WO2017170595A1 - Cleaning method, cleaning liquid, and cleaning device - Google Patents

Abstract

A method for cleaning a body to be cleaned comprises: a step (a) of causing a cleaning agent to become attached and held on a surface of a face to be cleaned of a body to be cleaned, the cleaning agent containing hydrogen peroxide, a quaternary ammonium hydroxide, and water and not containing ozone or a metal ion; and a step (b) of irradiating the cleaning liquid attached and held on the surface of the face to be cleaned with ultraviolet radiation having a wavelength of not less than 200 nm and not more than 250 nm from an ultraviolet radiation light source. In step (b), the irradiation time t (unit: seconds) of ultraviolet radiation and/or the emission output P (unit: mW) of the ultraviolet radiation light source are controlled so that the accumulated amount of irradiation I (unit: mJ/cm²) of ultraviolet radiation with which the cleaning liquid being held on the surface of the face to be cleaned is irradiated within the irradiation time becomes a prescribed predetermined accumulated amount of irradiation I₀ or more.

Description

Cleaning method, cleaning liquid, and cleaning apparatus

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

In the surface cleaning of electronic materials such as silicon wafer plates for semiconductors, there is known a method of cleaning while decomposing ozone by irradiating ultraviolet rays using ozone water. For example, Patent Document 1 discloses a cleaning method characterized in that an object to be cleaned is immersed obliquely in a liquid in which ozone is dissolved, and the surface of the immersed object to be cleaned is irradiated with ultraviolet light for cleaning. ing. In this method, strong detergency can be obtained by the strong oxidizing power of hydroxyl radicals (also referred to as OH radicals) generated when ozone decomposes.

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. It is also possible to remove.

As a method for 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, with regard to cleaning devices used for surface cleaning of electronic materials, single-wafer cleaning devices are becoming mainstream because cross contamination can be prevented and high yield can be expected. As such a single wafer cleaning device, Patent Document 9 describes, “a support member that supports an object to be cleaned, an ultrasonic vibration plate that is disposed opposite to the cleaning surface of the object to be cleaned supported by the support member, A liquid supply nozzle for supplying a cleaning liquid between the vibration plate and an object to be cleaned, a drive member for moving the support member in parallel with the surface of the vibration plate, and an ultrasonic oscillator for ultrasonically vibrating the vibration plate. A single wafer cleaning device for cleaning the surface of an object to be cleaned with an intervening cleaning liquid by ultrasonically vibrating the vibration plate while moving the object to be cleaned supported by the support member, the vibration surface of the vibration plate Is a single-wafer type cleaning apparatus characterized in that the average sound pressure on the cleaning surface of the object to be cleaned is disposed close to the highest point or a position within the vicinity thereof.

Further, in Patent Document 10, “in a single wafer cleaning apparatus that cleans and / or dries at least one surface of an object to be cleaned in a chamber, liquid and / or along at least a cylindrical recess and an inner wall surface of the recess. A cleaning table having at least one swirling flow forming portion having a discharge port for discharging gas, and disposed so that the swirling flow forming portion is close to at least one surface for cleaning and / or drying the object to be cleaned; And a holding body that is disposed around the cleaning table and that is fixedly held in contact with a side surface of the object to be cleaned that is adjacent to the swirl flow forming portion of the cleaning table, and a discharge port of the swirl flow forming portion The liquid and / or gas is discharged from the container, the side surface of the object to be cleaned is fixedly held by the holding body, and at least one surface of the object to be cleaned is cleaned and / or cleaned by the discharged liquid and / or gas. It describes a single wafer cleaning apparatus ", characterized in that it is intended to drying.

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 JP 2006-95458 A JP 2012-49247 A

Since the lifetime of OH radicals is extremely short, even if the substrate is cleaned immediately after the cleaning solution is irradiated with ultraviolet rays, the OH radical concentration is drastically lowered. According to the method described in Patent Document 1, since cleaning is performed while irradiating with ultraviolet rays, it is considered that a high cleaning effect by OH radicals can be obtained. It is limited to the cleaning liquid contained in the state. Further, in this method, it is necessary to constantly maintain a high dissolved ozone concentration or ozone gas concentration by supplying an organic solvent in which high-concentration ozone is dissolved, or supplying and renewing a liquid for bubbling ozone gas. The use of a large amount of ozone necessitates safety measures (by the way, the allowable concentration of ozone recommended by the Japan Society for Occupational Health is 0.1 ppm). Further, not only the utilization rate of ozone is lowered, but also waste liquid contains a large amount of ozone, so that the treatment requires labor and cost.

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

The second object of the present invention is to provide a high detergency of OH radicals efficiently even when a cleaning agent containing a relatively low concentration of ozone or a cleaning solution not containing ozone is used without using a large amount of ozone. It is providing the washing | cleaning apparatus which can utilize.

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.

In addition, 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 when the ultraviolet rays are irradiated.

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.

In addition, since the detergency with respect to the surface crested resist depends on the OH radical concentration and is promoted by the coexistence of quaternary ammonium hydroxide such as TMAH, it is difficult to remove substances such as the surface crested resist. The shortest irradiation time t _min can also be determined for the object to be cleaned. 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.

In the cleaning agent of the second aspect of the present invention, it is preferable that it 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, “low-k material” means an insulator material having a relative dielectric constant of less than 3.5.

