JP2009004719A - Surface processing method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power requirements for plasma making and to enable continuous processing. <P>SOLUTION: An object W to be processed is arranged under almost atmospheric pressure. Gas (processing fluid) from a processing fluid source 1 is introduced to a plasma making means 20 with pressure lower than the almost atmospheric pressure to be made plasma under low pressure. A pressurizing means 30 pressurizes the gas after being made plasma to the almost atmospheric pressure to be brought into contact with the object W to be processed under the almost atmospheric pressure from a supplying part 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method and apparatus for surface-treating an object to be processed by converting plasma into a processing fluid using plasma, for example, processing a reactive gas or the like on an object to be processed such as a glass substrate for a flat panel display or a semiconductor wafer. The present invention relates to a method and an apparatus for performing surface treatment such as etching, cleaning, film formation, and surface modification by bringing a fluid into contact therewith.

In recent years, in the field of semiconductor manufacturing or the like, atmospheric pressure plasma surface treatment is performed in which a processing gas that has been converted to plasma is brought into contact with a substrate at substantially atmospheric pressure (atmospheric pressure or a pressure in the vicinity thereof). Generation of radicals with high throughput and reactive stable compounds (such as HF) is also possible. Since it is not necessary to create a reduced pressure environment, the processing object can be smoothly put in and out of the processing chamber, and continuous processing is possible. There is a great merit that it can easily cope with the processing of LCD which tends to be large (see Patent Document 1).
Japanese Patent No. 3147137

On the other hand, under a pressure of about atmospheric pressure, the discharge start voltage rises and a large amount of electric power is required to generate plasma compared with a low pressure. Correspondingly, it is necessary to enlarge the transformer, which increases the cost of the apparatus. In addition, it is preferable to increase the electric field strength by reducing the gap between the electrodes. However, in order to secure the plasma volume necessary for the reaction, the electrode area must be increased, which further increases the cost of the apparatus. As the substrate to be processed becomes larger, the power supply scale becomes larger and the equipment cost further increases. Since most of the input power is finally converted into heat, the incidental facilities such as chillers will also become larger.
In view of the above circumstances, the inventor has conceived that the pressure of plasmatization is different from the pressure of the arrangement environment of the workpiece.

The present invention has been made on the basis of the above idea, and the gist of the present invention is that the processing fluid is brought into a plasma state under an environment lower in pressure than the environment in which the object is to be processed, that is, converted into plasma (decomposition, excitation, radicals). (Including plasma formation and ionization) (plasma formation step), and then pressurizing to contact the object to be processed (post-plasma treatment step).
The surface treatment apparatus according to the present invention includes a pair of electrodes between which a pressure environment is lower than the pressure of the environment in which the workpiece is disposed, and the plasma processing means for converting the processing fluid into plasma between the electrodes, and the plasma And a post-plasma treatment means that pressurizes the treated fluid and supplies it to the object to be treated.
As a result, the power required for plasmaization can be reduced as compared with the case where the pressure is almost the same as that of the arrangement environment of the object to be processed.

In the plasma process, the source gas (a gaseous processing fluid before the plasma process) may be changed to a plasma state to obtain a reaction gas (a gaseous processing fluid after the plasma irradiation).
In the post-plasma treatment step, the reaction gas is pressurized to a pressure higher than the arrangement environment (pressurization step), and the pressurized reaction gas (a gaseous treatment fluid after pressurization) is treated as the object to be treated. You may make it contact (contact process).
The plasmarization means generates a reaction gas by bringing the raw material gas into a plasma state between the electrodes, and the post-plasmaization processing means pressurizes the reaction gas to a pressure higher than the arrangement environment; and And a supply unit that supplies the pressurized reaction gas to the object to be processed.

The pressure in the environment in which the object is disposed is preferably approximately atmospheric pressure, and the pressure environment for the plasma treatment is preferably lower than approximately atmospheric pressure.
As a result, the power required for plasma generation can be reliably reduced, and the power supply equipment can be reduced in size and cost. In addition, since the processing of the object to be processed is performed under substantially atmospheric pressure, it is not necessary to return to the atmospheric pressure or reduce the pressure every time the object to be processed is taken in or out, and continuous processing becomes possible.
Here, the substantially atmospheric pressure is atmospheric pressure or a pressure in the vicinity of atmospheric pressure, and specifically, preferably within ± 10% of atmospheric pressure (1.013 bar).

  The processing fluid is preferably plasmatized in a gaseous state, but may be plasmatized in a liquid state such as a mist or a solid state such as a particle. The gas may contain a mist-like liquid or a particulate solid.

Pressurization of the processing fluid after the plasma treatment may be performed in a gaseous state. In this case, for example, a compressor may be used as the pressurizing means. The processing environment of the workpiece is approximately atmospheric pressure. When the plasma environment is lower than about atmospheric pressure, a vacuum pump may be used as the compressor. It is preferable that the low-pressure environment is created by the vacuum pump. When the gas is corrosive, it is preferable to use a diaphragm pump made of a corrosion-resistant material such as Teflon (registered trademark).
It is preferable to provide a particle filter for removing particles on the downstream side of the compressor such as the vacuum pump.
Thereby, even if particles are generated in the compressor or the like, it is possible to prevent the particles from being attached to the object to be processed.

An ejector may be used as the pressurizing means. The ejector sucks the processing fluid after being converted into plasma by the ejection of the driving fluid and guides it to the object to be processed. The suction creates the low pressure environment.
Since the ejector has no moving parts, maintenance is easy and the cost is low.
For example, if the process fluid comprises CF ₄ and _{H 2} O, by injecting two-fold or more of _{H 2} O CF ₄ plasma can generate almost completely decompose CF ₄ HF. At this time, condensation of H ₂ O and HF can be suppressed by setting the plasma space in a low pressure environment with an ejector. If condensation still occurs, the plasmatization means may be heated. However, since the pressure is low, the heating temperature may be relatively low, and the degree of freedom of material selection for the components of the plasmatization means is high.
The main component of the driving fluid may be air, N ₂ gas, CO ₂ gas, or Ar gas. In particular, CO ₂ and Ar gas have a molecular weight greater than that of air or N ₂ , so that the flow rate of the driving fluid can be reduced. Since N ₂ has a molecular weight smaller than that of air, it may be necessary to separately pressurize it with a compressor. However, since it is non-corrosive, selection of the compressor is easy, and a scroll compressor or the like can be used. It is preferable to provide a filter at the outlet of the compressor to remove particles.

The post-plasmaization treatment step condenses or solidifies the plasma-treated treatment fluid and pressurizes it to obtain a condensate composed of a liquid or solid having a higher pressure than the low-pressure environment, and vaporizes the condensate. It is preferable to include a vaporizing step. Furthermore, it is preferable that the post-plasmaization treatment step includes a supply step of supplying the treatment fluid vaporized from the aggregate in the vaporization step to an object to be treated.
The post-plasmaization processing means condenses or solidifies the plasma-processed processing fluid and pressurizes it to obtain a high-pressure condensate from the low-pressure environment, and a vaporization means for vaporizing the condensate. May be included.
In the aggregate generation step, it is preferable to obtain the aggregate by condensing and pressurizing the processing fluid after the plasma formation from a gaseous state.
The aggregate after pressurization only needs to have a pressure higher than that of the low-pressure environment, and is preferably equal to or higher than the pressure of the environment in which the object is disposed, but may be lower than the environment in which the object is disposed.

In the plasma treatment step, the raw material gas (a gaseous processing fluid before the plasma treatment) is changed to a plasma state to obtain a primary reaction gas (a gaseous treatment fluid after the plasma treatment). , Condensing and pressurizing the primary reaction gas to obtain a condensate having a pressure higher than that of the low-pressure environment, that is, a liquid or solid processing fluid after the condensing pressurization (condensate forming step) A secondary reaction gas having a pressure higher than the environment, that is, a treatment fluid after vaporization may be obtained (vaporization step), and the secondary reaction gas may be brought into contact with the object to be treated (contact step).
The plasmarization means generates a primary reaction gas by putting the raw material gas in a plasma state between the electrodes, and the post-plasmaization treatment means condenses and pressurizes the primary reaction gas to condense at a pressure higher than the low pressure environment. A condensate generating means for obtaining a secondary reaction gas generating means for vaporizing the condensate to obtain a secondary reaction gas having a pressure higher than the arrangement environment, and a supply for supplying the secondary reaction gas to the object to be treated May be included.
Thereby, in addition to reducing the power required for plasma formation, the volume of the fluid can be significantly reduced by condensation.

Here, “condensation” refers to condensation or solidification. Solidification includes the case where the gas becomes solid through the liquid and the case where the gas sublimes from the gas.
“Condensation of the processing fluid” includes a case where a part of the constituents of the processing fluid condenses and the rest maintains a gas state before the condensing.

The processing fluid (primary reaction gas) after the plasma may be condensed by pressurization.
The aggregate generation means may include a pressurizing means for the primary reaction gas, and the aggregate may be condensed by pressurizing the primary reaction gas.

The processing fluid (primary reaction gas) after the plasma treatment may be condensed by cooling.
The aggregate generation means may include a cooler that cools the primary reaction gas.
As a result, the primary reaction gas can be reliably condensed.

You may decide to perform the said cooling by flowing the processing fluid (primary reaction gas) after the said plasma-izing, and the cooling medium which cools this in the mutually opposing direction. As a result, the processing fluid (primary reaction gas) can be gradually cooled and condensed so as not to solidify.
You may make it distribute | circulate so that the processing fluid (primary reaction gas) and cooling medium after the said plasma-ization may mutually become a parallel flow.

The condensate generating step includes a condensing step of condensing or solidifying the processing fluid after the plasma formation in the low-pressure environment to obtain the pre-pressurized condensate, and then a pressurizing step of pressurizing the condensate. It is preferable to include. It is preferable to pressurize after condensing the processing fluid (primary reaction gas) after the plasmatization.
Condensate generating means condenses or solidifies the plasma-treated processing fluid in the low-pressure environment to obtain a pre-pressurized aggregate, and pressurizing means for pressurizing the aggregate from the condensing means And may be included.
The aggregate generation means may include condensing means for condensing the primary reaction gas and liquid pressurizing means for pressurizing the condensed liquid aggregate.
As a result, the volume of the pressurization target can be greatly reduced, the pressurizing means can be greatly reduced in size, and the cost can be reduced. When the condensation is condensation and a liquid condensation product (reaction liquid) is obtained, a liquid pressure pump such as a tube pump or a diaphragm pump can be used as the pressure means, and it is easy to ensure corrosion resistance. . Further, the generation of particles from the pressurizing means can be suppressed.

In the case where the aggregate generation means is to pressurize after condensing the processing fluid (primary reaction gas) before the plasma formation to obtain a liquid aggregate, liquid pressurization for the liquid aggregate As a means, it is preferable to use a tube pump or a diaphragm pump. As a result, it becomes easy to ensure corrosion resistance, and maintenance can be simplified. Further, the generation of particles from the pressurizing means can be suppressed.
The tube pump includes, for example, a flexible tube through which a liquid aggregate is passed, and crushing means such as a roller that crushes the tube to pressurize and feed the liquid aggregate.
The tube of the tube pump and the diaphragm of the diaphragm pump are preferably made of a highly corrosion-resistant resin such as Teflon (registered trademark).

The condensing means may include a cooler that cools the primary reaction gas. In this case, it is preferable to cool to such an extent that solidification does not occur.
The condensing means may have a condensing path through which the primary reaction gas passes, and a cooling path through which a refrigerant for cooling the condensing path passes in a direction facing the primary reaction gas.
Thus, the primary reaction gas can be gradually cooled and reliably condensed so as not to solidify.

In the aggregate generation step, the plasma-treated processing fluid (primary reaction gas) may react with the reactant (coagulant) that can generate the aggregate.
Reactant addition means for adding a reactive agent (coagulant) capable of generating the aggregate by reacting with the plasma-treated processing fluid may be connected to the condensation means. A coagulant adding means for adding a reactive agent (coagulant) capable of reacting with the plasma-treated processing fluid (primary reaction gas) to generate the aggregate before pressurization is connected to the aggregate generating means. It may be.
Thereby, the processing fluid (primary reaction gas) after the plasma can be reliably condensed.
The processing fluid (primary reaction gas) after being converted to plasma may acquire reaction capability by reaction with a coagulant. For example, as will be described later, an intermediate substance may be generated by plasmatization, and a target substance may be generated by a reaction between the intermediate substance and a coagulant.

The coagulant may be a gas, a liquid (mist, etc.), or a solid (particles, etc.).
For example, H ₂ O may be used as the coagulant. This makes it possible to obtain the coagulant inexpensively and easily and to handle it easily. H ₂ O may be water vapor, liquid water, or ice.
Alternatively, an OH group-containing compound such as alcohol may be used as the coagulant instead of H ₂ O. By using an H ₂ O or OH group-containing compound as the coagulant, a coagulate can be obtained by a hydrolysis reaction or a reduction reaction.

The coagulant may be obtained by adding the coagulant to the primary reaction gas and flowing the primary reaction gas after the addition and a cooling medium for cooling the coagulant in directions opposite to each other.
This method is effective when the freezing point is lowered as the concentration of the aggregate is increased. That is, the concentration and the amount of the aggregate can be increased while gradually cooling the coagulant and the aggregate so as not to solidify.

  The coagulant is preferably composed of gas, liquid, particles, etc. and has fluidity. The aggregate may be obtained by flowing the primary reaction gas and the coagulant in opposite directions. As a result, a high-concentration aggregate can be obtained, and the loss of reaction gas can be reduced.

The aggregate may be obtained by flowing the primary reaction gas and the coagulant in parallel directions.
Even if the said aggregate production | generation means has a condensation container which accommodates the said primary reaction gas (processed fluid after plasma-ized) and the coagulant which can react with this primary reaction gas and can condense so that it can mutually contact. Good.
As a result, the primary reaction gas can be reliably condensed.

