JP2013206652A - Antenna device, and plasma processing apparatus and sputtering apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna device capable of generating an inductively-coupled plasma and suppressing raise in a plasma potential.SOLUTION: An antenna device 20 comprises: an antenna 30 located in a vacuum container 2; a high-frequency power supply 40 applying a high-frequency current Ito the antenna 30; and a matching circuit 42. The antenna 30 has a coaxial structure having an internal conductor 32, an external conductor 34 covering the outside of the internal conductor 32 at least over the total length located in the vacuum container 2, and a dielectric body 36 electrically insulating between both the conductors. The antenna 30 also has a water-cooling structure for cooling the antenna 30 by circulating cooling water in the internal conductor 32. The high-frequency power supply 40 is connected to one end part of the internal conductor 32 via the matching circuit 42. The other end part of the internal conductor 32 is grounded. The external conductor 34 consists of a non-magnetic body, and is grounded at one end part.

Description

  The present invention relates to an antenna apparatus for generating inductively coupled plasma in a vacuum vessel, a plasma processing apparatus including the antenna apparatus, and a sputtering apparatus. The ion means a positive ion in this application.

  A high-frequency current is passed from a high-frequency power source through a matching circuit to a coil-shaped metal pipe antenna provided in the vacuum vessel, and an inductively coupled plasma (abbreviated as ICP) is generated in the vacuum vessel by an induced electric field generated thereby. Conventionally, an antenna device has been proposed. For example, the sputtering apparatus described in Patent Document 1 includes the antenna device as described above.

Japanese Patent Laid-Open No. 2003-313662 (paragraphs 0007, 0027-0029, FIGS. 1 and 4)

  When plasma is generated by the conventional antenna device as described above, even if one end of the antenna is grounded, the power supply side of the high frequency power has a voltage amplitude determined by the product of the high frequency current flowing through the antenna and the impedance of the antenna, In addition, since it vibrates with respect to the ground potential at the frequency of the high frequency power, more electrons enter the antenna than the ions from the plasma, and the plasma potential rises greatly (becomes a positive plasma potential). Simply put, ions are heavier than electrons and cannot follow the fluctuations in the electric field, leaving the ions in the plasma, so the plasma potential does not follow the antenna potential fluctuations and remains high. Be drunk. As an example, the plasma potential is about +1 kV to +3 kV.

  When the plasma potential is greatly increased as described above, charged particles (for example, ions) in the plasma impinge on and collide with the substrate with high energy due to the plasma potential, so that damage to the film formed on the substrate increases and the film quality increases. Decreases.

  In addition, when the plasma potential is greatly increased as described above, a large voltage is applied to dust or the like adhering to the inner wall of the vacuum vessel, so that discharge (arcing) easily occurs in the dust or the like. . Moreover, since this dust and the like are unstable, this discharge is also unstable, and this discharge causes the plasma to become unstable.

  Accordingly, the main object of the present invention is to provide an antenna device that can generate inductively coupled plasma and can suppress an increase in plasma potential.

  An antenna device according to the present invention is an antenna device for generating inductively coupled plasma in a vacuum vessel, wherein the antenna is located in the vacuum vessel, a high-frequency power source for supplying a high-frequency current to the antenna, and the antenna and the high-frequency wave The antenna includes a matching circuit for matching with a power source, and the antenna includes an inner conductor, an outer conductor that covers at least the entire length of the outer conductor located in the vacuum vessel, and between the inner conductor and the outer conductor. A water-cooling structure that cools the antenna by flowing cooling water into at least one of the inner conductor and the outer conductor. The high frequency power supply is connected to one end of the inner conductor of the antenna via the matching circuit, and the other end of the inner conductor is grounded. And, the outer conductor of the antenna is made of non-magnetic material, and the external conductor is grounded only at its one end portion, and characterized in that.

  In this antenna device, since the outer conductor of the antenna is made of a non-magnetic material, the outer conductor is grounded only at one end thereof, and does not form an electrical closed loop via the ground. Even if the outer conductor is provided, the action of attenuating the high-frequency magnetic field generated by the high-frequency current flowing through the inner conductor is very small. Therefore, inductively coupled plasma can be generated by an induction electric field generated by a high frequency magnetic field generated by a high frequency current flowing through the inner conductor.