A cleaning apparatus according to a fourth aspect of the present invention is an apparatus for cleaning a plate-shaped object to be cleaned, and is mounted on a support base having an upper surface on which the object to be cleaned is mounted and an upper surface of the support base. A cleaning agent supplying means for supplying a cleaning agent consisting of an aqueous solution in which a substance or ions that decompose by ultraviolet irradiation in the presence of water in the presence of water to generate hydroxyl radicals are dissolved on the entire surface to be cleaned, and the cleaning Cleaning agent holding means for holding the cleaning agent supplied from the agent supply means on the surface to be cleaned with a predetermined thickness, and the object to be cleaned placed on the upper surface of the support base And an ultraviolet light source for irradiating the cleaning agent held on the surface with ultraviolet rays.

Any of the following embodiments (1) to (3) can be preferably used for the cleaning device of the fourth aspect of the present invention.

(1) The support is in a disk shape rotatable around its central axis, and the cleaning agent holding means is for an annular outer weir provided in contact with the outer periphery of the support so as to be raised and lowered. A side wall and a height control means for controlling the height of the outer dam side wall, and is defined by an upper surface of the support base and an inner peripheral side wall surface of the outer dam side wall. Forming a recess for retaining the cleaning agent on which the cleaning body is placed, the depth of the recess for retaining the cleaning agent is adjusted to a predetermined depth by the height control means, and the support stand is stationary, According to the fourth aspect of the present invention, a predetermined amount of a cleaning agent is supplied from the cleaning agent supply means to the cleaning agent retention recess, and the cleaning agent is held at a predetermined thickness on a surface to be cleaned of the object to be cleaned. Cleaning device.

(2) The support base has a disk shape that can rotate on a central axis thereof, and the cleaning agent holding means is an annular ring having a predetermined height that is erected in the vicinity of the center of the support base. An inner weir side wall, and an annular outer weir side wall having a predetermined height, which is erected on the outer periphery of the support base, and an inner peripheral side wall surface of the outer weir side wall, An outer peripheral side wall surface of the inner dam side wall, an inner peripheral side wall surface of the outer dam side wall, and an upper surface of the support base sandwiched between the outer peripheral side wall surfaces of the inner dam side wall, and inside the object to be cleaned Forming a recess for retaining the cleaning agent on which the body is placed, supplying the cleaning agent continuously or intermittently from the cleaning agent supplying means to the recess for retaining the cleaning agent while rotating the support base, and surplus Of the object to be cleaned by causing the cleaning agent to flow out from the sidewall of the outer weir. Held at a predetermined thickness on the surface, the fourth cleaning apparatus of the present invention.

(3) The cleaning agent holding means is fixed in a watertight manner to an annular outer dam side wall that is slidably provided in contact with the outer peripheral portion of the support base and to an upper end portion of the outer dam side wall. And an ultraviolet transmissive plate-shaped skylight, and is defined by a surface of the support base, an inner peripheral side wall surface of the outer weir side wall, and an inner surface of the skylight, and the object to be cleaned is disposed therein. A cleaning agent retention space having a predetermined height is formed, and the cleaning agent is filled on the surface to be cleaned of the object to be cleaned by filling the cleaning agent retention space with the cleaning agent from the cleaning agent supply means. The cleaning apparatus according to the fourth aspect of the present invention, which is held at a predetermined thickness.

In the cleaning device of the fourth aspect of the present invention according to the embodiment of (2), the inner dam side wall is kept in contact with the inner dam side wall and the support base in a watertight manner. It is preferable to have first height control means for changing the height of the first height control means. Moreover, it is preferable that the said outer dam side wall has a 2nd height control means to change the height of this outer dam side wall. In addition, the outer dam side wall is provided to be higher than the inner dam side wall, and a discharge means for discharging excess cleaning agent is provided at a center side of the support base on the inner dam side wall. It is preferable that at least a part of the excess cleaning agent is discharged by the discharging means.

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. Further, 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 invention can be preferably used as a cleaning liquid in the cleaning method of the first 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.

According to the cleaning apparatus of the fourth aspect of the present invention, since the ultraviolet rays can be irradiated throughout the cleaning, new OH radicals can be constantly generated even if the lifetime of the OH radicals is short. In addition, since the cleaning agent can be irradiated with ultraviolet rays while being thinly held on the surface to be cleaned, the entire cleaning agent can be irradiated with ultraviolet rays, and the generation efficiency of OH radicals is high. For this reason, it is possible to obtain a high cleaning effect without using a large amount of ozone. The cleaning apparatus of the fourth aspect of the present invention can be preferably used in the cleaning method of the first aspect of the present invention.

