JP4111186B2 - Ion irradiation equipment - Google Patents

Description

  The present invention relates to an ion irradiation apparatus for irradiating ions to an ion irradiation target article, and in particular, an electron emitted from an electron source using a filament that emits thermoelectrons by resistance heating by energization is introduced into the vacuum chamber. The present invention relates to an ion irradiation apparatus that generates plasma by colliding with a gas and irradiates an ion irradiation target article with ions in the plasma.

  In general, processes such as film formation, ion implantation, and surface modification on articles such as machine parts, tools, and automobile parts are often performed in a vacuum chamber. A series of processes for such treatment often involves cleaning the surface of the article, moderately roughening the article surface, or increasing the surface temperature of the article.

  For example, in the film formation process, before film formation, in order to improve the adhesion between the article and the film formed thereon, dirt or dust adhering to the article surface is removed, It has been practiced to increase the contact area between the article and the film by making the surface moderately roughened, or to increase the surface temperature of the article to diffuse the film to the article side.

  These include, for example, a gas in which electrons emitted from an electron source using a filament that emits thermoelectrons by resistance heating by energization from a filament power source are introduced into the vacuum chamber (for example, an inert gas such as argon gas). It is performed using an ion irradiation apparatus that collides with an active gas) to generate a plasma and irradiates an ion irradiation target article with ions in the plasma.

  In this type of conventional ion irradiation apparatus, the filament constituting the electron source is arranged at one corner of the vacuum chamber, or at a place where it is too far from the ion irradiation target portion of the article, so that the ion irradiation of the article is performed. In many cases, uniform ion irradiation to the entire target portion was impossible. As a result, for example, problems such as insufficient adhesion of a film formed in subsequent film formation on an article often occur.

  Therefore, in order to solve such a problem, Japanese Patent Laid-Open No. 2000-336492 uses an electron source over a long range in a vacuum chamber, or is long in the longitudinal direction of the article so as to face the ion irradiation object article. An improved ion irradiation apparatus employing an electron source is disclosed.

  An example of such an improved ion irradiation apparatus is shown in FIG. FIG. 11 (B) is a diagram showing the positional relationship between the ion irradiation target article W and the filament 2 to be described later, as viewed from the right side in FIG. 11 (A).

An ion irradiation apparatus shown in FIG. 11A includes a vacuum chamber 1, a filament 2 constituting an electron source disposed in the chamber, an article holder 3 installed in the chamber, and the like.
The vacuum chamber 1 can maintain the reduced pressure inside the chamber at a predetermined ion irradiation pressure by exhausting from the exhaust port 11 by an exhaust device (not shown), and a gas for generating irradiation ions from the gas introduction port 12. An inert gas such as argon gas can be introduced into the chamber.

  In this example, the ion irradiation target article W has a cylindrical shape and is supported vertically by the holder 3. The holder 3 can be rotationally driven by a rotational driving device (not shown), and thereby the article W can be rotated during ion irradiation. The filament 2 is supported by the upper and lower terminal blocks 21 and 22, is linearly stretched between the two terminal blocks in the vertical direction, extends in the longitudinal direction of the article W (rotation center line direction), and faces the entire article W. is doing.

  In the ion irradiation, gas (for example, argon gas) is introduced from the gas introduction port 12 while maintaining the inside of the vacuum chamber 1 at a predetermined pressure, and a current is supplied from the power source PW1 to the filament 2 to thereby resistance-heat the filament. While the thermoelectrons are emitted, a voltage is applied to the chamber 1 from the discharge power source PW2 so as to have a higher potential than the filament 2, thereby extracting the thermoelectrons from the filament 2, generating a DC discharge and introducing the thermoelectrons. The plasma is generated by colliding with the gas, and ions in the plasma are irradiated from the bias power source PW3 to the article W to which a negative bias voltage is applied.

  In addition to the above, although not a conventional example, the present inventor can also illustrate the apparatus of FIG. 12 as an improved ion irradiation apparatus. The ion irradiation apparatus of FIG. 12 is the ion irradiation apparatus shown in FIG. 11 (A). Instead of one long filament 2, a plurality of filaments 2 ′ are discontinuous in a plurality of stages along the longitudinal direction of the article W. The filament power supply PW1 'is connected to each filament 2'. Each filament 2 ′ is stretched linearly between the terminal blocks 21 ′ and 22 ′ and extends in a direction perpendicular to the longitudinal direction of the article W. Other points are the same as those of the ion irradiation apparatus of FIG.

  Both of the ion irradiation apparatuses shown in FIGS. 11A and 12 are arranged such that the filament constituting the electron source is arranged at one corner of the vacuum chamber or is too far from the ion irradiation target portion of the article. Compared with the ion irradiation apparatus made, it is possible to uniformly irradiate the entire ion irradiation target portion of the article.

JP 2000-336492 A

  However, in the ion irradiation apparatus disclosed in Japanese Patent Laid-Open No. 2000-336492 or the ion irradiation apparatus shown in FIG. As shown in A), when a DC power source is used as a power source for heating the filament (filament power source), the filament becomes too long, so that the voltage applied to the filament for resistance heating becomes too large. The potential difference between the negative potential side and the vacuum chamber becomes too large, and the filament is vigorously sputtered from the plasma generated in the vacuum chamber, so that the filament is consumed violently and cuts in a short time.

  If the output voltage of the discharge power supply is lowered or the polarity of the filament power supply is reversed in order to solve this problem, the potential difference between the positive potential side of the filament and the vacuum chamber becomes too small to sufficiently extract thermoelectrons. . As a result, the density of the plasma generated in the vicinity of the positive potential side of the filament becomes extremely low, and it becomes difficult to perform uniform ion irradiation on the ion irradiation target article as a whole. As a result, for example, in the subsequent film forming process, there is a problem that a film portion formed in a region where the ion irradiation amount is small cannot obtain a sufficient adhesion force to the article body.

  Using the ion irradiation apparatus of FIG. 11 (A), an experiment was conducted in which the surface of the article was cleaned by etching while rotating a cylindrical article W made of stainless steel having a diameter of 150 mm and a length of 600 mm three times per minute. . The position dependency of the etching amount on the article at this time is shown by a line connecting white circles (◯) in FIG.

The ion irradiation conditions in this experiment were as follows.
Argon gas introduction amount: 100 sccm,
Pressure inside chamber in ion irradiation: 0.7 Pa,
Filament size and number: one filament having a diameter of 1.0 mm and a length of 600 mm Filament voltage and current: voltage 36 V, current 60 A,
Discharge voltage and current: voltage 30V, current 31A,
Bias voltage and current to the article W: voltage −500V, current 9A,
Treatment time: 60 minutes.

As shown in FIG. 2, the etching is performed by about 0.5 μm from the upper end to the vicinity of the center of the article W, but it can be seen that the etching amount is greatly reduced from the vicinity of the center to the lower end. This indicates that the density of the plasma generated in the vicinity of the positive potential side of the filament is extremely low, and the article W is not uniformly irradiated with ions as a whole.
Moreover, when the apparatus was operated under the same experimental conditions but without limiting the processing time, the filament life was as short as about 10 hours.

  Even if the filament is simply stretched for a long time, or as described in Japanese Patent Application Laid-Open No. 2000-336492, the electrons drawn from the filament are induced by the filament itself. As a result, it becomes difficult to generate a high-density plasma, and as a result, the amount of ion irradiation on the ion irradiation target article decreases, and the ion irradiation processing takes a long time. There is also a problem.

