination as impurities is allowed. The lower the concentration of these components inevitably mixed as impurities, the better. However, it is usually 1 ppm or less, preferably 0.1 ppm or less, most preferably 0.01 ppm or less, and 0 ppm based on the total mass of the cleaning agent. May be.

  The concentration of hydrogen peroxide in the cleaning agent is preferably 10 ppm to 4%, particularly preferably 100 ppm to 2%, and most preferably 200 ppm to 1%, based on the total mass of the cleaning agent.

  Examples of the quaternary ammonium hydroxide include tetramethylammonium hydroxide (TMAH), benzyltetramethylammonium hydroxide (BTMAH), tetrabutylammonium hydroxide (TBAH), and tris (2-hydroxyethyl) methylammonium hydroxide. (THEMAH) and mixtures thereof can be used. Among these, it is preferable to use TMAH or TBAH. The concentration of the quaternary ammonium hydroxide is preferably 1 to 20%, particularly preferably 3 to 15%, based on the total mass of the cleaning agent.

  As the water used for the cleaning agent, ultrapure water is preferable. The water content is preferably 8.999% or more and 98.999% or less, particularly preferably 19.99% or more and 99.99% or less, based on the total mass of the cleaning agent, and 46.98%. It is most preferable that it is 96.98% or more.

  The cleaning agent is a primary alkanolamine such as ethanolamine, a polyalkylenepolyamine such as ethylenediamine, or an amine compound such as polyoxyalkylenepolyamine such as N- (2-hydroxyethyl) ethylenediamine, based on the total mass of the cleaning agent. The water-soluble organic solvent such as alcohols such as isopropyl alcohol and alkylene glycols such as ethylene glycol is 90% or less, preferably 80% or less, most preferably May contain 50% or less.

  In the cleaning method of the present invention, the method for attaching and holding the cleaning agent on the surface of the surface to be cleaned in step (a) is not particularly limited. For example, the object to be cleaned is a plate-like body such as a wafer. For this, a method of fixing the object to be cleaned to a support stand or the like so that the surface to be cleaned is an exposed horizontal surface facing upward, and supplying the cleaning liquid to the surface of the surface to be cleaned can be suitably employed. At this time, in order to perform reliable cleaning, the entire surface to be cleaned is surely covered with the cleaning agent, and the thickness of the cleaning agent layer covering the surface of the surface to be cleaned is made as thin as possible. It is preferable to do. In general, when short-wave ultraviolet rays pass through a solution layer, they are absorbed rapidly and are not easily transmitted. Depending on the type of cleaning agent and the output of the UV light source, increasing the thickness of the cleaning agent layer increases the surface to be cleaned. There is a possibility that ultraviolet rays do not reach and the cleaning effect by OH radicals cannot be sufficiently obtained. The thickness of the cleaning agent layer (for example, an effective optical path length to be described later) such that the ultraviolet rays reach the surface to be cleaned is grasped in advance, and the thickness of the cleaning agent layer existing on the surface to be cleaned is equal to or less than the thickness. By doing so, the cleaning effect by the OH radicals can be surely obtained on the surface to be cleaned.

In the cleaning method of the present invention, the cleaning agent covers the entire surface to be cleaned, and the thickness of the cleaning agent layer covering the surface to be cleaned is not more than an effective optical path length, preferably not more than 1/10 of the effective optical path length. It is particularly preferable that the thickness be 1/50 or less of the effective optical path length. The effective optical path length is a cleaning agent layer in which the irradiance of transmitted ultraviolet light is 0.01 mW / cm ² when the ultraviolet light irradiated from the ultraviolet light source passes through the layer (cleaning agent layer) made of the cleaning agent. Is defined as the thickness of

The irradiance value defining the effective optical path length: 0.01 mW / cm ² (10 μW / cm ² ) is an effective concentration in the vicinity of the surface to be cleaned in a practical processing time (ultraviolet irradiation time). This value is determined from the viewpoint that OH radicals can be generated.

Effective optical path length (. Which hereinafter may be abbreviated as _{L a)} of the decision, for example the following step (1) can be carried out by ~ (5) (S101 to S105):
(1) Step S101 of filling a cleaning agent into an ultraviolet light transmitting optical measurement cell having a predetermined optical path length (hereinafter, simply referred to as “cell”);
(2) The distance between the light source and the cell is the same as the distance from the light source to the surface of the cleaning agent layer during actual cleaning (step (b)), and during actual cleaning (step (b)). A step S102 of irradiating the inside of the cell with ultraviolet light emitted under the same light emission conditions as the ultraviolet irradiation;
(3) Step S103 of measuring the irradiance (unit: mW / cm ² ) of the transmitted ultraviolet light that has passed through the cell;
(4) Step S104 for obtaining the relationship between the irradiance of transmitted ultraviolet light and the optical path length by performing the above steps (1) to (3) (S101 to S103) for a plurality of cells having different optical path lengths; and
(5) steps were determined in the above step (4) (S104), based on the relationship between the irradiance and the optical path length of the transmitted ultraviolet light, it determines the effective optical length _{L a} S105.