It is a longitudinal section explaining the washing device 100 concerning one embodiment of the present invention typically. 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 cleaning apparatus 100 'concerning other one Embodiment of this invention. FIG. 4 is an EE arrow view of FIG. 3. FIG. 4 is a view taken along the line FF in FIG. 3. 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 '. FIG. 6 is a longitudinal sectional view schematically illustrating a cleaning apparatus 100 ″ according to another embodiment of the present invention. It is a figure explaining an example of the form of the side wall 14 for inner side dams in cleaning apparatus 100 '. (A) It is a top view of the side wall 14 for inner side dams, and is an EE arrow line view in FIG. (B) It is GG sectional drawing of (A), Comprising: The 2nd inner side ring-shaped side wall member 14b is lowered | hung with respect to the 1st inner side ring-shaped side wall member 14a, and the height of the side wall 14 for inner side dams is made. It is a figure showing the attitude | position which became the lowest. (C) It is GG sectional drawing of (A), Comprising: The 2nd inner side ring-shaped side wall member 14b is raised with respect to the 1st inner side ring-shaped side wall member 14a, and the height of the side wall 14 for inner side dams is made. It is a figure showing the increased attitude | position. It is a figure explaining an example of the form of the side wall 12 'for outer dams in washing | cleaning apparatus 100'. (A) It is a top view of the side wall 12 'for outer side dams, and is a EE arrow view in FIG. (B) It is HH sectional drawing of (A), Comprising: 2nd outer side ring-shaped side wall member 12'c descend | falls with respect to 1st outer side ring-shaped side wall member 12'b, and it is side wall 12 for outer weirs. It is a figure showing the attitude | position where the height of 'became the minimum. (C) It is HH sectional drawing of (A), Comprising: 2nd outer side ring-shaped side wall member 12'c is raised with respect to 1st outer side ring-shaped side wall member 12'b, and side wall 14 for outer weirs It is a figure showing the attitude | position where the height of was increased.

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 .

A cleaning apparatus according to a fourth aspect of the present invention is an apparatus for cleaning a plate-shaped object to be cleaned, and is mounted on a support base having an upper surface on which the object to be cleaned is mounted and an upper surface of the support base. A cleaning agent supplying means for supplying a cleaning agent consisting of an aqueous solution in which a substance or ions that decompose by ultraviolet irradiation in the presence of water in the presence of water to generate hydroxyl radicals are dissolved on the entire surface to be cleaned, and the cleaning Cleaning agent holding means for holding the cleaning agent supplied from the agent supply means on the surface to be cleaned with a predetermined thickness, and the object to be cleaned placed on the upper surface of the support base And an ultraviolet light source for irradiating the cleaning agent held on the surface with ultraviolet rays.

The cleaning device of the fourth aspect of the present invention is characterized in that ultraviolet light can be irradiated from the ultraviolet light source in a state where the cleaning liquid is held at a predetermined thickness on the surface to be cleaned. Have

As an object to be cleaned, an article having a substance to be removed by cleaning, preferably a plate-like article, such as a semiconductor silicon wafer, a wafer on which a device pattern is formed, a photomask, a liquid crystal glass substrate, etc. Electronic 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. . Since the merit of adopting the cleaning method or the cleaning apparatus 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. Exposure 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 per unit area It is preferable to use a semiconductor wafer having a photoresist 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. is there.

The cleaning agent used in the cleaning method of the first aspect of the present invention (hereinafter sometimes referred to as “the cleaning agent according to the first embodiment”) includes hydrogen peroxide, quaternary ammonium hydroxide, and water. Contains and does not contain ozone or 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, but usually 1 ppm by mass or less, preferably 0.1 ppm by mass or less, most preferably 0.01 ppm by mass or less, based on the total mass of the cleaning agent. It may be 0 ppm by mass.

The concentration of hydrogen peroxide in the cleaning agent according to the first embodiment is preferably 10 mass ppm or more and 4 mass% or less, particularly preferably 100 mass ppm or more and 2 mass% or less, and 200 mass% based on the total mass of the cleaning agent. Most preferably, the content is not less than ppm and not more than 1% by mass.

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 in the cleaning agent according to the first embodiment is preferably 1 to 20% by mass, particularly preferably 3 to 15% by mass, based on the total mass of the cleaning agent. .

As the water used for the cleaning agent according to the first embodiment, ultrapure water is preferable. The content ratio of water in the cleaning agent according to the first embodiment is preferably 8.999% by mass or more and 98.999% by mass or less, and 16.99% by mass or more and 99.99% by mass based on the total mass of the cleaning agent. The content is particularly preferably no greater than mass%, and most preferably no less than 46.98 mass% and no greater than 96.98 mass%.

The cleaning agent according to the first embodiment includes an amine compound such as a primary alkanolamine such as ethanolamine, a polyalkylenepolyamine such as ethylenediamine, and a polyoxyalkylenepolyamine such as N- (2-hydroxyethyl) ethylenediamine. The water-soluble organic solvent such as alcohols such as isopropyl alcohol and alkylene glycols such as ethylene glycol may be contained in an amount of 90% by mass or less based on the total mass of the cleaning agent. It may be contained in an amount of 80% by mass or less, most preferably 50% by mass or less.

The cleaning agent used in the cleaning device of the fourth aspect of the present invention (hereinafter sometimes referred to as “the cleaning agent according to the second embodiment”) is decomposed by ultraviolet irradiation in the presence of water to generate hydroxyl radicals. If it consists of the aqueous solution which the substance to perform or an ion melt | dissolved, it will not specifically limit. Here, the aqueous solution means a solution containing water. Moreover, as a substance or ion which decomposes | disassembles by ultraviolet irradiation in the presence of water and produces | generates a hydroxyl radical, the substance or ion in which such a function is known is not specifically limited, It can use. Examples of these substances and ions include ozone, hydrogen peroxide, urethane compounds, cellulose derivatives, nitrate ions, and nitrite ions. Among these, from the viewpoint of OH radical generation efficiency, it is preferably at least one selected from nitrate ion, nitrite ion, ozone and hydrogen peroxide, which is nitrate ion and / or nitrite ion, or ozone. Most preferably, it is hydrogen peroxide.