  In addition, since the outer side of the inner conductor is covered over the entire length located in the vacuum vessel by the electrically grounded outer conductor, the electric field between the inner conductor and the plasma can be shielded. Therefore, the potential of the inner conductor does not affect the plasma potential. In addition, since the outer conductor is fixed to the ground potential and the potential of the outer conductor does not vibrate at a high frequency as in the conventional antenna, the inflow of electrons from the generated plasma to the outer conductor is small as diffusion. This is due to the plasma sheath voltage, and therefore the rise in plasma potential is small. The above action can suppress an increase in plasma potential.

  Furthermore, since the antenna has a water cooling structure as described above, an increase in temperature of the antenna can be suppressed.

  The antenna may further include a dielectric layer that covers the outside of the outer conductor over at least the entire length located in the vacuum vessel.

  According to the first aspect of the present invention, since the outer conductor of the antenna is made of a non-magnetic material, the outer conductor is grounded only at one end thereof to form an electrical closed loop via the ground. Therefore, even if the outer conductor is provided, the action of attenuating the high-frequency magnetic field generated by the high-frequency current flowing through the inner conductor is very small. Therefore, inductively coupled plasma can be generated by an induction electric field generated by a high frequency magnetic field generated by a high frequency current flowing through the inner conductor.

  In addition, since the outer side of the inner conductor is covered over the entire length located in the vacuum vessel by the electrically grounded outer conductor, the electric field between the inner conductor and the plasma can be shielded. Therefore, the potential of the inner conductor does not affect the plasma potential. In addition, since the outer conductor is fixed to the ground potential and the potential of the outer conductor does not vibrate at a high frequency as in the conventional antenna, the inflow of electrons from the generated plasma to the outer conductor is small as diffusion. This is due to the plasma sheath voltage, and therefore the rise in plasma potential is small. The above action can suppress an increase in plasma potential. As a result, stable plasma generation can be performed. In addition, the energy of charged particles incident on the substrate from the plasma can be reduced. Thereby, for example, damage to the film formed on the substrate can be suppressed to a small level, and the film quality can be improved.

  Furthermore, since the antenna has a water cooling structure as described above, an increase in temperature of the antenna can be suppressed. As a result, for example, an increase in the temperature of the substrate due to heat radiation from the antenna can be suppressed.

  According to invention of Claim 2, there exists the following further effect. That is, the antenna further includes a dielectric layer that covers at least the entire length of the outer conductor located in the vacuum vessel, and electrons and ions flow from the plasma into the surface of the dielectric layer. Since the potential of the surface of the dielectric layer is almost balanced with the plasma potential immediately, the potential difference between the surface of the dielectric layer and the plasma becomes small. As a result, it is possible to prevent instability factors such as arcing from occurring on the surface of the antenna.

  According to invention of Claim 3, there exists the following further effect. That is, the antenna device can suppress the rise of the plasma potential by the above action and suppress the sputtering of the antenna by the ions in the generated plasma. Therefore, in the case of forming a film on the substrate or the surface of the substrate Contamination of the film can be suppressed.

  According to invention of Claim 4, there exists the following further effect. That is, the antenna device can suppress the increase of the plasma potential by the above action and suppress the sputtering of the antenna by the ions in the generated plasma, so that the contamination of the target, the substrate and the film formed on the surface thereof can be prevented. Can be suppressed.

It is a schematic sectional drawing which shows an example of the plasma processing apparatus provided with the antenna apparatus which concerns on this invention. It is a schematic sectional drawing which shows the plasma processing apparatus shown in FIG. 1 from the side. It is the schematic which shows an example of the antenna device which concerns on this invention. It is the schematic which shows the other example of the antenna device which concerns on this invention. It is the schematic which shows the further another example of the antenna device which concerns on this invention. It is a schematic sectional drawing which shows an example of the sputtering device provided with the antenna device which concerns on this invention. It is a schematic sectional drawing which shows the sputtering apparatus shown in FIG. 6 from the side. It is the schematic which shows the further another example of the antenna device which concerns on this invention. FIG. 9 is a schematic view partially showing an example in which the antenna device shown in FIG. 8 is applied to the sputtering device shown in FIGS. 6 and 7. It is the schematic which shows the example of the antenna apparatus used for the experiment which investigates the influence which the presence or absence of an external conductor, and the way of grounding of an external conductor exert on a generated magnetic field. It is a figure which shows an example of the experimental result which investigated the influence which the presence or absence of the external conductor of the antenna apparatus shown in FIG.