Incidentally, in the above step (2) (S102), when using a light source that emits ultraviolet (UV) as collimated light, since UV transmittance of air is very high the effective optical length L _a cleaning agent layer from the light source Since it is not affected by the distance to the liquid surface, it is not particularly necessary to match the distance between the light source and the cell with the distance from the light source to the surface of the cleaning agent layer during actual cleaning (step (b)). However, when using a light source that emits UV radiation radially, the irradiation amount per unit area is inversely proportional to the square of the distance from the light source to the liquid surface of the cleaning agent layer. It is necessary to match the distance from the light source to the surface of the cleaning agent layer during the cleaning (step (b)).

In the above steps (4) to (5) (S104 to S105), the relationship between the irradiance of transmitted ultraviolet rays and the optical path length follows Lambert-Beer's law. That is, the irradiance I ₁ of transmitted ultraviolet rays is in the relationship of the following equation (1) with respect to the optical path length L.
log (I ₁ / I ₀ ) = − αL (1)
In Expression (1), I ₀ is the irradiance of ultraviolet light having a wavelength λ before entering the medium, and α is a proportional constant (absorption coefficient) determined corresponding to the cleaning agent and the wavelength λ. In general, the peak width of the emission spectrum of the UV-LED is extremely narrow. Therefore, when the UV-LED is used as the light source, the emission peak wavelength λ of the UV-LED is discussed in discussing the optical path length dependence of the irradiance of transmitted ultraviolet rays. considering absorption coefficient α only (lambda _peak) at _peak is sufficient. Equation (1) can be transformed into the following equation (2).
logI ₁ = −αL + logI ₀ (2)
Therefore, by obtaining a plurality of pairs of the logarithm of the transmitted ultraviolet irradiance I _{1 at} the main peak wavelength λ _peak and the optical path length L of the cell, the transmitted ultraviolet irradiance I ₁ and the optical path length L at the main peak wavelength λ _peak Can be obtained (step (4) (S104)). For example, a known method such as a least square method can be used to calculate the regression line. And the effective optical path length _{L a} of the ultraviolet light source can be obtained as an optical path length L to provide a ^{_{I 1 = 0.01mW / cm 2 (}} 10μW / cm 2) in the regression line (the step (5) (S105)) .

  As a method for controlling the thickness of the cleaning agent layer that covers the surface of the surface to be cleaned, for example, the object to be cleaned, which is a plate-like body such as a wafer, is exposed to an exposed horizontal surface with the surface to be cleaned facing upward. In the case where cleaning is performed while being fixed to a support stand or the like, the following method can be suitably employed. That is, a method of controlling the layer thickness (depth) of the cleaning agent by supplying a cleaning liquid to the inside of the weir and using a cleaning device provided with a weir on the outer periphery of the object to be cleaned (see FIGS. 1 to 6), A cover having an ultraviolet light-transmissive plate-shaped skylight capable of watertightly covering the object to be cleaned fixed to the support base, the surface to be cleaned of the object to be cleaned when the object to be cleaned is covered with the cover, and the skylight A method of using a cleaning device having a mechanism for adjusting the distance from the inner surface (while maintaining a watertight state) and enclosing or distributing a cleaning agent inside the cover (see FIG. 9) can be suitably employed.

  At this time, the object to be cleaned may be stationary at the time of cleaning, or may be moved by rotating or swinging. However, the former method (method using a cleaning device provided with a weir outside the outer periphery of the object to be cleaned, supplying a cleaning liquid to the inside of the weir and controlling the layer thickness (depth) of the cleaning agent (FIGS. 1 to 1) In the case of adopting 6))), since the liquid level of the cleaning liquid changes when the object to be cleaned is moved, a control means other than the weir is required. For example, when the object to be cleaned is rotated, the central portion of the rotating shaft is thinned by centrifugal force and the liquid overflows from the weir. Therefore, a constant amount of cleaning agent is continuously supplied to the central portion to compensate for the overflow. The surface of the weir is increased by increasing the height of the weir or by providing a cover for preventing overflow and providing an outlet for the washing liquid in the weir to balance the supply speed of the washing liquid and the extraction speed according to the rotational speed. Is preferably kept in a steady state (see FIGS. 3 to 5).

  In the step (b) of the cleaning method of the present invention, the cleaning liquid adhered to and held on the surface to be cleaned is irradiated with ultraviolet rays having a wavelength of 200 nm or more and 250 nm or less. The generation efficiency (quantum efficiency) of OH radicals can be increased by irradiating ultraviolet rays having a short wavelength of 250 nm or less (see Non-Patent Document 5). In addition, since ultraviolet rays having a wavelength of less than 200 nm are not used, it is unlikely to be absorbed by a substance such as oxygen in the atmosphere and cause a decrease in strength, and the cleaning agent can be irradiated with ultraviolet rays while maintaining high strength. The generation of ozone can be suppressed. From the viewpoint of preventing ozone generation, it is preferable that the ultraviolet rays to be irradiated do not contain ultraviolet rays having a wavelength of less than 200 nm.

  As a light source when performing ultraviolet irradiation, the apparatus can be made compact, and not only maintenance is easy, but also output control can be easily performed by controlling the forward current. It is preferable to use an ultraviolet light source having an ultraviolet light emitting diode (UV-LED) that emits ultraviolet light having a peak in a wavelength region of 250 nm or less, and substantially emits ultraviolet light having a wavelength of less than 200 nm that may generate ozone. It is particularly preferable to use an ultraviolet light source having a UV-LED that emits ultraviolet light having a peak in a wavelength region of 220 nm or more and 250 nm or less because it does not emit light.