  As described in Japanese Patent Application Laid-Open No. 2000-336492, for example, in the apparatus shown in FIG. 11A, when an AC power supply is adopted as a filament power supply instead of a DC power supply and an AC current is passed through the filament, the article W The ion irradiation is made more uniform than when a DC power supply is used, but even in that case, electrons extracted from the filament are trapped by the magnetic field induced by the filament itself, so that a high-density plasma is generated. Is difficult, and it takes a long time for the ion irradiation treatment.

  In order to solve this problem, if the current flowing through the filament is increased to extract more thermoelectrons, the filament's operating temperature (the temperature at which it is heated to release the thermoelectrons) becomes too high, and the filament evaporates violently. Moreover, the sputtering rate when receiving sputtering increases, and as a result, the filament breaks in a short time.

  In the ion irradiation apparatus shown in FIG. 12, since the filament 2 ′ group is arranged in parallel in a plurality of stages so as to face the article W as a whole, the entire article W can be uniformly irradiated with ions. Since the length of each filament 2 'is shorter than that in the case of the apparatus of 11 (A), it can be heated by applying a low voltage to emit electrons as compared with the case of using a single long filament. Is less consumed.

  However, since electrons extracted from the filament are trapped by the magnetic field induced by the filament itself, it is difficult to generate a dense plasma. To solve this problem, the current flowing through the filament is increased. When trying to extract a large number of thermionic electrons, the operating temperature of the filament becomes too high, the evaporation of the filament becomes intense, and the sputtering rate when receiving sputtering increases, resulting in the filament breaking in a short time. There is a problem.

Even when the ion irradiation apparatus shown in FIG. 12 was operated under the following conditions close to the experimental conditions in the apparatus of FIG. 11A, the filament life was as short as about 10 hours.
In this case, the experimental conditions with the apparatus of FIG.
For article W, the same conditions as above,
Argon gas introduction amount: 100 sccm,
Pressure inside chamber in ion irradiation: 0.7 Pa,
Filament size and number: three filaments with a diameter of 1.0 mm and a length of 200 mm, each filament voltage and current: voltage 12V, current 60A,
Discharge voltage and current: voltage 40V, current 31A,
Bias voltage and current to article W: Voltage -500V, current 9A.

  The above problem is not only when the electron source is the filament itself, but by drawing currents through the filament and drawing the thermoelectrons, and causing the thermoelectrons to collide with the thermoelectron emission member and / or the secondary electron emission member separately. Then, thermionic electrons and / or secondary electrons are extracted, and thermionic electrons are extracted by passing an electric current through the filament, and the thermoelectrons are introduced into a preliminary plasma chamber separated from the vacuum chamber. This also occurs in the case of an electron source of a type in which preliminary plasma is generated by colliding with gas and electrons are extracted from the preliminary plasma.

  Therefore, in the present invention, in the vacuum chamber, electrons emitted from an electron source using a filament that emits thermoelectrons by resistance heating by energization from a filament power source are collided with a gas introduced into the vacuum chamber to generate plasma, An ion irradiation apparatus for irradiating an ion irradiation target article with ions in the plasma, the ion irradiation target portion of the ion irradiation target article being subjected to an ion irradiation treatment uniformly over the whole and without requiring a long time. It is an object of the present invention to provide a long-life ion irradiation apparatus that can be applied.

In order to solve the above problems, the present invention provides the following first and second ion irradiation apparatuses.
(1) 1st ion irradiation apparatus In a vacuum chamber, the electron emitted from the electron source using the filament which discharge | releases a thermoelectron by the resistance heating by the electricity supply from a filament power supply is made to collide with the introduction gas in a vacuum chamber, and plasma The ion irradiation apparatus irradiates the ion irradiation target article with ions in the plasma, and is capable of rotating around a predetermined rotation center line while supporting the ion irradiation target article in the vacuum chamber. An article holder is provided, and the electron source is provided extending in the direction of the rotation center line of the article holder so as to be able to face the ion irradiation target portion of the ion irradiation target article supported by the article holder. The filament in the electron source extends in the direction of the article holder rotation center line over the entire direction of the article holder rotation center line of the electron source. The filaments of the plurality of stages are bent and arranged so as to include at least one pair of opposing portions that are parallel or substantially parallel to each other so that currents in opposite directions flow. The ion irradiation apparatus in which the opposed portions that are parallel or substantially parallel to each other are close to each other so that the magnetic fields generated by the currents that flow in opposite directions to the opposed portions cancel each other.

(2) Second ion irradiation device
In the vacuum chamber , electrons emitted from an electron source using a filament that emits thermoelectrons by resistance heating by energization from a filament power source collide with the introduced gas in the vacuum chamber to generate plasma, and ions in the plasma An ion irradiation apparatus that irradiates an ion irradiation target article, and an article holder that supports the ion irradiation target article and is rotatable around a predetermined rotation center line in the vacuum chamber. The electron source is provided so as to extend in the rotation center line direction of the article holder so as to face the ion irradiation target portion of the ion irradiation target article supported by the article holder. filaments, discontinuously distributed parallel in a plurality of stages in said article holder rotation center line direction throughout the object holder rotation center line direction of the electron source The at least one set of adjacent filaments of the plurality of stages of filaments includes at least one opposing portion that is parallel or substantially parallel to each other and in which currents flowing in opposite directions flow. An ion irradiation apparatus in which an opposing part parallel to or substantially parallel to is approached so that magnetic fields generated by currents flowing in opposite directions to the opposing part cancel each other.

In the first and second ion irradiation apparatuses, the “introduced gas in the vacuum chamber” is introduced into the vacuum chamber, and is converted into plasma by the collision of electrons emitted from the electron source, thereby to the ion irradiation target article. It is a gas that generates ions for irradiation .
In addition, “magnetic field cancels” includes not only the case where the magnetic field completely cancels but also the case where the magnetic field can be considered to cancel each other.

In either of the first and second ion irradiation apparatuses, the filaments in the electron source are discontinuously distributed and arranged in a plurality of stages in the article holder rotation center line direction throughout the electron holder article rotation center line direction. Therefore, the electrons can be uniformly emitted from the whole or almost the whole of the electron source, and the electron source can face the ion irradiation target portion of the ion irradiation target article supported by the article holder. Is provided so as to extend in the direction of the rotation center line of the article holder, so that when the electrons emitted from the electron source collide with the introduced gas in the vacuum chamber to form plasma, the plasma is ionized by the article. It is generated so as to uniformly face the entire irradiation target portion, and thus the ion irradiation target portion can be irradiated with ions uniformly from the plasma. Kill.

  In addition, each of a plurality of filaments that are discontinuously arranged in parallel in a plurality of stages is a single piece that is continuously stretched long so as to face the ion irradiation target portion of the article as in the past. Compared with other filaments, the applied voltage for thermionic emission by resistance heating can be reduced for each filament, and the consumption of the filament due to evaporation of the filament and sputtering from the plasma is suppressed. Thus, the lifetime of the ion irradiation apparatus can be extended.