An example of a plasma processing apparatus provided with the antenna device according to the present invention is shown in FIGS. In FIG. 1, the feeding portion of the high-frequency current I _R to the antenna 30 is conceptually illustrated, and the vicinity of both ends of the antenna 30 specifically has the structure shown in FIG. 2.

  This plasma processing apparatus is an apparatus for processing the substrate 10 using the plasma 16 generated by the antenna device 20.

  The plasma processing apparatus includes, for example, a metal vacuum vessel 2, and the inside thereof is evacuated by a vacuum evacuation device 4. The vacuum vessel 2 is electrically grounded.

A gas 8 is introduced into the vacuum vessel 2 through a gas introduction pipe 6. The gas 8 may be in accordance with the content of processing performed on the substrate 10. For example, when film formation is performed on the substrate 10 by plasma CVD, the gas 8 is a source gas or a gas obtained by diluting it with a diluent gas (for example, H ₂ ). More specifically, an Si film is formed on the surface of the substrate 10 when the source gas is SiH _4, an SiN film is formed when SiH ₄ + NH ₃ is used, and an SiO ₂ film is formed when SiH ₄ + O ₂ is used. be able to.

  A holder 12 that holds the substrate 10 is provided in the vacuum vessel 2. As in this example, a bias voltage may be applied to the holder 12 from the substrate bias power supply 14. The bias voltage may be a negative DC voltage, a negative pulse voltage, an AC voltage, or the like. Reference numeral 50 denotes an insulating part having a vacuum sealing function.

  The plasma processing apparatus includes an antenna device 20 for generating inductively coupled plasma 16 in the vacuum vessel 2.

The antenna device 20 includes an antenna 30 located in the vacuum vessel 2, the matching between the high-frequency power source 40 and the antenna 30 and the high-frequency power source 40 for supplying a high-frequency current I _R to the antenna 30 (specifically, impedance matching) A matching circuit 42 is provided.

In this example, a plurality of antennas 30 (specifically three) are arranged along the long side of the rectangular substrate 10 in the direction along the short side of the substrate 10. Specifically, a high-frequency current I _R is supplied in parallel from the high-frequency power supply 40 via the matching circuit 42 to the inner conductor 32. However, the number of antennas 30 may be one or more, and the number of antennas 30 may be appropriately determined according to the shape, dimensions, etc. of the substrate 10.

  Each antenna 30 is provided between the inner conductor 32, the outer conductor 34 that covers at least the entire length of the inner conductor 32, and the outer conductor 34 between the inner conductor 32 and the outer conductor 34. A coaxial structure having a dielectric 36 that electrically insulates each other. In this example, the cooling water 38 is allowed to flow in the internal conductor 32 to cool the antenna 30.

  In this example, both end portions of each antenna 30 are bent upward, penetrate the ceiling surface of the vacuum vessel 2 and are located outside the vacuum vessel 2. An insulating portion 51 having a vacuum sealing function is provided at a portion where each antenna 30 penetrates the vacuum vessel 2.

  The configuration of the antenna device 20 will be described in more detail with reference to FIG. 3, taking one antenna 30 as an example. In FIG. 3, in order to simplify the illustration, the antenna 30 is illustrated with a reduced length. The antenna 30 is shown as a straight line, but is not limited thereto. The same applies to other examples described later.

  The antenna 30 is provided between a tubular inner conductor 32, an outer conductor 34 that covers at least the entire length of the inner conductor 32 located in the vacuum chamber 2, and the inner conductor 32 and the outer conductor 34. A coaxial structure having a dielectric 36 that electrically insulates between the conductors 32 and 34 is formed. In this example, the dielectric 36 covers the entire length of the inner conductor 32 positioned inside the outer conductor 34.

  The antenna 30 has a water cooling structure in which the cooling water 38 is allowed to flow in the internal conductor 32 to cool the antenna 30. More specifically, the inner conductor 32 and the dielectric 36 and the dielectric 36 and the outer conductor 34 are in thermal contact (that is, contact in which thermal conduction occurs), respectively. Accordingly, by flowing the cooling water 38 through the inner conductor 32, the dielectric 36 and the outer conductor 34 can be efficiently cooled by heat conduction.

