Patent Description:
Examples of a plasma generation device include a structure in which a processing gas that is plasmatized in a reaction chamber, and the plasma gas that is plasmatized is ejected from an ejection port formed in a nozzle or the like. An example of such plasma generation devices is described in the following Patent Literature.

An object of the present specification is to improve the usefulness of a plasma generation device having a structure in which a plasma gas is ejected from an ejection port. Solution to Problem.

In order to solve the above-mentioned problems, the present specification discloses a plasma generation device according to claim <NUM>.

Accordingly, the present invention provides a plasma generation device comprising:
a device main body in which a reaction chamber for plasmatizing a processing gas is formed; a ceramic nozzle in which a first ejection port for ejecting a plasma gas that is plasmatized in the reaction chamber is formed, a nozzle cover in which a second ejection port for ejecting a gas so as to cover the plasma gas is formed to cover the first ejection port (<NUM> A), wherein the nozzle cover includes a ceramic cover main body and a metal cover tip, wherein the cover tip is shaped so as to extend in a direction away from the cover main body, so that the cover main body is closer to the reaction chamber and the cover tip is distant from the reaction chamber.

In addition, the present specification describes, as an example not being part of the present invention, a plasma treatment method including: a plasma gas ejecting step of ejecting a plasma gas from a first ejection port toward a treatment target object; and a shielding gas ejecting step of shielding the plasma gas by ejecting a shielding gas from a second ejection port formed in a metal member toward the plasma gas ejected from the first ejection port.

According to the present invention, it is possible to improve the usefulness of the plasma generation device having the structure in which the plasma gas is ejected from the ejection port.

Hereinafter, as exemplary embodiments of the present invention, examples of the present invention will be described in detail with reference to the drawings.

As illustrated in <FIG>, plasma device <NUM> includes plasma head <NUM>, robot <NUM>, and control box <NUM>. Plasma head <NUM> is attached to robot <NUM>. Robot <NUM> is, for example, a serial link-type robot (may also be referred to as a multi-joint-type robot). Plasma head <NUM> is configured to be capable of irradiating plasma gas in a state where plasma head <NUM> is held at a tip of robot <NUM>. Plasma head <NUM> is configured to be three-dimensionally movable in accordance with the driving of robot <NUM>.

Control box <NUM> is configured mainly by a computer, and collectively controls plasma device <NUM>. Control box <NUM> has power source section 15A for supplying electric power to plasma head <NUM> and gas supply section 15B for supplying gas to plasma head <NUM>. Power source section 15A is connected to plasma head <NUM> via a power cable (not illustrated). Power source section 15A changes a voltage to be applied to electrode <NUM> (refer to <FIG> and <FIG>) of plasma head <NUM> based on the control of control box <NUM>.

Gas supply section 15B is connected to plasma head <NUM> via multiple (four in the present embodiment) gas tubes <NUM>. Gas supply section 15B supplies a reaction gas, a carrier gas, and a heat gas, which will be described later, to plasma head <NUM> based on the control of control box <NUM>. Control box <NUM> controls gas supply section 15B, and controls an amount or the like of the gas supplied from gas supply section 15B to plasma head <NUM>. Therefore, robot <NUM> operates based on the control of control box <NUM> to irradiate treatment target object W placed on table <NUM> with the plasma gas from plasma head <NUM>.

Control box <NUM> includes operation section 15C having a touch panel and various switches. Control box <NUM> displays various setting screens, operation states (for example, a gas supply state, and the like), and the like on the touch panel of operation section 15C. In addition, control box <NUM> receives various types of information by operation inputs to operation section 15C.