Furthermore, in the first ion irradiation apparatus, each of the plurality of stages of filaments in the electron source is bent and arranged so as to include at least one pair of facing portions facing each other in parallel or substantially in parallel so that currents in opposite directions flow. The opposing portions that are parallel or substantially parallel to each other are close to each other so that the magnetic fields generated by the currents flowing in the opposite directions to the opposing portions cancel each other. Therefore, even if the filament power supply for energizing the filament is a direct current power supply, the current flowing in one of the parallel or substantially parallel portions and the current flowing in the other are in opposite directions, whereby current flows in these portions. The magnetic fields formed by the flow of each other cancel each other, and the thermoelectrons generated from these portions can be sufficiently drawn out while being trapped in the magnetic field. Therefore, even if the voltage applied to the filament is lowered so as to suppress filament consumption, the plasma for obtaining the irradiation ions can be formed at a high density, and therefore, the predetermined voltage can be obtained without taking a long time. The ion irradiation treatment can be efficiently applied to the article with the ion irradiation amount of.

  As a result, the ion irradiation target portion of the ion irradiation target article can be uniformly and entirely subjected to ion irradiation treatment without requiring a long time, and the life of the filament and thus the ion irradiation apparatus can be extended. .

In the first ion irradiation apparatus, when a DC power source is adopted as a filament power source that energizes a filament that is bent and arranged so as to include mutually parallel or substantially parallel opposing portions that are close to each other, What is necessary is just to position the substantially parallel opposing part near the negative polarity side edge part of a filament . By doing so, the discharge voltage can be effectively applied to the mutually parallel or substantially parallel facing portions that are close to each other, so that sufficient hot electrons can be drawn out.

  In the second ion irradiation apparatus, at least one pair of adjacent filaments among the plurality of stages of filaments in the electron source has at least one opposing portion parallel to or substantially parallel to each other, in which currents flowing in opposite directions flow. The opposed portions parallel or substantially parallel to each other are close to each other so that the magnetic fields generated by the currents flowing in the opposite directions to the opposed portions cancel each other.

Therefore, as such a filament power source for energizing adjacent filaments, a direct current power source that applies currents in opposite directions to mutually parallel or substantially parallel opposing portions can be adopted. The formed magnetic fields cancel each other, so that the thermoelectrons generated from the opposed portions can be sufficiently extracted in a state where trapping by the magnetic fields is suppressed. Therefore, even if the voltage applied to the filament is lowered so as to suppress filament consumption, the plasma for obtaining the irradiation ions can be formed with a high density, and thus without taking a long time, The article can be efficiently subjected to ion irradiation treatment with a predetermined ion irradiation amount.

When a DC power source is adopted as a filament power source for adjacent filaments arranged so as to include mutually parallel or substantially parallel facing portions that are close to each other, the mutually parallel or substantially parallel facing portions that are close to each other are What is necessary is just to be located near the negative polarity side edge part of those filaments . By doing so, it is possible to draw out the thermoelectrons sufficiently by causing the discharge voltage to effectively act on the mutually parallel or substantially parallel facing portions.

In the first ion irradiation apparatus, at least one pair of adjacent filaments among the plurality of stages of filaments includes at least one opposing portion that is parallel or substantially parallel to each other and in which currents in opposite directions flow. Also good. The opposing portions which are parallel or substantially parallel to each other are brought close to each other so that the magnetic fields generated by the currents flowing in the opposite directions to the opposing portions cancel each other. That is, a Filament that so adjacent, one another may be contaminated with a bent arranged filaments to include a parallel or substantially parallel to the facing portion in a filament.

Further, in the second ion irradiation apparatus, at least one pair of adjacent filaments in a plurality of stages includes at least one opposing portion that is parallel or substantially parallel to each other and in which currents in opposite directions flow. And the opposing portions that are parallel or substantially parallel to each other may be close to each other so that the magnetic fields generated by the currents that flow in opposite directions to the opposing portions cancel each other. There may be two or more sets of filaments, or only such sets of filaments.
Further, at least one stage of the filaments is bent so as to include at least one pair of opposing portions that are parallel or substantially parallel to each other so that currents in opposite directions flow, and the opposing portions that are parallel or substantially parallel to each other. May be close to each other so that the magnetic fields generated by the currents flowing in opposite directions to the opposing portions cancel each other. That is, the filaments arranged in such a manner may be mixed with adjacent filaments that form a pair so as to include mutually parallel or substantially parallel facing portions that are close to each other.

In both the first and second ion irradiation apparatuses, the following (1) to (3) can be exemplified as the mode of the electron source.
(1) An electron source using thermoelectrons emitted from the filament by resistance heating by energizing the filament as electrons to be emitted from the electron source to collide with the introduced gas in the vacuum chamber and generate the plasma.

(2) A thermoelectron emitting member that emits thermoelectrons by collision of thermoelectrons emitted from the filament by resistance heating by energization of the filament, and thermoelectrons emitted from the filament by resistance heating by energization of the filament At least one of secondary electron emitting members that emit secondary electrons upon collision of the electron beam, and as electrons to be emitted from the electron source to collide with the gas introduced into the vacuum chamber and generate the plasma, An electron source using electrons emitted from a thermionic emission member and / or a secondary electron emission member.
In the case of this electron source, the thermionic emission member and the secondary electron emission member may be provided for each of the plurality of stages of filaments, or one common element is provided for the plurality of stages of fillants. Alternatively, a predetermined number of filaments of a plurality of stages may be provided in common, and in short, provided so that electrons can be uniformly emitted from the entire electron source or substantially the entire electron source. That's fine.
The thermal electron emission member may have a function of a secondary electron emission member. Alternatively, the secondary electron emission member may have a function of a thermionic emission member.

(3) including a preliminary plasma chamber, generating a preliminary plasma by colliding thermal electrons emitted from the filament with a gas introduced into the preliminary plasma chamber by resistance heating by energizing the filament, and generating the vacuum An electron source using electrons emitted from plasma generated in the preliminary plasma chamber as electrons to be emitted from the electron source in order to collide with a gas introduced into a chamber and generate the plasma.
In the case of this electron source, a preliminary plasma chamber may be provided for each of a plurality of stages of filaments, a common one for a plurality of stages of fillants, or a plurality of stages. Of these filaments, a common one may be provided for each predetermined number of groups, and in short, it is sufficient that the filaments are provided so that electrons can be uniformly emitted from the whole or substantially the whole of the electron source.

  In any of the above-described ion irradiation apparatuses, at least one stage among the plurality of stages of filaments is used in order to form plasma for obtaining irradiation ions at a higher density so that ion irradiation can be performed more efficiently. A magnetic field forming means (permanent magnet, electromagnet, combination thereof, or the like) that cancels at least a part of the magnetic field induced by the current flowing through the filament may be provided.

  In any ion irradiation system, it is possible to measure the spatial distribution of plasma and the amount of ion current, and individually control the amount and energy of electrons extracted from the electron source or the amount and energy of electrons extracted from the filament. By controlling the amount and energy of electrons extracted from thermionic emission member, secondary electron emission member, preliminary plasma, etc., it is possible to control the uniformity of plasma and the uniformity of ions irradiated to articles. Also good.

For example, an ion current distribution measuring device that measures a spatial distribution of ion current based on ions irradiated on the ion irradiation target article, and an ion current distribution based on the ion current distribution measured by the ion current distribution measuring device. You may provide the control apparatus which controls the said filament power supply output so that it may equalize | homogenize with respect to the whole ion irradiation object part of articles | goods.
Further, for example, a plasma distribution measuring device that measures the spatial distribution of plasma formed by collision of electrons emitted from the electron source with the gas introduced into the vacuum chamber, and a plasma distribution measured by the plasma distribution measuring device. Based on this, a controller for controlling the filament power output may be provided so as to make the plasma distribution uniform over the entire ion irradiation target portion of the article.
An example of such a plasma distribution measuring apparatus is one that measures the plasma distribution by monitoring the discharge current shared by each filament. This is based on the fact that the plasma density usually increases with the discharge current, and the plasma density can be substantially monitored by monitoring the discharge current. When monitoring the discharge current in this way, the plasma distribution measuring apparatus includes a discharge current measuring device that monitors the discharge current shared by each filament. And the control apparatus which controls a filament power supply output controls each filament power supply output based on the discharge current monitored with this discharge current measuring device.

