JP2571304B2 - Substrate surface treatment method and apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a substrate surface treatment method and apparatus for cleaning and removing organic substances and heavy metals adhering to a substrate surface in manufacturing a semiconductor.

<Prior Art> Conventionally, surface treatment of this kind of substrate is performed by
There were the following.

A. First Conventional Example As disclosed in Japanese Patent Application Laid-Open No. 1-278028, a substrate is exposed to a cleaning gas such as HCl gas or Cl ₂ gas while irradiating ultraviolet rays while applying heat to the substrate. Thus, a film such as a natural oxide film or a contaminant layer is removed by cooperation between a thermal reaction and a photochemical reaction.

B. Second Conventional Example As disclosed in JP-A-1-225123, by irradiating the surface of the substrate with ultraviolet light in an oxygen atmosphere, carbo-based contaminants are removed in the gas phase, Subsequently, by irradiating the surface of the substrate with light in a chlorine atmosphere, metal-based contaminants are removed in the gas phase together with etching.

C. Third Conventional Example As disclosed in JP-A-62-272541, a substrate is placed in an atmosphere containing halogen such as chlorine gas, and the surface of the substrate is radicalized by radiating ultraviolet rays to radicalize the halogen. Is etched, and at the same time, a contaminant, such as sodium or potassium, is chemically bonded to a halogen ion. Thereafter, a compound of a substrate constituent material and a halogen is washed with a solution.

D. Fourth conventional example As disclosed in JP-A-60-216558, when a contaminant is a metal, a chlorine gas is brought into contact with the substrate surface, and the chlorine gas is irradiated with light to form ions or ions. Active species such as radicals are generated, and contaminants on the substrate surface are changed to chlorides easily detached from the surface by the action of the active species, so that they can be easily removed.

<Problems to be Solved by the Invention> However, in the above-mentioned conventional technology, it is dangerous because toxic gases such as chlorine gas and hydrogen chloride gas are used as the reaction gas.

When a reactive gas is activated by irradiation with ultraviolet rays, for example, when a mercury lamp or the like is used, the efficiency of ultraviolet rays is low, and contaminants such as heavy metals on the substrate surface are converted into other substances such as chlorides. However, there is a disadvantage that the removal is insufficient due to the difficulty.

Also, even if a mercury lamp with low UV efficiency is used,
If the substrate is heated to a high temperature, it will be possible to sufficiently remove contaminants such as heavy metals by sublimation, but with chromium Cr, nickel Ni, iron Fe, etc., the sublimation temperature will be as high as 1000 ° C, When such high-temperature heating is performed, the electrical characteristics of the dehighs are easily deteriorated, and there is a defect that the product becomes defective and the product yield decreases.

The present invention has been made in view of such circumstances, and an object of the present invention is to make it possible to remove organic substances and inorganic substances satisfactorily in a simple and inexpensive manner and safely.

<Means for Explaining the Problems> In order to achieve such an object, the method for treating a surface of a substrate of the present invention supplies an acid-containing vapor generated from an aqueous solution containing an acid to the substrate surface under ultraviolet irradiation. Thereafter, a cleaning process is performed by supplying pure water to the substrate surface.

Further, in order to achieve the above-mentioned object, the substrate surface treatment apparatus of the present invention stores an acid-containing aqueous solution therein, and generates an acid-containing vapor generating means for generating a vapor of the aqueous solution; Acid-containing vapor supply means for supplying the acid-containing vapor generated by the vapor generation means to the surface of the substrate housed in the room, and ultraviolet irradiation for irradiating the acid-containing vapor generated by the acid-containing vapor generation means and the substrate surface with ultraviolet light Means for providing a substrate surface treatment unit comprising: a pure water cleaning treatment chamber adjacent to the substrate surface treatment unit; and supplying pure water to the pure water cleaning treatment chamber to the surface of the substrate housed in the room. The apparatus is provided with pure water supply means.

As the aqueous solution containing an acid, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, acetic acid and the like can be used.