The higher the concentration of the substance or ions in the cleaning liquid according to the second embodiment, the easier it is to generate OH radicals. However, if the concentration is too high, the generated OH radicals react with each other and disappear. The problem of precipitation occurs. For these reasons, the concentration of these substances or ions in the cleaning liquid according to the second embodiment is a concentration not higher than the saturation solubility, and is 0.01 mM to 10 M, particularly 0.05 mM to 5 M. Preferably, it is 0.1 mM to 1 M. Here, M represents mol / liter.

In addition, in order for ions that decompose by ultraviolet irradiation in the presence of water to generate hydroxyl radicals (OH radicals) exist in the aqueous solution, the acid or salt of these ions may be dissolved in water. Nitric acid, ammonium nitrate, nitrous acid, and ammonium nitrite are preferably used as the substance that dissolves to give nitrate ions.

The cleaning agent according to the second embodiment includes, as necessary, a water-soluble organic solvent such as isopropyl alcohol; an ammonium compound such as quaternary ammonium hydroxide and ammonium fluoride; and a wiring material in an object to be cleaned such as copper. An anticorrosive agent or a chelating agent for preventing dissolution of the resin can be included. However, it is preferable not to include metal ions.

The method for adhering and holding the cleaning agent on the surface of the surface to be cleaned is not particularly limited. For example, when the object to be cleaned is a plate-like body (for example, a wafer), the surface to be cleaned is upper. It is possible to employ a method in which the object to be cleaned is fixed to the upper surface of the support base so that the exposed horizontal surface faces the surface, and the cleaning liquid is supplied so as to adhere to the surface of the surface to be cleaned. 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-wavelength ultraviolet rays are transmitted through a layer, they are absorbed rapidly and are not easily transmitted.Therefore, depending on the type of cleaning agent and the output of the UV light source, increasing the thickness of the cleaning agent layer causes UV light to reach the surface to be cleaned. There is a possibility that the cleaning effect by OH radicals cannot be obtained sufficiently. The thickness of the cleaning agent layer that allows the ultraviolet rays to reach the surface to be cleaned (for example, the thickness that becomes the effective optical path length described later) is grasped in advance, and the thickness of the cleaning agent layer existing on the surface to be cleaned is determined. By setting the thickness to be equal to or less than the thickness, a cleaning effect by OH radicals can be surely obtained on the surface to be cleaned.

At this time, 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, particularly preferably effective. It is preferable that the thickness is 1/50 or less of the optical path length. Here, the effective optical path length is a cleaning agent in which the irradiance of transmitted ultraviolet light becomes 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. Defined as layer thickness.

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 ~ 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 ultraviolet rays emitted under the same light emission conditions as in the ultraviolet irradiation from the light source toward the inside of the cell;
(3) Step S103 of measuring the irradiance (unit: mW / cm ² ) of the transmitted ultraviolet light that has passed through the cell;
(4) Steps S104 for obtaining the relationship between the irradiance of transmitted ultraviolet rays 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 the 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 when discussing the dependence of the irradiance of transmitted ultraviolet rays on the optical path length. 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)) .

In the first and fourth aspects of the present invention, as a method for controlling the thickness of the cleaning agent layer that covers the surface of the surface to be cleaned, the surface to be cleaned is, for example, a plate-shaped body to be cleaned. In the case where cleaning is performed while fixing to a support stand or the like so that the exposed horizontal surface faces upward, the following method can be suitably employed. That is, using a cleaning device provided with a weir outside the outer periphery of the object to be cleaned, a cleaning liquid is supplied to the inside of the weir to control the layer thickness (depth) of the cleaning agent (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.

During cleaning, the object to be cleaned may be stationary, or may be moved by rotating or swinging. However, the former method (method using a cleaning device provided with a dam outside the outer periphery of the object to be cleaned and supplying the cleaning liquid to the inside of the dam to control the layer thickness (depth) of the cleaning agent (FIG. 1 to FIG. 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 maintained in a steady state (see FIGS. 3 to 5).

In the cleaning method of the first aspect 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. 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.

In the cleaning method of the first aspect of the present invention, as the ultraviolet light source, 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. For this reason, 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 200 nm or more and 250 nm or less, and has 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 substantially emit ultraviolet light.

In the cleaning device according to the fourth aspect of the present invention, the ultraviolet light source is not particularly limited as long as it can emit ultraviolet rays. However, since the generation efficiency (quantum efficiency) of OH radicals can be increased, the wavelength is as short as 250 nm or less. It is preferable to use a light source that emits ultraviolet light having a wavelength, particularly ultraviolet light having a wavelength of 180 nm to 250 nm. As an ultraviolet light source, the apparatus can be made compact and easy to maintain, and the wavelength of 200 nm or more and 250 nm or less can be easily controlled 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 the region.

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 first aspect 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). In addition, it is necessary that 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 to be cleaned is not less than a predetermined predetermined cumulative irradiation dose I _0. There is. This makes it possible to perform reliable cleaning with a high yield.