  In order to increase the cleaning efficiency, it is preferable that the temperature of the object to be cleaned or the temperature of the cleaning liquid is 50 ° C. or higher and 80 ° C. or lower during the ultraviolet irradiation. Furthermore, ultrasonic irradiation may be performed on the cleaning agent in combination with ultraviolet irradiation.

In the cleaning method of the present invention, the ultraviolet irradiation is performed within the irradiation time by controlling the ultraviolet irradiation time: t (unit: second) and / or the light emission output of the ultraviolet light source: P (unit: mW). It is necessary to make the cumulative irradiation dose I (unit: mJ / cm ² ) of the ultraviolet rays irradiated to the cleaning liquid held on the surface of the surface equal to or higher than a predetermined cumulative irradiation dose I ₀ . This makes it possible to perform reliable cleaning with a high yield.

In the cleaning method of the present invention, the emission intensity of the ultraviolet light source for each cleaning basic condition comprising a combination of the type of the object to be cleaned, the temperature of the object to be cleaned or the temperature of the cleaning liquid at the time of ultraviolet irradiation, and the type of the cleaning agent. P is set to a predetermined emission intensity P ₀ , the irradiation time t is changed, and repeated cleaning (steps (a) and (b)) is performed to determine the shortest irradiation time t _{min at} which a sufficient cleaning effect is obtained, It is preferable that the integrated dose calculated as the product of the emission intensity P ₀ and the shortest irradiation time t _min is the predetermined integrated dose I ₀ when cleaning is performed under the same cleaning basic conditions.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited to these forms. The drawings do not necessarily reflect accurate dimensions. In the drawing, some symbols may be omitted. Unless otherwise specified in this specification, the notation “A to B” for numerical values A and B means “A or more and B or less”. In this notation, when a unit is attached to only the numerical value B, the unit is also applied to the numerical value A. Further, the terms “or” and “or” mean logical sums unless otherwise specified.

  1 and 2 are longitudinal sectional views schematically illustrating a cleaning apparatus 100 that can suitably perform the cleaning method of the present invention. 1 and 2, the vertical direction on the paper surface represents the vertical direction. The cleaning device 100 is a device for cleaning the object 1 to be cleaned, which is a disk-shaped wafer, and supports the support base (disk-shaped turntable) 10 on which the object 1 to be cleaned 1 is mounted and the support base 10 so as to be rotatable. A support column 11, a ring-shaped weir side wall 12 provided so as to be movable up and down in contact with the outer periphery of the support base 10, a cleaning agent supply nozzle 20, and an ultraviolet light source 30 provided so as to face the support base 10. And a rinsing liquid supply nozzle 40.

  The support base 10 is connected to a motor via a support column 11 and is rotatable about the support column 11. The contact between the weir side wall 12 and the support base 10 is watertight so that the cleaning liquid can be stored in the recess 13 defined by the support base 10 and the weir side wall 12. The weir side wall 12 can be moved up and down in the direction of arrow A in the figure by lifting means (not shown). By raising and lowering the weir side wall 12 in the direction of arrow A in the figure, it is possible to adjust the height of the weir side wall 12 as viewed from the support base 10 (that is, the depth of the recess 13).

  The ultraviolet light source 30 includes a circular substrate 31 having substantially the same shape as the surface 1a to be cleaned 1 and a plurality of ultraviolet light emitting diodes 32, 32,. -LED 32 "), and a UV-transmissive lid 33 that seals the UV-LED 32, and a heat sink 34 that is thermally coupled to the substrate 31. The UV-LED 32 may be packaged as necessary. The ultraviolet transmissive lid 33 is made of an ultraviolet transmissive material such as sapphire or quartz, for example, and seals the UV-LED 32 in a space defined by the lid 33 and the substrate 31. The heat sink 34 has heat radiation fins, and the heat radiation fins are exposed in the ultraviolet light emitting diode cooling fluid flow path, and the heat generated in the UV-LED by the ultraviolet light emitting diode cooling fluid flowing in the flow path. Can be dissipated.

  The cleaning agent supply nozzle 20 is provided so as to be movable in the direction of arrow B in FIG. 1 by a driving means (not shown), and supplies the cleaning agent to the object to be cleaned 1 from the discharge port 20a provided at the tip of the nozzle. . When it is not necessary to supply the cleaning agent, the cleaning agent supply nozzle 20 is retracted to a position where the discharge port 20a comes to the outside of the dam sidewall 12.

  The rinsing liquid supply nozzle 40 is provided so as to be movable in the direction of arrow C in FIG. 2 by a driving means (not shown), and supplies the rinsing liquid to the object 1 to be cleaned from the discharge port 40a provided at the nozzle tip. . When it is not necessary to supply the rinsing liquid, the rinsing liquid supply nozzle 40 is retracted to a position where the discharge port 40a comes to the outside of the dam sidewall 12.

The operation of the cleaning apparatus 100 will be described with reference to FIGS. 1 and 2.
Before the start of the step (a), the object to be cleaned 1 is not yet placed on the support base 10, and the upper end portion of the dam side wall 12 is the same as or lower than the placement surface of the support base 10. It is in. The cleaning agent supply nozzle 20 a is retreated to a position where the discharge port 20 a comes outside the dam side wall 12. The ultraviolet light source 30 is disposed at a position not facing the support base 10.

