JP2011119657A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To freely and minutely control the plasma density distribution by using a simple correction coil in an inductively coupled plasma process. <P>SOLUTION: An inductively coupled plasma processing apparatus is configured such that inductively coupled plasma is generated so as to have a doughnut shape under a dielectric window 52 close to an RF antenna 54 and the doughnut-shaped plasma is dispersed in a large processing space so as to level the plasma density near a susceptor 12 (namely, on a semiconductor wafer W). In order to radially equalize the plasma density distribution near the susceptor 12, electromagnetic-field correction is applied to an RF magnetic field generated via the RF antenna 54 by a correction coil 70 while the height position of the correction coil 70 is variable by an antenna-coil interval control part 72 according to the pressure in a chamber 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for performing plasma processing on a substrate to be processed, and particularly to an inductively coupled plasma processing apparatus and a plasma processing method.

  In processes such as etching, deposition, oxidation, and sputtering in the manufacture of semiconductor devices and FPDs (Flat Panel Displays), plasma is often used to cause a favorable reaction at a relatively low temperature with a processing gas. Conventionally, plasma of high frequency discharge in the MHz region is often used for this type of plasma processing. Plasma by high frequency discharge is roughly classified into capacitively coupled plasma and inductively coupled plasma as more specific (device-like) plasma generation methods.

  In general, an inductively coupled plasma processing apparatus is configured such that at least a part (for example, a ceiling) of a wall of a processing container is formed of a dielectric window, and a high frequency power is applied to a coiled RF antenna provided outside the dielectric window. Supply. The processing container is configured as a vacuum chamber that can be depressurized, and a processing space is set between the dielectric window and the substrate in which a substrate to be processed (for example, a semiconductor wafer, a glass substrate, etc.) is disposed in the center of the chamber A processing gas is introduced into the system. The RF current flowing through the RF antenna generates an RF magnetic field around the RF antenna so that the magnetic lines of force pass through the dielectric window and pass through the processing space in the chamber. An induced electric field is generated in the azimuth direction. Then, the electrons accelerated in the azimuth direction by the induced electric field cause ionization collision with the molecules and atoms of the processing gas, and a donut-shaped plasma is generated.

  By providing a large processing space in the chamber, the doughnut-shaped plasma is efficiently diffused in all directions (particularly in the radial direction), and the density of the plasma is fairly uniform on the substrate. However, using only a normal RF antenna, the plasma density uniformity obtained on the substrate is insufficient for most plasma processes. Even in the inductively coupled plasma processing apparatus, improving the uniformity of the plasma density on the substrate is one of the most important issues because it affects the uniformity and reproducibility of the plasma process and, in turn, the manufacturing yield. So far, several related techniques have been proposed.

  Conventional typical plasma density equalization techniques divide the RF antenna into a plurality of segments. This RF antenna division method includes a first method (for example, Patent Document 1) that supplies individual high-frequency power to each antenna segment, and the impedance of each antenna segment is varied by an additional circuit such as a capacitor. There is a second method (for example, Patent Document 2) that controls the division ratio of RF power distributed to all antenna segments from one high-frequency power source.

  Further, a technique (Patent Document 3) in which a single RF antenna is used and a passive antenna is disposed in the vicinity of the RF antenna is also known. This passive antenna is configured as an independent coil that is not supplied with high-frequency power from a high-frequency power source, and simultaneously reduces the magnetic field strength in the loop of the passive antenna against the magnetic field generated by the RF antenna (inductive antenna). It behaves so as to increase the magnetic field strength near the outside of the loop of the passive antenna. As a result, the radial distribution of the RF electromagnetic field in the plasma generation region in the chamber is changed.

US Pat. No. 5,401,350 US Pat. No. 5,907,221 Special table 2005-534150

  However, among the RF antenna division methods as described above, the first method requires not only a plurality of high-frequency power sources but also the same number of matching units, which is a bottleneck due to the complexity of the high-frequency power feeding unit and the significant cost increase. ing. In the second method, the impedance of each antenna segment is affected not only by the other antenna segments but also by the plasma impedance. Therefore, the division ratio cannot be arbitrarily determined only by the additional circuit, and the controllability It is difficult to use.

  Further, the conventional method using a passive antenna as disclosed in Patent Document 3 affects the magnetic field generated by the RF antenna (inductive antenna) due to the presence of the passive antenna, thereby causing a plasma generation region in the chamber to be generated. Although it is taught that the radial distribution of the RF electromagnetic field can be changed, the consideration and verification of the action of the passive antenna is insufficient, and the passive antenna can be used to freely and accurately control the plasma density distribution. I cannot imagine the specific device configuration.

  Today's plasma processes require lower-pressure, higher-density, and larger-diameter plasma as the substrate becomes larger and devices become finer, and process uniformity on the substrate is more difficult than ever. It has become an issue.