In the cleaning method of the first aspect of the present invention, an ultraviolet light source is used 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 at the time of ultraviolet irradiation or the temperature of the cleaning liquid, and the type of cleaning agent. The emission intensity P is set to a predetermined emission intensity P ₀ , and the irradiation time t is changed to perform repeated cleaning (steps (a) and (b)) to determine the shortest irradiation time t _{min at} which a sufficient cleaning effect can be obtained. The integrated dose calculated as the product of the 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 described above, the cleaning apparatus according to the fourth aspect of the present invention can irradiate the ultraviolet light from the ultraviolet light source with the cleaning liquid held at a predetermined thickness on the surface to be cleaned of the object to be cleaned. The point has the greatest feature. For structures other than the cleaning agent holding means, for example, a to-be-cleaned object holding mechanism and a rotating mechanism in the support base, the cleaning agent supply means, an ultraviolet light source, and the like, known modes in a single wafer cleaning apparatus can be adopted.

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 the numerical values A and B means “A to B”. 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 according to one embodiment of the present invention. 1 and 2, the vertical direction on the paper surface represents the vertical direction. The cleaning apparatus 100 is an apparatus for cleaning the object 1 to be cleaned, which is a disk-shaped wafer, and rotates a support base (disk-shaped turntable) 10 on which the object 1 to be cleaned is placed, and the support base 10. Oppositely supports the support column 11, the ring-shaped weir side wall (outer weir side wall) 12 provided in contact with the outer peripheral portion of the support base 10, the cleaning agent supply nozzle 20, and the support base 10. An ultraviolet light source 30 and a rinsing liquid supply nozzle 40 that can be provided are provided.

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 cleaning agent retention 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 (height control 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 for retaining the cleaning agent). is there.

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 the UV-LED 32 is sealed in a space defined by the lid 33 and the substrate 31. The heat sink 34 has heat radiating fins, and the heat radiating 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 to be cleaned 1 from the discharge port 40a provided at the tip of the nozzle. . 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 cleaning method and the operation of the cleaning apparatus 100 will be described with reference to FIGS. 1 and 2.

In a state where the object to be cleaned 1 is not yet placed on the support 10, that is, before the start of the step (a), the upper end of the dam sidewall 12 is the same as or lower than the placement surface of the support 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.

Next, the member 1 to be cleaned is placed on the support 10 and the dam sidewall 12 is raised to a predetermined height. The cleaning agent supply nozzle 20 moves forward to the position shown in FIG. 1, and the cleaning agent is supplied from the cleaning agent supply nozzle 20 to the cleaning agent retention recess 13 defined by the support 10 and the dam sidewall 12. When the liquid level of the cleaning agent stored in the cleaning agent retention recess 13 reaches the upper end of the dam sidewall 12, the supply of the cleaning agent is stopped, and the cleaning agent supply nozzle 20 has the discharge port 20 a again at the dam sidewall 12. Retreat to the position outside. As a result, the cleaning agent adheres to and is held on the surface 1a of the surface 1a to be cleaned 1 (step (a)).

Thereafter, the ultraviolet light from the ultraviolet light source 30 is applied to the cleaning liquid adhered to and held on the surface to be cleaned 1a. 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 solution (stored in the recess 13 for storing the cleaning agent) is irradiated with ultraviolet rays from the ultraviolet light source 30 (step (b)).

In the ultraviolet irradiation, the support base 10 (disk-shaped turntable) is not rotated and is held stationary while the ultraviolet irradiation is performed.

In addition, the cleaning agent is continuously or intermittently supplied from the cleaning agent supply means to the vicinity of the central portion of the cleaning agent retention recess while rotating the support base, and excess cleaning agent is supplied from the outer weir sidewall. It is possible to hold the cleaning agent at a predetermined thickness on the surface to be cleaned by flowing it out, but in this case, the liquid in the peripheral portion rather than the central portion is caused by centrifugal force due to rotation. There is a tendency to deepen.

The cleaning apparatus 100 preferably has temperature control means such as a heater for controlling the temperature of the object to be cleaned and / or the temperature of the cleaning liquid during the ultraviolet irradiation. Cleaning efficiency can be increased by setting the temperature of the object to be cleaned and / or the temperature of the cleaning liquid to 50 ° C. or higher and 80 ° C. or lower. The cleaning apparatus 100 may further include an ultrasonic generator for performing ultrasonic irradiation on the cleaning agent in combination with ultraviolet irradiation.

In order to perform reliable cleaning with a high yield, the ultraviolet irradiation is an integrated irradiation of the ultraviolet rays irradiated to the cleaning liquid held on the surface of the surface to be cleaned 1a within the irradiation time in accordance with the light emission output P of the ultraviolet light source 30. It is preferable that the amount I (unit: mJ / cm ² ) is controlled to be equal to or greater than a predetermined integrated irradiation amount I ₀ . That is, by controlling the ultraviolet irradiation time: t (unit: second) and / or the light emission output of the ultraviolet light source: P (unit: mW), the cleaning liquid held on the surface of the surface to be cleaned within the irradiation time is controlled. It is preferable that the integrated dose I (unit: mJ / cm ² ) of the ultraviolet rays irradiated to the ultraviolet ray is equal to or greater than a predetermined cumulative dose I ₀ set in advance. In order to perform such control, in advance 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, It is preferable that 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, and the cleaning is repeatedly performed to determine the shortest irradiation time t _{min at} which a sufficient cleaning effect is obtained. The integrated dose calculated as the product of the emission intensity P ₀ and the shortest irradiation time t _min is preferably the predetermined integrated dose I ₀ when performing cleaning under the same basic cleaning conditions. .