  Step (a) is a step of attaching and holding the cleaning agent to the surface of the surface to be cleaned 1a of the object to be cleaned 1. First, the object to be cleaned 1 is placed on the support 10 and the dam sidewall 12 is raised to a predetermined height. The cleaning agent supply nozzle 20 advances to the position shown in FIG. 1, and the cleaning agent is supplied from the cleaning agent supply nozzle 20 to the recess 13 defined by the support 10 and the dam sidewall 12. When the liquid level of the cleaning agent stored in the recess 13 reaches the upper end of the dam side wall 12, the supply of the cleaning agent is stopped, and the discharge port 20 a of the cleaning agent supply nozzle 20 comes to the outside of the dam side wall 12 again. Retreat to position.

The step (b) is a step of irradiating the cleaning liquid adhered and held on the surface to be cleaned 1a with ultraviolet rays having a wavelength of 200 nm or more and 250 nm or less from the ultraviolet light source 30. The ultraviolet light source 30 is moved to a position facing the support 10 (that is, a position facing the surface to be cleaned 1a of the object to be cleaned 1; see FIG. 1), and adhered and held on the surface of the surface to be cleaned 1a (that is, The cleaning liquid (stored in the recess 13) is irradiated with ultraviolet rays from the ultraviolet light source 30. As described above, in the step (b), the ultraviolet irradiation time t and / or the light emission output P of the ultraviolet light source 30 are the ultraviolet rays irradiated to the cleaning liquid held on the surface to be cleaned 1a within the irradiation time. The integrated dose I (unit: mJ / cm ² ) is controlled to be equal to or greater than a predetermined integrated dose I ₀ . While the ultraviolet irradiation is performed, the support base 10 (disk-shaped turntable) is not rotated and is held stationary.

  When step (b) is completed, a rinsing step is performed. The ultraviolet light source 30 is moved to a position not facing the support base 10, the dam side wall 12 is lowered, and the upper end portion of the dam side wall 12 is set to a height equal to or lower than the placement surface of the support base 10. The rotation of the support base 10 (disk-shaped turntable) (arrow D in FIG. 2) is started, and the cleaning agent is discarded. The rinsing liquid supply nozzle 40 advances to the position shown in FIG. 2, and the rinsing process is performed by supplying the rinsing liquid from the rinsing liquid supply nozzle 40 to the surface to be cleaned 1a while the rotation of the support base 10 is continued. As the rinsing liquid in the rinsing step, for example, pure water or isopropyl alcohol can be used. The rinse process is completed by stopping the supply of the rinse liquid and stopping the rotation of the support base 10.

  FIG. 3 is a longitudinal sectional view schematically illustrating another cleaning apparatus 100 ′ that can suitably perform the cleaning method of the present invention. In FIG. 3, the vertical direction on the paper surface represents the vertical direction. FIG. 4 is an EE arrow view of FIG. FIG. 5 is a view taken along the line FF in FIG. The cleaning apparatus 100 ′ is a single wafer cleaning apparatus, and rotates a disk-shaped support table (disk-shaped turntable) 10 ′ on which a plurality of objects 1 to be cleaned, which are disk-shaped wafers, can be mounted. And a support column 11 ′ that supports the same. The support base 10 'has a through hole 10'a at the center. The cleaning device 100 ′ further stands on a ring-shaped outer weir side wall 12 ′ erected on the outer peripheral portion of the support base 10 ′ and an inner peripheral portion (the outer peripheral portion of the through hole 10′a) of the support base 10 ′. It has a ring-shaped inner weir side wall 14 provided and a waste liquid tray 16 disposed so as to surround the side and lower side of the support base 10 ′. Below the through hole 10'a of the support base 10 ', a support base overflow cleaning liquid discharge recess 15 is formed by a support column 11' so as to be connected to the through hole 10'a. Discharge ports 17b, 17b,... (Hereinafter sometimes simply referred to as “discharge port 17b”) are provided at the bottom of the support base overflow cleaning liquid discharge recess 15, and the cleaning liquid is discharged toward the waste liquid tray 16. It is possible. An overflow suppression cover 12′a is provided at the upper end of the outer weir side wall 12 ′ so as to protrude toward the upper inside of the support base 10 ′, and at the lower end of the outer weir side wall 12 ′. , Discharge ports 17a, 17a,... (Hereinafter, simply referred to as “discharge port 17a”) are provided. Further, at the bottom of the waste liquid tray 16, there are provided discharge ports 17c, 17c,... (Hereinafter, simply referred to as “discharge port 17c”).

  The cleaning apparatus 100 ′ further includes cleaning agent supply nozzles 20 ′, 20 ′,... (Hereinafter, simply referred to as “cleaning agent supply nozzle 20 ′”) and ultraviolet light sources 30 ′, 30 ′,. Simply “ultraviolet light source 30 ′”). The cleaning agent supply nozzle 20 ′ and the ultraviolet light source 30 ′ are alternately arranged in the circumferential direction above the support base 10 ′ (see FIG. 5). The cleaning agent supply nozzle 20 'is arranged so that the cleaning liquid discharged from the discharge port 20'a falls near the outer peripheral side of the inner weir side wall 14 (outer weir side wall 12' side).