  In this regard, the inductively coupled plasma processing apparatus generates a plasma in a donut shape inside a dielectric window close to the RF antenna, and diffuses the donut plasma toward the substrate in all directions. The plasma diffusion form changes depending on the pressure in the chamber, and the plasma density distribution on the substrate tends to change. Therefore, even if the pressure is changed in the process recipe, the magnetic field generated by the RF antenna (inductive antenna) cannot be corrected so that the uniformity of the plasma density on the substrate can be maintained following the change. The diverse and advanced process performance required for today's plasma processing equipment cannot be met.

  The present invention has been made in view of the prior art as described above, and does not require any special work on the RF antenna for plasma generation or the high-frequency power feeding system, and the plasma density distribution using a simple correction coil. Provided are an inductively coupled plasma processing apparatus and a plasma processing method that can freely and precisely control the above.

  A plasma processing apparatus according to a first aspect of the present invention includes a processing container having a dielectric window on a ceiling, a coiled RF antenna disposed on the dielectric window, and a substrate to be processed in the processing container. A substrate holding portion for holding the substrate, a processing gas supply portion for supplying a desired processing gas into the processing vessel in order to perform a desired plasma treatment on the substrate, and a plasma of the processing gas by inductive coupling in the processing vessel. In order to control the plasma density distribution on the substrate in the processing vessel, and a high-frequency power supply unit that supplies the RF antenna with high-frequency power having a frequency suitable for high-frequency discharge of the processing gas A correction coil disposed outside the processing container at a position that can be coupled to the antenna by electromagnetic induction; and the RF antenna while keeping the correction coil parallel to the RF antenna Antenna variably controls the separation distance between the correction coil - and a coil interval control unit.

  In the plasma processing apparatus according to the first aspect, when the high frequency power is supplied from the high frequency power feeding unit to the RF antenna by the above configuration, particularly by the configuration including the correction coil and the antenna-coil spacing control unit. In addition, the action of the correction coil against the RF magnetic field generated around the antenna conductor by the high-frequency current flowing through the RF antenna (the effect of locally reducing the density of the core plasma generated by inductive coupling around the position overlapping the coil conductor ) In a typical and stable manner, and the degree of such a correction coil effect (an effect of locally reducing the density of the core plasma) can be controlled substantially linearly. This makes it possible to arbitrarily and finely control the plasma density distribution in the vicinity of the substrate on the substrate holding unit, and to easily improve the uniformity of the plasma process.

  A plasma processing apparatus according to a second aspect of the present invention includes a processing container having a dielectric window on a ceiling, a coiled RF antenna disposed on the dielectric window, and a substrate to be processed in the processing container. A substrate holding portion for holding the substrate, a processing gas supply portion for supplying a desired processing gas into the processing vessel in order to perform a desired plasma treatment on the substrate, and a plasma of the processing gas by inductive coupling in the processing vessel. In order to control the plasma density distribution on the substrate in the processing vessel, and a high-frequency power supply unit that supplies the RF antenna with high-frequency power having a frequency suitable for high-frequency discharge of the processing gas A correction coil disposed outside the processing container at a position that can be coupled to the antenna by electromagnetic induction, and a relative up-and-down movement, parallel posture, and inclination between the RF antenna and the correction coil And a handling mechanism for causing the energization or periodic undulations movement.

  In the plasma processing apparatus according to the second aspect, with the above-described configuration, in particular, a configuration in which a relative up / down movement, a parallel posture, a tilted posture, or a periodic undulation motion is performed between the RF antenna and the correction coil. In addition to the same effects as the plasma processing apparatus according to the first aspect, the degree of the correction coil effect (the effect of locally reducing the density of the core plasma) or the plasma density distribution near the substrate is oriented. It can be more easily and finely uniform in the angular direction, or can be controlled arbitrarily.

  The plasma processing method of the present invention includes a processing container having a dielectric window on a ceiling, a coiled RF antenna disposed on the dielectric window, and a substrate holding for holding a substrate to be processed in the processing container. For generating a plasma of the processing gas by inductive coupling in the processing container, and a processing gas supply section for supplying a desired processing gas into the processing container in order to perform a desired plasma processing on the substrate A plasma processing method for performing desired plasma processing on the substrate in a plasma processing apparatus having a high-frequency power supply unit that supplies high-frequency power having a frequency suitable for high-frequency discharge of a processing gas to the RF antenna, A correction coil that can be coupled to the RF antenna by electromagnetic induction is arranged in parallel with the RF antenna, and the correction coil is kept parallel to the RF antenna. One, the distance interval between the RF antenna and the correction coil variably controlled to, controlling the plasma density distribution on the substrate.

  In the plasma processing method of the present invention, the correction coil that can be coupled to the RF antenna and electromagnetic induction is arranged in parallel with the RF antenna, in particular, outside the processing container by the technique as described above, and the correction coil is attached to the RF antenna. By keeping the parallel and variably controlling the distance interval between the RF antenna and the correction coil, when high-frequency power is supplied to the RF antenna from the high-frequency power feeding unit, the high-frequency current flowing through the RF antenna causes the antenna conductor to surround the antenna conductor. The action of the correction coil against the generated RF magnetic field (the action effect of locally reducing the density of the core plasma generated by inductive coupling around the position overlapping the coil conductor) can be obtained in a fixed and stable manner. Moreover, the degree of the correction coil effect (effect of locally reducing the density of the core plasma) is substantially linear. It is also possible to control. This makes it possible to arbitrarily and finely control the plasma density distribution in the vicinity of the substrate on the substrate holding unit, and to easily improve the uniformity of the plasma process.