  For example, the internal conductor 32 is made of copper, aluminum, stainless steel, or the like.

  The outer conductor 34 is made of, for example, a nonmagnetic material such as copper, aluminum, or nonmagnetic stainless steel. The reason for using a non-magnetic material will be described later.

The dielectric 36 is made of, for example, quartz, alumina (Al ₂ O ₃ ), fluorine resin, polyethylene, or the like.

A high frequency power supply 40 is connected to one end 32a of the internal conductor 32 via a matching circuit 42, and the other end 32b of the internal conductor 32 is grounded. More specifically, the high frequency power supply 40 has an output end 41 a and a ground end 41 b, and the output end 41 a is connected to one end 32 a of the internal conductor 32 via a matching circuit 42. The ground terminal 41b is grounded. As a result, a high-frequency current I _R can flow from the high-frequency power supply 40 to the internal conductor 32 via the matching circuit 42.

High-frequency power outputted from the high frequency power source 40, the frequency of the high frequency current I _R is, for example, is a common 13.56 MHz, the invention is not limited thereto.

  The matching circuit 42 includes a capacitor 43 in series with a line and a capacitor 44 in parallel. Both capacitors 43 and 44 are variable in capacity in this example.

  The outer conductor 34 is grounded only at one end thereof. The reason will be described later. In this example, the other end 34 b of the outer conductor 34, that is, the end on the same side as the ground side of the inner conductor 32 is grounded. Instead of this, the one end 34 a of the outer conductor 34, that is, the end on the same side as the power feeding side to the inner conductor 32 may be grounded.

In this antenna device 20, the outer conductor 34 of the antenna 30 is made of a non-magnetic material, and the outer conductor 34 is grounded only at one end thereof to form an electrical closed loop via the ground. since there, even if provided with the outer conductor 34, acting to attenuate the high-frequency magnetic field formed by the high frequency current I _R flowing through the inner conductor 32 is very small.

  The experimental results confirming the above will be described with reference to FIGS.

In the experiment, the antenna device shown in FIG. 10 was used. In this example, the antenna 30 having the coaxial structure as described above has a four-turn coil shape with a diameter of 80 mm in order to increase the generated magnetic field and facilitate measurement. A high frequency power supply 40 was connected to one end 32 a of the inner conductor 32 of the antenna 30 via a matching circuit 42, the other end 32 b was grounded, and a high frequency current I _R was passed through the inner conductor 32. Not only the magnitude of the high-frequency current I _R but also the frequency was changed to 100 kHz, 500 kHz, 1 MHz, and 2 MHz. The external conductor 34 is made of copper, and (A) when it is grounded only at the power feeding side, that is, at one end 34a, (B) when grounded only at the other end 34b on the opposite side, and (C) external An experiment was conducted in the case where the conductor 34 was not provided.

  The high frequency magnetic field generated by the antenna 30 in the above case was detected by the pickup coil 76 disposed near the center of the end face of the coil, and the output voltage was evaluated. The result is shown in FIG.

  FIG. 11 is a graph showing the pickup coil output (vertical axis) at each frequency in the cases (B) and (C) with the pickup coil output in the case (A) as a reference for comparison (horizontal axis). It has become. The result in the case of (B) is on the straight line B (y = 0.9649x), and the result in the case of (C) is on the straight line C (y = 1.0535x).

In the ideal case where there is no influence of the external conductor 34, the pickup coil output is on a straight line y = x, but even if the external conductor 34 is provided, the ideal case can be seen from the straight lines B and C. Therefore, it can be seen that even if the outer conductor 34 is provided, the action of attenuating the high-frequency magnetic field generated by the high-frequency current I _R flowing through the inner conductor 32 is very small. . Further, it can be seen from the straight line B that the outer conductor 34 is not greatly different even if it is grounded at either one end.

Referring again to FIGS. 1 to 3, in the antenna device 20, even when the outer conductor 34 is provided as described above, the function of attenuating the high-frequency magnetic field generated by the high-frequency current I _R flowing through the inner conductor 32 is extremely high. because small, it can be by the induction electric field generated by the high frequency magnetic field formed by the high frequency current I _R flowing through the inner conductor 32, to generate an inductively coupled plasma 16. That is, a high-frequency magnetic field is generated around the antenna 30 by the high-frequency current I _R flowing through the inner conductor 32, thereby generating an induction electric field in a direction opposite to the high-frequency current I _R. Due to this induced electric field, electrons are accelerated in the vacuum chamber 2 to ionize the gas 8 in the vicinity of the antenna 30 and generate plasma 16 in the vicinity of the antenna 30.