The condensing container may be formed with a counter flow space in which the primary reaction gas and the condensing agent flow in directions facing each other.
As a result, a high-concentration aggregate can be obtained, and the loss of reaction gas can be reduced.
The aggregate generation means has an outer tube and an inner tube that is inserted into the outer tube and forms an annular outer passage between the outer tube,
The inner pipe is formed with a large number of fine holes connecting the outer passage and the inner passage in the inner pipe,
One of the primary reaction gas and the coagulant may be introduced into the outer passage, and the other of the primary reaction gas and the coagulant may be introduced into the inner passage.
One of the primary reaction gas and the coagulant may be introduced into one end of the outer passage, and the other of the primary reaction gas and the coagulant may be introduced into the opposite end of the inner passage. . Accordingly, the primary reaction gas and the coagulant can be caused to flow in directions facing each other.
It is preferable that the primary reaction gas is introduced into the outer passage and the coagulant is introduced into the inner passage. As a result, the primary reaction gas in the outer passage enters the inner passage through the fine holes, so that a gas flow in the radially inward direction can be formed in the vicinity of the inner wall of the inner tube, and the coagulant is contained in the inner passage. It can suppress adhering to the inner wall of a pipe | tube.

It is preferable that non-condensed components such as uncondensed gas that has not condensed or solidified in the aggregate generation step in the processing fluid (primary reaction gas) after the plasma formation is returned to the plasma formation step.
An uncondensed component path that conveys an uncondensed component that has not condensed or solidified among the processing fluid after the plasma treatment may extend from the condensing means and continue to the plasma forming means.
An uncondensed gas path (non-condensed component path) for discharging the non-condensed gas (non-condensed component) that has not been condensed from the primary reaction gas extends from the aggregate generating means, and this non-condensed gas path is converted into the plasma It may be connected to means.
The non-condensed gas may be converted into plasma together with the raw material gas.
Thereby, non-condensed components such as non-condensed gas can be reused, the required amount of processing fluid such as raw material gas can be reduced, and the cost can be reduced.
In this case, it is preferable to perform the mixing after removing unnecessary components from the non-coagulated components such as the non-coagulated gas. It is preferable that an unnecessary substance removing unit that removes unnecessary substances among non-condensed components such as non-condensed gas is interposed in the non-condensed component path or the non-condensed gas path.
Thus, unnecessary components can be prevented from being introduced into the plasmar and circulated.
The unnecessary substance is, for example, carbon dioxide. In that case, it is preferable that the said unnecessary substance removal part contains lime water.

A low-pressure maintenance path may be branched from the non-condensation component path or the non-condensation gas path, and low-pressure maintenance means for maintaining the plasmarization means in the low-pressure environment may be provided in the low-pressure maintenance path.
When the unnecessary substance removing unit is provided in the non-condensed component channel or the non-condensed gas channel, the low-pressure maintenance channel may be branched from the non-condensed component channel or the non-condensed gas channel upstream of the unnecessary substance removing unit. Further, it may be branched from an uncondensed component path or an uncondensed gas path on the downstream side of the unnecessary substance removing section.

  The low pressure maintaining means is, for example, a vacuum pump. By sucking the vacuum pump, non-condensed components such as non-condensable gas can be appropriately discharged (exhaust), and a low-pressure environment can be maintained.

The low-pressure maintaining means may be a cryogenic cooler that cools and liquefies uncondensed components such as the uncondensed gas to a cryogenic temperature.
By liquefying the non-condensable components such as non-condensable gas, the volume can be greatly reduced, thereby maintaining a low-pressure environment.

The secondary reaction gas generation means preferably includes a vaporization means for vaporizing the aggregate.
The internal pressure of the vaporizing means may be equal to or higher than the pressure of the environment in which the workpiece is disposed. The secondary reaction gas can be reliably supplied to the object to be processed by the pressure difference between the vaporizing means and the environment in which the object is disposed.
The internal pressure of the vaporization means may be lower than the arrangement environment of the object to be processed. This facilitates vaporization. In this case, it is preferable that the secondary reaction gas generation unit includes the vaporization unit and a pressurizing unit (blower unit) provided in a subsequent stage. By this latter pressurizing means, the secondary reaction gas from the vaporization means can be pressurized to a pressure higher than the pressure of the environment in which the object is disposed, and the secondary reaction gas can be reliably supplied to the object by the pressure difference. it can.

In the vaporization step, the aggregate may be vaporized by heating.
The vaporization means may include a heater for heating the condensed body after the pressurization.
As a result, the aggregate can be reliably vaporized, and the secondary reaction gas can be reliably obtained.

The vaporization may be carried out by contact with a carrier gas in addition to heating and decompression of the processing fluid or the condensed body after pressurization.
The vaporization means may include a vaporization container that accommodates the condensed body after pressurization and the carrier gas so as to be in contact with each other.
As a result, a gas mixture of the vaporized component and the carrier gas from the aggregate can be obtained as the secondary reaction gas, and the vaporized component can be carried on the carrier gas and supplied to the object to be processed.

The vaporization may be performed by flowing the condensed body after pressurization and the carrier gas in opposite directions.
The vaporizing container may be formed with a counter flow space through which the condensed body after pressurization and the carrier gas flow in directions facing each other. The aggregate in this case is preferably a fluid such as liquid or solid particles.
Thereby, a high concentration secondary reaction gas can be obtained.

  The vaporization may be performed by flowing the condensed body after pressurization and the carrier gas in parallel directions. The vaporizing means may be configured so that the post-pressurized aggregate and the carrier gas constitute a parallel flow. The aggregate in this case is preferably a fluid such as liquid or solid particles.

The vaporizing means has an outer tube and an inner tube that is inserted into the outer tube and forms an annular outer passage between the outer tube,
The inner pipe is formed with a large number of fine holes connecting the outer passage and the inner passage in the inner pipe,
One of the post-pressurized aggregate and carrier gas may be introduced into the outer passage, and the other of the post-pressurized aggregate and carrier gas may be introduced into the inner passage.
One of the post-pressurized aggregate and carrier gas is introduced into one end of the outer passage, and the other of the post-pressurized aggregate and carrier gas is introduced into the opposite end of the inner passage. It may be. Accordingly, the condensed body and the carrier gas after pressurization can be caused to flow in directions facing each other.
It is preferable that a carrier gas is introduced into the outer passage and the aggregate after pressurization is introduced into the inner passage.
As a result, the carrier gas in the outer passage enters the inner passage through the fine holes, so that a gas flow in the radially inward direction can be formed near the inner wall of the inner tube. Can be prevented from adhering to the inner wall of the inner tube.

A carrier gas may be bubbled through the aggregate.
You may make it the sum total pressure of the vaporization component and carrier gas from the said post-pressurization process fluid (condensate) become more than the arrangement | positioning environmental pressure of a to-be-processed object.

It is preferable to return the vaporization component that has not been vaporized in the vaporization step (hereinafter, also referred to as “devaporized material”) of the aggregate to the aggregate generation step. The deaerator may be mixed into the primary reaction gas or the aggregate before pressurization.
The vaporization means includes a devaporization component return means (devaporization body return means) for returning an unvaporized component (hereinafter also referred to as “non-condensate”) of the aggregate to the aggregate generation means. It may be connected. When the vaporized body is a liquid (vaporized liquid), a vaporized liquid path for discharging the vaporized liquid from the vaporized means extends as the vaporized body returning means, and the vaporized liquid path forms the aggregate. It may be connected to a means (preferably a condensing means of the aggregate generating means).
As a result, the vaporized aggregate such as the vaporized liquid can be returned to the aggregate generation means, and can be used as the coagulant.
A coagulant addition path for adding the coagulant may be connected to the vaporization liquid path.

  The aggregate includes a target substance capable of reacting with the workpiece, and in the vaporization step, the aggregate is a vaporized component (secondary reaction gas) in which the target substance is concentrated, and the target substance is diluted. Alternatively, the vaporized component may be separated. Thus, a high concentration target substance can be supplied to the object to be treated, and the vaporized component diluted with the target substance can be returned to the primary reaction gas or the aggregate before pressurization and circulated.

It is preferable that the processing fluid before the plasma treatment includes a starting material that can be changed into a target material having reactivity with the object to be processed by the plasma treatment step or the post-plasma treatment step.
The target substance is not limited to being formed into plasma, but may be generated at the time of condensation, or may be generated at the time of vaporization. The target substance in the condensed phase may be in a state dissolved in a solvent such as H ₂ O.
The processing fluid before the plasma treatment may contain a starting material that can be converted into a target material by reacting with a component of the reactant by the plasma treatment.
The processing fluid before the plasma treatment may include a starting material that can be changed into an intermediate material by the plasma treatment step, and the intermediate material has reactivity with the object to be processed in the post-plasma treatment step. The target substance may be changeable.

It is preferable that the processing fluid (raw material gas) before the plasma formation includes, for example, a halogen-containing compound as the starting material.
Examples of the halogen-containing compound include CF ₄ , fluorocarbons such as CH ₃ F, CH ₂ F ₂ , CHF ₃ , C ₂ F ₆ , C ₃ F ₈ , c-C ₄ F ₈ , and C ₄ F ₆ . Other examples include fluorine compounds such as SF ₆ , SiF ₄ , NF ₃ , and ClF ₃ , and chlorine compounds. The processing fluid before the plasma treatment may be a mixed gas having a plurality of these halogen-containing compounds as components. For example, when the object to be processed is a silicon-based material such as silicon oxide, and this is etched, the starting material is preferably a fluorocarbon such as CF ₄ , and the intermediate material is COF ₂ . Preferably, the target substance is HF. HF is a stable compound having an etching ability for silicon oxide.
The pre-plasmaization treatment fluid (raw material gas) further contains hydrogen-containing compounds such as H ₂ O, OH group-containing compounds (alcohols), hydrocarbons, hydrogen (H ₂ ), in addition to the halogen-containing compounds. May be. Thus, hydrogen halide such as HF can be obtained as a target substance by the plasma process or plasma process.

The reactant is preferably a hydrogen-containing compound. The hydrogen-containing compound constituting the reactant may be a hydrocarbon such as CH ₄ or hydrogen (H ₂ ). However, in consideration of handleability and safety, an H ₂ O or OH group-containing compound (alcohol or the like) ) Is preferable. Thereby, a primary reaction gas and a reactant can be subjected to a hydrolysis reaction or a reduction reaction to obtain a secondary reaction gas. The H ₂ O or OH-containing compound may be vapor or liquid. A wet gas in which an H ₂ O or OH-containing compound or the like as the reactant is contained in an inert gas such as N ₂ or Ar or air may be added to the processing fluid.

The pre-plasmaization processing fluid contains a starting material that can be converted into a target substance by reacting with the components of the reactant by plasmatization, and the reactant is added to the processing fluid before the plasmatization step. It is preferable to carry out the adding step. Moreover, it is preferable to further comprise an adding means for adding a reactant to the processing fluid before the plasma treatment.
For example, when the starting material in the processing fluid is a halogen-containing compound such as CF ₄ and the reactant is a hydrogen-containing compound such as H ₂ O, HF is used as the target substance by the plasma forming step or the plasma generating means. Etc. can be obtained. As described above, HF is a stable compound, and can reliably reach the object to be processed without being decomposed or deactivated in the pressurizing step or the conveying step after being plasmatized. Thereby, the etching process of silicon oxide or the like can be reliably performed.

It is preferable to add the reactant before the plasma formation under a lower pressure than the arrangement environment of the object to be processed. As a result, when water vapor (H ₂ O) or alcohol vapor (OH group-containing compound) is used as the reactant, the addition concentration can be increased, and a high concentration target substance (for example, HF) can be obtained by plasmatization. it can. In addition, the input amount of the starting material (CF ₄ or the like) can be saved. Since the plasma formation is also performed in a low pressure environment, condensation in the plasma conversion means can be suppressed, and corrosion of the electrode and dissolution of the target substance (HF or the like) in the condensed phase can be prevented.
In the case of using a hydrocarbon or hydrogen gas CH ₄ or the like as a reaction agent (H _2), by a low pressure, it is possible to ensure safety.

  The addition of the reactant prior to the plasma formation may be performed at a temperature higher than room temperature instead of or in addition to being performed at a lower pressure than the arrangement environment of the object to be processed. Thereby, similarly to the above, the concentration of addition can be increased, a high concentration of the target substance can be obtained, and the input amount of the starting material can be reduced.

The processing fluid (raw material gas) before the plasma treatment may further contain oxygen (O ₂ ) or an oxygen-containing compound.
Thereby, an intermediate substance containing oxygen, such as COF ₂ , can be obtained in the plasma step or the plasma means. Also, oxygen-based active species such as ozone and oxygen radicals can be generated. When the object to be processed is composed of silicon, silicon can be oxidized by the oxygen-based active species, and etching can be performed by reacting the silicon oxide with a target substance such as HF.

You may decide to contact oxidizing agents, such as ozone, with the said to-be-processed object further.
You may decide to further provide the ozone introduction system which introduces ozone between the said plasmarization means to the said supply part.
Thereby, for example, when the object to be processed is made of silicon, it can be oxidized, and this silicon oxide and a target substance such as HF can be reacted and etched.
Ozone may be mixed into the processing fluid path at approximately atmospheric pressure or may be mixed into the low-pressure processing fluid path. Alternatively, ozone may be supplied separately from the processing fluid path.