<Function> According to the configuration of the method for treating the surface of a substrate of the present invention, oxygen or moisture in the atmosphere is irradiated with ultraviolet rays to generate active oxygen, and the active oxygen converts organic substances (C _X H _Y O _Z ) to carbon dioxide. It is decomposed into gas (CO ₂ ) and water (H ₂ O) and removed. Active hydrogen generated at the same time promotes decomposition of organic substances by active oxygen. On the other hand, since the acid-containing vapor generated from the aqueous solution containing the acid is supplied to the substrate surface under irradiation of ultraviolet light,
The acid-containing vapor is activated near the substrate surface and reaches the substrate surface in a highly active state, easily converting inorganic contaminants such as heavy metals into salts such as halides, and washing it away with pure water. To remove. Further, since the acid-containing vapor containing water is supplied to the substrate surface, the acid-containing vapor is easily adsorbed on the substrate surface, and the acid contained in the acid-containing vapor can efficiently convert heavy metals on the substrate surface into salts. . In addition, since the substrate surface is irradiated with ultraviolet rays as described above, the acid rapidly converts heavy metals into salts. The converted salt is energized by the ultraviolet light, acts to separate from the substrate surface, and easily detaches from the substrate surface.

On the other hand, the moisture of the acid-containing vapor adsorbed on the substrate is decomposed by the irradiated ultraviolet rays to generate active oxygen, and the active oxygen decomposes organic substances on the substrate surface. The decomposed organic matter is easily separated from the substrate surface because energy is given by the ultraviolet light. Even in the case where the ultraviolet ray efficiency is low, since the acid-containing vapor is ion-bonded with an inorganic substance such as a metal in the presence of water (H ₂ O), a metal salt is generated, and thus the removal with pure water is possible. Becomes

According to the configuration of the substrate surface treatment apparatus of the present invention,
In the substrate surface treatment section, as described above, the conversion of inorganic substances such as heavy metals to salts such as halide salts and the decomposition of organic substances are performed well, and salts such as halide salts and the like are decomposed by energy given by ultraviolet rays. The organic material thus removed is easily separated from the substrate surface, and the substrate after the surface treatment is transferred to a pure water cleaning treatment chamber, where salts such as halide salts and decomposed organic materials are washed and removed with pure water.

<Example> Next, an example of the present invention will be described in detail with reference to the drawings.

First Embodiment FIG. 1 is a schematic longitudinal sectional view showing a first embodiment of a substrate surface treating apparatus. A spin chuck 3 having a heater 2 for heating a substrate W is provided in a first housing 1. An ultraviolet lamp 4 provided as ultraviolet irradiation means
Is provided with a nozzle 5 made of quartz as an acid-containing vapor supply means incorporating therein. The ultraviolet lamp 4 is connected to the nozzle 5
Instead of being built in the nozzle 5, it may be arranged below the nozzle 5.

Spin chuck 3 is configured to drive rotation about a vertical axis by a motor M _1.

In the bottom plate of the nozzle 5, a large number of diffusion holes 5a are formed in a state of being uniformly distributed at predetermined intervals.

In order to increase the efficiency of decomposing and removing organic substances and the conversion efficiency of inorganic substances, the distance between the substrate W on the spin chuck 3 and the ultraviolet lamp 4 should be as short as possible.

A carry-in port 1a and a carry-out port 1b for the substrate W are formed in a state of being diametrically opposed to the peripheral wall portion of the first housing 1. Shutter that can be opened and closed by sliding
6a and 6b are provided.

Outside the first housing 1, a first substrate transport mechanism 7 a for transporting the substrate W into the first housing 1 through the entrance 1 a, and unloading the substrate W from the first housing 1 to the outside through the exit 1 b. In addition, a second substrate transport mechanism 7b for carrying in the second housing 9 constituting the pure water cleaning processing chamber 8 and a third substrate transport mechanism 7c for carrying out of the second housing 9 are provided. ing.

These first, second and third substrate transfer mechanisms 7a, 7b
And 7c each have the same structure, and as shown in the perspective view of FIG.
A first arm 11 attached to a rotary shaft of
Second arm 12 rotatably attached to the free end of 11
A transmission mechanism 13 for transmitting the rotational motion of the first arm 11 to rotate the second arm 12; and a vacuum chuck port 14 formed at the free end of the second arm 12 for sucking and holding the placed substrate W.
And so on.

An acid-containing steam generating means 15 for evaporating an aqueous solution containing an acid such as hydrochloric acid or nitric acid is connected to an introduction pipe 5b of the nozzle 5 via a steam supply pipe 17 provided with an opening / closing valve 16.