  According to the plasma processing apparatus or the plasma processing method of the present invention, with the above-described configuration and operation, a simple correction coil is used without requiring any special work on the RF antenna for generating plasma or the high-frequency power feeding unit. The plasma density distribution can be freely and finely controlled.

It is a longitudinal cross-sectional view which shows the structure of the inductively coupled plasma processing apparatus in the 1st Embodiment of this invention. It is a perspective view which shows an example of RF antenna of a spiral coil shape. It is a perspective view which shows an example of a concentric coil-shaped RF antenna. It is a figure which shows typically an example of an electromagnetic effect | action when a correction coil is arrange | positioned far away from RF antenna. It is a figure which shows typically an example of an electromagnetic effect when arrange | positioning a correction coil near RF antenna. It is a figure which shows typically another example of the electromagnetic effect | action when a correction coil is arrange | positioned far away from RF antenna. It is a figure which shows typically another example of the electromagnetic effect | action when arrange | positioning a correction coil near RF antenna. It is a figure which shows the change of the current density distribution in the process space near a dielectric material window when the distance space | interval of a correction coil and RF antenna is changed. It is a figure which shows the process of a multilayer resist method in steps. It is a figure which shows the method of variably controlling the height position of a correction coil in the multistep etching process by a multilayer resist method. It is a figure which shows the method of variably controlling the height position of a correction coil in consideration of plasma ignitability. It is a perspective view which shows typically the structure of the correction coil with a fixed capacitor | condenser in 2nd Embodiment, and arrangement | positioning relationship with RF antenna. It is a figure which shows a mode that the current density distribution of the radial direction in inductively coupled plasma changes depending on the height position of the correction coil with a fixed capacitor. It is a perspective view which shows typically the structure of the correction coil with a variable capacitor in 2nd Embodiment, and arrangement | positioning relationship with RF antenna. It is a figure which shows the example of 1 structure of the correction coil with a capacitor | condenser. It is a perspective view which shows one structural example which makes a capacitor | condenser integrally in a correction coil. It is a top view which shows the winding structure of the correction coil in one structural example. It is a longitudinal cross-sectional view which shows the apparatus structure of one Example provided with the mechanism in which a correction coil is rotationally moved or rotationally displaced. It is a perspective view which shows a mode that a correction | amendment coil is rotationally moved or rotationally displaced by the coil rotation mechanism of FIG. It is a perspective view which shows a mode that a correction | amendment coil is rotationally moved or rotationally displaced by the coil rotation mechanism of FIG. It is a figure which shows the Example which cools a correction | amendment coil by an air cooling type. It is a figure which shows one Example which cools a correction coil via a refrigerant | coolant. It is sectional drawing which shows the structure of the coil handling mechanism for making a correction coil perform a raising / lowering movement, a horizontal attitude | position, arbitrary inclination attitude | positions, or a periodic undulation motion. It is a top view which shows the attachment structure of the said coil handling mechanism. It is a figure showing the characteristic of a phase-amplitude in the case of making a correction coil perform periodic undulation motion by a three-phase conductive actuator. It is a perspective view which shows the attitude | position of the correction coil in each phase in a periodic undulation motion. It is a perspective view which shows the attitude | position of the correction coil in each phase in a periodic undulation motion.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[Embodiment 1]

  A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows the configuration of an inductively coupled plasma processing apparatus according to the first embodiment. This inductively coupled plasma processing apparatus is configured as a plasma etching apparatus using a planar coil type RF antenna, and has a cylindrical vacuum chamber (processing vessel) 10 made of metal such as aluminum or stainless steel. . The chamber 10 is grounded for safety.

  First, the configuration of each part not related to plasma generation in this inductively coupled plasma etching apparatus will be described.

  A disc-shaped susceptor 12 on which, for example, a semiconductor wafer W is mounted as a substrate to be processed is horizontally disposed as a substrate holding table that also serves as a high-frequency electrode in the lower center of the chamber 10. The susceptor 12 is made of, for example, aluminum, and is supported by an insulating cylindrical support portion 14 that extends vertically upward from the bottom of the chamber 10.

  An annular exhaust path 18 is formed between the conductive cylindrical support section 16 extending vertically upward from the bottom of the chamber 10 along the outer periphery of the insulating cylindrical support section 14 and the inner wall of the chamber 10. An annular baffle plate 20 is attached to an upper portion or an inlet of 18 and an exhaust port 22 is provided at the bottom. In order to make the gas flow in the chamber 10 uniform on the axis of the semiconductor wafer W on the susceptor 12, it is preferable to provide a plurality of exhaust ports 22 at equal intervals in the circumferential direction.