  As described above, according to the present invention, in the vacuum chamber, electrons emitted from an electron source using a filament that emits thermoelectrons by resistance heating by energization from a filament power source are caused to collide with a gas introduced into the vacuum chamber. An ion irradiation apparatus that generates plasma and irradiates an ion irradiation target article with ions in the plasma, and the ion irradiation target portion of the ion irradiation target article is entirely uniform and requires a long time. Thus, it is possible to provide an ion irradiation apparatus having a long lifetime that can be subjected to ion irradiation treatment without any problem.

Embodiments of the present invention will be described below with reference to the drawings.
In the following description, “the magnetic field cancels” includes not only the case where the magnetic field cancels completely but also the case where it is safe to assume that the magnetic fields cancel each other.
1 (A) is shows an example of ion-irradiation device. An ion irradiation apparatus A in FIG. 1A employs three filaments 2a, 2a ′, 2a ″ instead of the filament 2 in the ion irradiation apparatus shown in FIG. The filaments are discontinuously arranged in three steps in the vertical direction, and each filament is stretched between the terminal blocks 21a and 22a arranged in the horizontal direction with respect to the longitudinal direction of the ion irradiation target article W. The positional relationship between each filament and the ion irradiation target article W is as shown in FIG.

  Each filament is energized from a DC filament power supply PWa provided for each filament, and these filaments and the like constitute an electron source 20A.

  As shown in FIG. 1C, the upper filament 2a is bent and disposed in the middle so as to include portions a1 and a1 that are close to each other and extend in the vertical direction in parallel. The lower filament 2a ″ is bent symmetrically with the filament 2a. As shown in FIG. 1D, the middle filament 2a ′ is arranged in the vertical direction so as to approach each other and become parallel to each other. It is bent and arranged so as to include the extended portions a1 ′, a1 ′ and a2 ′, a2′.The middle portions a1 ′, a2 ′ are vertically aligned, and the filaments are parallel to each other in the vertical direction. A bent portion having an extending portion faces the article W.

  Points other than the above are substantially the same as those of the ion irradiation apparatus shown in FIG. 11A, and components and parts that are substantially the same as those in the apparatus of FIG. It is.

  According to this ion irradiation apparatus A, gas (for example, argon gas) is introduced from the gas introduction port 12 while maintaining the inside of the vacuum chamber 1 at a predetermined pressure, and each of the filaments 2a, 2a ′, 2a ″ from each power source PWa. In this way, each filament is heated by resistance to emit thermoelectrons, while a voltage is applied to the chamber 1 from the discharge power source PW2 so as to have a higher potential than each filament, whereby the filaments 2a, 2a ′ 2a ″, each of which draws thermoelectrons to generate a DC discharge and collides the thermoelectrons with the introduced gas to generate plasma, and an article W to which ions in the plasma are applied with a negative bias voltage from a bias power source PW3. To clean the surface of the article W, moderately roughen it, or raise the surface temperature of the article Processing can be carried out such as that.

  According to the ion irradiation apparatus A, since the filaments 2a, 2a ′, 2a ″ in the electron source 20A are discontinuously distributed and arranged in a plurality of stages throughout the electron source 20A, the whole or almost the whole of the electron source 20A is correspondingly increased. The electron source 20A is provided so as to face the entire ion irradiation target portion of the article W. Therefore, the electrons emitted from the electron source are disposed in the vacuum chamber. When the plasma is formed by colliding with the introduced gas, the plasma is generated so as to uniformly reach the entire ion irradiation target portion of the article W, and thus ions are uniformly generated from the plasma to the ion irradiation target portion. Can be irradiated.

  Further, each of the plurality of filaments 2a, 2a ', 2a "arranged in parallel in a plurality of stages is continuously stretched long so as to face the entire portion of the article to be irradiated with ions as in the prior art. Compared to a single filament, the applied voltage for thermionic emission by resistance heating (in other words, to obtain the filament operating temperature) can be reduced for each individual filament. The lifetime of the ion irradiation apparatus A can be extended by suppressing filament consumption due to filament evaporation and sputtering from plasma.

  Further, as described above, the filaments in the electron source 20A are close to each other in parallel, that is, a1 and a1 in the filaments 2a and 2a ″, a1 ′ and a1 ′ in the filament 2a ′, a2 ′ and a2 ′. Therefore, when a direct current is passed from the filament power supply PWa, the current flowing in one of the mutually parallel parts and the current flowing in the other flow in opposite directions, thereby The magnetic fields formed by the current flow in these parts cancel each other, and the thermoelectrons generated from these parts are sufficiently drawn out while being trapped in the magnetic field. Even if it is low so as to suppress filament consumption, plasma for obtaining irradiation ions can be formed at high density, Information, without requiring unnecessarily long time, Hodokoseru ion irradiation process efficiently article W at a predetermined dose of ion irradiation.

  Using the ion irradiation apparatus A, an experiment was conducted in which the surface of the article was cleaned by etching while rotating a cylindrical article W made of stainless steel having a diameter of 150 mm and a length of 600 mm three times per minute. The position dependency of the etching amount on the article at this time is shown in FIG. 2 by a line connecting black dots (●).

In this experiment, the total length including the bent portions of the filaments 2a and 2a ″ is 200 mm, the length h1 of the portion a1 is 77 mm, the length w between the portions a1 is 6 mm, and the total length of the bent portions is 160 mm. (2 × h1 + w).
The total length including the filament 2a ′ and the bent portion is 200 mm, each length h2 of the portions a1 ′ and a2 ′ is 37 mm, each length w between the portions a1 ′ and a2 ′ is 6 mm, and the total length of the bent portions Is 160 mm (4 × h2 + 2 × w).
The diameter of the filament is 1.0 mm.

Also,
Argon gas introduction amount: 100 sccm,
Pressure inside chamber in ion irradiation: 0.7 Pa,
Each filament voltage and current: voltage 10V, current 52A,
Discharge voltage and current: voltage 60V, current 31A,
Bias voltage and current to the article W: voltage −500V, current 9A,
Treatment time: 60 minutes.
From FIG. 2, it can be seen that almost uniform (uniformity <10%) etching is performed over the entire article W.

  It should be noted here that the filament voltage / current for each filament is small. That is, even when the filament voltage / current is small, the thermoelectrons can be efficiently extracted from the filament, and etching with high uniformity can be performed in a short time. The reason why the thermoelectrons can be efficiently extracted from each filament is that the magnetic field for trapping the thermoelectrons is weakened. In other words, by including parallel parts that are close to each other in the filament and flowing currents in the opposite directions to each other, the magnetic fields induced by those currents can be canceled with each other, and as a result, they are drawn from each filament. The trapped hot electrons are less likely to be trapped, and more hot electrons can contribute to plasma generation. Therefore, a sufficiently high density plasma can be generated even if the filament voltage / current is reduced.

  It was confirmed that the amount of thermoelectrons extracted from the parallel parts close to each other in each of the filaments 2a, 2a 'and 2a "was about 2 to 5 times the amount of thermoelectrons extracted from the other parts.