In the plasma step, a primary reaction gas (process fluid after plasma) containing an intermediate substance is obtained, and the target substance can be generated by reacting with the intermediate substance before pressurization in the post-plasma process step reactant (additives, such as H _{2 O} or OH group-containing compound) may be a in the performing the added step of adding to said process fluid.
For example, when the source gas contains CF ₄ as a starting material and further contains oxygen alone (O ₂ ) or an oxygen-containing compound, COF ₂ can be generated as the intermediate substance by plasmatization. This COF ₂ comes to be included in the primary reaction gas. COF ₂ reacts with water (H ₂ O), thereby generating HF as a target substance.
In this case, it is preferable to add H ₂ O or an OH group-containing compound to the primary reaction gas, the aggregate before pressurization, or the vaporized body. Thus, H 2 _O or OH group-containing compound acts as the coagulant.

The addition flow rate of the H ₂ O or OH group-containing compound may be set to a magnitude that takes into account the amount of the H ₂ O or OH group-containing compound that reacts with the intermediate substance and the amount of the H ₂ O or OH group-containing compound that is mixed with the secondary reaction gas and supplied to the workpiece. This allows the amount of H ₂ O or OH group containing compound in the system to be kept in equilibrium.
The content of the H ₂ O or OH group-containing compound in the secondary reaction gas is preferably zero or very small. Thereby, processing quality can be ensured.
Moreover, the humidity of the secondary reaction gas can be adjusted by adding H ₂ O or an OH-containing compound, thereby ensuring that a condensed phase is formed on the surface of the object to be processed, thereby ensuring a processing reaction such as etching. You can get up.

The ratio between the addition flow rate of the H ₂ O or OH group-containing compound and the production flow rate of the intermediate substance due to the plasma formation is substantially the same as the reaction ratio between the H ₂ O or OH group-containing compound and the intermediate substance. It is preferable that they are set as follows.
Accordingly, the target substance can be generated without waste using the intermediate substance generated by the plasmatization and the added H ₂ O or OH group-containing compound.

Furthermore, the ratio of the addition flow rate of the H ₂ O or OH group-containing compound, the production flow rate of the intermediate substance due to the plasma treatment, and the supply flow rate of the target substance to the object to be processed is determined by the production reaction of the target substance. It is preferable that the molar ratio of the H ₂ O or OH group-containing compound, the intermediate substance, and the target substance is substantially the same. As a result, the system can be brought into a substantially equilibrium state.
Here, when the intermediate substance is COF ₂ , the additive is water (H ₂ O), and the target substance is HF, these reaction ratios are COF ₂ : H ₂ O: HF = 1: 1: 2. Therefore, it is set so that (addition flow rate of H ₂ O or OH group-containing compound) :( production flow rate of intermediate substance) :( feed flow rate of target substance to object) ≈1: 1: 2. preferable.
The mol% of the target substance with respect to the total number of moles of the target substance and H ₂ O or OH group-containing compound in the secondary reaction gas is the total mole of the target substance and H ₂ O or OH group-containing compound in the aggregate. The total number of moles of the target substance and the H ₂ O or OH group-containing compound in the vaporized body (before addition when adding the H ₂ O or OH group-containing compound) is larger than the mol% of the target substance relative to the number. It is preferable that the mol% of the target substance is less than the mol% of the target substance with respect to the total number of moles of the target substance and H ₂ O or OH group-containing compound in the aggregate. Thus, a high concentration target substance can be supplied to the object to be treated, and the liquid in which the target substance is diluted can be returned to the primary reaction gas or the aggregate before pressurization and circulated.

When the pressurizing means is an ejector, the reactant may be added to the driving fluid. Thereby, the primary reaction gas can be sucked with the ejector and brought into contact with the reactant to generate the target substance.
For example, by introducing CF ₄ and O ₂ as starting materials into the plasma, COF ₂ is generated as the intermediate material. By adding H ₂ O as the reactant to the driving fluid, COF _{2 as} an intermediate substance reacts with H ₂ O as a reactant to generate HF as a target substance. When the driving fluid is gas, the adiabatic expansion is caused by the injection in the ejector, the temperature is lowered, and H ₂ O mist is generated. COF ₂ dissolves in this mist, and HF is generated.
The driving fluid may be heated by heating means. As a result, it is possible to prevent the reactant such as H ₂ O from solidifying due to a temperature drop accompanying adiabatic expansion of the driving fluid.

The processing fluid after pressurization in the post-plasma treatment process may be allowed to react with the object to be processed by a chemical reaction and brought into contact with the object to be processed.
For example, in the plasma process, a primary reaction gas (processed fluid after plasma) is obtained including an intermediate substance, and after the pressurization of the process fluid (primary reaction gas) in the post-plasma process, the intermediate substance is obtained. A reaction agent (additive) that can generate a target substance by reacting with the reaction fluid (primary reaction gas) may be added (addition step). As a result, the intermediate substance and the reactant come into contact with each other to obtain a secondary reaction gas (a gaseous processing fluid after the reaction) containing the target substance capable of reacting with the object to be processed. You may make it contact a thing.
The plasma generating means is configured to generate a post-plasmaized processing fluid (primary reaction gas) including an intermediate substance (for example, COF ₂ ) by bringing the processing fluid (source gas) into a plasma state between the electrodes. The post-plasmaization processing means can generate a target substance by reacting the post-plasmaization processing fluid (primary reaction gas) containing the intermediate substance with the intermediate substance and pressurizing means for pressurizing the post-plasmaization processing fluid (primary reaction gas) A reactor that is brought into contact with a reactive agent (such as a compound containing H ₂ O or OH). In this reactor, a secondary reaction gas containing a target substance capable of reacting with the object to be processed can be generated. Furthermore, it is preferable that the post-plasmaization processing means includes a supply unit that supplies the secondary reaction gas to the object to be processed.
Since the chemical reaction is performed after pressurization, the reaction equipment can be simplified.

  In the pressurizing means, it is preferable to pressurize the primary reaction gas to a pressure equal to or higher than the environment in which the object to be processed is disposed. The internal pressure of the reactor may be lower than the arrangement environment of the object to be treated, and a blowing means (other pressurizing means) is provided at the rear stage of the reactor, and the secondary discharged from the reactor by the blowing means. The reaction gas may be blown and supplied to the object to be processed.

  The primary reaction gas after the pressurization and the reactant need only be in contact with each other, and may constitute a counterflow with each other or may constitute a parallel flow with each other. It may be mixed uniformly in the vessel, the primary reactant gas may be bubbled through the liquid reactant, and the primary reactant gas contacts the surface of the liquid or solid stationary reactant. It may be like this.

For example, an azeotropic aggregate containing the target substance may be generated by the primary reaction gas and the reactant.
In this case, it is preferable to cool or adjust the temperature of the reaction system so as to be below the dew point of the reactant such as H ₂ O until the aggregate reaches the azeotropic point. Thereby, the aggregate can be reliably grown. It is preferable to cool or adjust the temperature for a while after exceeding the azeotropic point. Thereby, the liquid phase can remain to some extent even after the azeotropic point, and the reaction can be ensured. And after reaction is fully performed, it is preferable to heat. As a result, the aggregate can be finally vaporized reliably, and a sufficient amount of secondary reaction gas can be secured.

The reactor has an outer tube and an inner tube inserted into the outer tube to form an annular outer passage between the outer tube;
The inner pipe is formed with a large number of fine holes connecting the outer passage and the inner passage in the inner pipe,
One of the pressurized primary reaction gas and the reactant may be introduced into the outer passage, and the other of the pressurized primary reaction gas and the reactant may be introduced into the inner passage.
In this case, it is preferable that the primary reaction gas is introduced into the outer passage and the reactant is introduced into the inner passage.
As a result, the primary reaction gas can enter the inner passage from the outer passage through the fine hole of the inner tube, and the reaction of the reactant to the inner peripheral surface of the inner tube due to the air flow of the primary reaction gas is prevented. Can do.

  The end of the outer passage opposite to the introduction end is preferably closed. Accordingly, the outer passage can be set to a pressure higher than that of the inner passage, and the primary reaction gas or the reactant introduced into the outer passage can be surely penetrated into the inner passage through the fine holes.

The reactor may be formed with a parallel flow space in which the pressurized primary reaction gas and the reactant are flowed in the same direction, and a counter flow space is formed in a direction facing each other. Also good.
When the reactor has a double tube structure of the outer pipe and the inner pipe, one end of the pressurized primary reaction gas and one of the reactants (preferably the primary reactive gas after the pressurization) are provided at one end of the outer passage. ), And one of the pressurized primary reaction gas and the reactant (preferably the reactant) may be introduced into the end portion on the same side of the inner passage. Thereby, a parallel flow can be constituted. Alternatively, one of the pressurized primary reaction gas and the reactant (preferably the pressurized primary reaction gas) is introduced into one end of the outer passage, and the pressurized primary reaction gas is introduced into the other end of the inner passage. One of the reaction gas and the reactant (preferably the reactant) may be introduced. Thereby, a counterflow can be constituted.

The reactor is preferably provided with a temperature controller for adjusting the temperature inside.
Accordingly, the reaction between the primary reaction gas and the reactant after the pressurization can be controlled so that a high concentration secondary reaction gas can be generated.
The upstream portion of the reactor may be relatively cooled, and the downstream portion may be relatively heated.

  According to the present invention, the power required for plasmaization can be reduced as compared with that required at the time of the pressure of the arrangement environment of the object to be processed.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the workpiece in this embodiment is a glass substrate W. On the substrate W, for example, an amorphous silicon film f is formed. In this embodiment, the silicon film f is removed by etching.

FIG. 1 shows a basic form of the present invention. The plasma surface treatment apparatus M includes plasmarizing means 20, a vacuum pump 31 (pressurizing means), and a substrate placement unit 4.
The substrate placement unit 4 includes a stage, a roller conveyor, and the like. A substrate W to be processed is arranged on the upper surface of the substrate arrangement unit 4. The substrate placement unit 4 and the substrate W to be processed are placed under atmospheric pressure or a pressure in the vicinity thereof (substantially atmospheric pressure).

  The plasma generating means 20 has a decompression chamber 21 and a pair of electrodes 22, 22 provided in the decompression chamber 21. One electrode 22 is connected to the power source 2 and the other electrode 22 is electrically grounded. A discharge passage 23 is formed between the pair of electrodes. An electric field is formed between the electrodes by voltage supply from the power supply 2, and plasma discharge is generated in the discharge passage 23. The supply voltage is preferably about Vpp = 1 to 10 kV, and the frequency is preferably about 1 to 100 kHz.

  A raw material introduction path 10 extends from the processing fluid source 1 and continues to the upstream end of the discharge path 23. The raw material introduction path 10 is provided with a pressure reducing valve 10V. As will be described later, the raw material introduction path 10 downstream of the pressure reducing valve 10V (on the side of the plasmification means 20) is at a low pressure.

The processing fluid source 1 mixes CF ₄ as a starting material with H ₂ O (water vapor) and a carrier gas, and sends a raw material gas composed of this mixed gas (a processing fluid before being plasmatized) to the raw material introduction path 10. It has become. The flow rate ratio between CF ₄ and H ₂ O is preferably about CF ₄ : H ₂ O = 9: 1 to 999: 1. In this embodiment, for example, CF ₄ : H ₂ O = 98: 2. When this raw material gas is exposed to the plasma in the discharge passage 23, a reaction gas (processing fluid after being converted to plasma) containing COF ₂ , HF, F ₂ , O _{3 and the} like is generated.

FIG. 2 shows the production of HF and COF ₂ per unit power with respect to the plasma pressure. Various conditions are as follows.
Frequency: 30kHz
Voltage waveform: Pulse wave with a pulse width of 4 μs Raw material gas flow rate: 250 scm
Raw material gas component: CF ₄ 98 vol%
H ₂ O ₂ vol%
The amount of HF produced increases as the plasma pressure decreases, and decreases as it approaches atmospheric pressure. On the other hand, the production amount of COF2 has a peak in the vicinity of 0.2 to 0.4 bar.

HF constitutes a target substance for etching the film f.
COF ₂ constitutes an intermediate substance in the middle of generating the target substance (HF). That is, as shown in the following reaction formula (1), COF ₂ reacts with H ₂ O to become HF, whereby the film f can be etched.
COF ₂ + H ₂ O → 2HF + CO ₂ Formula (1)

The primary reaction gas passage 11 extends from the downstream end of the discharge passage 23 and continues to the vacuum pump 31. The gas path between the pressure reducing valve 10V of the raw material introduction path 10 and the vacuum pump 31 is maintained at a pressure lower than the atmospheric pressure by the vacuum pump 31. Therefore, the inside of the chamber 21 and thus the discharge passage 23 is in a low pressure environment. The pressure in the chamber 21 is set to 0.2 bar, for example.
As a constituent member of the vacuum pump 31, it is preferable to use a material having high corrosion resistance.

The secondary reaction gas path 14 is connected to the outlet port of the vacuum pump 31. The secondary reaction gas path 14 extends toward the substrate placement portion 4. A supply nozzle 40 (supply unit) is provided at the tip (downstream end) of the secondary reaction gas path 14. The supply nozzle 40 is arranged close to the upper side of the substrate W arranged under substantially atmospheric pressure.
The vacuum pump 31 and the supply nozzle 40 constitute a post-plasmaization processing means 30.

A method of etching the film f of the substrate W using the plasma surface processing apparatus M having the above configuration will be described.
A substrate W to be processed is set on the substrate placement unit 4. Since the substrate placement unit 4 is in an atmospheric pressure environment, no pressure operation is required, and the substrate W to be processed can be placed smoothly and easily.