  An arrow G in FIG. 3 indicates the flow of the cleaning agent supplied from the cleaning agent supply nozzle 20 '. The cleaning liquid supplied from the cleaning agent supply nozzle 20 ′ to the recess 13 ′ defined by the support 10 ′, the outer dam side wall 12 ′, and the inner dam side wall 14 is applied to the surface 1 a to be cleaned of the body 1 to be cleaned. After flowing through the surface, it flows out from the discharge port 17a provided at the lower end of the outer weir side wall 12 'and is received by the waste liquid tray 16. The cleaning liquid overflowing from the recess 13 'beyond the inner dam side wall 14 is received by the support base overflow cleaning liquid discharge recess 15 through the through hole 10' of the support base 10 ', and then discharged from the discharge port 17b. It flows out and is received in the waste liquid tray 16. The cleaning liquid received in the waste liquid tray 16 is discharged from a discharge port 17 c provided at the bottom of the waste liquid tray 16.

  The ultraviolet light source (ultraviolet light emitting module) 30 ′ has a rod-shaped light source that emits ultraviolet light and a light collecting device that collects the ultraviolet light emitted from the light source, and the rod-shaped light source is a cylindrical or polygonal column base. 111 and a plurality of deep ultraviolet light emitting diodes 112, 112,..., And the plurality of deep ultraviolet light emitting diodes 112, 112,. The ultraviolet light source is configured to emit ultraviolet light radially with respect to the central axis 114 by being arranged on the side surface of the base 111 so as to pass through the central axis 114 of the magnetic head 111. Such an ultraviolet light source is described in Patent Document 8, the contents of which are incorporated herein by reference.

  FIG. 6 shows a transverse sectional view and a longitudinal sectional view of the rod-shaped light source (rod-shaped ultraviolet light emitting module) 110 (when cut along the XX ′ plane). As shown in FIG. 6, the rod-shaped light source 110 has a plurality of ultraviolet light emitting diodes 112, 112,... (Hereinafter sometimes abbreviated as “UV-LED 112”) arranged on the surface of a cylindrical substrate 111. A cooling medium channel 113 is formed inside the cylindrical base body. The cylindrical substrate 111 on which the UV-LED 112 is mounted is covered with a cover 116 formed of an ultraviolet light transmissive material such as quartz. The cover 116 is attached to the cylindrical substrate 111 in an airtight or watertight manner using a sealing member 117 such as a sealant, packing, or O-ring, and an inert gas is provided inside the cover 116 in order to enhance the durability of the UV-LED 112. Or dry air is enclosed.

  The UV-LEDs 112, 112,... Are arranged in a state where the element is mounted on a submount or accommodated in a package, and emit ultraviolet rays in a certain direction. Although not shown, the submount or package is provided with wiring for supplying power to the UV-LED 112 from the outside of the module, a circuit for operating the UV-LED 112 normally, and the like. Electric power is supplied to the circuit via wiring formed on the surface of or inside the cylindrical substrate 111.

  The cylindrical substrate 111 functions as a support for fixing and holding the UV-LED 112, and also has a function as a heat sink. The cooling medium such as cooling water or cooling air is provided in the cooling medium flow path 113 inside. By circulating 118, temperature rise due to heat generated by the UV-LED 112 can be prevented, stable operation of the device can be facilitated, and device life can be extended. When used in the portable ultraviolet sterilizer of the present invention, it is preferable to attach a small fan and blow cooling air to the cooling medium flow path 113 as the cooling medium 118.

  In order to efficiently remove the heat generated in the UV-LED 112, the cylindrical substrate 111 is preferably mainly composed of a metal having high thermal conductivity such as copper or aluminum, ceramics, or the like. In order to increase the heat exchange area, it is preferable to groove the inner wall surface of the cooling medium flow passage 113. Further, when the cylindrical base 111 is made of a metal material, in order to insulate from a battery disposed inside or outside the housing or a copper wire or a circuit for supplying power to the UV-LED 112 from an external power source. It is preferable that an insulating layer is formed.

  On the side surface of the cylindrical substrate 111, a plurality of UV-LEDs 112, 112,... Are arranged along the circumferential direction so that the optical axis 115 of each deep ultraviolet LED 112 passes through the central axis 114 of the substrate 111. Yes. As a result, the ultraviolet rays emitted from the UV-LED 112 are emitted radially with respect to the central axis 114. The optical axis 115 of the UV-LED 112 means the central axis of the light beam emitted from the UV-LED 112, and is almost synonymous with the traveling direction of the light beam. In addition, here, “arranging so that the optical axis 115 passes through the central axis 114 of the substrate 111” means that the optical axis 115 is arranged to realize such a state as much as possible, and is slightly inclined from the state. There is no problem.

  FIG. 6 shows an example in which four UV-LEDs are arranged in the circumferential direction of the base 111, but the present invention is not limited to this form, and the number of deep ultraviolet LEDs 112 arranged is outside the cylindrical base 111. It can be appropriately changed according to the diameter. The number of deep ultraviolet LEDs 112 arranged in the circumferential direction is usually in the range of 3 to 20, preferably 4 to 12. However, the larger the number of deep ultraviolet LEDs 112 arranged in the circumferential direction, the more emitted from the ultraviolet light source 30 ′. Since the intensity of the ultraviolet rays (photon flux density) increases, when higher intensity ultraviolet rays are required, the diameter of the cylindrical substrate 111 is increased and the number of ultraviolet light emitting elements arranged in the circumferential direction is within the above range. Can be more than.

  The UV-LEDs 112, 112,... Are preferably arranged so as to form a row in the longitudinal direction of the cylindrical substrate 111 as shown in the longitudinal sectional view of FIG. At this time, it is preferable that the deep ultraviolet LEDs 112, 112,... Be arranged so as to be densely and regularly arranged on the side surface of the cylindrical substrate 111 so that the intensity in the ultraviolet irradiation region is uniform.