  Also, the fact that the filament current / voltage is small means that the filament operating temperature is low, so that when the sputtering is performed from the plasma, the sputtering rate is lowered, and therefore the consumption of the filament is considerably suppressed. . The amount of evaporation of the filament itself is also reduced.

  In addition, the length of each of the filaments 2a, 2a ′, 2a ″ is shorter than that of the filament in the apparatus of FIG. 11A, so that the voltage applied to the filament can be reduced, and the voltage of the discharge power supply PW2 can be set appropriately. By making the voltage, a sufficient amount of thermionic electrons can be extracted without causing the potential difference between the filament and the chamber 1 to become extremely large or small, and it is also difficult to receive sputtering from the plasma. When the apparatus A was operated under the above experimental conditions, but without limiting the processing time, the filament life was as long as about 100 hours.

FIG. 3 shows an example of an ion irradiation apparatus according to the present invention. This ion irradiation apparatus B is the apparatus A in FIG. 1A in which a bent portion including a portion parallel to each other in each filament is positioned closer to the negative polarity side end portion of the filament. These filaments constitute an electron source 20B. The other points are substantially the same as those of the apparatus A, and the same reference numerals as those of the apparatus A are attached to substantially the same parts and parts as the apparatus A.

  For some reason, for example, there is a case where the interval between the filament support terminal blocks has to be increased due to the arrangement of the components. In that case, the filament length must be increased to some extent. Even in that case, each filament may be bent and arranged so as to include a parallel portion. In that case, as illustrated in the ion irradiation apparatus B of FIG. 3, the parallel portion is brought closer to the negative polarity side of each filament. do it. By doing so, a discharge voltage equivalent to that in the case of the ion irradiation device A is applied to the parallel portion of each filament, and thermoelectrons can be efficiently extracted, and the same effect as in the case of the device A can be obtained. In addition, since a low discharge voltage is applied to a portion that is not a parallel portion of the filament (a horizontal straight portion extending to the left from the article W in FIG. 3), it is difficult to extract thermoelectrons from this portion. Since the amount of thermionic electrons drawn out of the horizontal straight line portion which is not a bent portion is originally as small as about 1/5 to 1/2 compared with the parallel portion, plasma generation by electrons drawn out from such a portion is not expected.

Figure 4 shows another example of ion-irradiation device. This ion irradiation apparatus C employs filaments 2c, 2c ′, 2c, and 2c ′ in place of the filaments 2a, 2a ′, and 2a ″ in the apparatus A of FIG. The filaments are arranged in parallel in four stages in the vertical direction, and each filament is stretched between the terminal blocks 21c and 22c arranged in the horizontal direction with respect to the vertical direction of the ion irradiation target article W. Each filament is stretched. The DC filament power supply PWc provided for each filament is energized, and these filaments and the like constitute the electron source 20C.

  The upper adjacent filaments 2c, 2c 'and the lower adjacent filaments 2c, 2c' are both bent and arranged so as to include mutually parallel portions c1, c1 '. Each set of mutually parallel portions c1 and c1 'approaching each other faces the article W.

The upper adjacent filaments 2c and 2c ′ are adapted to receive currents in opposite directions from the power source PWc connected thereto, and similarly, the lower adjacent filaments 2c and 2c ′ However, currents are being flown in opposite directions from the power source PWc connected to them.
Points other than the above are substantially the same as those of the ion irradiation apparatus A shown in FIG. 1A, and components and parts that are substantially the same as those of the apparatus A of FIG. It is.

According to this ion irradiation apparatus C, currents in opposite directions are caused to flow in parallel portions c1 and c1 ′ that are close to each other in the filaments 2c and 2c ′ adjacent to each other on the upper and lower sides. Cancel each other. Therefore, as in the case of the ion irradiation apparatus A, the thermoelectrons extracted from the filament are not easily trapped in the magnetic field, and even if the voltage applied to the filament is lowered to obtain the filament operating temperature, it is efficient. Plasma generation can be performed. In addition, since the applied voltage of the filament can be reduced, the life of the filament and thus the device C can be extended. Further, similarly to the device A, the ion irradiation can be performed uniformly over the entire portion of the article W targeted for ion irradiation.
In the case of the device C in FIG. 4, the adjacent filaments 2c and 2c ′ are stretched in a straight line and brought close to each other, so that the magnetic fields induced by the currents flowing in the opposite directions cancel each other. You may make it meet.

FIG. 5 shows another example of the ion irradiation apparatus according to the present invention. In the ion irradiation apparatus D, in the apparatus C, parallel portions c1 and c1 ′ approaching each other in the filaments 2c and 2c ′ adjacent to each other are positioned close to the end on the negative polarity side of the filament. The other points are substantially the same as those of the apparatus C, and substantially the same parts, parts, etc. as those of the apparatus C are denoted by the same reference numerals as those of the apparatus C.

  Also in the ion irradiation device D, a discharge voltage equivalent to that in the case of the ion irradiation device C is applied to the portion of each filament that is close to and parallel to the adjacent filament, and the thermoelectrons can be efficiently extracted, An effect equivalent to that of the device C can be obtained.

Figure 6 shows another example of ion-irradiation device. In this ion irradiation apparatus E, in the ion irradiation apparatus A of FIG. 1A, a common thermoelectron emission member or secondary electron emission member 4 is arranged in front of the filaments 2a, 2a ′, 2a ″ with respect to these filaments. The member 4 is also a constituent member of the electron source 20 E. The member 4 generally faces the ion irradiation target portion of the ion irradiation target article W. The member 4 receives each filament from the impact power source PW4. On the other hand, a voltage is applied so as to be a high potential, and a discharge voltage is applied to the chamber 1 from the discharge power source PW2 ′ so as to be a high potential with respect to the member 4. The other points are substantially the same as those of the apparatus A. The components, parts, etc., which are substantially the same as the parts, parts, etc. in the apparatus A are given the same reference numerals as those in the apparatus A. However, illustration of gas exhaust ports, gas introduction ports, etc. is omitted. .

  In this ion irradiation apparatus E, a voltage is applied to each filament from a filament power supply PWa to emit thermoelectrons, while a voltage is applied to the member 4 from the impact power supply PW4 so that the filament has a high potential with respect to the filament. It is possible to cause the thermoelectrons generated from the electron beam to collide with the member 4 and emit the thermoelectrons (or secondary electrons, or both the thermoelectrons and the secondary electrons) from the member 4. Further, by applying a voltage from the discharge power source PW2 ′ to the chamber 1 so as to have a high potential with respect to the member 4, the electrons emitted from the member 4 are accelerated and collided with the introduced gas in the chamber to cause a direct current discharge. , Plasma can be generated. Furthermore, ions in the plasma can be irradiated to the article by applying a negative bias voltage to the article W from the bias power source PW3.

The electron source 20E faces the entire portion of the article W subject to ion irradiation, and the thermionic emission member (or secondary electron emission member) 4 and the filaments 2a, 2a ′, 2a ″ in the electron source extend over the entire electron source. Since it is provided, ion irradiation can be performed uniformly and efficiently over the entire ion irradiation target portion of the article W. Further, the filament life is long as in the case of the apparatus A, and the life of the ion irradiation apparatus E is also long.
Examples of the thermoelectron emitting member include a member made of metal, metal oxide, and ceramic material, and the secondary electron emitting member also includes a member made of metal, metal oxide, and ceramic material.

Figure 7 shows another example of ion-irradiation device. In this ion irradiation apparatus F, in the ion irradiation apparatus A of FIG. 1 (A), a common preliminary plasma chamber 5 is provided in front of the filaments 2a, 2a ′, 2a ″ for these filaments, and this also constitutes the electron source 20F. It is an element.