When the ultraviolet irradiation (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 a cleaning apparatus 100 ′ according to another embodiment of the present invention. In FIG. 3, the vertical direction on the paper surface represents the vertical direction. FIG. 4 is a view taken along the line EE in FIG. FIG. 5 is a view taken along the line FF in FIG. The cleaning apparatus 100 ′ is a single wafer cleaning apparatus, and 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 on the upper surface of the cleaning apparatus 100 ′. And a support column 11 for rotatably supporting '. 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 ′.

It is preferable that the inner dam side wall 14 further has a height control means for changing its height while keeping the contact with the support base 10 ′ watertight. As the inner dam side wall 14 having such a height control means, for example, the inner dam side wall 14 having the form shown in FIG. 10 can be cited. The inner dam side wall 14 shown in FIG. 10 has a first inner ring-shaped side wall member 14a erected on the inner peripheral portion of the support base 10 ′ (the outer peripheral portion of the through hole 10′a); A second inner ring-shaped side wall member 14b slidably provided in watertight contact with the inner or outer peripheral portion of the side wall member 14a; and the first inner ring-shaped side wall member 14a and the second inner side There is an actuator (not shown) that raises and lowers the second inner ring-shaped side wall member 14b relative to the first inner ring-shaped side wall member 14a while maintaining watertight contact with the ring-shaped side wall member 14b. FIG. 10 (A) is a plan view of such an inner weir sidewall 14 and is a view taken along the line EE in FIG. FIGS. 10B and 10C are cross-sectional views taken along the line GG of FIG. 10A, and FIG. 10B shows that the second inner ring-shaped side wall member 14b is the first inner ring-shaped side wall. FIG. 10C shows a posture in which the height of the inner dam side wall 14 is lowered to the minimum with respect to the member 14a; FIG. 10 (C) shows that the second inner ring-shaped side wall member 14b is the first inner ring. It is a figure showing the attitude | position which was raised with respect to the shape side wall member 14a and the height of the side wall 14 for inner side dams was increased. In FIG. 10, the first inner ring-shaped side wall member 14a is disposed on the inner peripheral side, and the second inner ring-shaped side wall member 14b is disposed on the outer peripheral side. It is also possible to arrange 14a on the outer peripheral side and the second inner ring-shaped side wall member 14b on the inner peripheral side.

It is preferable that the outer weir side wall 12 'further has a height control means for changing the height thereof. Examples of the outer dam sidewall 12 'having such height control means include the outer dam sidewall 12' having the configuration shown in FIG. The outer dam side wall 12 ′ shown in FIG. 11 includes a first outer ring-shaped side wall member 12′b erected on the outer periphery of the support base 10 ′; an inner periphery of the first outer ring-shaped side wall member 12′b. A second outer ring-shaped side wall member 12′c and a first outer ring-shaped side wall member 12′b and a second outer ring-shaped member that are slidably provided in watertight contact with the outer peripheral portion or the outer peripheral portion. An actuator (not shown) for raising and lowering the second outer ring-shaped side wall member 12'c with respect to the first outer ring-shaped side wall member 12'b while maintaining watertight contact with the side wall member 12'c. . FIG. 11A is a view taken along the line EE in FIG. 3 of such an outer weir sidewall 12 '. FIGS. 11B and 11C are cross-sectional views taken along the line HH of FIG. 11A. FIG. 11B shows a case where the second outer ring-shaped side wall member 12′c is a first outer ring. FIG. 11C shows a posture in which the height of the outer weir sidewall 12 ′ is minimized with respect to the outer sidewall member 12′b, and FIG. 11C shows the second outer ring-shaped sidewall member 12 ′. It is a figure showing the attitude | position where c was raised with respect to 1st outer side ring-shaped side wall member 12'b, and the height of the side wall 14 for outer weirs was increased. In FIG. 11, the first outer ring-shaped side wall member 12′b is disposed on the outer peripheral side, and the second outer ring-shaped side wall member 12′c is disposed on the inner peripheral side. It is also possible to dispose the ring-shaped side wall member 12′b on the inner peripheral side and the second outer ring-shaped side wall member 12′c on the outer peripheral side.

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 overflowed beyond the inner weir side wall 14. Excess cleaning liquid can be discharged toward the waste liquid tray 16. Thus, the through-hole 10'a and the support base overflow cleaning liquid discharging recess 15 serve as a discharging means for discharging excess cleaning agent.

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).