  An exhaust device 26 is connected to each exhaust port 22 via an exhaust pipe 24. The exhaust device 26 has a vacuum pump such as a turbo molecular pump, and can depressurize the plasma processing space in the chamber 10 to a desired degree of vacuum. Outside the side wall of the chamber 10, a gate valve 28 that opens and closes a loading / unloading port 27 for the semiconductor wafer W is attached.

A high frequency power source 30 for RF bias is electrically connected to the susceptor 12 via a matching unit 32 and a power feed rod 34. The high-frequency power source 30 can output a high-frequency RF _L having a constant frequency (13.56 MHz or less) suitable for controlling the energy of ions drawn into the semiconductor wafer W with variable power. The matching unit 32 accommodates a reactance variable matching circuit for matching between the impedance on the high frequency power source 30 side and the impedance on the load (mainly susceptor, plasma, chamber) side. A blocking capacitor for generating a self-bias is included in the matching circuit.

  On the upper surface of the susceptor 12, an electrostatic chuck 36 for holding the semiconductor wafer W with an electrostatic attraction force is provided, and a focus ring 38 that surrounds the periphery of the semiconductor wafer W in an annular shape is provided radially outward of the electrostatic chuck 36. Provided. The electrostatic chuck 36 is obtained by sandwiching an electrode 36 a made of a conductive film between a pair of insulating films 36 b and 36 c, and a high voltage DC power supply 40 is electrically connected to the electrode 36 a through a switch 42 and a covered wire 43. It is connected. The semiconductor wafer W can be attracted and held on the electrostatic chuck 36 with an electrostatic force by a high-voltage DC voltage applied from the DC power supply 40.

  Inside the susceptor 12, for example, an annular refrigerant chamber or refrigerant flow path 44 extending in the circumferential direction is provided. A refrigerant having a predetermined temperature, such as cooling water cw, is circulated and supplied to the refrigerant chamber 44 through pipings 46 and 48 from a chiller unit (not shown). The temperature during processing of the semiconductor wafer W on the electrostatic chuck 36 can be controlled by the temperature of the coolant. In this connection, a heat transfer gas such as He gas from a heat transfer gas supply unit (not shown) is supplied between the upper surface of the electrostatic chuck 36 and the back surface of the semiconductor wafer W via the gas supply pipe 50. Is done. Further, for loading / unloading of the semiconductor wafer W, lift pins that can vertically move through the susceptor 12 and a lifting mechanism (not shown) and the like are also provided.

  Next, the configuration of each part related to plasma generation in this inductively coupled plasma etching apparatus will be described.

  A circular dielectric window 52 made of, for example, a quartz plate is airtightly attached to the ceiling of the chamber 10 at a relatively large distance from the susceptor 12. On the dielectric window 52, a coiled RF antenna 54 is disposed horizontally, usually coaxially with the chamber 10 or the susceptor 12. The RF antenna 54 preferably has, for example, a spiral coil (FIG. 2A) or a concentric coil (FIG. 2B) having a constant radius within each circumference, and an antenna fixing member (not shown) made of an insulator. Is fixed on the dielectric window 52.

  One end of the RF antenna 54 is electrically connected to an output terminal of a high-frequency power source 56 for plasma generation via a matching unit 58 and a feeder line 60. Although not shown, the other end of the RF antenna 54 is electrically connected to the ground potential via an earth wire.

The high-frequency power source 56 can output a high-frequency RF _H having a constant frequency (13.56 MHz or more) suitable for generating plasma by high-frequency discharge with variable power. The matching unit 58 accommodates a reactance variable matching circuit for matching between the impedance on the high frequency power supply 56 side and the impedance on the load (mainly RF antenna, plasma, correction coil) side.

  A processing gas supply unit for supplying a processing gas to the processing space in the chamber 10 is an annular manifold or buffer unit 62 provided inside (or outside) the side wall of the chamber 10 at a position somewhat lower than the dielectric window 52. A plurality of side wall gas discharge holes 64 facing the plasma generation space from the buffer unit 62 at equal intervals in the circumferential direction, and a gas supply pipe 68 extending from the processing gas supply source 66 to the buffer unit 62. The processing gas supply source 66 includes a flow rate controller and an on-off valve (not shown).

  This inductively coupled plasma etching apparatus is provided on the top plate of the chamber 10, that is, the dielectric window 54 in order to variably control the density distribution of the inductively coupled plasma generated in the processing space in the chamber 10 in the radial direction. The correction coil 70 that can be coupled to the RF antenna 54 by electromagnetic induction in the antenna room in the atmospheric pressure space, and the correction correction with the RF antenna 54 while keeping the correction coil 70 parallel (that is, horizontal) to the RF antenna 54 An antenna-coil spacing control unit 72 for variably controlling the distance between the coil 70 and the coil 70 is provided. Detailed configurations and operations of the correction coil 70 and the antenna-coil interval control unit 72 will be described later.