  A gas (for example, an inert gas such as argon gas) is introduced into the preliminary plasma chamber 4 from a gas introduction port 51. The electron extraction opening 52 of the preliminary plasma chamber 5 faces the ion irradiation target portion of the ion irradiation target article W as a whole. A voltage is applied to the preliminary plasma chamber 5 from the preliminary discharge power source PW5 so that each filament has a high potential, and the chamber 1 is discharged from the discharge power source PW2 ″ so as to have a high potential with respect to the preliminary plasma chamber 5. A voltage is applied, and the other points are substantially the same as those of the device A, and the same reference numerals as those of the device A are attached to substantially the same parts and portions as the components and parts in the device A. However, illustration of a gas exhaust port, a gas introduction port, and the like of the chamber 1 is omitted.

  In this ion irradiation apparatus F, a voltage is applied to each filament from the filament power supply PWa to emit thermoelectrons, while gas is introduced into the preliminary plasma chamber 5 from the gas introduction port 51 and from the power supply PW5 to the filament. By applying a voltage so as to be a potential, the thermoelectrons generated from the filament collide with the introduced gas, and a preliminary plasma can be formed.

  Further, by applying a voltage from the discharge power source PW2 ″ to the chamber 1 so as to have a high potential with respect to the preliminary plasma chamber 5, electrons in the preliminary plasma generated in the chamber 5 are extracted, accelerated, and introduced into the chamber. The plasma can be generated by colliding with the gas and generating a plasma, and ions in the plasma can be irradiated to the article by applying a negative bias voltage to the article W from the bias power source PW3.

  In the electron source 20F, the opening 52 of the preliminary plasma chamber 5 faces the entire ion irradiation target portion of the article W, and the preliminary plasma chamber 5 and the filaments 2a, 2a ′, 2a ″ in the electron source extend over the entire electron source. Since it is provided, ion irradiation can be performed uniformly and efficiently over the entire ion irradiation target portion of the article W. Further, the filament life is long as in the case of the apparatus A, and the life of the ion irradiation apparatus F is also long.

In this ion irradiation apparatus F, the gas introduced into the preliminary plasma chamber 5 and the gas introduced into the chamber 1 can be different. For example, when it is desired to irradiate the article W with oxygen ions, oxygen gas may be introduced into the chamber 1. However, when this oxygen gas forms an atmosphere around the filament, the filament is oxidized and its life is extremely shortened. However, in this apparatus F, if an inert gas such as argon gas is introduced into the preliminary plasma chamber 5, the oxygen gas from the chamber 1 can be prevented to some extent, so that the length of the filament and thus the length of the apparatus F is increased. Life can be extended. If the gas flow rate ratio is adjusted, the oxygen gas plasma can be mainly generated in the chamber 1 in the end, so that the article W can be mainly irradiated with oxygen ions.
As is clear from three examples of the electron source in the ion irradiation apparatus in [Means for Solving the Problems], the thermal electron emission member or the secondary electron emission member shown in FIG. It is also possible to configure an electron source arranged in front of the filaments 2a, 2a ′, 2a ″ of the ion irradiation apparatus shown in FIG. 3 and an electron source arranged in front of the filaments 2c, 2c ′ of the ion irradiation apparatus shown in FIG. Further, for example, the preliminary plasma chamber shown in Fig. 7 is arranged in front of the filaments 2a, 2a ', 2a "of the ion irradiation apparatus shown in Fig. 3, and the filaments 2c, 2c of the ion irradiation apparatus shown in Fig. 5 are used. It is also possible to construct an electron source placed in front of '.

  FIG. 8 shows still another example of the ion irradiation apparatus according to the present invention. This ion irradiation apparatus G is provided with four stages of magnets (permanent magnets) 6 for forming a magnetic field behind the filaments 2a, 2a ′, 2a ″ and outside the chamber wall in the ion irradiation apparatus B of FIG. This is a component of the source 20G.

These magnets are provided in the horizontal linear portions of the filaments 2a, 2a ′, 2a ″ so as to provide a magnetic field that cancels or weakens the magnetic field formed by the current flowing therethrough.
The other points are substantially the same as those of the apparatus B, and the same reference numerals as those of the apparatus B are given to substantially the same parts and portions as the parts and parts in the apparatus B. However, each filament is illustrated in a simplified manner, and illustration of a power source and the like is omitted.

  In this apparatus G, sufficient thermoelectrons can be drawn out from the horizontal straight line portion of each filament, thereby making it possible to further increase the plasma density and to irradiate the article W uniformly with a larger amount of ion irradiation. The ion processing time can be shortened accordingly.

  The magnet 6 may not be a permanent magnet, but may be a magnetic field forming coil or the like. When a coil is used, a power supply is required, which increases the cost and costs. However, the magnetic field strength can be changed freely to some extent, so it is possible to achieve a more appropriate magnetic field strength and filament. In the case where the current to be passed through is alternating current, the magnetic field induced by the linear portion of the filament can be effectively canceled or weakened by reversing the direction of the magnetic field by reversing the coil current.

  Such magnetic field forming means can also be applied to ion irradiation apparatuses A to F and ion irradiation apparatuses H and J described below. Further, in the ion irradiation apparatuses A to G and the ion irradiation apparatuses H and J to be described next, a DC power supply is adopted as a filament power supply, but an alternating power supply may be adopted instead.

FIG. 9 shows still another example of the ion irradiation apparatus according to the present invention. In this ion irradiation apparatus H, in the ion irradiation apparatus B of FIG. 3, an ion current distribution measuring instrument 7 is provided in the vicinity of the article W, and the output of the controller 8 is variable based on the ion current distribution information measured by the measuring instrument 7. The output of each filament power supply PWa 'is controlled so that ion irradiation to the article W can be made more uniform.
The other points are substantially the same as those of the apparatus B. Parts, portions, and the like that are substantially the same as parts, portions, and the like in apparatus B are denoted by the same reference numerals as in apparatus B.

  The ion current distribution measuring instrument 7 in the apparatus H measures the amount of ion current based on ions irradiated on the article W, in other words, the spatial distribution of ion current density. This measuring instrument 7 may be moved in front of the article W temporarily, that is, only at the time of measurement, or may always be arranged in the vicinity of the article W as in the illustrated example. In the case of the arrangement of the illustrated example, a value slightly different from the ion current amount or the ion current density based on the ions actually irradiated to the article W may be measured. What is necessary is just to obtain | require the correlation between an actual value and a measured value, and to convert into an actual value after measurement in the control part 8. FIG.

  The control unit 8 will be described in more detail. The spatial distribution information of the ion current amount or the ion current density measured by the ion current distribution measuring instrument 7 is transmitted to the control unit 8, and the control unit 8 calculates the uniformity based on the information. Etc. are processed. If the uniformity condition is not met, the filament power supply PWa 'is controlled in the illustrated example, and the current flowing from the filament power supply to the filament is adjusted so that the uniformity meets the condition.

  For example, when the ion current amount or ion current density in the central region between the upper and lower filaments 2a and 2a ″ is larger than that in the region corresponding to the upper and lower filaments 2a and 2a ″, the filament power supply PWa ′ in the middle is controlled. Then, the current of the middle filament 2a ′ is lowered, the amount of thermionic emission therefrom is reduced, the plasma density in the central region is reduced, and thereby ion irradiation with good uniformity can be performed as a whole.