The acid-containing vapor generating means 15 is composed of a storage tank 18 for storing an aqueous solution containing an acid, and a temperature control means 19 such as a heater provided on an outer peripheral portion of the storage tank 18, and the acid stored in the storage tank 18. Is heated and evaporated by the temperature control means 19, and the acid-containing vapor generated by the evaporation is supplied to the nozzle 5 through the vapor supply pipe 17. Although not shown,
The steam supply pipe 17 is covered with a heat insulating material, and is configured so as not to be liquefied when flowing through the inside thereof.

An aqueous solution supply pipe 20 for replenishing an aqueous solution containing an acid and a carrier gas supply pipe 21 for supplying nitrogen N ₂ gas as a carrier gas are connected to the storage tank 18.
On / off valves 20a and 21a are interposed in 20, 20, respectively.

An exhaust chamber 22 for a gas such as CO ₂ and H ₂ O generated at the time of decomposing and removing organic substances is formed in the bottom plate of the first housing 1, and an exhaust pipe 23 communicating therewith is connected to a blower (not shown).

The above-described structure including the first housing 1 in which the ultraviolet lamp 4 and the nozzle 5 are housed, the acid-containing steam generating means 15, and the steam supply pipe 17 connecting the two are referred to as a substrate surface treatment unit.

The pure water cleaning processing chamber 8 has a substrate mounting table 24 inside the second housing 9 so as to be able to move up and down, and a pure water for supplying pure water at a predetermined temperature to the top plate of the second housing 9. A supply nozzle 25 is provided.

The substrate mounting table 24 is configured to be rotated about a vertical axis by a motor M _2. Further, pins 24a are erected on the substrate mounting table 24 at positions diametrically opposed to each other, and projections 24b for holding the substrate are mounted inside the pins 24a.

A carry-in port 9a and a carry-out port 9b for the substrate W are formed in a state of being diametrically opposed to the peripheral wall portion of the second housing 9, and each of the carry-in port 9a and the carry-out port 9b is vertically moved by a driving mechanism (not shown). Shutters 26a and 26b are provided so as to be opened and closed by sliding.

A drain 27 and a pipe 27 for exhaust are connected to the bottom plate of the second housing 9.

The substrate surface treatment method of the present invention is performed by using the substrate surface treatment apparatus having the above-described configuration.

That is, the acid-containing vapor generated by the evaporation of the acid-containing aqueous solution in the acid-containing vapor generating means 15 is supplied to the nozzle 5, and the acid-containing vapor is irradiated with ultraviolet rays from the ultraviolet lamp 4. Ultraviolet light from the ultraviolet lamp 4 passes through a quartz nozzle 5 and irradiates the substrate surface. In this manner, the acid-containing vapor activated by the ultraviolet irradiation is uniformly supplied to the surface of the substrate W held by the spin chuck 3 through the diffusion holes 5a in a highly active state.
It decomposes and removes organic substances on the substrate surface and converts inorganic substances such as heavy metals into salts such as halides.

After the processing, the substrate W is transferred to the substrate mounting table 24 in the pure water cleaning processing chamber 8 by the second transfer mechanism 7b,
Pure water is supplied from the pure water supply nozzle 25 to the substrate W mounted on the substrate mounting table 24 to wash and remove the above-described salts such as halides.

As the pure water to be supplied from the pure water supply nozzle 25, for example, the use of pure water heated to a temperature of 50 ° C. to 80 ° C. can promote the removal of salts such as halides. Alternatively, an ultrasonic wave having a frequency of 800 kHz or more may be added to pure water to increase the cleaning efficiency, or pure water at room temperature may be supplied.

Second Embodiment FIG. 3 is a schematic longitudinal sectional view showing a second embodiment of the substrate surface treating apparatus, and FIG. 4 is a plan view of a substrate boat, and FIG.
And the second housings 31 and 32 are capable of accommodating a substrate boat 33 for accommodating a large number of substrates W.
While the substrate surface treatment apparatus of the second embodiment is of a single-wafer type for processing substrates W one by one, the substrate surface treatment apparatus of the second embodiment is of a batch type.

Above the first housing 31, a nozzle 35 made of quartz is provided as an acid-containing vapor supply means having a built-in ultraviolet lamp 34 as an ultraviolet irradiation means. The ultraviolet lamp 34 may be provided below the nozzle 35.

In the bottom plate of the nozzle 35, a large number of diffusion holes 35a are formed in a state of being uniformly distributed at predetermined intervals.

The bottom plate of the first housing 31 is provided with an exhaust pipe 36 for exhausting gases such as CO ₂ and H ₂ O generated at the time of decomposing and removing organic substances, and a blower (not shown) is connected to the exhaust pipe 36. I have.