  The main control unit 74 includes, for example, a microcomputer. Each unit in the plasma etching apparatus, for example, the exhaust device 26, the high frequency power sources 30, 56, the matching units 32, 58, the electrostatic chuck switch 42, the processing gas supply source 66, It controls individual operations of the antenna-coil spacing control unit 72, the chiller unit (not shown), the heat transfer gas supply unit (not shown), and the operation (sequence) of the entire apparatus.

In order to perform etching in this inductively coupled plasma etching apparatus, the gate valve 28 is first opened, and the semiconductor wafer W to be processed is loaded into the chamber 10 and placed on the electrostatic chuck 36. After the gate valve 28 is closed, the etching gas (generally a mixed gas) is supplied from the processing gas supply source 66 through the gas supply pipe 68, the buffer unit 62, and the side wall gas discharge holes 64 at a predetermined flow rate and flow rate ratio. The pressure in the chamber 10 is set to a set value by the exhaust device 26. Further, the high frequency power source 56 is turned on to output a high frequency RF _H for plasma generation at a predetermined RF power, and a current of the high frequency RF _H is supplied to the RF antenna 54 via the matching unit 58 and the feeder line 60. On the other hand, the high frequency power supply 30 is turned on to output a high frequency RF _L for controlling the ion attraction at a predetermined RF power, and this high frequency RF _L is applied to the susceptor 12 via the matching unit 32 and the power feed rod 34. Further, the heat transfer gas (He gas) is supplied from the heat transfer gas supply unit to the contact interface between the electrostatic chuck 36 and the semiconductor wafer W, and the electrostatic chucking force of the electrostatic chuck 36 is turned on by turning on the switch 42. The heat transfer gas is confined in the contact interface.

The etching gas discharged from the side wall gas discharge holes 64 is uniformly diffused into the processing space below the dielectric window 52. By the current of the high frequency RF _H flowing RF antenna 54, RF magnetic field that the magnetic force lines to pass through the plasma generation space in the chamber through the dielectric window 52 is generated around the RF antenna 54, the time of the RF magnetic field Due to such a change, an RF induction electric field is generated in the azimuth direction of the processing space. Then, the electrons accelerated in the azimuth direction by the induced electric field cause ionization collisions with the molecules and atoms of the etching gas, and a donut-shaped plasma is generated. The radicals and ions of the doughnut-shaped plasma diffuse in all directions in a wide processing space, the radicals flow isotropically, and the ions are pulled by a DC bias, so that the top surface (surface to be processed) of the semiconductor wafer W To be supplied. In this way, the active species of plasma cause a chemical reaction and a physical reaction on the surface to be processed of the wafer W, and the film to be processed is etched into a desired pattern.

This plasma etching apparatus generates inductively-coupled plasma in a donut shape under the dielectric window 52 close to the RF antenna 54 as described above, and disperses the donut-shaped plasma in a wide processing space, thereby producing a susceptor. The density of plasma is averaged in the vicinity of 12 (that is, on the semiconductor wafer W). Here, the density of the donut-shaped plasma depends on the strength of the induction electric field, and in turn depends on the magnitude of the power of the high-frequency RF _H supplied to the RF antenna 54 (more precisely, the current flowing through the RF antenna 54). That is, as the power of the high frequency RF _H is increased, the density of the donut-shaped plasma is increased, and the density of the plasma in the vicinity of the susceptor 12 is generally increased through the diffusion of the plasma. On the other hand, the form in which the donut-shaped plasma diffuses in all directions (especially in the radial direction) mainly depends on the pressure in the chamber 10, and the lower the pressure, the more plasma gathers at the center of the chamber 10, and the vicinity of the susceptor 12. The plasma density distribution tends to swell in the center. Further, the plasma density distribution in the donut-shaped plasma may change depending on the power of the high-frequency RF _H supplied to the RF antenna 54, the flow rate of the processing gas introduced into the chamber 10, or the like.

  Here, the “doughnut-shaped plasma” is not limited to a strictly ring-shaped plasma in which plasma does not stand on the radially inner side (center portion) of the chamber 10 but only on the radially outer side. This means that the volume or density of plasma on the outer side in the radial direction is larger than the inner side in the radial direction. Further, depending on conditions such as the type of gas used for the processing gas and the pressure value in the chamber 10, the “doughnut-shaped plasma” may not occur.

  In the inductively coupled plasma etching apparatus, the plasma density distribution in the vicinity of the susceptor 12 is made uniform in the radial direction, and the RF magnetic field generated by the RF antenna 54 is electromagnetically corrected by the correction coil 70. The height position of the correction coil 70 is varied by the antenna-coil spacing control unit 72 according to the process conditions (pressure in the chamber 10 and the like).

  Hereinafter, the configuration and operation of the correction coil 70 and the antenna-coil spacing control unit 72, which are main features in the plasma etching apparatus, will be described.