As illustrated in <FIG>, plasma head <NUM> includes plasma generation section <NUM>, heat gas supply section <NUM>, and the like. Plasma generation section <NUM> plasmatizes the processing gas supplied from gas supply section 15B (refer to <FIG>) of control box <NUM> to generate plasma gas. Heat gas supply section <NUM> heats the gas supplied from gas supply section 15B to generate heat gas. Plasma head <NUM> of the present embodiment ejects the plasma gas generated in plasma generation section <NUM> to treatment target object W illustrated in <FIG> together with the heat gas generated by heat gas supply section <NUM>. The processing gas is supplied to plasma head <NUM> from an upstream side to a downstream side in a direction of an arrow illustrated in <FIG>. Plasma head <NUM> may have a configuration in which heat gas supply section <NUM> is not provided. That is, the plasma device of the present disclosure may have a configuration in which the heat gas is not used.

As illustrated in <FIG> and <FIG>, plasma generation section <NUM> includes head main body section <NUM>, a pair of electrodes <NUM>, plasma irradiation section <NUM>, and the like. <FIG> is a sectional view cut along with positions of the pair of electrodes <NUM> and multiple body-side plasma paths <NUM> described later, and <FIG> is a sectional view in line AA of <FIG>. head main body section <NUM> is formed of ceramic having a high heat resistance, and reaction chamber <NUM> for generating plasma gas is formed in an inside of head main body section <NUM>. Each of the pair of electrodes <NUM> has, for example, a cylindrical shape, and is fixed in a state where a tip portion thereof protrudes into reaction chamber <NUM>. In the following description, the pair of electrodes <NUM> may be simply referred to as electrode <NUM>. In addition, a direction in which the pair of electrodes <NUM> are arranged is referred to as an X direction, a direction in which plasma generation section <NUM> and heat gas supply section <NUM> are arranged is referred to as a Y direction, and an axial direction of cylindrical electrode <NUM> is referred to as a Z direction. In the present embodiment, the X direction, the Y direction, and the Z direction are directions orthogonal to each other.

Heat gas supply section <NUM> includes gas pipe <NUM>, heater <NUM>, connection section <NUM>, and the like. Gas pipe <NUM> and heater <NUM> are attached to an outer peripheral surface of head main body section <NUM> and are covered with cover <NUM> illustrated in <FIG>. Gas pipe <NUM> is connected to gas supply section 15B of control box <NUM> via gas tube <NUM> (refer to <FIG>). Gas (for example, air) is supplied to gas pipe <NUM> from gas supply section 15B. Heater <NUM> is attached to an intermediate portion of gas pipe <NUM>. Heater <NUM> warms the gas flowing through gas pipe <NUM> to generate heat gas.

As illustrated in <FIG>, connection section <NUM> connects gas pipe <NUM> to plasma irradiation section <NUM>. In a state where plasma irradiation section <NUM> is attached to head main body section <NUM>, a first end portion of connection section <NUM> is connected to gas pipe <NUM>, and a second end portion thereof is connected to heat gas flow path <NUM> formed in plasma irradiation section <NUM>. Heat gas is supplied to heat gas flow path <NUM> via gas pipe <NUM>.

As illustrated in <FIG>, a part of an outer periphery portion of electrode <NUM> is covered with electrode cover <NUM> made of an insulator such as ceramic. Electrode cover <NUM> has a substantially hollow tubular shape, and openings are formed at both end portions in a longitudinal direction. A gap between an inner peripheral surface of electrode cover <NUM> and an outer peripheral surface of electrode <NUM> functions as gas flow path <NUM>. An opening of electrode cover <NUM> on a downstream side is connected to reaction chamber <NUM>. A lower end of electrode <NUM> protrudes from the opening of electrode cover <NUM> on the downstream side.

Reaction gas flow path <NUM> and a pair of carrier gas flow paths <NUM> are formed in the inside of head main body section <NUM>. Reaction gas flow path <NUM> is provided substantially at a center portion of head main body section <NUM>, is connected to gas supply section 15B via gas tube <NUM> (refer to <FIG>), and allows the reaction gas supplied from gas supply section 15B to flow into reaction chamber <NUM>. The pair of carrier gas flow paths <NUM> are disposed at positions where reaction gas flow path <NUM> is interposed therebetween in the X direction. Each of the pair of carrier gas flow paths <NUM> is connected to gas supply section 15B via gas tube <NUM> (refer to <FIG>), so that the carrier gas is supplied from gas supply section 15B. Carrier gas flow path <NUM> allows the carrier gas to flow into reaction chamber <NUM> via gas flow path <NUM>.