On the other hand low pressure maintained process, maintaining the line between the valve 10V and Honpu 31 to a low pressure (0.2 bar) than the substrate placed environment by vacuum Honpu 31. Therefore, the inside of the chamber 21 and thus the inside of the discharge passage 23 is maintained in a low pressure environment (0.2 bar).
Plasma process and, by applying an electric field to form a discharge between the electrodes 22, 22 by the power supply from the power source 2, to generate plasma in the discharge passage 23. Since the discharge passage 23 is in a low pressure environment, plasma discharge can be sufficiently generated even if the power supplied from the power source 2 is small. Therefore, a small power source can be used, the heat generation countermeasure facility can be reduced in size, and the cost can be reduced. In addition, the plasma electron temperature can be increased, and good plasma can be obtained.
A raw material gas (CF ₄ + H ₂ O) is introduced into the discharge passage 23 from the processing fluid source 1. Thereby, the raw material gas is converted into plasma and decomposed, and a low-pressure reaction gas containing COF ₂ , F ₂ , HF, O _{3 and the} like is generated. Incidentally, the reaction gas also contains _{H 2} O and the like of unreacted this _{H 2} O reacts with COF _2, HF is produced.

Thereafter, the following post-plasma treatment process is performed.
Pressurization Step The reaction gas is sucked into the vacuum pump 31 through the primary reaction gas path 11 and is pressurized to approximately atmospheric pressure by the vacuum pump 31.

In the supply process, the reaction gas that has become substantially atmospheric pressure is sent to the secondary reaction gas passage 14, blown out from the supply nozzle 40, and blown onto the surface of the substrate W. Silicon is oxidized when O ₃ in the reaction gas comes into contact with the silicon film f. When HF in the reaction gas comes into contact with this silicon oxide via a condensed phase, volatile SiF ₄ is generated as shown in the following equation (2). Thereby, the film f can be etched.
SiO ₂ + 4HF → SiF ₄ + 2H ₂ O Formula (2)
2H ₂ O in the second term on the right side of the reaction formula (2) is provided as the condensed phase on the silicon oxide surface.
Usually, in the pressurizing step, the reaction gas is pressurized so as to be slightly higher than the pressure of the substrate placement portion 4 so that the reaction gas is supplied onto the substrate W by the pressure difference. In the pressurization step, the reaction gas is pressurized below the pressure (substantially atmospheric pressure) of the substrate placement portion 4, and the reaction gas is blown toward the substrate W by providing a blowing means in the secondary reaction gas path 14. You may decide to supply. In this case, the vacuum pump 31 and the blower unit constitute a pressurizing unit.

After completion of the workpiece replacement process etching, the processed substrate W is taken out from the substrate placement portion 4. Then, the substrate W to be newly processed is set in the substrate placement unit 4. Since it is an atmospheric pressure environment, it can be easily taken out and set, and there is no need to return the pressure of the substrate placement portion 4 to atmospheric pressure or reduce the pressure. Therefore, the plurality of substrates W, W... Can be processed continuously, and the processing time can be shortened. A large substrate W can be easily accommodated.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the drawings for the same configurations as those of the above-described embodiments, and the description thereof is omitted as appropriate.
FIG. 3 shows a modification of the first embodiment. An ozone introduction system 50 is added to the apparatus M. The ozone introduction system 50 includes an ozone source 51 such as an ozonizer and an ozone supply path 52 extending from the ozone source 51. As shown by the solid line in FIG. 3, the ozone supply path 52 is joined to the secondary reaction gas path 14.

  As a result, a gas containing ozone from the ozone source 51 can be added to the secondary reaction gas path 14 and supplied to the substrate W together with the secondary reaction gas. Thereby, the silicon film f can be reliably oxidized to silicon oxide. By reacting this silicon oxide with HF which is the main component of the secondary reaction gas, the film f can be reliably etched.

As shown by the two-dot chain line in FIG. 3, the ozone supply path 52 may be connected to the primary reaction gas path 11 instead of the secondary reaction gas path 14.
By mixing the ozone-containing gas, the concentration of hydrofluoric acid in the gas can be reduced, and condensation can be made difficult to occur.

FIG. 4 shows a second embodiment of the present invention.
In the surface treatment apparatus of this embodiment, instead of the vacuum pump 31, a reaction liquid generating means (condensate generating means) 60X comprising a condensing means (condensing means) 60 and a liquid pressurizing means 100, and a secondary reaction gas generating means. (Vaporizing means) 110. The aggregate generation unit 60X, the vaporization unit 110, and the supply unit 40 constitute a post-plasmaization processing unit 30.
A mixed gas of CF ₄ and O ₂ is used as the raw material gas (gaseous processing fluid) introduced from the processing fluid source 1 into the plasmification means 20. The flow rate ratio is, for example, about CF ₄ : O ₂ = 3: 2. In addition to the raw material gas components, a gas containing H ₂ O is mixed from a non-condensable gas return path 15b described later. As a result, a primary reaction gas (a low-pressure processing fluid after being plasmatized) containing COF ₂ , O ₃ , F ₂ , HF, CO ₂ , H ₂ O and the like is generated in the discharge passage 23 of the plasmarization means 20.

The plasmarizing means 20 is maintained in a low pressure environment of 0.3 bar, for example. As shown in FIG. 5, the production flow rate of COF ₂ per unit input power at the above flow rate ratio becomes the largest when the pressure of the plasmarizing means 20 is about 0.3 bar. The COF ₂ concentration at the outlet of the plasmification means 20 at 0.3 bar is 80000 ppm, and the COF ₂ partial pressure is 2400 Pa.

A condenser 60 (condensing means) is provided in the subsequent stage of the plasmification means 20 via the primary reaction gas path 11.
The condenser 60 has a condensing container 61 and a condensing pipe 62 and a cooling pipe 66 (cooler) provided in the container 61. The primary reaction gas path 11 is connected to the upper end portion of the condensing pipe 62.

In the vicinity of the connecting portion between the primary reaction gas path 11 and the condensing pipe 62, a water vapor adding means 70 (condensing agent (coagulant) adding means, reactant adding means) is connected. The steam addition means 70 has a steam source 71 and a steam addition path 72 extending from the steam source 71. The steam addition path 72 is joined near the downstream end of the primary reaction gas path 11 or near the upstream end of the condensation pipe 62. Thereby, water vapor (condensation agent (coagulant), reactant) from the water vapor source 71 is added to the primary reaction gas from the primary reaction gas passage 11. Water vapor may be added by bubbling the primary reaction gas in water.
Instead of water vapor, liquid phase water may be added to the primary reaction gas in the form of a mist.

  The condensing pipe 62 and the cooling pipe 66 are both in a coil shape and are arranged side by side so that they can exchange heat with each other. The primary reaction gas after the addition of water vapor is passed through the condenser 62. A cooling medium is passed through the cooling pipe 66. The flow direction of the primary reaction gas in the condensing pipe 62 and the flow direction of the cooling medium in the cooling pipe 66 are opposite to each other to form an opposing flow. As a result, the temperature of the condensing pipe 62 gradually decreases toward the downstream of the pipe 62. The vicinity of the upstream end of the condensing tube 62 is at room temperature, whereas the vicinity of the downstream end of the condensing tube 62 is set to be, for example, about −30 ° C. The primary reaction gas introduced into the condenser 60 is condensed in the process of flowing through the condenser tube 62, and thereby, a low-pressure reaction liquid (liquid condensate (processing fluid) before pressurization) is generated. ing.

  The lower part of the condensing container 61 is provided with a liquid phase part in which the reaction liquid exiting from the outlet of the condensing pipe 62 is stored, and the upper part is non-condensed remaining without being condensed (condensed) in the primary reaction gas A gas phase part in which gas (non-condensable gas, non-condensed component) is stored is provided. A non-condensable gas delivery path 15a extends from the gas phase portion. The non-condensable gas delivery path 15 a is connected to the unnecessary substance removing unit 80.

The unnecessary substance removing unit 80 includes an unnecessary material removing container 81, a removing medium source 89 connected to one end of the container 81 via a removing medium introduction path 82, and a removing medium outlet path 84 extending from the other end of the container 81. And a medium distribution pump 85 provided. The removal medium source 89 stores lime water as a removal medium. The lime water is introduced into the container 81 through the introduction path 82. The introduction passage 82 is provided with a pressure reducing valve 83, and the secondary pressure of the pressure reducing valve 83 is maintained at a low pressure of about 0.3 bar.
A non-condensable gas delivery path 15 a from the condenser 60 is connected to the lower end of the container 81.

An uncondensed gas return path 15 b extends from the unnecessary substance removal container 81. A gas circulation pump 15P is provided in the non-condensable gas return path 15b. The non-condensable gas return path 15b is joined to the raw material introduction path 10 on the lower pressure side (downstream side) than the valve 10V.
The non-condensable gas delivery path 15a and the non-condensed gas return path 15b constitute a non-condensable gas path (non-condensed component path) 15.

  A low-pressure maintenance path 16 is branched from a non-condensable gas return path 15b between the unnecessary substance removing unit 80 and the gas circulation pump 15P. A vacuum pump 90 for reducing pressure (low pressure maintaining means) is provided in the low pressure maintaining path 16. By this vacuum pump 90 for reducing pressure, the plasma generating means 20, the condenser 60, and the unnecessary substance removing unit 80 are placed in an environment (0.3 bar in this embodiment) lower than the pressure (atmospheric pressure) of the environment in which the workpiece W is arranged. ) Can be maintained.

The unnecessary substance removing unit 80 may be omitted, and the exhaust flow rate of the vacuum pump 90 for decompression may be increased by the amount of CO ₂ that is no longer excluded.

  As shown in FIG. 7, a cryogenic cooler 91 may be provided as a low pressure maintaining means instead of the vacuum pump 90 for decompression. The cryogenic cooler 91 cools the non-condensable gas to a cryogenic temperature, for example, liquefies it, and discharges it. The low pressure is maintained by the volume reduction associated with liquefaction.

As shown in FIG. 4, the liquid pressurizing means 100 is connected to the liquid phase portion of the condensing container 61 via the low-pressure reaction liquid path 12.
The liquid pressurizing means 100 is constituted by a tube pump. The tube pump 100 has a known structure and includes, for example, a tube 101 and a roller 102. The tube 101 is made of a corrosion-resistant flexible resin such as Teflon (registered trademark). A low-pressure reaction channel 12 is connected to the upstream end of the tube 101. Thereby, the reaction liquid condensed by the condenser 60 is sent to the tube 101.

  The roller 102 is relatively moved in the downstream direction of the tube 101 while crushing the tube 101 from the outside. Thereby, the reaction liquid in the tube 101 is pressurized while being pushed out in the downstream direction.

  A pressurized reaction liquid path 13 extends from the downstream end of the tube 101. The reaction liquid path 13 is connected to a container-like vaporizer 110 (vaporization means). Thereby, the reaction liquid (condensed substance after pressurization) pressurized by the tube pump 100 is supplied into the vaporizer 110 via the flow path 13.

  A heating temperature controller 115 is incorporated in the vaporizer 110. The heating temperature controller 115 adjusts the temperature of the vaporizer 110 to preferably 0 to 100 ° C., more preferably about 15 ° C.

Further, a carrier gas introduction system 120 is connected to the vaporizer 110. The carrier gas introduction system 120 has a carrier source 121 that stores a carrier gas such as argon, nitrogen, and air. A carrier gas path 122 extends from the carrier source 121 and continues to one end of the vaporizer 110.
In the vaporizer 110, the reaction liquid is vaporized in the carrier gas from the carrier gas introduction system 120. As a result, a secondary reaction gas (a processing fluid after vaporization having a higher pressure than the low-pressure environment) made of a mixed gas of the vaporized component of the reaction liquid and the carrier gas is generated.

  The secondary reaction gas path 14 extends from the other end of the vaporizer 110 (the end opposite to the connection end with the carrier gas path 122) toward the substrate placement section 4. A supply nozzle 40 (supply unit) is provided at the tip (downstream end) of the secondary reaction gas path 14. The supply nozzle 40 is arranged close to the upper side of the substrate W arranged under substantially atmospheric pressure.

In the second plasma forming step , the plasma generating means 20 generates a primary reaction gas containing COF ₂ having a partial pressure of 2400 Pa.

Thereafter, the following post-plasma treatment process is performed. The post-plasmaization process includes an aggregate generation process and a vaporization process. The aggregate generation process includes a reactant addition process, a condensation process, and a pressurization process.
Condensant addition process (coagulant addition process, reactant addition process)
Water vapor (condensing agent (coagulant), reactant) from the water vapor source 71 is added to the primary reaction gas. The amount added is, for example, such that the water vapor partial pressure in the primary reaction gas is 4600 Pa.

Condensation process (condensation process)
The primary reaction gas after the addition of water vapor is introduced into the condensation tube 62 and flows through the condensation tube 62. A cooling medium flows in the cooling pipe 66 so as to make a counter flow with the cooling medium. Thereby, the primary reaction gas is gradually cooled toward the downstream of the condensing pipe 62. First, water vapor (H ₂ O) in the primary reaction gas is condensed to form water droplets. COF ₂ dissolves in the water droplets, the reaction of the above reaction formula (1) occurs, and HF having a mole number twice the amount of decomposition of COF ₂ is generated. Thereby, droplets of hydrofluoric acid water (HF aqueous solution) are formed. The freezing point of this droplet is below 0 ° C. Therefore, even if the temperature of the condensing tube 62 becomes 0 ° C. or lower, the droplets do not freeze. Droplets, gradually increasing the HF concentration further by absorbing the COF ₂ according to flows the condensation tube 62. Accordingly, the freezing point of the droplet is further lowered. As a result, the droplet can be cooled to a set temperature of −30 ° C. without solidifying the droplet. Thus, COF ₂ can be decomposed by almost 100%. As a result, the high-concentration HF reaction liquid (condensate) exits from the outlet (downstream end) of the condensing pipe 62 and accumulates in the liquid phase portion on the lower side of the condensing container 61.