The arrow G in FIG. 3 shows 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 cleaning agent retention recess 13 ′ defined by the support base 10 ′, the outer dam side wall 12 ′, and the inner dam side wall 14 is covered by the object to be cleaned 1. After flowing through the surface of the cleaning surface 1 a, it flows out from a discharge port 17 a provided at the lower end of the outer weir side wall 12 ′ and is received by the waste liquid tray 16. Further, after the cleaning liquid overflowing from the cleaning agent retaining recess 13 'beyond the inner dam sidewall 14 is received by the support base overflow cleaning liquid discharge recess 15 through the through hole 10' of the support base 10 ', It flows out from the discharge port 17b 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 (when cut along the X-X ′ plane) of the rod-shaped light source (rod-shaped ultraviolet light emitting module) 110. 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. Further, the cylindrical substrate 111 on which the UV-LED 112 is mounted is covered with a cover 116 made 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 the 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 not only as a support for fixing and holding the UV-LED 112 but also as a heat sink, and a cooling medium such as cooling water or cooling air is provided in the cooling medium channel 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 by the UV-LED 112, the cylindrical substrate 111 is preferably mainly composed of a metal or ceramic having high thermal conductivity such as copper or aluminum, and the cooling medium 118 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 or a copper wire or a circuit for supplying power to the UV-LED 112 from a battery or an external power source disposed inside or outside the housing. 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 UV-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 body 111, but the present invention is not limited to this form, and the number of UV-LEDs 112 is arranged outside the cylindrical base body 111. It can be appropriately changed according to the diameter. The number of UV-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 UV-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 UV- LEDs 112, 112,... Are 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 the ultraviolet light source 30 ′ having the rod-like 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 first invention, the step (b) may be performed while performing the step (a), or the step (b) may be performed after performing the step (a). For example, in the cleaning apparatus 100 ′, 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 weir side wall 14 of the cleaning agent retention recess 13 ′ is started. The cleaning liquid supplied in the vicinity of the inner weir side wall 14 of the cleaning agent retention 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 reaching the outer weir side wall 12 ′ flows out from the discharge port 17 a and is received in 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 with 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 in the agent retention recess 13 is adjusted to maintain a steady state. At this time, the supply rate of the cleaning agent may be increased so that excess cleaning liquid overflows beyond the inner weir sidewall 14. The height of the outer weir side wall 12 'is made higher than the height of the inner weir side wall 14, and an overflow suppression cover 12'a is further provided as necessary to remove excess cleaning liquid from the inner weir side wall 14 through the through hole 10'. By letting it flow out to a, even if the rotational speed of the support base is increased, the liquid depth of the cleaning agent in the vicinity of the center of the support base can be prevented from becoming too shallow.

Along with the supply of the cleaning liquid, ultraviolet light is irradiated from the ultraviolet light source 30 ′ to the cleaning liquid adhered and held on 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 ′. As described above, a rinsing step may be further performed after the steps (a) and (b) are completed.

In the above description relating to the present invention, cleaning is performed in which a weir (12, 12 ') is provided outside the outer periphery of the object to be cleaned, and the cleaning liquid is supplied to the inside of the weir to control the layer thickness (depth) of the cleaning agent. Although apparatus 100,100 'was illustrated, the washing | cleaning apparatus of this 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 the description thereof is omitted.

The cleaning apparatus 100 ″ supports the support base (disk-shaped turntable) 10 on which the cleaning target 1 is placed on the upper surface thereof, and supports the support base 10 so that the support base 10 can be rotated and moved up and down (arrow I in FIG. 9). Ultraviolet-transmitting UV light fixed to the upper end of the column 11 ', the ring-shaped outer weir side wall 12' 'that can slide in a watertight manner on the outer periphery of the support base 10, and the outer weir partition wall 12' '. The plate-shaped skylight 18, the cleaning agent supply pipe 50 and the cleaning agent discharge pipe 51 provided through the outer weir side wall 12 ″, and the support base 10 through the skylight 18 are provided. And an ultraviolet light source 30. A cover is formed by the outer weir side wall 12 ″ and the skylight 18. That is, when the outer peripheral portion of the support base 10 is in contact with the inner peripheral surface of the outer weir side wall 12 ″, the cleaning agent retention space 19 is formed by the support base 10, the outer weir side wall 12 ″, and the skylight 18. Is defined. The cleaning agent supply pipe 40 and the cleaning agent discharge pipe 41 are arranged so that the cleaning agent staying space 19 can be filled with the cleaning agent and sealed or circulated.

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 so that the outer peripheral portion of the support base 10 is in contact with the inner peripheral surface of the outer weir sidewall 12 ″, and the cleaning agent The thickness of the stay space 19 is adjusted so that the distance from the surface to be cleaned 1a of the object to be cleaned 1 to the skylight 18 becomes a desired value. The cleaning agent is supplied and filled into the space 19 from the cleaning agent supply pipe 50 to fill the cleaning agent retention space 19 with the cleaning agent (step (a)), and the cleaning agent in the cleaning agent retention space 19 (that is, the surface to be cleaned 1a). The cleaning agent adhered and held on the surface of the substrate is irradiated with ultraviolet rays 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 flow in the cleaning agent retention 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.

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 are stopped, whereby the steps (a) and (b) are completed. 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' Concave for cleaning agent retention 14 Inner dam side wall 15 Support stand overflow cleaning liquid discharge recess 16 Waste liquid trays 17a, 17b, 17c Discharge port 18 Skylight 19 Cleaning agent retention space 20, 20 'Cleaning agent supply nozzles 20a, 20'a (cleaning agent) discharge Exit 30, 30 'UV light source 31 Substrate 32 UV 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 (17)