  7 and 8 show a cross-sectional view and a side view of an ultraviolet light source 30 ′ having a rod-shaped light source 110. The ultraviolet light source 30 ′ includes an emission-side housing 125 whose inner surface is an emission-side reflection mirror 120 made of an ellipsoidal reflection mirror, and a condensing-side reflection mirror 123 whose inner surface is made of an ellipse reflection mirror, and ultraviolet rays. A condensing side housing 126 in which an exit opening 130 is formed, and a main body 150 including a collimating optical system 140 disposed in the ultraviolet exit opening 130, and the rod-shaped light source 110 is inside the main body 150. Has been placed. In the main body 150, it is preferable that the emission side casing 125 and the condensing side casing casing 126 are detachable from each other or can be opened and closed using a hinge or the like. 7 and 8 of the main body 150 are provided with covers (not shown) for preventing ultraviolet rays from leaking to the outside.

  7 and 8, the exit-side reflecting mirror 120 and the condensing side reflecting mirror 123 are substantially elliptical reflecting mirrors having substantially the same shape. The shape of the internal space formed by coupling with the side housing 126 is an elliptical cross-section with two axes of the focal axis 121 of the exit-side reflecting mirror and the condensing axis 122 of the exit-side reflecting mirror, respectively. However, a portion corresponding to the opening 130 is missing.) The surfaces of the exit-side reflecting mirror 120 and the condensing-side reflecting mirror 123 are made of materials having high reflectivity with respect to ultraviolet rays, such as platinum group metals such as Ru, Rh, Pd, Os, Ir, and Pt, Al, Ag, Ti, and the like. It is preferably made of an alloy containing at least one kind of metal or magnesium oxide, and is made of Al, an alloy containing a platinum group metal or a platinum group metal, or magnesium oxide because of its particularly high reflectance. Is particularly preferred.

  The condensing-side reflecting mirror 123 and the condensing-side housing 126 are provided with an ultraviolet emitting opening 130 in a slit shape, and the condensed ultraviolet is converted into a parallel or substantially parallel light flux in the opening 130. A collimating optical system 140 is disposed. The collimating optical system 140 is preferably made of a material having high ultraviolet transparency such as synthetic or natural quartz, sapphire, or ultraviolet transmissive resin. The collimating optical system 140 is preferably detachably attached to the ultraviolet light emitting opening 130.

  In the ultraviolet light source 30 ′, the rod-shaped light source 110 is arranged so that the central axis 114 thereof coincides with the focal axis 121 of the exit side reflection mirror. Since the rod-shaped light source 110 is arranged at such a position, the ultraviolet rays emitted radially from the rod-shaped light source 110 are reflected by the emitting-side reflecting mirror 120 and the collecting-side reflecting mirror 123 to be the focal axis of the collecting-side reflecting mirror. The condensed ultraviolet rays are converged so as to converge on 124 (that is, the condensing axis 122 of the emission-side reflecting mirror), and the collected ultraviolet rays are emitted from the ultraviolet emission window 13 toward the mirror 14.

  Thus, in principle, the ultraviolet light source 30 ′ can condense all of the ultraviolet light emitted radially from the rod-shaped light source 110 onto the focal axis 124 of the condensing side reflection mirror 123, and the ultraviolet light emitting opening 130. Ultraviolet rays emitted in a direction that does not face the direction (for example, the opposite direction or the lateral method) can also be used effectively. That is, in the rod-shaped light source 110, it is not necessary to arrange all of the UV-LEDs 112, 112,... On the same plane so that the optical axis 115 is directed toward the ultraviolet ray emitting opening 130, and is directed in the lateral direction or the opposite direction. It can also be arranged. Therefore, in the rod-shaped light source 110, the number of ultraviolet light-emitting elements arranged per unit space can be greatly increased, and the ultraviolet light source 30 'can emit ultraviolet rays with stronger intensity. Further, it is not necessary to use a large-diameter field lens in the ultraviolet light source 30 '. Furthermore, in the ultraviolet light source 30 ′, the irradiation area is not a narrow spot shape but can irradiate the rectangular area with a long long side with a uniform intensity of ultraviolet light, so that the surface of the object to be sterilized can be uniformly sterilized with the ultraviolet light. It is. Furthermore, since the ultraviolet rays can be emitted as collimated parallel light beams, the intensity of the ultraviolet rays is not easily lowered even when the optical path length from the ultraviolet light source 30 'to the cleaning liquid surface is long.

  In the cleaning apparatus 100 ′, the step (b) is performed while performing the step (a). That is, after the objects to be cleaned 1, 1,... Are placed on the support base 10 ', rotation of the support base 10' (arrow H in FIG. 3) is started. Then, the supply of the cleaning liquid from the cleaning liquid supply nozzle 20 ′ to the vicinity of the inner dam side wall 14 of the recess 13 ′ is started. The cleaning liquid supplied to the vicinity of the inner dam side wall 14 of the recess 13 ′ flows toward the outer peripheral portion of the support base 10 ′ by centrifugal force derived from the rotational movement of the support base 10 ′. At this time, the cleaning liquid flows on the surface 1a to be cleaned of the body 1 to be cleaned. The cleaning liquid that has reached the outer weir sidewall 12 flows out of the discharge port 17 a and is received by the waste liquid tray 16. At this time, the supply speed of the cleaning liquid from the cleaning liquid supply nozzle 20 ′ and the shape of the discharge port 17a are balanced by the supply speed of the cleaning liquid from the cleaning liquid supply nozzle 20 ′ and the discharge speed of the cleaning liquid from the discharge port 17a. The cleaning liquid level at 13 is adjusted so as to maintain a steady state.