When COF ₂ which was 2400 Pa at the outlet of the plasmarization means 20 is decomposed almost 100%, 2400 Pa of 4600 Pa of added H ₂ O is consumed for the reaction of the reaction formula (1) with COF _2, and the rest is 2200 Pa. become. In addition, the amount of HF produced is 4800 Pa, twice the amount of COF ₂ consumed. The total of the remaining amount of H ₂ O and the amount of HF produced is 7000 Pa, of which the proportion occupied by HF is
HF / (H ₂ O + HF) = 4800/7000 = 0.69
It is.
Since the primary reaction gas is 0.3 bar (= 30000 Pa), about 24% (= 7000/30000) of the primary reaction gas became the reaction liquid (H ₂ O + HF). The remaining 76% is non-condensable gas.

FIG. 6 shows a pressure-composition diagram of HF and H ₂ O at −30 ° C., a solid line indicates a liquidus line, and a two-dot chain line indicates a gas phase line. A solid thin line is a pressure-composition line of HF and H ₂ O when 76% of non-condensable components are contained.
As shown in the figure, when the primary reaction gas, that is, the gas having 76% of the non-condensable component is condensed at −30 ° C., the HF concentration in the liquid phase is HF / (H ₂ O + HF) = 0.66. Further, the HF concentration of only the two components H ₂ O and HF excluding the non-condensed components in the gas phase is HF / (H ₂ O + HF) ≈1, that is, approximately 100% HF. The partial pressure of this nearly 100% HF gas is 650 Pa. Therefore, 4150 Pa out of 4800 Pa HF is liquefied as a component of the reaction solution.
Therefore, the liquefaction efficiency of HF is 4150/4800 = 86%.
In addition, substantially the entire amount of the remaining 2200 Pa of the added H ₂ O becomes a component of the reaction solution, and the non-condensable gas from the outlet of the condensing tube 62 hardly contains H ₂ O. The main components of the non-condensable gas are CF ₄ , O ₂ , CO _{2 and the} like. The starting CF ₄ does not condense at -30 ° C. Thereby, CF ₄ can be easily and reliably extracted and separated from the primary reaction gas or reaction solution. CO ₂ in the non-condensable gas is generated along with the HF generation reaction by COF ₂ and H ₂ O in the condenser 60.

Unnecessary Substance Removal Step The non-condensable gas containing CF ₄ and CO ₂ is introduced from the condenser 60 into the lime water of the unnecessary substance removal container 81 through the non-condensable gas delivery path 15a. CO ₂ (unnecessary substance) in the non-condensable gas dissolves in the lime water, and calcium carbonate and water are generated. As a result, it is possible to remove the unnecessary substance CO ₂ from the non-condensable gas. In addition, the calcium carbonate solution absorbs HF and generates calcium fluoride. Thereby, HF in the non-condensable gas can be removed, and corrosion of the pumps 15P, 90, etc. at the subsequent stage can be prevented. Therefore, the main component of the non-condensable gas is CF ₄ , H ₂ O, or the like. The calcium carbonate and calcium fluoride are led out from the container 81 to the lead-out path 84.

Non-condensable gas return step The non-condensable gas from the unnecessary substance removing unit 80 is mixed with the raw material gas in the raw material introduction passage 10 from the return passage 15b by the circulation pump 15P. As a result, a non-condensable gas containing CF ₄ or the like as a starting material can be reintroduced into the plasmification means 20. As a result, the raw material gas flow rate from the processing fluid source 1 can be reduced, the loss of the raw material can be prevented, and the cost can be reduced. In addition, CF ₄ can be circulated and confined among the plasmarization means 20, the condenser 60, and the unnecessary substance removal container 81, and the CF ₄ can be reliably prevented from leaking out of the system.

The reaction liquid made of high-concentration hydrofluoric acid water generated in the pressurization process condenser 60 is sent to the tube pump 100 through the low-pressure reaction liquid passage 12 and pressurized to a pressure corresponding to atmospheric pressure.
By using the corrosion-resistant resin tube 101, pump corrosion and damage can be prevented, durability can be improved, and maintenance can be facilitated.
Since the volume of the fluid becomes very small due to the condensation, the pump can be greatly reduced in size, and the cost can be greatly reduced.

The reaction liquid pressurized by the vaporization process tube pump 100 is sent to the vaporizer 110 via the pressurized reaction liquid path 13. And it is heated from -30 degreeC to about 15 degreeC by the temperature controller 115, for example. As a result, HF can be selectively vaporized (more than H ₂ O) from a reaction solution (condensate) made of hydrofluoric acid water, and high-concentration HF vapor can be obtained. This HF vapor is mixed with the carrier gas from the carrier gas introduction system 120. Thereby, a secondary reaction gas of 1 bar as a whole can be obtained.

Supply Process The secondary reaction gas is blown from the supply nozzle 40 through the gas passage 14 and blown to the substrate W. At the same time, ozone from the ozone introduction system 50 merges into the secondary reaction gas path 14, is mixed with the secondary reaction gas, and is sprayed onto the substrate W. Thereby, the silicon film f can be efficiently etched and removed.

FIG. 8 shows a third embodiment. In this embodiment, the condensation and vaporization structure in the second embodiment of FIG. 4 is modified.
The condenser 60A is configured such that the gas path and the liquid path are opposed to each other.
More specifically, the primary reaction gas path 11 from the plasmarization means 20 is connected to the upper part of one end of the condenser 60A. A non-condensable gas delivery path 15a is connected to the upper side of the other end of the condenser 60A (the side opposite to the end connected to the primary reaction gas path 11). Thereby, the flow of the primary reaction gas from the one end side (the connection side with the primary reaction gas path 11) to the other end side (the connection side with the non-condensable gas delivery path 15a) is formed in the upper part of the condenser 60A. It has come to be.

The pressure condition of the plasmification means 20 is, for example, 0.3 bar as in the second embodiment. Therefore, the primary reaction gas introduced from the primary reaction gas path 11 to one end of the condenser 60A contains COF ₂ having a partial pressure of 2400 Pa.

  A degassing liquid path (degasification component return means) 17 is connected to the lower side of the other end of the condenser 60A (the end on the same side as the connection portion of the noncondensable gas delivery path 15a). As will be described later, the vaporization liquid passage 17 is drawn from the vaporizer 110, and passes through the vaporized components that have not been vaporized by the vaporizer 110 (devaporized material, hydrofluoric acid water having a low HF concentration). It has become so. A decompression valve 17 </ b> V is provided in the middle of the degassing liquid passage 17. The degassing liquid passage 17 on the primary side of the pressure reducing valve 17V is substantially at atmospheric pressure, and the degassing liquid passage 17 on the secondary side is at a low pressure equivalent to 0.3 bar.

The low-pressure reaction liquid path 12 extends from the lower side of one end of the condenser 60 </ b> A (the end on the same side as the connection part of the primary reaction gas path 11) and is connected to the tube pump 100.
As a result, the flow of the reaction liquid from the other end side (the connection side with the deaeration liquid path 17) to the one end side (the connection side with the low pressure reaction liquid path 12) is formed in the lower part of the condenser 60A. It has become so.

  A condenser 65 is incorporated in the condenser 60A. The inside of the condenser 60A is maintained at −30 ° C. by the cooler 65.

  In the third embodiment, the water addition means 70A (coagulant addition means) is connected not to the gas path of the condenser 60A but to the upstream end of the liquid path. The water supply source 71A of the water adding means 70A supplies liquid water instead of water vapor. A water addition path 72 </ b> A from the water supply source 71 </ b> A is connected near the downstream end of the degassing liquid path 17. Thereby, water is added to the vaporized body of the vaporized liquid path 17 and introduced into the liquid path of the condenser 60A.

The amount of water added by the water addition means 70A is set to be substantially the same as the reaction molar ratio (1: 1) of H ₂ O and COF ₂ with respect to the production flow rate of COF ₂ in the plasmification means 20. That is, the amount of water added is set to be approximately the same number of moles as the amount of COF ₂ produced (partial pressure 2400 Pa).

  Here, the HF concentration of the vaporized body (hydrofluoric acid water) sent from the vaporizer 110 to the vaporization liquid path 17 is set to 60 mol%. This HF concentration becomes, for example, 50 mol% by the above water addition. In short, water of one third of the amount of HF in hydrofluoric acid water at the outlet of the vaporizer 110 is added. The reaction liquid composed of hydrofluoric acid water having an HF concentration of 50 mol% is introduced into the condenser 60A from the vaporization liquid passage 17.

Thereby, in the condenser 60A, the primary reaction gas containing COF ₂ and the reaction liquid made of hydrofluoric acid water come into contact with each other while flowing in opposite directions. As a result, COF ₂ in the primary reaction gas sequentially dissolves in the reaction solution and reacts with H ₂ O in the reaction solution to generate HF. Therefore, the COF ₂ concentration of the primary reaction gas decreases as it goes downstream (the other end side of the condenser 60A), and the HF concentration of the reaction solution increases as it goes downstream (one end side of the condenser 60A). .

By appropriately setting the length and temperature of the condenser 60A, almost all of the COF ₂ in the primary reaction gas can be consumed in the HF production reaction. As a result, H ₂ O in the reaction solution is consumed by an amount corresponding to the amount added from the water addition means 70A. The amount of HF produced is twice the amount of COF ₂ or H ₂ O consumed.
In short, in the condenser 60A, HF that is (2/3) times the amount of HF in the reaction liquid at the outlet of the vaporizer 110 is newly generated, and the total amount of HF is (5/3) times that of the outlet of the vaporizer 110. become. Therefore, the HF concentration of the reaction liquid (hydrofluoric acid water), which was 50 mol% at the liquid inlet of the condenser 60A (connection end with the degassing liquid path 17), is the liquid outlet (connection end with the low-pressure reaction liquid path 12). Is concentrated to 71 mol%.
This highly concentrated reaction liquid is sent to the tube pump 100 via the low-pressure reaction liquid path 12.

  On the other hand, as shown in the graph of FIG. 6, the vapor pressure in 50 mol% hydrofluoric acid water is 110 Pa, and the HF partial pressure of the vapor at that time is 110 × 0.93 = 102 Pa. That is, the HF partial pressure of the primary reaction gas at the gas outlet (the same side as the liquid inlet) of the condenser 60A is 102 Pa, which is extremely small. Thereby, the amount of HF discharged to the non-condensable gas delivery path 15a can be made extremely small. As a result, the utilization efficiency of HF can be significantly improved.

The vaporizer 110 has a structure similar to that of the condenser 60A, and is configured such that the gas path and the liquid path are opposed to each other.
The pressurized reaction liquid path 13 from the tube pump 100 is connected to the lower side of one end of the vaporizer 110. A degassing liquid path 17 is connected to the lower side of the other end of the vaporizer 110 (the side opposite to the connection end with the pressurized reaction liquid path 13). The evacuation liquid path 17 extends toward the condenser 60A.

  The carrier gas passage 122 of the carrier gas introduction system 120 is connected to the upper side of the other end of the vaporizer 110 (the end on the same side as the connection portion of the degassing liquid passage 17). The secondary reaction gas path 14 is connected to the upper part of one end of the vaporizer 110 (the end on the same side as the connection part of the pressurized reaction liquid path 13). The secondary reaction gas path 14 extends toward the substrate W under substantially atmospheric pressure.

  A temperature controller 116 is incorporated in the vaporizer 110. The inside of the vaporizer 110 is maintained at a room temperature of, for example, about 25 ° C. by the temperature controller 116.

  The reaction liquid (hydrofluoric acid water having an HF concentration of 71 mol%) exiting from the condenser 60A is pressurized to a pressure corresponding to atmospheric pressure by the tube pump 100, and then passes through the pressurized reaction liquid path 13 to one end of the vaporizer 110. To be introduced. On the other hand, the carrier gas of the carrier gas introduction system 120 is introduced into the other end of the vaporizer 110. Thereby, in the vaporizer | carburetor 110, a reaction liquid and carrier gas contact, flowing in the mutually opposing direction. In this flow process, HF in the reaction solution is sequentially vaporized and mixed in the carrier gas, and a reaction gas containing HF is generated. The HF partial pressure of the reaction gas increases as it goes downstream. Conversely, the HF concentration of the reaction solution decreases as it goes downstream (upstream of the secondary reaction gas flow). As described above, the HF concentration at the liquid inlet in the vaporizer 110 is 71 mol%, and the HF concentration at the liquid outlet is set to be 60 mol%.

The HF partial pressure of the secondary reaction gas and the HF concentration of the reaction liquid at the same position in the vaporizer 110 have an approximately linear relationship.
As shown in FIG. 9, the gas outlet of the vaporizer 110 corresponds to a position where the HF concentration of hydrofluoric acid water is 71 mol%, where the HF partial pressure is 15500 Pa. Accordingly, a secondary reaction gas containing a high concentration of HF can be obtained. The secondary reaction gas composed of the high-concentration HF gas is supplied from the gas outlet of the vaporizer 110 to the substrate W through the secondary reaction gas path 14. Thereby, etching efficiency can be improved.

On the other hand, in the vaporizer 110, H ₂ O in the reaction solution is also vaporized into the carrier gas together with HF. However, as shown in FIG. 9, the H ₂ O partial pressure at the gas outlet is less than 20 Pa, which is extremely small. That is, the H ₂ O partial pressure at the gas outlet can be made sufficiently small by making the gas flow and the liquid flow counter flow. Thereby, the amount of water supplied to the substrate W can be greatly reduced. As a result, it is possible to avoid a decrease in the etching rate, to prevent the etching surface from being roughened, and to ensure good processing quality.

FIG. 10 shows a modification of the vaporizer of the third embodiment.
The vaporizer 130 has an outer tube 131 (vaporization container) and an inner tube 132 provided coaxially inside the outer tube 131, and has a double tubular shape.

These tubes 131 and 132 are made of a corrosion-resistant material such as Teflon (registered trademark). Further, the inner tube 132 is configured by a filter tube (porous member) having a large number of fine holes 133.
An annular outer passage 134 is formed between the outer tube 131 and the inner tube 132. The outer passage 134 and the inner passage 135 inside the inner tube 132 are separated from each other by the tube wall (partition wall) of the inner tube 132 and communicate with each other through the fine holes 133.