  In addition, since the outer conductor 34 that is electrically grounded covers the outside of the inner conductor 32 over at least the entire length located in the vacuum chamber 2, the electric field between the inner conductor 32 and the plasma 16 is shielded. be able to. Therefore, the potential of the inner conductor 32 does not affect the plasma potential. In addition, since the external conductor 34 is fixed to the ground potential and the potential of the external conductor 34 does not vibrate at a high frequency as in the conventional antenna, the inflow of electrons from the generated plasma 16 to the external conductor 34 is prevented. This is due to diffusion and a small plasma sheath voltage (this is, for example, about several tens of volts), and therefore the rise in plasma potential is small. The above action can suppress an increase in plasma potential.

  As a result, stable plasma generation can be performed. That is, since the rise of the plasma potential can be suppressed, it is possible to prevent the occurrence of discharge at a portion such as dust attached to the inner wall of the vacuum vessel, which has been a factor of plasma instability in the conventional antenna device. be able to.

  In addition, the energy of charged particles (for example, ions) incident on the substrate 10 from the plasma 16 can be suppressed to a low level. Accordingly, for example, when a film is formed on the substrate 10 by the plasma 16, damage to the film can be suppressed to be small, and the film quality can be improved.

  Furthermore, since the antenna 30 has the above-described water cooling structure, the temperature rise of the antenna can be suppressed. As a result, for example, the temperature rise of the substrate 10 due to thermal radiation from the antenna 30 can be suppressed.

  The antenna 30 may have a water cooling structure in which the cooling water 38 is allowed to flow inside at least one of the inner conductor 32 and the outer conductor 34 to cool the antenna 30. For example, as in the example shown in FIG. 4, the antenna 30 may be cooled by flowing cooling water 38 in both the inner conductor 32 and the outer conductor 34. By doing so, the cooling action of the antenna 30 can be further enhanced. In this case, the dielectric 36 and the outer conductor 34 do not need to be in thermal contact. Further, the antenna 30 may be cooled by flowing the cooling water 38 only in the outer conductor 34.

  Even if a film is formed on the surface of the outer conductor 34 as the plasma 16 is generated, stable plasma generation can be performed. That is, when a dielectric film (in other words, an insulating film) is deposited on the surface of the outer conductor 34, for example, electrons and ions flow from the plasma 16 into the surface of the dielectric film, thereby causing a potential on the surface of the dielectric film. Is immediately balanced with the plasma potential, so the potential on the surface of the dielectric coating is only about the plasma potential even if it is large. Moreover, as described above, the plasma potential in the case of the antenna device 20 does not increase greatly and is low, so it can be said that the antenna 30 is basically an antenna having a small surface potential increase. Therefore, instability factors such as arcing on the antenna surface can be prevented from occurring.

  Further, when a conductive film such as a metal is deposited on the surface of the external conductor 34, the film and the external conductor 34 are electrically connected, so there is no difference from the case of the external conductor 34 alone.

  As in the example shown in FIG. 5, a dielectric layer 39 that covers at least the entire length of the outer conductor 34 located in the vacuum vessel 2 may be provided. The same applies to the case of adopting the water cooling structure described with reference to FIG.

The dielectric layer 39 is made of, for example, quartz, alumina, yttria (yttrium oxide Y ₂ O ₃ ), or the like.

  When the dielectric layer 39 is provided, the potential of the surface of the dielectric layer 39 is almost balanced with the plasma potential immediately after electrons and ions flow from the plasma 16 to the surface of the dielectric layer 39. The potential difference between the surface 39 and the plasma 16 becomes small. As a result, it is possible to prevent instability factors such as arcing from occurring on the surface of the antenna 30.

  In addition, the material of the dielectric layer 39 can be the same as that of the film formed on the substrate 10, and by doing so, the possibility of contamination of the film formed on the substrate 10 can be further reduced. it can.