Along with the supply of the cleaning liquid, the ultraviolet light having a wavelength of 200 to 250 nm is irradiated from the ultraviolet light source 30 ′ to the cleaning liquid attached and held on the surface of the surface to be cleaned 1 a (step (b)). As described above, the ultraviolet irradiation time: t (unit: second) and / or the light emission output of the ultraviolet light source: P (unit: mW) is relative to the cleaning liquid held on the surface to be cleaned 1a within the irradiation time. The integrated irradiation dose I (unit: mJ / cm ² ) of the ultraviolet rays irradiated is controlled so as to be equal to or greater than a predetermined integrated irradiation dose I ₀ .

  Steps (a) and (b) are completed by stopping the supply of the cleaning agent from the cleaning agent supply nozzle 20 'and the irradiation of the ultraviolet light from the ultraviolet light source 30'.

  In the above description regarding the cleaning apparatus for carrying out the cleaning method of the present invention, weirs (12, 12 ') are provided outside the outer periphery of the object to be cleaned, and the cleaning liquid is supplied to the inside of the weir to provide a layer thickness of the cleaning agent. Although the cleaning apparatuses 100 and 100 ′ in the form of controlling (depth) are illustrated, the cleaning apparatus for carrying out the cleaning method of the present invention is not limited to these forms. For example, a cover having an ultraviolet light-transmitting plate-shaped skylight capable of watertightly covering the object to be cleaned fixed to the support base, the surface to be cleaned when the object to be cleaned is covered with the cover, and the above The thickness of the cleaning agent layer formed on the surface of the surface to be cleaned by sealing or circulating the cleaning agent inside the cover. It is also possible to use a cleaning device that controls the thickness. FIG. 9 is a longitudinal sectional view schematically illustrating such another cleaning apparatus 100 ″. The vertical direction on the paper surface of FIG. 9 represents the vertical direction. 9, the same elements as those already shown in FIGS. 1 to 8 are denoted by the same reference numerals as those in FIGS. 1 to 8, and description thereof is omitted.

  The cleaning apparatus 100 ″ includes a support base (disk-shaped turntable) 10 on which the object to be cleaned 1 is placed, and a support 11 ′ that supports the support base 10 so that the support base 10 can rotate and move up and down (arrow I in FIG. 9). A ring-shaped outer weir side wall 12 '' that can slide in a water-tight manner on the outer periphery of the support base 10, and a UV-transmitting plate-like plate that is water-tightly fixed to the upper end of the outer weir partition wall 12 ''. A cleaning agent supply pipe 50 and a cleaning agent discharge pipe 51 provided through the skylight 18, the outer weir sidewall 12 ″, and an ultraviolet light source 30 provided so as to face the support base 10 through the skylight 18. And having. A cover is formed by the outer weir side wall 12 ″ and the skylight 18. That is, when the outer periphery of the support base 10 is in contact with the inner peripheral surface of the outer weir side wall 12 ″, the space 19 is defined by the support base 10, the outer weir side wall 12 ″, and the skylight 18. The The cleaning agent supply pipe 40 and the cleaning agent discharge pipe 41 are arranged so that the cleaning agent can be sealed or circulated inside the space 19.

Before placing the object to be cleaned 1 on the support base 10, the support base 10 is lowered so that the outer peripheral portion of the support base 10 and the inner peripheral surface of the outer weir side wall 12 ″ are not in contact with each other. . After the object to be cleaned 1 is placed on the support base 10, the support base 10 is raised to bring the outer peripheral portion of the support base 10 into contact with the inner peripheral surface of the outer weir side wall 12 ″ and the space 19. Is adjusted so that the distance from the surface 1a to be cleaned to the skylight 18 becomes a desired value. The cleaning agent is supplied from the cleaning agent supply pipe 50 to the space 19 to fill the space 19 with the cleaning agent (step (a)), and is attached and held on the cleaning agent in the space 19 (that is, the surface of the surface to be cleaned 1a). The cleaning agent is irradiated with ultraviolet light having a wavelength of 200 to 250 nm from the ultraviolet light source 30 (step (b)). At this time, the cleaning agent discharge pipe 51 may be closed so that the cleaning agent is sealed in the space 19, and the cleaning agent is continuously supplied from the cleaning agent supply pipe 50 without closing the cleaning agent discharge pipe 51. Accordingly, the cleaning agent may be circulated in the space 19. Similarly to the above, the ultraviolet irradiation time: t (unit: second) and / or the light emission output of the ultraviolet light source: P (unit: mW) are applied to the cleaning liquid held on the surface of the surface to be cleaned 1a within the irradiation time. Control is performed so that the cumulative dose I (unit: mJ / cm ² ) of the irradiated ultraviolet rays is equal to or greater than a predetermined cumulative dose I ₀ set in advance.