A pure water supply nozzle that supplies heated high-temperature pure water to an upper side of the second housing 32 that constitutes the pure water cleaning processing chamber.
A drain pipe 38 is connected to the bottom plate of the second housing 32, and an exhaust pipe is
39 is connected.

On each of the peripheral walls of the first housing 31 and the second housing 32 facing each other, carry-in ports 40 and 41 for carrying in and out the substrate boat 33 are provided.

Each of the carry-in entrances 40 and 41 is provided with a shutter 42 that is opened and closed by sliding in a vertical direction by a drive mechanism (not shown).

Between the first housing 31 and the second housing 32,
The substrate boat 33 is moved to the first housing 31 through the loading port 40.
Transport mechanism for loading and unloading to and from the second housing 32 through the loading port 41
43 are provided.

An acid-containing steam generator having the same configuration as that of the first embodiment is connected to the nozzle 35 via a steam supply pipe 44.

Next, the results of an experiment performed using hydrochloric acid vapor as the acid-containing vapor will be described.

In the experiment, a substrate surface treatment was performed using the same structure as the substrate surface treatment unit in the first embodiment described above, and pure surface treatment was performed in the same first housing 1 after the substrate W surface treatment. A water supply nozzle was introduced, and a cleaning treatment with pure water was performed.

A 6-inch P (100) type silicon wafer was used as a sample substrate, and the surface of the silicon wafer was SU
After rubbing the S304 plate lightly three times in the y-axis direction perpendicular to the orientation flat, the Al plate was lightly rubbed three times in the y-axis direction to contaminate with iron, Fe, Cr, Al, Ni, Cu, and the like.

Such a contaminated silicon wafer is placed on a spin chuck, and hydrochloric acid, that is, an azeotropic mixture of hydrogen chloride HCl and water H ₂ O (hydrogen chloride concentration: 21%) is generated by an acid-containing vapor generating means. Hydrochloric acid vapor is generated under pseudo-azeotropic conditions using nitrogen N ₂ gas as a carrier gas, and this hydrochloric acid vapor is irradiated with ultraviolet light having a wavelength of 184.9 nm and 253.7 nm by a low-pressure mercury lamp to provide a reactive chlorine radical. After the chlorine radicals were supplied to the substrate surface while the spin chuck was rotated at 100 rpm, pure water of 2 was supplied to the salt converted by the chlorine radicals for one minute to wash and remove the salts.
Here, the azeotropic condition means that at a predetermined pressure and temperature,
A state in which the concentration of the azeotropic mixture and the concentration of the azeotropic mixture vapor coincide with each other.The pseudo-azeotropic condition is a condition in which an inert gas or the like is mixed into the evaporated vapor and diluted. Although the vapor concentration does not coincide with the concentration of the azeotropic mixture, it refers to a state in which the vapor concentration of the diluted vapor excluding the diluent gas coincides with the concentration of the azeotropic mixture.

The silicon wafer treated in this manner was used as an example product.

On the other hand, a silicon wafer in a contaminated state where no treatment is performed is referred to as a first comparative example, and a silicon wafer in a contaminated state which is subjected to a cleaning treatment by supplying 2 pure waters for one minute is referred to as a second comparative example. A third comparative product was obtained by supplying hydrochloric acid vapor for 1 minute to perform surface treatment without irradiation with ultraviolet rays, followed by supplying 2 pure waters for 1 minute and washing.

For each of the above-mentioned Example product and the first to third comparative example products, at predetermined three points, ²⁸ Si ⁺ , ²⁷ Al ⁺ , ⁵² Cr ⁺ , ⁵⁶ Fe ⁺ were determined by SiMS analysis (secondary ion mass spectrometry). , ⁵⁸
Ni ⁺ out respective average value with measuring the ionic ^{strength, 27 Al +, 52 Cr +} , 56 Fe +, was obtained ⁵⁸ Ni ^{+ 28} Si ⁺ ratio ions altitude of each ionic strength.

²⁸ Si ^{+ for} each of these examples and the first to third comparative examples (in this order, A, B1, B2, and B3)
The following table shows the measurement results for the ionic strength of each of ²⁷ Al ⁺ , ⁵² Cr ⁺ , ⁵⁶ Fe ⁺ , and ⁵⁸ Ni ⁺ , and
The ionic strength ratios of ²⁷ Al ⁺ , ⁵² Cr ⁺ , ⁵⁶ Fe ⁺ , and ⁵⁸ Ni ^{+ for the} example product and the first to third comparative examples are shown in the bar graph of FIG. Note that two examples were obtained for the third comparative example product.