  The shape of the antenna 30 may be a straight line as shown in FIGS. 1 to 5 or other shapes. For example, the antenna 30 may be any of a U shape, a U shape, a circular shape wound once or more, an elliptical shape, a coil shape such as a racetrack shape, and the like. As in the example shown in FIG. 8, it may be a long and thin coiled shape. If it is coiled, the generated magnetic field can be made stronger. The same applies to the antenna device 20 used in a sputtering device described later.

  In the plasma processing apparatus shown in FIG. 1 and FIG. 2, parts other than the antenna apparatus 20 that has already been described will be described. The substrate 10 can be processed using the plasma 16 generated by the antenna apparatus 20. .

  The substrate 10 is, for example, a substrate for a flat panel display (FPD) such as a liquid crystal display or an organic EL display, a flexible substrate for a flexible display, a substrate for a semiconductor device such as a solar cell, or the like. is not.

  The planar shape of the substrate 10 is, for example, a circle or a rectangle, and is not limited to a specific shape.

  The processing applied to the substrate 10 is, for example, film formation by plasma CVD, etching, ashing, sputtering, or the like.

  This plasma processing apparatus uses plasma 16 to form a plasma CVD apparatus when forming a film by plasma CVD, a plasma etching apparatus when performing etching, a plasma ashing apparatus when performing ashing, and a sputtering when performing sputtering. Also called a device. More specific examples of the sputtering apparatus will be described below.

An example of a sputtering apparatus provided with the antenna device 20 as described above is shown in FIGS. In Figure 6, the feeding portion of the high frequency current I _R of the antenna 30 is conceptually shown, near both ends of the antenna 30 is specifically has a structure shown in FIG.

  This sputtering apparatus includes the antenna apparatus 20 as described above, and forms a film on the surface of the substrate 10 by sputtering the target 60 with the plasma 16 generated thereby. In the following, differences from the plasma processing apparatus described with reference to FIGS. 1 and 2 will be mainly described.

  This sputtering apparatus includes a target 60 provided in a position in the vacuum vessel 2 and facing the substrate 10. In this example, the target 60 has a rectangular planar shape as an example. The target 60 is held by a target holder (backing plate) 62 provided on the ceiling of the vacuum vessel 2. The target holder 62 has a water passage (not shown) for allowing cooling water to flow therein, thereby cooling the target 60 with water. An insulating part 52 having a vacuum sealing function is provided between the target holder 62 and the vacuum vessel 2.

  The material of the target 60 may be set according to the film formed on the surface of the substrate 10. The target 60 is, for example, quartz, alumina, IGZO (oxide semiconductor having an In—Ga—Zn—O composition), ZnO (zinc oxide), or the like.

  A target bias power supply 64 is connected to the target 60 via a target holder 62. In this example, the target bias power source 64 includes an AC power source 66 that applies an AC voltage to the target 60 via a matching circuit 68, a DC power source 70 that applies a negative DC voltage to the target 60, and a selector switch 72 that switches between the two. However, it is also possible to apply only one of an AC voltage and a DC voltage. The AC power supply 66 is, for example, a low frequency power supply having a frequency lower than the output of the high frequency power supply 40 (for example, about 10 kHz to 100 kHz). By doing so, interference with the plasma generation operation using the high frequency power supply 40 can be avoided.

In the vicinity of the surface of the target 60, the antenna 30 of the antenna device 20 described above is arranged. More specifically, two antennas 30 are arranged along each long side of the target 60. A high-frequency current I _R is supplied in parallel to each antenna 30 (specifically to its internal conductor 32) from a high-frequency power supply 40 via a matching circuit 42.

  Although it is preferable to arrange the two antennas 30 as described above as in this example because the surface of the target 60 can be used more uniformly, one antenna 30 is arranged on one side of the target 60. You may arrange | position along a long side.

  In this example, the gas 8 introduced into the vacuum vessel 2 is a sputtering gas. For example, the gas 8 is argon gas. When reactive sputtering is performed, the gas 8 is a mixed gas of argon gas and an active gas (for example, oxygen gas, nitrogen gas, etc.).