  The correction coil 70 is composed of an annular single-turn coil or a double-turn coil closed at both ends, and is arranged coaxially with the RF antenna 54, and the coil conductor is between the inner periphery and the outer periphery of the RF antenna 54 in the radial direction. The coil diameter is such that it is preferably located in the vicinity of the middle. The material of the correction coil 70 is preferably, for example, a copper metal having high conductivity.

  In the present invention, “coaxial” means a positional relationship in which the central axes of a plurality of coils or antennas overlap each other, and the respective coil surfaces or antenna surfaces are offset from each other in the axial direction or the vertical direction. This includes not only the case but also the case of matching on the same plane (concentric positional relationship).

  The antenna-coil spacing control unit 72 is operatively coupled to the insulating horizontal support plate 74 holding the correction coil 70 and the horizontal support plate 74 via a ball screw 76, and rotates the feed screw 76a of the ball screw 76 for correction. The stepping motor 78 that changes the height position of the coil 70, the coil height control unit 80 that variably controls the height position of the correction coil 70 through the stepping motor 78 and the ball screw 76, and the horizontal support plate 74 are kept horizontal. It has a guide bar 82 for guiding in the vertical (vertical) direction.

  More specifically, the correction coil 70 is horizontally attached to the horizontal support plate 74 by an insulating coil fixing member (not shown). The horizontal support plate 74 is provided with a nut portion 76b that is screwed with the feed screw 76a, and a through hole 84 through which the guide rod 82 is slidable is also formed. The feed screw 76a of the ball screw 76 extends in the vertical direction and is coupled to the rotating shaft of the stepping motor 78 directly or via a speed reduction mechanism (not shown).

  When the stepping motor 78 is operated to rotate the feed screw 76a, the horizontal support plate 74 on the nut portion 76b side of the ball screw 76 moves up and down along the feed screw 76a, and the correction coil 70 is horizontally integrated with the horizontal support plate 74. Move vertically while maintaining posture. The coil height control unit 80 receives a signal for instructing the height position (target value or set value) of the correction coil 70 from the main control unit 74, controls the rotation direction and the rotation amount of the stepping motor 78, and supports the horizontal support. The height of the plate 74 is controlled to adjust the height position of the correction coil 70 to the target value.

  In the illustrated configuration example, a plurality of ball screws 76 that are operatively coupled to the horizontal support plate 74 at a plurality of locations are individually driven by a plurality of stepping motors 78. As another configuration example, a configuration in which a plurality of ball screws 76 are simultaneously driven by a single stepping motor 78 via a pulley or a belt mechanism is also possible.

In this embodiment, a linear scale 84 that actually measures the height position of the correction coil 70 and feeds back the measured value Sh ₇₀ to the coil height controller 80 is also provided. The linear scale 84 includes a vertical scale portion 86 attached to the horizontal support plate 74 and a scale reading portion attached to the main body or extension of the chamber 10 for optically reading the scale of the scale portion 86. 88. The coil height control unit 80 can also make the target height position of the correction coil 70 coincide with the actual measurement value Sh ₇₀ obtained by the linear scale 84.

  The antenna-coil spacing control unit 72 has a configuration as described above, and keeps the correction coil 70 parallel (horizontal) to the horizontally arranged RF antenna 54 while maintaining the correction coil 70 relative to the RF antenna 54. The height position can be varied arbitrarily and finely within a certain range (for example, 1 mm to 50 mm). Preferably, the upper limit value of the height position of the correction coil 70 is set to a position far enough not to substantially affect the RF magnetic field generated by the RF antenna 54, that is, as far as there is no correction coil 70. It's okay. Further, the lower limit value of the height position of the correction coil 70 may be set to an approach position where the influence on the RF magnetic field generated by the RF antenna 54 is maximized as long as it does not contact the RF antenna 54.

  Here, the basic operation of the correction coil 70 will be described.

First, as shown in FIG. 3A, when the height position of the correction coil 70 is set near the upper limit value, the RF magnetic field H generated around the antenna conductor due to the high-frequency RF _H current flowing through the RF antenna 54 is corrected. A loop-shaped magnetic field line that passes through the processing space under the dielectric window 52 in the radial direction without being affected by the coil 70 is formed.

The radial (horizontal) component Br of the magnetic flux density in the processing space is always zero at the center (O) and the peripheral portion of the chamber 10 irrespective of the magnitude of the high-frequency RF _H current, and in the RF antenna 54 in the radial direction. It becomes a maximum at a position that overlaps the middle of the periphery and the periphery (hereinafter referred to as “antenna middle part”), and the maximum value increases as the current of the high frequency RF _H increases. The intensity distribution of the induced electric field in the azimuth direction generated by the RF magnetic field H also has a profile similar to the magnetic flux density Br in the radial direction. Thus, a donut-shaped plasma is formed near the dielectric window 52 and coaxially with the RF antenna 54.

  This donut-shaped plasma diffuses in all directions (particularly in the radial direction) in the processing space. As described above, the diffusion form depends on the pressure in the chamber 10, but as an example, as shown in FIG. 3A, the electron density (plasma density) in the radial direction in the vicinity of the susceptor 12 relatively corresponds to the antenna middle part. In some cases, the profile is high (while remaining at the maximum) and falls in the center and the periphery.

