JP2000011960A - Surface treatment device and method using dielectric barrier discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of cleaning a material to be treated by accommodating a krypton-filled dielectric barrier discharge lamp and a dielectric barrier discharge lamp filled with a mixed gas of krypton and chlorine in an enclosure filled with ultraviolet ray transmitting gas, and to have materials to be treated outside the enclosure irradiated at the same time with emitted ultraviolet rays. SOLUTION: A first dielectric barrier discharge lamp 12 filled with krypton gas or xenon gas and a second dielectric barrier discharge lamp 13 filled with mixed gas of krypton and chlorine are provided in parallel in a closed lamp house 11, and the interior of the lamp house 11 is filled with gas(nitrogen) transmitting ultraviolet rays. High voltage of about 10 kV is applied to the first discharge lamp 12 to emit ultraviolet ray with a wavelength of about 146 nm, and high voltage about 10 kV is applied to the second discharge lamp 13 to make it emit ultraviolet ray with a wavelength of about 222 nm. The ultraviolet rays are transmitted through an ultraviolet ray transmitting plate 14 to be applied simultaneously to a material 15 to be cleaned which is placed outside a lamp house 11 for performing cleaning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment apparatus and method using a dielectric barrier discharge lamp, and more particularly to dry cleaning (dry precision cleaning) for removing organic contamination from semiconductor devices, glass substrates, and the like. The present invention relates to a surface treatment apparatus and method useful for surface modification.

[0002]

2. Description of the Related Art Currently, 50 semiconductor devices such as LSIs are used.
It is manufactured through a large number of manufacturing steps of ~ 100 steps. Between each process, the semi-finished product is transported or left, or an operator is involved. Therefore, the device surface is contaminated by various substances, that is, organic substances, alkalis, heavy metals, fine particles, and the like. Among the contaminant cleaning techniques, a dry cleaning method is widely known as a method for effectively removing organic substances from the device surface.

In dry cleaning, ultraviolet light is used. When a sample is irradiated with ultraviolet light in an atmosphere containing oxygen, oxygen molecules O ₂ in the atmosphere absorb the energy of light and generate active oxygen O.
Decomposed into ⁽¹ D) and ozone O _3. On the other hand, contaminants are also excited by light energy to be ionized or generate free radicals. To this the O ⁽¹ D) and O ₃ react, CO _2, H ₂
O, it becomes volatile molecules, such as N _2, so that the contaminants from the sample surface is removed.

Conventionally, a low-pressure mercury lamp has been known as a lamp used for generating ultraviolet light by dry cleaning. Low-pressure mercury lamps have wavelengths of 185 nm and 254 nm.
It emits two ultraviolet lights having peaks at nm. Oxygen molecules in the atmosphere, is excited by ultraviolet light of 185nm to irradiation of a low pressure mercury lamp, to generate the active oxygen O ⁽¹ D) or ozone O _3. Ozone O ₃ generated by 185 nm ultraviolet light is excited by active oxygen O ( ¹ D) by 185 nm ultraviolet light irradiated by a low-pressure mercury lamp.

However, oxygen molecules O_TwoOxidation directly from
Active oxygen O (¹D) can be generated at 175 nm or less
Low-pressure water with a wavelength of 185 nm and a peak at 185 nm
Ultraviolet light from a silver lamp directly provides enough active oxygen
It is difficult. At 185 nm, the excitation of oxygen molecules
Is very low, so that a sufficient concentration of ozone cannot be obtained.
As a result, the activity finally obtained by the low-pressure mercury lamp
Oxygen O ( ¹D) production efficiency becomes extremely poor,
No cleaning effect was obtained.

As a method for solving this problem, Japanese Patent Application Laid-Open No. 8-124923 discloses a method in which a deuterium lamp having an emission peak near 160 nm is used together with a low-pressure mercury lamp, and the oxide thin film is heat-treated by these two lamps. Is disclosed. Light from a deuterium lamp, can be converted to molecular oxygen efficiently ozone O _3, thereby,
The production efficiency of active oxygen is improved.

[0007]

However, a deuterium lamp has a lower output than a low-pressure mercury lamp, and in order to obtain a sufficient amount of ozone, it is necessary to install a large number of deuterium lamps. There is a problem that expected effects cannot be obtained. In addition, since a deuterium lamp and a low-pressure mercury lamp have different driving circuits, they must be prepared separately. As a result, there has been a problem that the apparatus is increased in size and cost is increased.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, to provide an active oxygen production efficiency, and to provide a surface treatment apparatus and method using a small and low-cost dielectric barrier discharge lamp.