As the reaction gas (refer tod gas), oxygen (O2) can be employed. Gas supply section 15B allows, for example, a mixed gas (for example, dry air (Air)) of oxygen and nitrogen (N2) to flow into between electrodes <NUM> of reaction chamber <NUM> via reaction gas flow path <NUM>. Hereinafter, this mixed gas may be referred to as the reaction gas for convenience, and oxygen may be referred to as the refer tod gas. As the carrier gas, nitrogen can be employed. Gas supply section 15B allows the carrier gas to flow from each of gas flow paths <NUM> so as to surround each of the pair of electrodes <NUM>.

An AC voltage is applied to the pair of electrodes <NUM> from power source section 15A of control box <NUM>. By applying the voltage, for example, as illustrated in <FIG>, pseudo arc A is generated between lower ends of the pair of electrodes <NUM> in reaction chamber <NUM>. When the reaction gas passes through pseudo arc A, the reaction gas is plasmatized. Accordingly, the pair of electrodes <NUM> generate discharge of pseudo arc A, plasmatize the reaction gas, and generate the plasma gas.

In addition, multiple (six in the present embodiment) body-side plasma paths <NUM> arranged at intervals in the X direction and extending in the Z direction are formed in a portion of head main body section <NUM> on the downstream side of reaction chamber <NUM>. An upstream end portion of each of multiple body-side plasma paths <NUM> is connected to reaction chamber <NUM>.

Plasma irradiation section <NUM> includes nozzle <NUM>, nozzle cover <NUM>, and the like. Nozzle <NUM> is generally T-shaped in side view from the X direction, and includes nozzle main body <NUM> and nozzle tip <NUM>. Nozzle <NUM> is an integral object of nozzle main body <NUM> and nozzle tip <NUM>, and is formed of ceramic having a high heat resistance. Nozzle main body <NUM> has a generally flange shape and is fixed to a lower surface of head main body section <NUM> by bolt <NUM>. Nozzle tip <NUM> has a shape extending downward from a lower surface of nozzle main body <NUM>. Nozzle <NUM> is formed with multiple (six in the present embodiment) nozzle-side plasma paths <NUM> that penetrate nozzle main body <NUM> and nozzle tip <NUM> in the vertical direction, that is, the Z direction, and multiple nozzle-side plasma paths <NUM> are arranged at intervals in the X direction. Multiple nozzle-side plasma paths <NUM> are formed at the same positions as multiple body-side plasma paths <NUM> in the Z direction. Therefore, body-side plasma path <NUM> and nozzle-side plasma path <NUM> communicate with each other.

As illustrated in <FIG>, nozzle cover <NUM> is generally T-shaped in side view from the X direction, and includes cover main body <NUM> and cover tip <NUM>. Cover main body <NUM> and cover tip <NUM> are separate members, cover main body <NUM> is formed of ceramic, and cover tip <NUM> is formed of metal, specifically, stainless steel.

Cover main body <NUM> is generally plate-shaped in plate thickness, and recess <NUM> having a shape open to an upper surface and recessed in the Z direction is formed in cover main body <NUM>. Cover main body <NUM> is fixed to the lower surface of head main body section <NUM> by bolts <NUM> so that nozzle main body <NUM> of nozzle <NUM> is housed in recess <NUM>. In addition, heat gas flow path <NUM> is formed in cover main body <NUM> so as to extend in the Y direction, a first end portion of heat gas flow path <NUM> is open to recess <NUM>, and a second end portion of heat gas flow path <NUM> is open to a side surface of cover main body <NUM>. An end portion of heat gas flow path <NUM> that is open to the side surface of cover main body <NUM> is connected to connection section <NUM> of heat gas supply section <NUM>.