In such a case, as shown in FIG. 3B, when the height position of the correction coil 70 is lowered to, for example, the vicinity of the lower limit value, the RF magnetic field H generated around the antenna conductor by the current of the high frequency RF _H flowing through the RF antenna 54. Is affected by the reaction of electromagnetic induction by the correction coil 70. This electromagnetic induction reaction is an action to counter the change of the magnetic field lines (magnetic flux) penetrating through the loop of the correction coil 70, and an induced electromotive force is generated in the loop of the correction coil 70 and a current flows.

  Thus, due to the reaction of electromagnetic induction from the correction coil 70, the radial direction (horizontal) component of the magnetic flux density in the processing space near the dielectric window 52 at a position almost directly below the coil conductor (particularly the antenna middle portion) of the correction coil 70. Br is locally weakened, so that the strength of the induced electric field in the azimuth angle direction is also locally weakened at a position corresponding to the antenna middle portion in the same manner as the magnetic flux density Br. As a result, the electron density (plasma density) is more uniform in the radial direction in the vicinity of the susceptor 12.

  The plasma diffusion form as shown in FIG. 3A is an example. For example, when the pressure is low, the plasma gathers too much in the center of the chamber 10 and the electron density (plasma density) in the vicinity of the susceptor 12 as shown in FIG. 4A. May show a mountain-shaped profile that is relatively maximum at the center.

  Even in such a case, as shown in FIG. 4B, when the correction coil 70 is lowered to, for example, the vicinity of the lower limit value, as shown in the drawing, the position near the dielectric window 52 at the position of the middle portion overlapping the coil conductor of the correction coil 70. The radial (horizontal) component Br of the magnetic flux density in the processing space is locally weakened, so that the plasma concentration at the center of the chamber is weakened, and the plasma density in the vicinity of the susceptor 12 is more uniform in the radial direction.

  The inventor verified the operation of the correction coil 70 as described above by electromagnetic field simulation. That is, the relative height position (distance interval) of the correction coil 70 with respect to the RF antenna 54 is used as a parameter, and the parameter value is selected from four types of 5 mm, 10 m, 20 mm, and infinity (no correction coil), and the donut-shaped plasma is selected. When the current density distribution (corresponding to the plasma density distribution) in the radial direction inside (at a position 5 mm from the upper surface) was obtained, a verification result as shown in FIG. 5 was obtained.

In this electromagnetic field simulation, the outer diameter (radius) of the RF antenna 54 was set to 250 mm, and the inner and outer radii of the correction coil 70 were set to 100 mm and 130 mm, respectively. The donut-shaped plasma generated by inductive coupling in the processing space in the chamber below the RF antenna 54 is simulated by a disk-shaped resistor. The resistor has a diameter of 500 mm, a resistivity of 100 Ωcm, and a skin thickness of 10 mm. Set to. The frequency of the high frequency RF _H for plasma generation was 13.56 MHz.

  From FIG. 5, when the correction coil 70 is disposed at a height position where it is coupled to the RF antenna 54 by electromagnetic induction, the plasma density in the donut-shaped plasma overlaps with the coil conductor of the correction coil 70 (in the example shown, the antenna middle portion and It can be seen that the local reduction near the overlapping position) and the degree of local reduction increases substantially linearly as the correction coil 70 is brought closer to the RF antenna 54.

  In this embodiment, as described above, the correction coil 70 is arranged coaxially with respect to the RF antenna 54, and between the inner periphery and the outer periphery of the RF antenna 54 in the radial direction (preferably facing the antenna middle portion). ) It is configured such that the coil conductor of the correction coil 70 is located. Then, the antenna-coil spacing control unit 72 keeps the correction coil 70 parallel (horizontal) to the horizontal RF antenna 54, and sets the relative height position of the correction coil 70 to the RF antenna 54 within a certain range (for example, 5 can be varied arbitrarily and finely within a range of 1 mm to 50 mm), so that the characteristics shown in FIG. 5 verified by electromagnetic field simulation can be realized as a device, and the degree of freedom and accuracy of plasma density distribution control can be greatly improved. be able to.

  The inductively coupled plasma etching apparatus in this embodiment can be suitably applied to, for example, an application that continuously etches a multilayer film on a substrate surface in a plurality of steps. Examples of the present invention relating to the multilayer resist method as shown in FIG. 6 will be described below.

  In FIG. 6, a SiN layer 102 is formed on the main surface of a semiconductor wafer W to be processed as a lowermost layer (final mask) on an original film to be processed (for example, a Si film for a gate) 100. An organic film (for example, carbon) 104 is formed as an intermediate layer, and an uppermost photoresist 108 is formed thereon via a Si-containing antireflection film (BARC) 106. For the formation of the SiN layer 102, the organic film 104 and the antireflection film 106, a coating film by CVD (chemical vacuum deposition) or spin-on is used, and for the patterning of the photoresist 108, photolithography is used.