  The pressurized reaction liquid path 13 is connected to one end of the inner tube 132, and the degassing liquid path 17 extends from the other end. As a result, the inner passage 135 is a liquid passage through which the reaction solution (hydrofluoric acid water) flows from one end side to the other end side.

  The secondary reaction gas passage 14 is connected to one end portion of the outer passage 134 (the end portion on the same side as the connection end of the inner tube 132 with the pressurized reaction liquid passage 13). The carrier gas passage 122 is connected to the other end portion of the outer passage 134 (the end portion on the same side as the connection end of the inner tube 132 with the degassing liquid passage 17). As a result, the outer passage 134 is a gas path through which the carrier gas flows from the other end side to the one end side.

The reaction liquid in the inner passage 135 and the carrier gas in the outer passage 134 flow in directions opposite to each other. In this flow process, HF in the reaction solution is vaporized, passes through the fine holes 133 of the inner tube 132, is mixed into the carrier gas in the outer passage 134, and a secondary reaction gas containing HF is generated.
The carrier gas may be passed through the inner passage 135 and the reaction solution may be passed through the outer passage 134.

  FIG. 11 shows a modification of the condenser of the third embodiment. The condenser 140 has the same configuration as the vaporizer 130 of FIG. That is, the condenser 140 has an outer tube 141 (condensation container) and an inner tube 142. These tubes 141 and 142 are made of a corrosion-resistant material such as Teflon (registered trademark). Furthermore, the inner tube 142 is configured by a filter tube (porous member) having a large number of fine holes 143.

  The primary reaction gas passage 11 is connected to one end portion of the outer passage 144, and the non-condensable gas delivery passage 15a extends from the other end portion. As a result, the outer passage 144 is a gas passage through which the primary reaction gas flows from one end side to the other end side.

  The low-pressure reaction liquid passage 12 extends from one end portion of the inner pipe 142 (the end portion on the same side as the connection end with the primary reaction gas passage 11 of the outer passage 144). The degassing liquid passage 17 is connected to the other end portion of the inner pipe 142 (the end portion on the same side as the connection end of the outer passage 144 with the non-condensing delivery passage 15a). As a result, the inner passage 145 is a liquid passage that allows the reaction liquid to flow from the other end side to the one end side.

The primary reaction gas of the outer passage 144 and the reaction liquid in the inner passage 145 flow in directions opposite to each other. In this flow process, a part of the reaction gas passes through the fine hole 143 of the inner tube 142 and is mixed into the reaction liquid in the outer passage 144, and COF ₂ in the mixed gas reacts with H ₂ O in the reaction liquid. Thus, HF is generated, and the HF concentration of the reaction solution is increased.
The primary reaction gas may be passed through the inner passage 145 and the reaction solution may be passed through the outer passage 144.

FIG. 12 shows a fourth embodiment.
In this embodiment, as in the first embodiment, a vacuum pump 31 is provided at the subsequent stage of the plasmification means 20. By means of this vacuum pump 31, the inside of the plasmification means 20 is maintained in a low pressure environment of, for example, 0.2 to 0.4 bar, preferably 0.3 bar.

As in the second and third embodiments, the processing fluid source 1 mixes CF ₄ and O ₂ and supplies them to the plasmarization means 20. As a result, a primary reaction gas containing COF ₂ , O ₃ , F ₂ , CO _{2 and the} like is generated in the plasmification means 20. The COF ₂ concentration in the primary reaction gas under a pressure of 0.3 bar is 80000 ppm (= 8%) as described above.

The primary reaction gas is sucked into the vacuum pump 31 through the primary reaction gas passage 11 and pressurized to approximately atmospheric pressure. As a result, the partial pressure of COF ₂ in the primary reaction gas after pressurizing from the vacuum pump 31 becomes 8000 Pa (= 1 bar × 8%).

  An intermediate gas 13 </ b> A extends from the outlet port of the vacuum pump 31. A particle removal filter 150 is interposed in the intermediate gas path 13A. Thereby, even if particles are generated from the vacuum pump 31 and mixed into the reaction gas, the particles can be removed by the filter.

A reactor 160 is provided in the intermediate gas passage 13 </ b> A on the downstream side of the particle removal filter 150. The reactor 160 constitutes the post-plasmaization processing means 31 together with the vacuum pump 3.
The reactor 160 has a structure similar to the vaporizer 130 and the condenser 140 shown in FIGS. More specifically, the reactor 160 has an outer tube 161 (reactor body) and an inner tube 162 provided coaxially inside the outer tube 161, and has a double tubular shape.

These tubes 161 and 162 are made of a corrosion-resistant material such as Teflon (registered trademark). Further, the inner tube 162 is configured by a filter tube (porous member) having a large number of fine holes 163.
An outer passage 164 is formed between the outer tube 161 and the inner tube 162. The outer passage 164 and the inner passage 165 are separated from each other by the tube wall (partition wall) of the inner tube 162 and communicate with each other through the fine hole 163.

  An intermediate gas passage 13 </ b> A is connected to one end of the outer passage 164. The other end of the outer passage 164 is closed.

The reactor 160 is connected with water vapor addition means 170 (reactant addition means). The water vapor addition means 170 has a water vapor source 171 and a water vapor addition path 172 extending from the water vapor source 171. The water vapor addition path 172 is continuous with one end of the inner pipe 162 (the end on the same side as the connection end of the outer passage 164 with the intermediate gas path 13A).
A secondary reaction gas path 14 is connected to the other end of the inner tube 162 (the end on the same side as the closed end of the outer passage 164), and the secondary reaction gas path 14 extends toward the substrate W.

  A temperature controller 166 is incorporated in the reactor 160. The temperature adjuster 166 adjusts the outer passage 164 and the inner passage 165 to be maintained at a set temperature. The set temperature of the reactor 160 is preferably 20 to 40 ° C., for example, about 30 ° C. is preferable.

The primary reaction gas (COF ₂ partial pressure: 8000 Pa) after being pressurized by the vacuum pump 31 is introduced into one end portion of the outer passage 164 through the intermediate gas passage 13A. In the outer passage 164, a flow of the primary reaction gas from one end to the other end is formed.

Reagent addition step Meanwhile, steam source 171 of steam adding means 170, moistened with water vapor to produce a steam-containing gas (reactant) in a carrier gas such as nitrogen. The partial pressure of water in the steam-containing gas is set to the same partial pressure (8000 Pa) as that of the primary reaction gas COF ₂ . This water vapor-containing gas is introduced into one end portion of the inner pipe 162 through the water vapor addition path 172. As a result, a flow of water vapor-containing gas from one end to the other end is formed in the inner passage 165. The flow direction of the water vapor-containing gas faces the same direction as the primary reaction gas of the outer passage 164 and constitutes a parallel flow.

  The inner passage 165 has a temperature (for example, 30 ° C.) lower than the dew point (for example, 42 ° C.) of the water vapor-containing gas. Therefore, moisture in the water vapor-containing gas is condensed and water droplets are formed.

  On the other hand, the primary reaction gas of the outer passage 164 sequentially enters the inner passage 165 through the fine hole 163 of the inner pipe 162 as it goes downstream. Therefore, an air flow in the radially inner direction is formed in the vicinity of the inner peripheral surface of the inner tube 162. This air flow can prevent water droplets from coming into contact with the inner peripheral surface of the inner tube 162, and can prevent condensation from forming on the inner peripheral surface of the inner tube 162.

The primary reaction gas that has entered the inner passage 165 is mixed with the water vapor-containing gas. The COF ₂ in the primary reaction gas dissolves in the droplets (condensed phase) in the water vapor-containing gas and reacts with H ₂ O. Thereby, HF is generated in the droplet, and the droplet becomes hydrofluoric acid water (HF aqueous solution).

FIG. 13 shows the concentration of the condensed phase in the inner passage 165 (liquid / (liquid + gas)), the wetness corresponding to the molar ratio of HF in the condensed phase (HF / (HF + H ₂ O)), and the HF in the gas phase. This shows changes in the partial pressure of water vapor and the partial pressure of water vapor.
As shown in the figure, the reaction between COF ₂ and H ₂ O proceeds from one end portion of the inner passage 165 toward the downstream side, and thereby a condensed phase (hydrofluoric acid water droplets) grows. The HF concentration in the condensed phase increases. In the upstream portion of the inner passage 165, the condensation of water vapor is promoted by the increase of the HF concentration, and the condensed phase further grows. The water vapor partial pressure decreases.

At an intermediate position of the inner passage 165, the HF concentration in the condensed phase reaches an azeotropic point. This stops the growth of the condensed phase. COF ₂ further dissolves in this condensed phase, and the HF concentration rises above the azeotropic point. On the downstream side of the intermediate position of the inner passage 165, vaporization of the condensed phase having a high HF concentration (generation of secondary reaction gas) is promoted. As a result, the HF partial pressure of the gas phase (secondary reaction gas) increases significantly.

Eventually, the condensed phase disappears and the reaction stops.
In this manner, a secondary reaction gas containing a high concentration of HF can be obtained, and by supplying this to the substrate W, etching can be performed efficiently. The remaining amount of H ₂ O of the secondary reaction gas is about 1 to 2%, and the etching quality can be ensured.
As shown in FIG. 14, when the 0 ℃ instead the set temperature of the temperature controller 166 to 30 ° C., H 2 _O almost all the consumed in the reaction almost of H _{2 O} remaining in the secondary reaction gas It can be made zero, and the etching quality can be further improved.
A heater may be provided on the downstream side of the reactor 160 so that the reaction liquid in the inner passage 165 is heated and vaporized reliably.

  FIG. 15 shows a modification of the plasmarization means 20. The plasma generating means 20 is not provided with the decompression chamber 21, and instead, solid dielectric plates 24, 24 are provided on the opposing surfaces of the pair of electrodes 22, 22, respectively. , 24 define a decompression chamber 23 (low pressure environment) having a pressure lower than approximately atmospheric pressure. The source gas passage 10 is connected to one end of the decompression chamber 23, and the primary reaction gas passage 11 extends from the other end. The electrode 22 is disposed outside the decompression chamber 23. This decompression chamber 23 becomes a plasma discharge space.

FIG. 16 shows a fifth embodiment of the present invention.
The plasma surface processing apparatus M is configured by sequentially connecting a processing fluid source 1, a humidifier (adding means) 180, a plasma generating means 20, a vacuum pump 31 (pressurizing means), and a supply nozzle 40. Yes. The vacuum pump 31 and the supply nozzle 40 constitute a post-plasmaization processing means 30.

The processing fluid source 1 stores a mixed gas of CF ₄ and Ar as a source gas (processing fluid). CF ₄ constitutes a starting material that can be changed into a target material (hydrogen fluoride) having reactivity with the object to be processed (silicon) by plasmatization. As starting material in place of the _{CF 4, CH 3 F, CH} 2 F 2, CHF 3, C 2 F 6, C 3 F 8, c-C 4 F 8, other fluorocarbons such as C 4 _{F 6} May be used, and other fluorine compounds and chlorine compounds such as SF ₆ , SiF ₄ , NF ₃ , and ClF ₃ may be used.

Ar in the source gas constitutes a carrier of the starting material. Instead of Ar as the carrier, other inert gas such as N ₂ may be used.
The mixing ratio of CF ₄ and Ar is, for example _CF 4: Ar = 1: is 10, the concentration of CF _{4 is, (CF 4 / (CF 4} + Ar)) = ones is a 9 vol%, which is limited to is not.
The pressure of the source gas (CF ₄ + Ar) in the processing fluid source 1 is preferably equal to or higher than atmospheric pressure, for example, 2 bar.

  A raw material supply path 10 </ b> A extends from the processing fluid source 1. An electromagnetically controlled pressure reducing valve 10Va is provided in the middle of the supply path 10A. The supply path 10 </ b> A is connected to the humidifier 180.

The humidifier 180 is a bubbling tank, for example, in which liquid phase water (H ₂ O) is stored as a reactant (additive). The water temperature is normal temperature (constant temperature). The downstream end of the supply path 10A is inserted into the water.

The inside of the humidifier 180 is at a lower pressure than the processing fluid source 1, and is set at a pressure lower than the atmospheric pressure (arrangement environment of the object to be processed) and within a range equal to or higher than the inner pressure of the decompression chamber 21.
A humidifying raw material introduction path 10 </ b> B extends from the upper side of the water surface of the humidifier 180. An electromagnetically controlled decompression valve 10Vb is provided in the middle of the humidified raw material introduction path 10B.

The humidified raw material path 10B is inserted into the decompression chamber 21 of the plasmarization means 20, and is connected to the upstream end of the discharge path 23 between the pair of electrodes 22,22.
The inside of the decompression chamber 21 and the inside of the discharge passage 23 are at a pressure lower than the atmospheric pressure (environment of the object to be processed), and are further lower than the humidifier 180, and are maintained at, for example, about 22 kPa. .

The primary reaction gas passage 11 extends from the downstream end of the discharge passage 23 and continues to the vacuum pump 31. The vacuum pump 31 maintains the inside of the decompression chamber 21 in a low pressure environment (for example, 22 kPa), and further maintains the inside of the humidifier 180 in a low pressure environment (for example, 51 kPa to 99 kPa).
The pressure in the humidifier 180 can be adjusted by the opening degree of the valve 10Vb.
The temperature in the humidifier 180 is controlled to be constant (for example, 25 degrees).
On the other hand, the internal pressure of the decompression chamber 21 is detected by a pressure sensor (not shown) and the output of the vacuum pump 31 is feedback-controlled, so that the internal pressure of the decompression chamber 21 and thus the pressure of the discharge passage 23 are maintained constant (for example, 22 kPa). be able to.