Cover tip <NUM> has a plate shape having a thickness dimension equivalent to a thickness dimension of cover main body <NUM>, and is fixed to the lower surface of cover main body <NUM> by bolts <NUM> so as to extend downward from the lower surface of cover main body <NUM>. One through-hole <NUM> penetrating in the Z direction is formed in cover tip <NUM>, and an upper end portion of through-hole <NUM> communicates with recess <NUM> of cover main body <NUM>. Nozzle tip <NUM> of nozzle <NUM> is inserted into through-hole <NUM>. Therefore, nozzle <NUM> is entirely covered with nozzle cover <NUM>. The lower end of nozzle tip <NUM> of nozzle <NUM> and the lower end of cover tip <NUM> of nozzle cover <NUM> are located at the same height.

In a state where nozzle <NUM> is covered with nozzle cover <NUM>, nozzle main body <NUM> of nozzle <NUM> is located in an inside of recess <NUM> of nozzle cover <NUM>, and nozzle tip <NUM> of nozzle <NUM> is located in through-hole <NUM> of nozzle cover <NUM>. In such a state, a gap exists between recess <NUM> and nozzle main body <NUM>, and between through-hole <NUM> and nozzle tip <NUM>, and the gap functions as heat gas output path <NUM>. The heat gas is supplied to heat gas output path <NUM> via heat gas flow path <NUM>.

According to such a structure, the plasma gas generated in reaction chamber <NUM> flows through body-side plasma path <NUM> and nozzle-side plasma path <NUM> together with the carrier gas, and is ejected from opening 81A at the lower end of nozzle-side plasma path <NUM>. The heat gas supplied from gas pipe <NUM> to heat gas flow path <NUM> flows through heat gas output path <NUM>. The heat gas functions as a shielding gas for protecting the plasma gas. The heat gas flows through heat gas output path <NUM>, and is ejected from opening 95A at the lower end of heat gas output path <NUM> along the ejection direction of the plasma gas. At this time, the heat gas is ejected so as to surround the periphery of the plasma gas ejected from opening 81A of nozzle-side plasma path <NUM>. In this manner, by ejecting the heated heat gas to the periphery of the plasma gas, the efficiency (wettability or the like) of the plasma gas can be enhanced.

Plasma device <NUM> is an example of a plasma generation device. Heat gas supply section <NUM> is an example of an ejection device. Head main body section <NUM> is an example of a device main body. Reaction chamber <NUM> is an example of a reaction chamber. Nozzle <NUM> is an example of a nozzle. Nozzle cover <NUM> is an example of a nozzle cover. Nozzle main body <NUM> is an example of a nozzle main body. Nozzle tip <NUM> is an example of a nozzle tip. Opening 81A of nozzle-side plasma path <NUM> is an example of a first ejection port. Cover main body <NUM> is an example of a cover main body. Cover tip <NUM> is an example of a cover section. Opening 95A of heat gas output path <NUM> is an example of a second ejection port. The heat gas is an example of the shielding gas.

Thus, the present embodiment, which has been described heretofore, provides the following effects.

In plasma head <NUM>, ceramic nozzle <NUM> is covered with nozzle cover <NUM> having metal cover tip <NUM>. Therefore, it is possible to prevent nozzle <NUM> from being damaged. That is, since nozzle <NUM> is formed of ceramic, it is brittle and susceptible to damage. On the other hand, cover tip <NUM> serving as a tip portion of nozzle cover <NUM> is formed of a metal and is not easily damaged. Therefore, even when the tip of plasma head <NUM> comes into contact with treatment target object W or the like during the plasma irradiation by plasma head <NUM> or the like, nozzle <NUM> is protected by metal nozzle cover <NUM>, so that nozzle <NUM> is prevented from being damaged. In addition, ceramic is relatively expensive, but metal is inexpensive. Accordingly, even if cover tip <NUM> is damaged, deformed, or the like, cover tip <NUM> can be exchanged at a reduced cost.