1. (A) attaching and holding a cleaning agent comprising hydrogen peroxide, a quaternary ammonium hydroxide, and water and not containing ozone and metal ions on the surface of the surface to be cleaned;
   (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 to 250 nm 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. An accumulated dose I (unit: mJ / cm ² ) of ultraviolet rays irradiated to the cleaning liquid held on the surface is set to be equal to or larger than a predetermined accumulated dose I ₀ set in advance. A method for cleaning an object to be cleaned.
2. 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 or 2, wherein the temperature of the object to be cleaned or the temperature of the cleaning liquid is set to 50 ° C or higher and 80 ° C or lower when the ultraviolet rays are irradiated.
4. The emission intensity P of the ultraviolet light source is determined in advance for each basic cleaning condition comprising a combination of the type of the object to be cleaned, the temperature of the object to be cleaned at the time of ultraviolet irradiation or the temperature of the cleaning liquid, and the type of cleaning agent. P ₀ , changing the irradiation time t, repeatedly performing the steps (a) and (b), determining the shortest irradiation time t _{min at} which a sufficient cleaning effect is obtained,
   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.
5. When the effective optical path length is defined as a thickness at which the irradiance of transmitted ultraviolet light when the ultraviolet light irradiated from the ultraviolet light source passes through the layer made of the cleaning agent is 0.01 mW / cm ² ,
   In the step (a), the cleaning target covers the entire surface to be cleaned, and the thickness of the cleaning agent layer covering the surface to be cleaned is equal to or less than the effective optical path length. Attach and retain the cleaning agent on the surface of the surface,
   In the step (b), ultraviolet light irradiation is performed without bringing the light source and the cleaning agent into contact with each other,
   The method according to claim 1.
6. The object to be cleaned has a structure made of a low-k material, and was 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. The method according to claim 1, which is a semiconductor wafer having a photoresist layer on a surface thereof.
7. A cleaning agent used in the method according to any one of claims 1 to 6, comprising hydrogen peroxide, quaternary ammonium hydroxide, and water, and free from ozone and metal ions. Washing soap.
8. The cleaning agent according to claim 7, further comprising a water-soluble organic solvent.
9. The cleaning agent according to claim 7 or 8, further comprising a chelating agent.
10. A method of manufacturing a semiconductor wafer having a structure made of a low-k material and an ion implantation region,
    A step of removing the photoresist layer exposed to the 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 by the cleaning method according to claim 6. A method for producing a semiconductor wafer, comprising:
11. An apparatus for cleaning a plate-shaped object to be cleaned,
    A support base having an upper surface on which the object to be cleaned is placed;
    A cleaning agent comprising an aqueous solution in which substances or ions that decompose by ultraviolet irradiation in the presence of water to generate hydroxyl radicals are dissolved on the entire surface to be cleaned of the object to be cleaned placed on the upper surface of the support table. Cleaning agent supply means for supplying;
    Cleaning agent holding means for holding the cleaning agent supplied from the cleaning agent supply means on the surface to be cleaned of the object to be cleaned at a predetermined thickness;
    An ultraviolet light source for irradiating the cleaning agent held on the surface to be cleaned placed on the upper surface of the support table with ultraviolet rays;
    A cleaning apparatus comprising:
12. The support base has a disk shape that can rotate around its central axis,
    The cleaning agent holding means is an annular outer dam side wall provided in a watertight manner in contact with the outer peripheral portion of the support base, and a height control means for controlling the height of the outer dam side wall; Have
    The upper surface of the support base and the inner peripheral side wall surface of the outer dam side wall are demarcated, and a cleaning agent retention recess for mounting the object to be cleaned is formed therein,
    The depth of the recess for retaining the cleaning liquid is adjusted to a predetermined depth by the height control means,
    With the support stand still, a predetermined amount of cleaning agent is supplied from the cleaning agent supply means to the cleaning agent retention recess, and the cleaning agent is held on the surface to be cleaned at a predetermined thickness. The cleaning apparatus according to claim 11.
13. The support base has a disk shape that can rotate around its central axis,
    The cleaning agent holding means includes an annular inner dam side wall having a predetermined height, which is erected in the vicinity of the center of the support base, and a predetermined erection side wall, which is erected on the outer periphery of the support base. An annular outer weir sidewall having a height,
    The support base sandwiched between an inner peripheral side wall surface of the outer dam side wall, an outer peripheral side wall surface of the inner dam side wall, an inner peripheral side wall surface of the outer dam side wall, and an outer peripheral side wall surface of the inner dam side wall. And a recess for retaining the cleaning agent, in which the object to be cleaned is placed,
    The cleaning agent is supplied by continuously or intermittently supplying the cleaning agent from the cleaning agent supply means to the cleaning agent retaining recess while rotating the support base, and the excess cleaning agent flows out from the outer weir sidewall. The cleaning apparatus according to claim 11, wherein the cleaning object is held at a predetermined thickness on a surface to be cleaned.
14. The side wall for the inner weir has a first height control means for changing the height of the side wall for the inner weir while keeping the contact between the side wall for the inner weir and the support base watertight. The cleaning device described.
15. 15. The cleaning apparatus according to claim 13 or 14, wherein the outer dam sidewall has second height control means for changing a height of the outer dam sidewall.
16. The outer weir side wall is provided to be higher than the inner weir side wall,
    Discharge means for discharging excess cleaning agent is provided on the center side of the inner dam side wall of the support base,
    The cleaning device according to any one of claims 13 to 15, wherein at least a part of the excess cleaning agent is discharged by the discharging means.
17. The cleaning agent holding means includes an annular outer weir side wall slidably provided in watertight contact with the outer peripheral portion of the support base, and an ultraviolet ray fixed to the upper end of the outer weir side wall in a watertight manner. A transparent plate-shaped skylight;
    A cleaning agent retention space having a predetermined height, which is defined by the surface of the support base, the inner peripheral side wall surface of the outer dam side wall, and the inner surface of the skylight, and in which the object to be cleaned is placed. Forming,
    The cleaning apparatus according to claim 11, wherein the cleaning agent is held in a predetermined thickness on the surface to be cleaned of the object to be cleaned by filling the cleaning agent retention space with the cleaning agent from the cleaning agent supply unit.

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