From the results of the above experiment, the ionic strength ratio of each of ²⁷ Al ⁺ , ⁵² Cr ^+, and ⁵⁸ Ni ⁺ can be significantly reduced in the example product as compared with any of the first to third comparative examples. It is clear that it can be removed. ^In the ionic strength ratio of ⁵⁶ Fe ⁺ , the peak was the same in atomic weight as ⁵⁶ Si ⁺ and overlapped, so that the ionic strength of ⁵⁶ Fe ⁺ itself could not be measured. In the example product, it is clear that the ionic strength of ²⁸ Si ⁺ is extremely high, and contaminants on the surface of the substrate can be removed well.

[Discussion] Next, the action of removing organic substances and inorganic substances in the above embodiment according to the present invention will be discussed.

First, the hydrochloric acid vapor is irradiated with ultraviolet light having a wavelength of 184.9 nm and 253.7 nm, so that the following photochemical reaction occurs to be converted into hydrogen radicals and chlorine radicals.

The chlorine radical Cl. Generated by this photochemical reaction reacts with the alkali metal M, heavy metal M, silicon Si and the like to form a salt as shown by the following formula.

Si + 4Cl → SiCl ₄ M + xCl → MCl _X Hydrogen chloride also forms a salt as shown by the following formula in the presence of water.

_{M + xHCl → MCl X + x} / 2 × H 2 These salts are easily soluble in water, can be easily removed by washing with pure water.

As a result of treating the surface of the silicon wafer with the hydrochloric acid vapor activated by the above-described ultraviolet light, an oxide film was formed on the surface of the silicon wafer, and the silicon wafer became completely hydrophilic. It is considered that a trace amount of oxygen in the atmosphere is converted into active oxygen radicals or ozone by ultraviolet light, or oxygen radicals and the like are generated by irradiating water vapor with ultraviolet light, and are combined with silicon. And maybe because of that, the contamination layer on the silicon surface,
It is considered that these are removed by an etching reaction by chlorine radicals and an oxidizing effect (organic substance removing effect) by oxygen radicals. For this reason, it is considered that the ionic strength of silicon ( ²⁸ Si ⁺ ) is significantly higher than before the treatment.

In the above embodiment, the ultraviolet lamp 4 is connected to the nozzle 5 made of quartz.
And irradiates the acid-containing vapor with ultraviolet rays in the nozzle 5 and irradiates the substrate surface with ultraviolet rays through the nozzle 5. For example, the acid-containing vapor is supplied to the substrate surface, and Ultraviolet rays may be applied.
In short, what is necessary is just to supply the acid-containing vapor to the substrate surface under ultraviolet irradiation.

In the substrate surface treatment apparatus of the above embodiment, the surface treatment with the acid-containing vapor and the cleaning treatment with pure water are performed in separate chambers, respectively. As described above, both processes may be performed in the same room.

In the above embodiment, the case where hydrochloric acid was used as the acid was described, but hydrofluoric acid (HF + H ₂ O) can also be used. At this time, the HF concentration of the hydrofluoric acid azeotropic mixture is about 39% at room temperature. When hydrofluoric acid is used, it is necessary to use sapphire glass for the ultraviolet lamps 4 (FIG. 1) and 34 (FIG. 3) to prevent corrosion by hydrofluoric acid vapor. In the case of hydrochloric acid vapor, a quartz glass ultraviolet lamp can be used.

Nitric acid (HNO ₃ / H
₂ O) and sulfuric acid (H ₂ SO ₄ / H ₂ O) can be used. At this time, the azeotropic concentration of nitric acid is 68 Wt% at an atmospheric pressure of 760 mmHg, and the azeotropic concentration of sulfuric acid is 98.3 Wt%. Furthermore, HF + HN
It is also possible to use a mixture such as O ₃ + H ₂ O or HCl + HNO ₃ + H ₂ O.