  The operation of generating the inductively coupled plasma 16 by ionizing the gas 8 by the antenna device 20 and the effect thereof (in brief, the suppression of the plasma potential increase, stable plasma generation, and charged particle incidence in the plasma) The suppression of damage given to the film and the suppression of the temperature rise of the substrate 10 due to thermal radiation from the antenna 30 are the same as those described above, and thus detailed description thereof is omitted here. Since the sputtering of the antenna 30 can be suppressed, contamination of the target 60, the substrate 10, and the film formed on the surface of the substrate 10 can be suppressed.

  In the case of this sputtering apparatus, inductively coupled plasma 16 is generated near the surface of the target 60 by the antenna apparatus 20. The ions in the plasma 16 can be attracted by, for example, an AC voltage applied to the target 60 from the AC power supply 66 and the matching circuit 68, whereby the surface of the target 60 is sputtered and the substrate 10 disposed opposite to the target 60. A film can be formed (deposited) on the surface. When the target 60 is conductive, a negative DC voltage may be applied to the target 60 from the DC power supply 70 instead of the AC voltage.

  In this sputtering apparatus, high-density plasma 16 can be generated in a wide range near the surface of the target 60 by inductively coupled plasma generation, so that the target 60 has a higher density than the sputtering apparatus using magnetron discharge. The surface can be used uniformly over a wide range. When magnetron discharge is used, the target surface is cut into a donut shape only in a specific region where the electric field and the magnetic field are orthogonal to each other. In the case of this sputtering apparatus, there is no such limitation. Therefore, the utilization efficiency of the target 60 can be increased.

  When the antenna device 20 having the elongated coil-shaped antenna 30 that is folded back as in the example shown in FIG. 8 is used in the sputtering device, the antenna 30 has a portion before and after the folding in the left-right direction (direction parallel to the surface of the target 60). It is preferable to arrange so that the portions before and after the folding are positioned in the vertical direction (direction parallel to the vertical line standing on the surface of the target 60) as in the example shown in FIG.

  In such a case, the magnetic field generated by each antenna 30 (which is schematically shown by the lines of magnetic force 74) spreads in the direction along the surface of the target 60, so that a strong high-frequency magnetic field is generated in a wide region along the surface of the target 60. It is possible to generate a high-density plasma 16 in a wide area along the surface of the target 60. Thereby, the target 60 can be sputtered more effectively.

  Further, when a plurality of targets 60 are arranged (in the case of so-called multi-target), one antenna 30 is arranged between two targets 60 one by one, so that one antenna 30 is connected to two targets 60 on both the left and right sides. Since it can be used for sputtering, the structure can be simplified.

  In addition, although the case where the planar shape of the target 60 was a rectangle was illustrated above, the planar shape of the target 60 is not limited thereto. For example, the planar shape of the target 60 may be a square, a circle, or the like. The shape of the antenna 30 may be a linear shape or a shape corresponding to the planar shape of the target 60. For example, when the planar shape of the target 60 is circular, the planar shape of the antenna 30 may be circular.

2 Vacuum container 10 Substrate 16 Plasma 20 Antenna device 30 Antenna 32 Inner conductor 34 Outer conductor 36 Dielectric 38 Cooling water 39 Dielectric layer 40 High frequency power supply 42 Matching circuit 60 Target

Claims (4)

An antenna device for generating inductively coupled plasma in a vacuum vessel,
An antenna located in the vacuum vessel, a high-frequency power source for supplying a high-frequency current to the antenna, and a matching circuit for matching between the antenna and the high-frequency power source,
The antenna includes an inner conductor, an outer conductor that covers at least the entire length of the inner conductor located in the vacuum vessel, and a dielectric that is provided between the inner conductor and the outer conductor to electrically insulate between the two conductors. A water-cooling structure that cools the antenna by flowing cooling water into at least one of the inner conductor and the outer conductor,
The high frequency power source is connected to one end of the inner conductor of the antenna via the matching circuit, and the other end of the inner conductor is grounded,
The antenna device according to claim 1, wherein the outer conductor of the antenna is made of a non-magnetic material, and the outer conductor is grounded only at one end thereof.   The antenna device according to claim 1, wherein the antenna further includes a dielectric layer that covers the outer side of the outer conductor over at least the entire length located in the vacuum vessel.   A plasma processing apparatus comprising the antenna device according to claim 1, wherein the substrate is processed using plasma generated thereby.   A sputtering apparatus comprising the antenna device according to claim 1, wherein the target is sputtered by plasma generated thereby to form a film on the surface of the substrate.

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