[0009]

To achieve the above object, a surface treatment apparatus according to the present invention comprises: a first dielectric barrier discharge lamp filled with krypton gas or xenon gas;
A second dielectric barrier discharge lamp filled with a mixed gas of krypton and chlorine, a housing filled with a gas that transmits ultraviolet light and containing the first and second dielectric barrier discharge lamps; An ultraviolet light transmitting plate that is provided on the body and that transmits ultraviolet light from the first and second dielectric barrier discharge lamps and that can simultaneously irradiate an object to be processed placed outside the housing. Is done.

It has been found that the light absorption coefficients of oxygen molecules O ₂ and ozone O ₃ depend on the wavelength of light. Oxygen molecules react to light of 175 nm or less, and have a strong oxidizing ability.
Generating a ⁽¹ D) and ozone O _3. Also, ozone O ₃ is 200
In response to light of to 300 nm, to produce the active oxygen O ⁽¹ D) has been elucidated.

[0011] In the above structure, the first dielectric barrier discharge lamp filled with krypton gas (in the xenon gas, wavelength 172 nm) Wavelength 146nm to emit ultraviolet light with a peak, thereby active oxygen O ⁽¹ D ) And ozone O ₃ are produced efficiently. The second dielectric barrier discharge lamp filled with a mixed gas of krypton and chlorine, emits ultraviolet light with a peak wavelength of 222 nm, whereby the ozone O ₃
Active oxygen O ⁽¹ D) is generated from. Further, organic substances and the like attached to the object to be processed are also excited by the energy of light from the krypton gas and ionized, or generate free radicals. To this the O ⁽¹ D) and O _{3 react, CO 2, H 2 O,} N
It becomes volatile molecules such as _2, and contaminants are removed from the sample surface. 2 that emits the above two types of ultraviolet light
Both lamps are dielectric barrier discharge lamps, and their driving circuits can be shared.

In this case, the housing includes a first housing accommodating the first dielectric barrier discharge lamp and a second housing.
And a second housing accommodating the dielectric barrier discharge lamp described above, wherein the ultraviolet light transmitting plate is provided in each of the first and second housings.

The present invention also relates to a surface treatment method using a dielectric barrier discharge lamp. In the surface treatment method of the present invention, ultraviolet light from a dielectric barrier discharge lamp filled with krypton gas or xenon gas and ultraviolet light from a dielectric barrier discharge lamp filled with a mixed gas of krypton and chlorine are treated. It is characterized by irradiating the body simultaneously.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a front view and a side view of a cleaning apparatus according to an embodiment of the present invention. Cleaning device 1 shown in the figure
0 indicates an example of removing an organic substance attached to one surface of the object 15 to be cleaned.

In FIG. 1, a cleaning apparatus 10 has a sealed lamp house 11 as a housing, and two dielectric barrier discharge lamps 12 and 13 are provided in parallel inside the lamp house. Cleaning object 1 of lamp house 11
An ultraviolet light transmitting plate 14 is provided on the surface on the 5th side (the bottom surface in the figure), and the dielectric barrier discharge lamp 12
And 13 are irradiated on the object 15 to be cleaned. As an example, a magnesium fluoride plate or a quartz glass plate can be used as the ultraviolet light transmitting plate 14.

A gas having a high transmittance in the vacuum ultraviolet region can be sealed in the lamp house 11.
Nitrogen is preferred as such a gas. By enclosing the nitrogen in the lamp house 11, the attenuation of the ultraviolet light inside the lamp house 11 is suppressed.

As the one dielectric barrier discharge lamp 12, a lamp filled with krypton gas is used as a discharge gas (a lamp filled with xenon gas may be used).
Dielectric barrier discharge lamp 12 filled with krypton gas
By applying a high voltage of about 10 kV, krypton excimer (Kr ₂ *) is generated, and ultraviolet light having a peak wavelength of 146 nm is emitted. Dielectric barrier discharge lamp 12
The ultraviolet light having a wavelength of 146 nm is transmitted through the ultraviolet light transmitting plate 14 and irradiates the surface of the object 15 to be cleaned.

As the other dielectric barrier discharge lamp 13, a lamp in which a mixed gas of krypton and chlorine (hereinafter referred to as krypton / chlorine gas) is used as a discharge gas is used. By applying a high voltage of about 10 kV to the dielectric barrier discharge lamp 13 containing krypton / chlorine gas, krypton chloride excimer (KrCl *) is generated, and ultraviolet light having a peak at a wavelength of 222 nm is emitted. Ultraviolet light having a wavelength of 222 nm from the dielectric barrier discharge lamp 13 passes through the ultraviolet light transmitting plate 14 and irradiates the surface of the object 15 to be cleaned.