  The secondary reaction gas path 11 extends from the vacuum pump 31 and is connected to the supply nozzle 40. The supply nozzle 40 is positioned on the substrate placement portion (processed matter placement portion) 4 in an atmospheric pressure environment and is opposed to the glass substrate W.

A method for etching the silicon oxide film f on the surface of the substrate W by the apparatus M of the fifth embodiment will be described.
A substrate W to be processed is set on the substrate placement unit 4.
Low pressure maintenance process The vacuum pump 31 is driven to maintain the inside of the decompression chamber 21 at a lower pressure (22 kPa) than the substrate arrangement environment (atmospheric pressure), and further maintain the inside of the humidifier 180 at a lower pressure (51 kPa to 99 kPa) than the atmospheric pressure. .

Addition process (humidification process)
The raw material gas (CF ₄ + Ar) from the processing fluid source 1 is introduced into the humidifier 180 through the supply path 10A and is bubbled in the water in the humidifier 180. Thereby, water (steam) is added to the raw material gas, and a humidified raw material gas (CF ₄ + H ₂ O + Ar, processing fluid after addition of the reactant) is formed.
Since the inside of the humidifier 180 is at a pressure lower than atmospheric pressure, the relative molar concentration of water vapor added to the humidified raw material gas can be sufficiently increased. The water vapor concentration can be arbitrarily adjusted by changing the internal pressure of the humidifier 180 within a range of 51 kPa to 99 kPa, for example.

The humidified raw material gas from the plasma process humidifier 180 is introduced into the discharge passage 23 through the introduction path 10B.
In parallel, an electric field is applied between the electrodes 22 and 22 by supplying power from the power source 2, and plasma is generated in the discharge passage 23. Since the discharge passage 23 is in a low pressure environment, plasma discharge can be sufficiently generated even when the power supplied from the power source 2 is small, and good plasma can be obtained. As a result, the humidified raw material gas CF ₄ and H ₂ O are respectively decomposed, and a reaction gas containing the target substance HF and the like is generated.
Since the water vapor concentration in the humidified raw material gas is sufficiently high, the conversion ratio from CF ₄ to HF can be increased, and a high concentration of HF can be obtained even if the input amount of CF ₄ from the processing fluid source 1 is small.

Pressurization Step The reaction gas containing high-concentration HF generated in the discharge space 23 is sucked into the vacuum pump 31 through the primary reaction gas path 11 and is pressurized to approximately atmospheric pressure by the vacuum pump 31.

In the supply process, the reaction gas that has become substantially atmospheric pressure is sent to the secondary reaction gas passage 14, blown out from the supply nozzle 40, and blown onto the surface of the substrate W. Thereby, the silicon oxide film f can be etched. Since the reaction gas contains a high concentration of HF, the etching efficiency can be sufficiently increased.

  When the film f to be etched is not silicon oxide but silicon, an ozone introduction system 50 may be provided as in the embodiment of FIG. Since high-concentration HF can be generated, the flow rate of the raw material gas from the processing gas source 1 can be reduced, and therefore ozone from the ozone introduction system 50 can be prevented from being diluted more than necessary. Thereby, etching can be performed with high efficiency.

In the apparatus of FIG. 16, when the HF concentration in the primary reaction gas at the outlet of the discharge passage 23 with respect to the water vapor concentration in the humidified raw material gas from the humidifier 180 was examined, the result shown in FIG. 17 was obtained.
When the water vapor concentration in the humidified raw material gas was about 4 vol%, the concentration of HF produced was approximately doubled to about 8 vol%. Therefore, it is considered that almost all of the water added by the humidifier 180 was consumed for HF generation. Further, the CF ₄ concentration in the raw material gas from the processing fluid source 1 was 9 vol%, and a high concentration ( ₄ vol% or more) of HF could be obtained with a small amount of CF ₄ input. (By the way, when the inside of the humidifier 180 is at atmospheric pressure and normal temperature, the production concentration of HF is a theoretical limit of 4 vol%, and is usually about 1 to 2 vol%.)

FIG. 18 shows a modification of the fifth embodiment. A temperature controller 181 is incorporated in the humidifier 180. The water temperature inside the humidifier 180 is adjusted by the temperature controller 181.
By increasing the water temperature, the concentration of water vapor added to the raw material gas can be increased. In this aspect, the humidifier 180 does not need to be at low pressure, and may be atmospheric pressure or higher than atmospheric pressure. When the humidifier 180 is at atmospheric pressure, the water temperature is preferably about 30 to 45 ° C. As a result, it is possible to achieve a water vapor addition concentration similar to that in the embodiment of FIG.
It is preferable to provide a temperature controller (not shown) for bringing the inside of the introduction path 10 </ b> B between the humidifier 180 and the valve 10 </ b> Vb to the same temperature as the humidifier 180. Thereby, dew condensation in the introduction path 10B can be prevented.
In the discharge passage 23 of the plasmification means 20, a temperature condition that is stricter than the water condensation condition is required. This is because at the stage where HF starts to be generated and H ₂ O still remains, the dew point increases and condensation of hydrofluoric acid water may occur.
For example, when the dew point of the gas entering the discharge passage 23 is 20 ° C. and the pressure in the discharge passage 23 is 0.2 bar, the temperature in the discharge passage 23 is preferably 30 ° C. or higher.

FIG. 19 shows a sixth embodiment. This embodiment is different from the embodiment of FIG. 18 in that an ejector 190 is used instead of the vacuum pump 31 as the pressurizing means.
The ejector 190 has an injection nozzle 191, a suction port 192, and a lead-out port 193. A driving fluid path 201 extending from the driving fluid source 200 is connected to the base end portion of the ejection nozzle 191. The driving fluid source 200 stores compressed gas such as CO ₂ , Ar, N ₂ , and air as the driving fluid. As the driving fluid, it is preferable to use CO ₂ gas or Ar gas having a large molecular weight.

The primary reaction gas path 11 from the plasmification means 20 is connected to the suction port 192.
A secondary reaction gas path 14 extends from the outlet 193 to the substrate W.

The driving fluid from the driving fluid source 200 is ejected from the ejection nozzle 191 through the driving fluid path 201. Thereby, the nozzle hole periphery of the injection nozzle 191 becomes a low pressure, and the primary reaction gas is sucked into the ejector 190 from the suction port 191. Furthermore, the inside of the discharge passage 23 of the plasmification means 20 can be in a low pressure environment.
The primary reaction gas sucked into the ejector 190 is mixed with the driving fluid, and a secondary reaction gas having an overall pressure equal to or higher than atmospheric pressure is generated. This secondary reaction gas is led out from the outlet 193, led to the substrate W by the secondary reaction gas path 14, and subjected to surface treatment.

An example of specific specifications of the sixth embodiment will be described.
For example, CF ₄ is bubbled by setting the source gas to CF ₄ 50 sccm and setting the H ₂ O to about 56 ° C. in the humidifier 180. This allows addition of the CF ₄ twice the number of moles of _H 2 O (water vapor) can generate the humidified feed gas _{0.2bar (CF 4 + H 2 O} ). This humidified raw material gas is introduced into the plasma generating means 20 to be converted into plasma. As a result, a reaction of the following formula occurs, and a primary reaction gas of 250 sccm containing 50 sccm of CO ₂ and 200 sccm of HF is generated.
CF ₄ + 2H ₂ O → CO ₂ + 4HF Formula (3)
The temperature in the plasmification means 20 is preferably about 80 ° C. As a result, as described below, it is possible to reliably prevent condensation from occurring in the plasmarization means 20.

In the above formula (3), the partial pressure of HF and _{P HF,} the partial pressure of _{H 2} O and _{P H2 O,} the number of initial molecules of CF ₄ and _{N CF4,} and the number of initial molecules of _{H 2} O and _{N H2 O} The ratio of the time variation of the partial pressure of H ₂ O and HF becomes a constant as shown in the following equation.
dP _H2O / dP _HF = − (N _H2O + (1/2) × N _CF4 ) / (N _H2O + N _CF4 ) (4)
In the above example, if N _H2O is 100, _NCF4 is 50.
dP _H2O / dP _HF = −5 / 6 Formula (4a)
It becomes.

FIG. 20 shows the condensation conditions (solid line) for each temperature of HF and H ₂ O and the composition change (two-dot chain line) given by equation (4a). As shown in the figure, condensation occurs when the temperature in the plasmification means 20 is 60 ° C., but condensation does not occur at 70 ° C. or higher. The temperature in the plasmification means 20 is preferably about 80 ° C. in order to reliably prevent condensation.

  As the ejector 190, for example, model ZH05BS (nozzle diameter 0.5 mm) manufactured by SMC Corporation is used. For example, when compressed air of 4.5 bar and 9.2 slm is introduced as a driving fluid from the driving fluid source 200 to the ejector 190 and the suction pressure of the ejector 190 is maintained at 0.2 bar, a suction flow rate of 250 sccm is obtained. Thereby, the primary reaction gas of 250 sccm can be sucked from the plasmification means 20. The HF concentration in the secondary reaction gas obtained by mixing the primary reaction gas and the driving fluid is about 2%. With this HF, the silicon oxide film f on the substrate W can be etched.

FIG. 21 shows another embodiment using an ejector 190 as the pressurizing means. In this embodiment, the humidifier 180 (adding means) is provided not in the raw material introduction path 10 but in the driving fluid path 201. Driving fluid from the driving fluid source 200 is introduced into the humidifier 180 and bubbled into the water. As a result, water (H ₂ O) is added as a reactant to the driving fluid. The driving fluid after the addition of water is ejected from the ejection nozzle 191 of the ejector 190. The drive fluid adiabatically expands due to the injection, and the temperature decreases. As a result, the water in the driving fluid is condensed to form a mist.

The source gas contains CF ₄ and O ₂ . This raw material gas is introduced into the plasmification means 20 to be converted into plasma, and a primary reaction gas containing intermediate substances COF ₂ and F ₂ is generated. The primary reaction gas is sucked into the ejector 190 from the suction port 191 and mixed with the humidified driving fluid. As a result, COF ₂ and F ₂ are dissolved in the H ₂ O mist, and the target substance HF is generated. The secondary reaction gas containing HF is led to the substrate W and subjected to surface treatment.

An example of specific specifications of the seventh embodiment shown in FIG. 21 will be described.
The flow rate of each component of the source gas is CF ₄ 125 sccm and O ₂ 62.5 sccm. Plasmaizing means 20 is brought to a low pressure environment of 0.2 bar by an ejector 190 and maintained at 80 ° C. In the plasma generating means 20, the following reaction occurs.
2CF ₄ + O ₂ → 2COF ₂ + 2F ₂ (5)
As a result, a total of 250 sccm primary reaction gas composed of COF ₂ 125 sccm and F ₂ 125 sccm is generated.

The humidifier 180 is kept at 50 ° C., for example, air is introduced into the humidifier 180 from the driving fluid source 200, and humidified air of 4.5 bar and 9.2 slm is obtained as the driving fluid. The amount of water vapor in the humidified air is 250 sccm, which is equal to the total flow rate of the primary reaction gas (COF ₂ + F ₂ ).

  The ejector conditions are the same as in the specific example of the sixth embodiment. That is, model ZH05BS manufactured by SMC Corporation is used as the ejector 190. A drive fluid of 4.5 bar and 9.2 slm is injected from the injection nozzle 191 of the ejector 190, and the suction pressure is kept at 0.2 bar. Thereby, the primary reaction gas of 250 sccm can be sucked into the ejector 190.

The driving fluid (humidified air) undergoes adiabatic expansion 2.92 times as a result of injection from the injection nozzle 191, and the temperature drops from about 50 ° C. to about −60 ° C. Therefore, most of the moisture in the humidified air is condensed. The primary reaction gases COF ₂ and F ₂ are dissolved in this condensed water (mist), and the following reaction occurs.
COF ₂ + H ₂ O → 2HF + CO ₂ Formula (6)
F ₂ + H ₂ O → 2HF + 1 / 2O ₂ Formula (7)
Thereby, the secondary reaction gas containing HF is produced | generated. The HF concentration in the secondary reaction gas is about twice (4 to 5%) that of the embodiment of FIG. Thereby, the etching efficiency of the silicon oxide film f can be increased.