  If the ion current distribution measuring instrument 7 is of a Faraday cup type, it can measure a more accurate ion current density. However, the ion current distribution measuring instrument 7 is not limited to this and may be a simple ion collector. In the latter case, it is difficult to calculate an accurate ion current density, but it is possible to calculate a relative ion current distribution, and it may still be sufficiently practical.

Further, instead of the ion current distribution measuring instrument 7, a plasma distribution measuring instrument or the like can be substituted. For example, it is possible to employ a device that detects light emission from plasma with a spectroscope or the like and obtains a spatial distribution of plasma density from the detected information. In this case, if the correlation between the spatial distribution of the plasma density thus obtained and the actual ion current distribution is calculated in advance, the measured value is converted into an actual value, and control is performed based on the calculated value. Good.
In an example in which filaments are continuously arranged in a long range as shown in FIG. 11A, such control is impossible. However, in the apparatus according to the present invention, since the filaments are discontinuously distributed and arranged in a plurality of stages, such control is possible.
In addition, this measuring device and control part are applicable also to the above-mentioned ion irradiation apparatus AG.

  Further, since the density of plasma usually increases with the discharge current, the spatial distribution of the plasma can also be known by monitoring the discharge current shared by each filament. FIG. 10 shows that the apparatus H of FIG. 9 is provided with discharge current measuring devices AM1, AM2, and AM3 for measuring the discharge currents shared by the filaments 2a, 2a ′, and 2a ″ in place of the ion current distribution measuring device 7. The ion irradiation apparatus J is shown.

  In the device J, the discharge current detected by the measuring instruments AM1, AM2, and AM3 is input to the control unit 9. In the control unit 9, a discharge current (which is obtained in advance by experiments or the like) to be shared by individual filaments in order to uniformly irradiate ions on the article W as a whole is set. The control unit 9 compares the current information from each measuring instrument with the set current, and controls the output of each filament power supply PWa 'so that the current information becomes the set current.

  The discharge current set value corresponding to each filament in the control unit 9 may be the same for each filament. For example, when there is a region where plasma is difficult to be generated due to the device configuration or the like, the discharge current for that region is So that the set value may be different for each filament.

Here, the filament will be further described.
The shorter the distance between adjacent parallel or substantially parallel parts in the middle of a filament, or between adjacent parallel or substantially parallel parts in adjacent filaments, the shorter is the mutual cancellation of magnetic fields generated in those parts. In fact, if it is too short, it may cause a short circuit due to thermal expansion of the filament.

  On the other hand, if the interval is too wide, the magnetic field will not easily cancel, and thermal electrons will be trapped. For example, if the filament has a diameter of about 0.8 mm to 1.5 mm, the distance between parallel parts or approximately parallel parts will vary depending on the diameter and length of the filament, the magnitude of the current to flow, and the operating environment conditions. Although not necessarily limited thereto, approximately 3 mm to 50 mm is preferable, and approximately 6 mm to 30 mm is more preferable. When the distance is smaller than 3 mm, short-circuiting is likely to occur, and when the distance is larger than 50 mm, it becomes difficult to cancel the magnetic field.

  Here, “the interval between the parallel portions or the substantially parallel portions is, for example, 6 mm to 30 mm” means that the interval is within the range of about 6 mm to 30 mm over a length of about 50 mm. As long as the magnetic fields formed by are substantially parallel to each other, they may be in a parallel or substantially parallel state.

  Further, two or more parallel portions or substantially parallel portions may be provided in one filament, and their arrangement is basically free. When two or more filaments are brought close to each other, there may be two or more parallel parts or almost parallel parts, and their arrangement is basically free. The current passed through the filament is not limited to a direct current, but may be an alternating current or a pulsed current. When an alternating current, a pulse current, or the like is passed, currents may flow in opposite directions in close parallel parts or close parallel parts as in the case of direct current.

  For example, in the ion irradiation apparatus A shown in FIG. 1A or the like, a direct current power source whose polarity is periodically reversed may be adopted as the filament power source, which further extends the life of the filament. In general, the negative side of the filament has a higher substantial discharge voltage than the positive side, so that it is more susceptible to sputtering from the plasma, and therefore the exhaustion is so severe that the filament is always cut. It is a portion close to the terminal block on the negative polarity side. Therefore, if the polarity of the filament power supply is periodically changed, the consumption can be dispersed and the filament life is extended.

  Actually, in the apparatus A shown in FIG. 1 (A), the operation is performed under the condition that the filament life is about 100 hours as described above. However, when the polarity of the DC filament power supply is changed every 20 hours (inverted). The filament life was extended to about 130 hours. The polarity replacement period is not particularly limited as in every 10 hours or every 30 hours, but if the replacement is performed in a time close to the above-mentioned 100 hours, which is the original life, for example 90 hours, the life is 110. The time is about 50 hours or less, but it is not limited to this.

The discharge power supply is not limited to one, and a plurality of discharge power supplies may be adopted as necessary. One filament power supply may be provided for each filament, but a single filament power supply may cause a current to flow through a plurality of filaments.
1 to 10, the negative side of the discharge power source is connected to the positive side (or the negative side) of the filament power source, but the negative side of the discharge power source is the positive side of the filament power source. And may be connected to either of the negative side. However, when the negative side of the discharge power source is connected to the positive side of the filament power source, the voltage of the discharge power source may be adjusted so that the discharge voltage on the negative side of the filament does not become too high.
The material of the filament is generally tungsten, but other materials may be used.

  As described above, ion irradiation by the ion irradiation apparatus according to the present invention including the ion irradiation apparatuses A to H can be used for cleaning the article surface, appropriately roughening the article surface, increasing the article surface temperature, etc. Can be used as well.

  That is, for example, in a film formation process, it can be used during film formation. It is possible to control the film quality by irradiating the product with ions during film formation, or to excite and ionize atoms, molecules, clusters, etc. that contribute as components of the film by the generated plasma. It is also possible to control the film quality by activating them.

Further, in order not to raise the temperature of the article too much, it is possible to perform non-steady operation such as pulse operation instead of steady operation. For example, plasma can be generated or extinguished by turning on and off the discharge power source, thereby enabling unsteady operation, and unsteady operation can also be performed by turning on and off the filament power source. This can also be done by turning the bias power supply on and off.
Note that the article can be irradiated with electrons by changing the polarity of the bias power source from negative to positive. When combined with high-speed bipolar pulse operation, when the article is an insulator, charge-up due to ion irradiation can be suppressed and ion irradiation can be performed efficiently.

  The present invention, for example, cleans the surface of an article by irradiating the article with ions as part of a process such as film formation, ion implantation, or surface modification on an article such as a machine part, tool, or automobile part. It can be used to moderately rough the surface or raise the surface temperature of the article.

FIG. 1A is a view showing an example of an ion irradiation apparatus according to the present invention, and FIG. 1B is a view of an arrangement relationship between an electron source filament and an ion irradiation target article in the apparatus viewed from above. FIG. FIG. 1C is a diagram showing the upper filament in the electron source, and FIG. 1D is a diagram showing the middle filament. It is a figure which shows the etching amount position dependence in the etching experiment of the articles | goods by each of the ion irradiation apparatus of FIG. 1 (A), and the conventional example ion irradiation apparatus of FIG. 10 (A). It is a figure which shows the other example of the ion irradiation apparatus which concerns on this invention. It is a figure which shows the further another example of the ion irradiation apparatus which concerns on this invention. It is a figure which shows the further another example of the ion irradiation apparatus which concerns on this invention. It is a figure which shows the further another example of the ion irradiation apparatus which concerns on this invention. It is a figure which shows the further another example of the ion irradiation apparatus which concerns on this invention. It is a figure which shows the further another example of the ion irradiation apparatus which concerns on this invention. It is a figure which shows the further another example of the ion irradiation apparatus which concerns on this invention. It is a figure which shows the further another example of the ion irradiation apparatus which concerns on this invention. FIG. 11A is a diagram showing a conventional example of an ion irradiation apparatus, and FIG. 11B shows a positional relationship between a filament and an ion irradiation target article in the apparatus as viewed from the right side of FIG. 11A. FIG. It is a figure which shows the apparatus of the improvement example which can be considered of the apparatus of FIG. 11 (A).