Two dielectric barrier discharge lamps 12 and 1
The two types of ultraviolet light from 3, namely, ultraviolet light having a peak at a wavelength of 146 nm, and ultraviolet light having a peak at a wavelength of 222 nm,
The surface of the object to be cleaned 15 is simultaneously irradiated through the ultraviolet light transmitting plate 14. Here, two dielectric barrier discharge lamps 1
The voltages applied to 2 and 13 can be supplied from one voltage circuit. In order to make the ultraviolet intensity distribution with respect to the surface of the object 15 to be cleaned as uniform as possible, it is preferable to relatively move the lamp house 11 and the object 15 in the direction of the arrow. As a result, the surface to be cleaned can be uniformly cleaned.

FIG. 2 is a front view and a side view of a cleaning apparatus according to another embodiment of the present invention. The present cleaning apparatus is used when the object to be cleaned is a material that transmits ultraviolet light, such as quartz glass.

The cleaning apparatus 20 includes two sealed lamp houses 21 and 22 arranged on both sides of the object 30 to be cleaned.
Having. Nitrogen gas is sealed inside each of the lamp houses 21 and 22, and ultraviolet light transmitting plates 23 and 24 are provided on the surface on the side of the object to be cleaned. One of the dielectric barrier discharge lamps, that is, the dielectric barrier discharge lamp 25 filled with krypton gas, is installed in the lamp house 21. The other dielectric barrier discharge lamp, that is, a dielectric barrier discharge lamp 2 containing krypton / chlorine gas
6 is installed in another lamp house 21.

Since the object 30 to be cleaned is made of a material that transmits ultraviolet light, such as quartz glass, even if the surface of the object 30 to be cleaned faces any one of the lamp houses 21 and 22, the two dielectric barrier discharges are performed. Two types of ultraviolet light from the lamps 25 and 26 can reach the surface.

The embodiment of the present invention has been described in detail with reference to the drawings. However, it is obvious that the scope of the present invention is not limited to the matters described in the above embodiment, and is determined based on the description in the claims.
In the above embodiment, the cleaning apparatus according to one embodiment of the present invention has been described. However, the present invention widely relates to surface treatment of an object to be processed, and includes a glass, a quartz plate, a Si wafer, a metal oxide, and a tantalum pentoxide film. (Ta ₂ O ₅ ) It can also be used for surface modification of other objects to be treated and heat treatment for compensating for oxygen deficiency.

[0024]

As described above, according to the present invention, the use of a dielectric barrier discharge lamp in which krypton gas or xenon gas is filled and a dielectric barrier discharge lamp in which krypton / chlorine gas is filled are used to reduce the processing efficiency. Extremely high,
A compact and low-cost surface treatment device can be provided.
Also, since only the dielectric barrier discharge lamp is used, only one type of driving circuit is required.

[Brief description of the drawings]

FIG. 1 is a front view and a side view of a cleaning device according to an embodiment of the present invention.

FIG. 2 is a front view and a side view of a cleaning apparatus according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Cleaning apparatus 11 Lamp house 12 Dielectric barrier discharge lamp filled with krypton gas 13 Dielectric barrier discharge lamp filled with krypton / chlorine gas 14 Ultraviolet light transmission plate 14 Transmission plate 15 Object to be cleaned

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C23C 8/12 H01L 21/26 J C23G 5/00 21/302 N

Claims (3)

[Claims] 1. A first dielectric barrier discharge lamp filled with krypton gas or xenon gas, a second dielectric barrier discharge lamp filled with a mixed gas of krypton and chlorine, and a gas that transmits ultraviolet light A housing for accommodating the first and second dielectric barrier discharge lamps; a housing provided in the housing for transmitting ultraviolet light from the first and second dielectric barrier discharge lamps; A surface treatment apparatus using a dielectric barrier discharge lamp, comprising: an ultraviolet light transmitting plate capable of simultaneously irradiating an object to be processed placed outside the body. 2. The apparatus according to claim 1, wherein the housing includes a first housing accommodating the first dielectric barrier discharge lamp, and a second housing accommodating the second dielectric barrier discharge lamp. The surface treatment apparatus using a dielectric barrier discharge lamp according to claim 1, wherein an ultraviolet light transmitting plate is provided in each of the first and second housings. 3. An object to be processed is irradiated with ultraviolet light from a dielectric barrier discharge lamp filled with krypton gas or xenon gas and ultraviolet light from a dielectric barrier discharge lamp filled with a mixed gas of krypton and chlorine. A surface treatment method using a dielectric barrier discharge lamp, wherein the irradiation is performed.