  FIG. 22 shows a modification of the seventh embodiment shown in FIG. 21, and the driving fluid path 201 is provided with heating means 210 such as a coil heater. The driving fluid is heated by the heating means 210. Thereby, even if the driving fluid injected from the injection nozzle 191 of the ejector 190 adiabatically expands and the temperature is lowered, it is possible to prevent moisture in the driving fluid from freezing.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, the reaction gas may be condensed inside the plasma generating means 20 by cooling the plasma generating means 20 or adding a large amount of H ₂ O into the discharge passage 23.
You may combine the structure of each embodiment. For example, also in the third and fourth embodiments, a cryogenic cooler 91 may be used as a low pressure maintaining unit instead of the vacuum pump 90.
In the second and third embodiments, H ₂ O as a condensing agent (coagulant, reactant) is not limited to water vapor or liquid water, and ice may be used. As the coagulant, an OH group-containing compound such as alcohol may be used instead of H ₂ O, and other hydrogen-containing compounds may be used.
Instead of the tube pump 100, a diaphragm pump, a reciprocating pump, or the like may be used as the liquid pressurizing means. The diaphragm of the diaphragm pump is preferably made of an elastic material having high corrosion resistance such as Teflon (registered trademark). A reciprocating pump or the like may be used as the liquid pressurizing means.
The primary reaction gas may be solidified by cooling or pressurization of the aggregate generation means 60X or addition of a coagulant to obtain a solid aggregate. A solid aggregate may be generated from the primary reaction gas via a reaction liquid (liquid aggregate), and a solid aggregate may be generated by sublimation of the primary reaction gas. Also good.
In the fourth embodiment, H ₂ O as a reactant is not limited to water vapor or liquid water, and ice may be used. As a reactive agent, an OH group-containing compound such as alcohol may be used instead of H ₂ O, and other hydrogen-containing compounds may be used. The reactant may be introduced into the outer passage 164 and the primary reaction gas may be introduced into the inner passage 165. The flow of the outer passage 164 and the flow of the inner passage 165 may be opposed to each other.
In the second to fourth embodiments, the connection position of the ozone introduction system 50 is replaced with the secondary reaction gas path 14, the pressurized reaction liquid path 13, the intermediate gas path 13 </ b> A, the low pressure reaction liquid path 12, and the primary reaction gas path. 11 or the like, and these processing fluid supply lines 11 to 14 may be supplied to the substrate W separately.
The internal pressure of at least the interelectrode space 23 of the plasmification means 20 may be low with respect to the pressure of the arrangement environment of the workpiece W. The arrangement environment of the workpiece W is not limited to substantially atmospheric pressure, and may be lower than substantially atmospheric pressure (in this case, the interelectrode space 23 is further reduced in pressure), or may be higher than substantially atmospheric pressure. The arrangement environment of the workpiece W may be set to a pressure higher than approximately atmospheric pressure, and the interelectrode space 23 may be set to approximately atmospheric pressure.
A blowing means (secondary reaction gas pressurizing means) is provided in the secondary reaction gas passage 14, and the upstream side of the blowing means is set to a pressure lower than the environment in which the workpiece W is disposed, and the secondary reaction gas is treated by the blowing means. You may decide to pressurize more than W arrangement | positioning environment and to supply blast to a to-be-processed object.
A water addition means may be connected to the secondary reaction gas path 14 to adjust the humidity of the secondary reaction gas. Thereby, a condensed phase can be reliably formed on the substrate surface, and an etching reaction can be reliably caused.
The starting material contained in the source gas is not limited to CF ₄ but may be other fluorocarbons such as CHF ₃ and C ₂ F ₆ , other halogen-containing compounds, and a mixture of a plurality of types of halogen-containing compounds. There may be.
In the fifth embodiment, alcohol (OH group-containing compound) may be used as the reactant instead of water (H ₂ O). Furthermore, instead of water or alcohol, other hydrogen-containing compounds such as hydrocarbons such as methane (CH ₄ ) or hydrogen gas (H ₂ ) may be used as the reactant.
Needless to say, the set values such as pressure, flow rate, concentration, and the like of this embodiment are examples, and the present invention is not limited thereto.
The present invention is applicable to various plasma surface treatments such as etching, ashing, film formation, cleaning, and surface modification.

  The present invention can be used for manufacturing a semiconductor substrate and a flat panel display (FPD), for example.

1 is a schematic configuration diagram of a surface treatment apparatus according to a first embodiment of the present invention. The raw material gas _{CF 4: H 2 O = 98} : 2 and the case is a graph showing an example of a production flow of HF and COF ₂ per unit electric power to the pressure of the plasma unit. It is a schematic block diagram which shows the modification of 1st Embodiment. It is a schematic block diagram of the surface treatment apparatus which concerns on 2nd Embodiment of this invention. The raw material gas _{CF 4:} O 2 = _3: 2 and the case is a graph showing a generation rate of COF ₂ per unit electric power to the pressure of the plasma unit. It is a pressure composition figure of hydrofluoric acid water (HF aqueous solution) in -30 ° C. It is a schematic block diagram which shows the modification of 2nd Embodiment. It is a schematic block diagram of the surface treatment apparatus which concerns on 3rd Embodiment of this invention. It is a graph which shows the component change of the gaseous phase in the vaporizer | carburetor of 3rd Embodiment, and a liquid phase. It is a schematic block diagram which shows the modification of the vaporizer | carburetor of 3rd Embodiment. It is a schematic block diagram which shows the modification of the condenser of 3rd Embodiment. It is a schematic block diagram of the surface treatment apparatus which concerns on 4th Embodiment of this invention. It is a graph which shows the component change of the gaseous phase in a reactor (reaction temperature: 30 degreeC) of 4th Embodiment, and a liquid phase. In FIG. 13, it is a graph which shows the component change of a gaseous phase when a reaction temperature is 0 degreeC, and a liquid phase. It is a schematic block diagram which shows the deformation | transformation aspect of a plasma-izing means. It is a schematic block diagram of the surface treatment apparatus which concerns on 5th Embodiment of this invention. It is a graph which shows the experimental result of the density | concentration of HF produced | generated by the plasma-izing means with respect to the density | concentration of the water vapor | steam added with the humidifier in the apparatus of FIG. It is a schematic block diagram which shows the modification of 5th Embodiment. It is a schematic block diagram of the surface treatment apparatus which concerns on 6th Embodiment of this invention. HF and H _{2 O} condensation conditions (solid line) and the composition change is a graph showing a (two-dot chain line). It is a schematic block diagram of the surface treatment apparatus which concerns on 7th Embodiment of this invention. It is a schematic block diagram of the surface treatment apparatus which concerns on the modification of 7th Embodiment.

Explanation of symbols

M Surface treatment equipment W Glass substrate (object to be treated)
DESCRIPTION OF SYMBOLS 1 Processing fluid source 2 Power supply 11 Primary reaction gas path 12 Low pressure reaction liquid path (low pressure condensate flow path)
13 Pressurized reaction channel (condensate channel after pressurization)
14 Secondary reaction gas path 15 Non-condensable gas path (non-condensing gas path, non-condensing component path)
16 Low-pressure maintenance path 17 Degassing liquid path (devaporized body returning means, degassed component returning means)
20 Plasmaizing means 21 Depressurizing chamber 22 Electrode 23 Discharge passage 30 Plasmaizing post-processing means 31 Vacuum pump (pressurizing means)
40 Supply nozzle (supply unit)
50 Ozone introduction system 60, 60A condenser (condensing means (condensing means))
60X reaction liquid generating means (condensate generating means)
62 Condensation tube (condensation path)
65 Cooler 66 Cooling pipe (cooler)
70 Water vapor addition means (coagulant addition means, reactant addition means)
70A Water addition means (coagulant addition means)
80 Unnecessary substance removal unit 90 Vacuum pump for pressure reduction (low pressure maintenance means)
91 Cryogenic cooler (low pressure maintenance means)
100 Tube pump (liquid pressurizing means)
110 Vaporizer (vaporizer, secondary reaction gas generator)
115 Heater 120 Carrier Gas Introduction System 130 Vaporizer 140 Condenser 150 Particle Removal Filter 160 Reactor 161 Outer Tube (Reactor Body)
162 Inner pipe 163 Fine hole 164 Outer passage 165 Inner passage 166 Temperature controller 170 Water vapor addition means (reactant addition means)
180 Humidifier (reactant addition means)
190 Ejector 200 Driving fluid source 210 Driving fluid heating means

Claims (37)

A method of processing the surface of an object to be processed using plasma,
A plasma forming step of converting the processing fluid into plasma in an environment at a pressure lower than the environment in which the workpiece is disposed;
A post-plasma treatment step of pressurizing the post-plasma treatment fluid and bringing it into contact with the workpiece;
A surface treatment method comprising:   The post-plasmaization treatment step condenses or solidifies the plasma-treated treatment fluid and pressurizes it to obtain a high-pressure condensate from the low-pressure environment, and a vaporization step vaporizes the condensate. The surface treatment method according to claim 1, further comprising:   3. The surface treatment method according to claim 2, wherein, in the aggregate generation step, the plasma-treated processing fluid reacts with the reaction fluid to contact the reactant capable of generating the aggregate.   4. The surface treatment method according to claim 2, wherein uncondensed components that have not condensed or solidified in the aggregate generation step in the plasma-treated processing fluid are returned to the plasmaization step. 5.   The surface treatment method according to any one of claims 2 to 4, wherein the vaporized component that has not been vaporized in the vaporization step of the aggregate is returned to the aggregate generation step. The processing fluid before plasma formation includes a starting material that can be changed into a target material having reactivity with the object to be processed by the plasma formation step or the aggregate generation step,
6. The surface treatment according to claim 5, wherein in the vaporization step, the aggregate is separated into a vaporized component in which the target substance is concentrated and an invaporized component in which the target substance is diluted. Method. The pre-plasmaization treatment fluid includes a starting material that can be converted into an intermediate material by the plasmatization step;
2. The addition step of adding a reactive agent capable of reacting with the intermediate substance to generate a target substance before or after pressurization in the post-plasma treatment step is added to the processing fluid. 7. The surface treatment method according to any one of 6 above.   2. The ejector for sucking in the processing fluid after being converted to plasma and ejecting it to the object to be processed by jetting the driving fluid is prepared, and the suction of the ejector forms the low-pressure environment. Surface treatment method. The pre-plasmaization treatment fluid includes a starting material that can be converted into an intermediate material by the plasmatization step;
9. The surface according to claim 8, wherein the jetting is performed after adding a changeable reactant to a target substance that reacts with the intermediate substance and reacts with the workpiece to the driving fluid. Processing method.   The surface treatment method according to claim 9, wherein the driving fluid is heated. The surface treatment method according to claim 8, wherein the driving fluid contains CO ₂ gas or Ar gas as a main component. Before the plasma step, perform an addition step of adding a reactant to the processing fluid,
The surface according to any one of claims 1 to 11, wherein the pre-plasmaization treatment fluid includes a starting material that can be converted into a target substance by reacting with a component of the reactant by plasmatization. Processing method.   The surface treatment method according to claim 12, wherein the adding step is performed under a lower pressure than an arrangement environment of the object to be treated.   The surface treatment method according to claim 13, wherein the reactant is a hydrogen-containing compound. The surface treatment method according to any one of claims 3,7,9,12～14 said reactant, characterized in that it is a _{H 2} O or OH-containing compounds.   The surface treatment method according to any one of claims 1 to 15, wherein the treatment fluid before the plasma treatment includes one or a plurality of halogen-containing compounds as a starting material. The surface treatment method according to claim 16, wherein the halogen-containing compound is one or more selected from the group consisting of CF ₄ , CHF ₃ , and C ₂ F ₆ .   The surface treatment method according to any one of claims 1 to 17, wherein the pressure of the environment in which the object is disposed is substantially atmospheric pressure. An apparatus for processing the surface of an object to be processed using plasma,
Including a pair of electrodes between which the pressure environment is lower than the environment in which the object to be processed is disposed, and plasmaizing means for converting the processing fluid into plasma between the electrodes;
Post-plasma treatment means for pressurizing the post-plasma treatment fluid and supplying it to the object to be treated;
A surface treatment apparatus comprising:   The post-plasmaization processing means condenses or solidifies the plasma-processed processing fluid and pressurizes it to obtain a high-pressure condensate from the low-pressure environment, and a vaporization means for vaporizing the condensate. The surface treatment apparatus according to claim 19, further comprising:   21. Reactant adding means for adding a reactant capable of generating the aggregate by reacting with the processing fluid after being plasmatized is connected to the aggregate generating means. Surface treatment equipment.   The non-condensed component path that conveys the non-condensed component that has not condensed or solidified among the processing fluid after the plasma treatment extends from the aggregate generating unit and is connected to the plasma generating unit. The surface treatment apparatus according to any one of 20 and 21.   The surface treatment apparatus according to claim 22, wherein an unnecessary substance removing unit that removes unnecessary substances from the non-condensed components is interposed in the non-condensed component path.   24. The low pressure maintaining path is branched from the non-condensing component path, and the low pressure maintaining path is provided with low pressure maintaining means for maintaining the plasmarization means in the low pressure environment. Surface treatment equipment.   25. The vaporization means is connected to a vaporization component return means for returning the vaporized component that has not been vaporized in the aggregate to the aggregate generation means. The surface treatment apparatus according to item. The pre-plasmaization treatment fluid includes a starting material that can be converted into an intermediate material by plasmatization,
The post-plasmaization processing means pressurizes the plasma-processed processing fluid, and a reactor in contact with a reactant capable of reacting the pressurized processing fluid with the intermediate substance to generate a target substance The surface treatment apparatus according to claim 19, comprising:   The post-plasmaization processing means includes, as pressurizing means for pressurizing the post-plasmaization processing fluid, an ejector that sucks in the processing fluid after plasmaization by jetting a driving fluid and guides it to the object to be processed. The surface treatment apparatus according to claim 19. The pre-plasmaization treatment fluid includes a starting material that can be converted into an intermediate material by the plasmatization step;
The addition means for adding a reactive agent that reacts with the intermediate substance to the driving fluid and that can change the target substance having reactivity with the object to be processed is further provided. Surface treatment equipment.   The surface treatment apparatus according to claim 28, further comprising a heating unit that heats the driving fluid. It said driving fluid is a surface treatment apparatus according to any one of claims 27 to 29, characterized in that it comprises a CO ₂ gas or Ar gas as a main component. An addition means for adding a reactant to the processing fluid before the plasma treatment is further provided,
The surface treatment apparatus according to claim 19, wherein the treatment fluid before the plasma treatment includes a starting material that can be changed into a target material by reacting with a component of the reactant by the plasma treatment.   32. The surface treatment apparatus according to claim 31, wherein the addition means performs the addition under a lower pressure than an environment in which the workpiece is disposed.   The surface treatment apparatus according to claim 32, wherein the reactant is a hydrogen-containing compound. The reactant, a surface treatment apparatus according to any one of claims 21,26,28,29,31～33, characterized in that the _{H 2} O or OH-containing compounds.   The surface treatment apparatus according to any one of claims 19 to 34, wherein the treatment fluid before plasma formation includes one or a plurality of halogen-containing compounds as a starting material. The halogen-containing _compound, CF _4, CHF _3, a surface treatment apparatus according to claim 35, characterized in that from the group consisting of C 2 _{F 6} is one or more selected.   The surface treatment apparatus according to any one of claims 19 to 36, wherein the pressure of the environment in which the object is disposed is substantially atmospheric pressure.

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