As described above, nozzle cover <NUM> includes cover main body <NUM> and cover tip <NUM>, cover main body <NUM> is formed of ceramic, and cover tip <NUM> is formed of stainless steel. Therefore, it is possible to secure appropriate plasmatization and to achieve cost reduction. That is, although the cost can be reduced by forming the entire nozzle cover with metal, if the upper end portion of the nozzle cover closer to reaction chamber <NUM> of head main body section <NUM>, that is, cover main body <NUM> is made of metal, discharge may generate in the periphery of cover main body <NUM> by the application to electrode <NUM> in reaction chamber <NUM>. In such a case, it is not possible to secure appropriate plasmatization by discharge in a region other than reaction chamber <NUM>. Accordingly, cover main body <NUM> closer to reaction chamber <NUM> is formed of ceramic, and cover tip <NUM> distant from reaction chamber <NUM> is formed of metal. Therefore, it is possible to secure appropriate plasmatization and to achieve cost reduction.

In other words, metal cover tip <NUM> is shaped so as to extend in a direction away from cover main body <NUM>. That is, metal cover tip <NUM> has a shape extending in a direction away from reaction chamber <NUM>. Therefore, it is possible to further suitably prevent discharge in a region other than reaction chamber <NUM>, and it is possible to further secure appropriate plasmatization.

Nozzle tip <NUM> of nozzle <NUM> also has a shape extending in a direction away from nozzle main body <NUM>, that is, downward, similarly to cover tip <NUM> of nozzle cover <NUM>. Nozzle tip <NUM> extending downward is inserted in an inside of cover tip <NUM> extending downward. Therefore, the plasma gas ejected from opening 81A of nozzle tip <NUM> can be appropriately ejected to the outside of nozzle cover <NUM>.

In plasma head <NUM>, heated heat gas flows between nozzle <NUM> and nozzle cover <NUM>, so that the heated heat gas is ejected to the periphery of the plasma gas. Therefore, as described above, the efficiency (wettability or the like) of the plasma gas can be enhanced.

The present disclosure is not limited to the above embodiments, and can be practiced in various forms without departing from the extent of the invention, which shall be determined by the appended claim. Specifically, for example, in plasma head <NUM>, although the heat gas flows between nozzle <NUM> and nozzle cover <NUM>, the heat gas need not to flow. That is, nozzle cover <NUM>, in which however, in accordance with the invention, a second ejection port for ejecting a gas so as to cover the plasma gas is formed to cover the first ejection port, may be disposed only as a cover for protecting nozzle <NUM>.

In the above embodiments, the plasma gas and the heat gas are ejected from one plasma head <NUM>, but the plasma gas and the heat gas may be ejected from two heads. That is, the plasma gas may be ejected from one head, and the heat gas may be ejected from a head different from the head. In addition, nozzle-side plasma path <NUM> and heat gas output path <NUM> may be formed at different positions on one head, and the plasma gas and the heat gas may be ejected from the respective paths.

In the above embodiments, nozzle <NUM> and nozzle cover <NUM> are fixed to head main body section <NUM>, but may be simply provided. That is, nozzle main body <NUM> may be provided in head main body section <NUM>. Nozzle tip <NUM> may also be provided in nozzle main body <NUM>.

Claim 1:
A plasma generation device (<NUM>) comprising:
a device main body (<NUM>) in which a reaction chamber (<NUM>) for plasmatizing a processing gas is formed;
a ceramic nozzle (<NUM>) in which a first ejection port (81A) for ejecting a plasma gas that is plasmatized in the reaction chamber (<NUM>) is formed; and
a nozzle cover (<NUM>) in which a second ejection port (95A) for ejecting a gas so as to cover the plasma gas is formed to cover the first ejection port (81A), wherein
the nozzle cover (<NUM>) includes
a cover main body (<NUM>) formed of ceramic, and
a cover tip (<NUM>) wherein
the cover tip (<NUM>) is shaped so as to extend in a direction away from the cover main body (<NUM>), so that the cover main body (<NUM>) is closer to the reaction chamber (<NUM>) and the cover tip (<NUM>) is distant from the reaction chamber (<NUM>),
characterised in that
the cover tip (<NUM>) is made of metal.