Explanation of symbols

A, B, C, D, E, F, G, H, J Ion irradiation apparatus 1 Vacuum chamber 11 Exhaust port 12 Gas introduction port 3 Article holder W Ion irradiation target article 20A, 20B Electron sources 2a, 2a ', 2a " Filaments 21a and 22a Terminal blocks a1 and a1, a1 'and a1', a2 'and a2' Parallel part PWa Filament power supply PW2 Discharge power supply PW3 Bias power supply 20C, 20D Electron source 2c, 2c 'Filaments 21c, 22c Terminal blocks c1 and c1 'Parallel part PWc Filament power supply 20E Electron source 4 Electron emission member (or secondary electron emission member)
PW4 Impact power supply PW2 'Discharge power supply 20F Electron source 5 Preliminary plasma chamber 51 Gas introduction port 52 Electron extraction opening PW5 Preliminary plasma chamber power supply PW2 "Discharge power source 20G Electron source 6 Magnet 20H Electron source PWa' Output variable filament power source 7 Ion current distribution Measuring instrument 8 Controller 2, 2 'Filament 21, 21', 22, 22 'Terminal block PW1, PW1' Filament power supply AM1, AM2, AM3 Discharge current measuring instrument 9 Controller

Claims (11)

In the vacuum chamber, electrons emitted from an electron source using a filament that emits thermoelectrons by resistance heating by energization from a filament power source collide with the introduced gas in the vacuum chamber to generate plasma, and ions in the plasma An ion irradiation apparatus that irradiates an ion irradiation target article, and an article holder that supports the ion irradiation target article and is rotatable around a predetermined rotation center line in the vacuum chamber. The electron source is provided so as to extend in the rotation center line direction of the article holder so as to face the ion irradiation target portion of the ion irradiation target article supported by the article holder. The filaments are distributed in a discontinuous manner in a plurality of stages in the direction of the article holder rotation center line of the electron source. Are arranged, each of the filaments of said plurality several stages, are bent arranged to include at least one pair of opposed portion opposed parallel or substantially parallel to one another as reverse current flow to one another, parallel to the each other or The substantially parallel facing portions are close to each other so that the magnetic fields generated by the currents flowing in the opposite directions to the opposing portions cancel each other. The filament power supply for energizing the filaments arranged to be bent is a DC power supply, and the filaments bent and arranged so as to include the mutually parallel or substantially parallel opposing portions approaching each other are parallel or substantially parallel to each other. An opposite irradiation part is located near the negative polarity side edge part of this filament, The ion irradiation apparatus characterized by the above-mentioned.   In the vacuum chamber, electrons emitted from an electron source using a filament that emits thermoelectrons by resistance heating by energization from a filament power source collide with the introduced gas in the vacuum chamber to generate plasma, and ions in the plasma An ion irradiation apparatus that irradiates an ion irradiation target article, and an article holder that supports the ion irradiation target article and is rotatable around a predetermined rotation center line in the vacuum chamber. The electron source is provided so as to extend in the rotation center line direction of the article holder so as to face the ion irradiation target portion of the ion irradiation target article supported by the article holder. The filaments are distributed in a discontinuous manner in a plurality of stages in the direction of the article holder rotation center line of the electron source. The at least one set of adjacent filaments of the plurality of stages of filaments includes at least one opposing portion that is parallel or substantially parallel to each other and in which currents flowing in opposite directions flow. The opposing portions parallel or substantially parallel to each other are close to each other so that the magnetic fields generated by the currents flowing in opposite directions to the opposing portions cancel each other. The filament power supplies that energize adjacent pairs of filaments that include portions are direct-current power supplies that pass currents in opposite directions to opposing portions that are close to or parallel to each other. The adjacent portions of adjacent filaments that are close to each other or parallel to each other are positioned near the negative side end of the filaments. Ion irradiation and wherein the.   2. The ion irradiation apparatus according to claim 1, wherein opposing portions of the filaments of each stage that face each other in parallel or substantially parallel to each other so that currents in opposite directions flow protrude in the direction of the rotation center line of the article holder.   At least one of the adjacent filaments in the set including the mutually parallel or substantially parallel facing portions that are close to each other is bent and disposed so as to provide the mutually parallel or substantially parallel facing portions that are close to each other. The ion irradiation apparatus according to claim 2.   The electron source uses thermoelectrons emitted from the filament by resistance heating due to energization of the filament as electrons emitted from the electron source to collide with the introduced gas in the vacuum chamber and generate the plasma. The ion irradiation apparatus in any one of Claim 1 to 4.   The electron source is emitted from the filament by resistance heating by energizing the filament, and a thermoelectron emitting member that emits thermoelectrons by collision of thermoelectrons emitted from the filament by resistance heating by energizing the filament, and resistance heating by energizing the filament As an electron to be emitted from the electron source to generate the plasma by colliding with the introduced gas in the vacuum chamber, including at least one of secondary electron emitting members that emit secondary electrons by the collision of thermionic electrons 5. The ion irradiation apparatus according to claim 1, wherein electrons emitted from the thermal electron emission member and / or secondary electron emission member are used.   The electron source includes a preliminary plasma chamber, and generates a preliminary plasma by colliding a thermal electron emitted from the filament with a gas introduced into the preliminary plasma chamber by resistance heating by energizing the filament, 5. The electron emitted from the plasma generated in the preliminary plasma chamber is used as an electron emitted from the electron source in order to collide with the introduced gas in the vacuum chamber and generate the plasma. The ion irradiation apparatus of description.   The magnetic field forming means for canceling at least a part of a magnetic field induced by a current flowing in the filament is provided for at least one of the plurality of stages of filaments. Ion irradiation device.   An ion current distribution measuring device for measuring a spatial distribution of ion current based on ions irradiated on the ion irradiation target article, and an ion current distribution of the article based on the ion current distribution measured by the ion current distribution measuring device. The ion irradiation apparatus according to claim 1, further comprising a control device that controls the filament power output so that the entire ion irradiation target portion is uniform.   A plasma distribution measuring device for measuring a spatial distribution of plasma formed by collision of electrons emitted from the electron source with the gas introduced into the vacuum chamber, and a plasma based on the plasma distribution measured by the plasma distribution measuring device. The ion irradiation apparatus according to any one of claims 1 to 8, further comprising a control device that controls the filament power output so as to make the distribution uniform over the entire ion irradiation target portion of the article.   The plasma distribution measuring apparatus for measuring the spatial distribution of the plasma measures the plasma distribution by monitoring the discharge current shared by each filament, and discharge current measurement for monitoring the discharge current shared by each filament. The ion irradiation apparatus according to claim 10, further comprising: a controller, wherein the controller for controlling the filament power output controls each filament power output based on a discharge current monitored by the discharge current measuring instrument.