<Effect of the Invention> According to the method for treating a surface of a substrate of the present invention, an acid-containing vapor is supplied to the substrate surface under irradiation of ultraviolet rays to decompose and remove organic substances by active oxygen, and to contaminate inorganic substances such as heavy metals. Is converted in the presence of moisture, so that it can be converted well even if the efficiency of ultraviolet rays is low, and the salts such as halide salts and the decomposed organic substances can be converted to the surface of the substrate by the energy given by the ultraviolet rays. Can be easily dissociated from water, and furthermore, salts such as halide salts thereof and decomposed organic substances can be dissolved and removed with pure water, and equipment having a simple structure such as a low-pressure mercury lamp can be used as an ultraviolet irradiation means. Moreover, it is harmless as compared with the prior art, and it has become possible to remove organic substances and inorganic substances such as heavy metals inexpensively, safely and well.

In addition, the decomposition and removal of organic substances and the conversion of inorganic substances to salts are performed by the acid-containing vapor generated by evaporation of the aqueous solution containing the acid, and the converted salts are removed by washing with pure water. Even if impurities are mixed in the aqueous solution containing, organic substances and inorganic substances such as heavy metals can be removed very well without supplying the impurities to the substrate surface.

In addition, according to the substrate surface treatment apparatus of the present invention, as described above, conversion of an inorganic substance such as a heavy metal to a salt such as a halide salt and decomposition of an organic substance are performed favorably, and halogen is applied by energy given from ultraviolet rays. Salts such as chlorides and decomposed organic matter are easily separated from the substrate surface, and the substrate after the surface treatment is transferred to a pure water cleaning treatment chamber, where organic substances are decomposed and salts of inorganic substances such as heavy metals which are contaminants are removed. Since the cleaning process using pure water is performed in a pure water cleaning processing room separate from the substrate surface processing unit that performs the conversion, the cleaning solution adheres to the peripheral wall in the processing chamber of the substrate surface processing unit as water droplets and contains the next acid. When the steam is supplied, it is possible to avoid that water drops of the pure water are mixed into the acid-containing steam, and it is possible to reliably prevent particles and impurities in the atmosphere from adhering to the substrate.

[Brief description of the drawings]

The drawings show an embodiment of a substrate surface treatment method and apparatus according to the present invention, FIG. 1 is a schematic longitudinal sectional view showing a first embodiment of a substrate surface treatment apparatus, and FIG. FIG. 3 is a schematic longitudinal sectional view showing a second embodiment of the substrate surface treating apparatus, FIG. 4 is a plan view of a substrate boat, and FIG. 5 is a bar graph showing the experimental results. 4 ... Ultraviolet lamp as ultraviolet irradiation means 5 ... Nozzle as acid-containing vapor supply means 8 ... Pure water cleaning treatment chamber 15 ... Acid-containing vapor generation means 24 ... Pure water supply nozzle as pure water supply means 32: a second housing constituting a pure water cleaning treatment chamber 34: an ultraviolet lamp as an ultraviolet irradiation means 35: a nozzle as an acid-containing vapor supply means 37: a pure water supply nozzle W as a pure water supply means W ……substrate

Continuation of the front page (56) References JP-A-63-110732 (JP, A) JP-A-62-291034 (JP, A) JP-A-63-240030 (JP, A) JP-A-63-33824 (JP) JP-A-63-78522 (JP, A) JP-A-63-84119 (JP, A) JP-A-1-114404 (JP, A) JP-A-63-84029 (JP, A) 62-15824 (JP, A) JP-A-63-204729 (JP, A) JP-A-63-266825 (JP, A) JP-A-63-173720 (JP, A) JP-A-3-254874 (JP, A A) JP-A-4-79374 (JP, A) JP-B-6-9195 (JP, B2)

Claims (2)

(57) [Claims] 1. A method for treating a surface of a substrate, comprising supplying an acid-containing vapor generated from an aqueous solution containing an acid to a substrate surface under ultraviolet irradiation, and then supplying pure water to the substrate surface to perform a cleaning treatment. . 2. An acid-containing vapor generating means for storing an aqueous solution containing an acid therein and generating a vapor of the aqueous solution, and a substrate containing the acid-containing vapor generated by the acid-containing vapor generating means in a room. A substrate surface treatment unit comprising: acid-containing vapor supply means for supplying the surface of the substrate; and ultraviolet irradiation means for irradiating the acid-containing vapor generated by the acid-containing vapor generation means and ultraviolet light to the substrate surface. A pure water cleaning processing chamber is provided adjacent to the substrate, and the pure water cleaning processing chamber is provided with pure water supply means for supplying pure water to the surface of the substrate housed in the room. Processing equipment.