  Steps (a) and (b) are completed by stopping the supply of the cleaning agent from the cleaning agent supply pipe 40 and the irradiation of the ultraviolet light from the ultraviolet light source 30. After completion of the steps (a) and (b), the support 10 is lowered so that the support 10 and the outer weir side wall 12 '' are completely separated, and the support 10 is rotated to remove the cleaning agent. Discard. Thereafter, as shown in FIG. 2, the rinsing process can be performed by supplying the rinsing liquid from the rinsing liquid supply nozzle 40 to the surface to be cleaned 1 a while rotating the support base 10.

A method for manufacturing a semiconductor wafer according to a third aspect of the present invention is a method for manufacturing a semiconductor wafer having a structure made of a low-k material and an ion implantation region, and the number of atoms per unit area is 1 × 10 ¹⁴ atoms / cm ^2. The method includes the step of removing the photoresist layer exposed to the ion implantation of 1 × 10 ¹⁷ atoms / cm ² or less by the cleaning method of the first aspect of the present invention. The method for producing a semiconductor wafer according to the present invention includes a step of forming a photoresist layer on the surface of a semiconductor wafer having a structure made of a low-k material, and a semiconductor wafer on which the photoresist layer is formed. The method may further include exposing to an ion implantation of 1 × 10 ¹⁴ atoms / cm ² or more and 1 × 10 ¹⁷ atoms / cm ² or less as a number. In forming the photoresist layer, a known photoresist forming method can be used without particular limitation. For ion implantation, a known ion implantation method can be used without particular limitation.

DESCRIPTION OF SYMBOLS 1 To-be-cleaned surface 1a To-be-cleaned surface 10, 10 'Support stand 11, 11', 11 '' Support | pillar 12, 12 ', 12''Outer weir side wall 12'a Overflow suppression cover 13, 13' Recessed part 14 Inner weir Side wall 15 Supporting stand overflow cleaning liquid discharge recess 16 Waste liquid tray 17a, 17b, 17c Discharge port 18 Skylight 19 Space 20, 20 'Cleaning agent supply nozzles 20a, 20'a (cleaning agent) discharge ports 30, 30' UV light source 31 Substrate 32 Ultraviolet light emitting diode (UV-LED)
33 Lid 34 Heat Sink 40 Rinse Solution Supply Nozzle 40a (Rinse Solution) Discharge Port 50 Cleaning Agent Supply Tube 51 Cleaning Agent Discharge Tube 100, 100 ′, 100 ″ Cleaning Device 110 Rod Light Source 111 (Cylindrical or Polygonal Column) Base 112 Ultraviolet light emitting diode (UV-LED)
120 Output-side Reflective Mirror 121 Output-side Reflective Mirror Focal Axis 122 Output-side Reflective Mirror Concentration Axis 125 Output-side Enclosure 123 Condenser-side Reflective Mirror 124 Concentration-side Reflective Mirror Focal Axis 126 Condenser-side Enclosure 130 Depth Ultraviolet light emitting aperture 140 Collimating optical system 150 Main body

Claims (4)

A method of manufacturing a semiconductor wafer having a structure made of a low-k material and an ion implantation region,
A photoresist layer having a structure made of a low-k material and exposed to ion implantation of 1 × 10 ¹⁴ atoms / cm ² or more and 1 × 10 ¹⁷ atoms / cm ² or less as the number of atoms per unit area on the surface from the cleaning object, which is a semiconductor wafer having, removing the photoresist layer, Ri Na comprise photoresist layer removing step,
The photoresist layer removal step includes
(A) A cleaning agent that contains hydrogen peroxide, quaternary ammonium hydroxide, water, and a water-soluble organic solvent, and that does not contain ozone and metal ions is attached to the surface of the surface to be cleaned. And a holding step;
(B) irradiating the cleaning agent adhered and held on the surface of the surface to be cleaned with an ultraviolet ray having a wavelength of 200 nm or more and 250 nm or less from an ultraviolet light source,
In the step (b), the ultraviolet irradiation time: t (unit: second) and / or the light emission output of the ultraviolet light source: P (unit: mW) are controlled, and the surface to be cleaned is within the irradiation time. integrated irradiation dose I (unit: mJ / cm ²⁾ of the ultraviolet ray irradiated to the cleaning agent held on the surface and characterized to Rukoto such that a predetermined total irradiation amount I ₀ or a predetermined A method for manufacturing a semiconductor wafer. As the ultraviolet light source, an ultraviolet light source having an ultraviolet light emitting diode that emits ultraviolet light having a peak in a wavelength region of 200 nm or more and 250 nm or less,
The light emission output P of the ultraviolet light source is controlled by controlling a forward current flowing through the ultraviolet light emitting diode.
The method of claim 1. 3. The method according to claim 1, wherein the temperature of the object to be cleaned or the temperature of the cleaning agent is set to 50 ° C. or more and 80 ° C. or less when the ultraviolet rays are irradiated. And type of the cleaning object, and the temperature of the temperature or detergent cleaning object during UV irradiation, each wash basic conditions, which consist of a combination of the type of detergent, the predetermined luminous emission intensity P of the ultraviolet light source The intensity P ₀ is set, the irradiation time t is changed, the steps (a) and (b) are repeated, and the shortest irradiation time t _{min at} which a sufficient cleaning effect is obtained is determined.
The integrated dose calculated as the product of the emission intensity P ₀ and the shortest irradiation time t _min is set as the predetermined integrated dose I ₀ when cleaning is performed under the same basic cleaning conditions. And
The method according to claim 1.