First, as a first step etching process, the Si-containing antireflection film 106 is etched using the patterned photoresist 108 as a mask as shown in FIG. In this case, a mixed gas of CF ₄ / O ₂ is used as the etching gas, and the pressure in the chamber 10 is relatively low, for example, set to 10 mTorr.

Next, as a second step etching process, as shown in FIG. 6B, the organic film 104 is etched using the photoresist 108 and the antireflection film 106 as a mask. In this case, a single gas of O ₂ is used as the etching gas, and the pressure in the chamber 10 is further lowered, for example, set to 5 mTorr.

Finally, as a third step etching process, as shown in FIGS. 6C and 6D, the SiN film 102 is etched using the patterned antireflection film 106 and organic film 104 as a mask. In this case, a mixed gas of CHF ₃ / CF ₄ / Ar / O ₂ is used as the etching gas, and the pressure in the chamber 10 is relatively high, for example, set to 50 mTorr.

  In the multi-step etching process as described above, all or a part of the process conditions (particularly the pressure in the chamber 10) is switched for each step, thereby changing the form of diffusion of the donut-shaped plasma in the processing space. . Here, when the correction coil 70 is not functioned (energized) at all, in the first and second step processes (pressure 10 mTorr or less), the electron density (plasma density) near the susceptor 12 is relatively centered as shown in FIG. 4A. It is assumed that a steep mountain-shaped profile that rises remarkably in the region appears, and a gentle mountain-shaped profile that slightly rises in the center portion appears in the third step process (pressure 50 mTorr).

  According to this embodiment, the height of the correction coil 70, for example in a process recipe, in a manner that is added to or linked to normal process conditions (high frequency power, pressure, gas type, gas flow rate, etc.). The position is set as one of recipe information or process parameters. When the multi-step etching process as described above is executed, the main control unit 74 reads out data representing the height position setting value of the correction coil 70 from the memory, and the coil height control unit 80 for each step. Through this, the height position of the correction coil 70 is adjusted to the set value (target value).

Therefore, in the etching process of the multilayer resist method as described above (FIG. 6), as shown in FIG. 7, the first step (10 mTorr) is set at a relatively low setting position h ₁ and the second step (5 mTorr) is further reduced. In the third step (50 mTorr), the height position of the correction coil 70 is switched to the lower position h ₂ for each step to the relatively higher position h ₃ .

As described above, the height position of the correction coil 70 can be variably adjusted in accordance with the change, switching, or change of process conditions while performing a single or a series of plasma treatments on one semiconductor wafer W. . Thus, the action (electromagnetic reaction) of the correction coil 70 with respect to the RF magnetic field H generated around the antenna conductor by the high-frequency RF _H current flowing through the RF antenna 54 throughout the entire processing time or steps of the single wafer plasma process. ), That is, the degree (strength) of the effect of locally reducing the plasma density in the donut-shaped plasma around the position overlapping the coil conductor of the correction coil 70 can be adjusted arbitrarily, finely, and linearly. It is also possible to keep the plasma density near the susceptor 12 uniform in the radial direction. Therefore, the uniformity of the plasma process can be improved.

In the multi-step method, while the etching process is not performed, as shown in FIG. 7, the height position of the correction coil 70 is substantially equal to the home position h _P near the upper limit value when there is no correction coil 70. You can bring it back.

Further, when the process of each step is started, that is, when a high-frequency RF _H current starts to flow through the RF antenna 54, a large induced current flows through the correction coil 70, making it difficult for the power to enter the plasma side. Ignition may be difficult. In such a case, as shown in FIG. 8, at the start of the process steps, the correction coil 70 allowed to temporarily retracted to the home position H _P stably reliably ignite the plasma, after plasma ignition ( For example, it may be moved up and down to a preset height position h _n (n = 1, 2, 3) after a predetermined time T _S has elapsed since the start of the process.

  As described above, according to the present invention, the correction coil 70 is sufficiently separated from the RF antenna 54 before the start of the plasma processing, and after a predetermined time elapses after the plasma is ignited in the chamber 10, A method of adjusting the distance interval to a preset value by moving the correction coil 70 (and / or the RF antenna 54) up and down so as to approach can be suitably employed.

  In this embodiment, as described above, the antenna-coil spacing control unit 72 for variably adjusting the distance or height position of the correction coil 70 with respect to the RF antenna 54 is configured by a ball screw mechanism. However, instead of the ball screw mechanism, a three-dimensional cam mechanism such as a rotating body cam or an end cam can be used. That is, although the detailed configuration is not shown, as another example of the antenna-coil interval control unit 72, an insulating coil holder that holds the correction coil 70 in parallel with the RF antenna 54, and a coil holder A motor that is coupled via a three-dimensional cam mechanism having a rotating body, rotates the rotating body of the three-dimensional cam mechanism, and changes the height position of the correction coil 70, and controls and corrects the rotation direction and amount of rotation of the motor. A configuration having a coil height control unit for controlling the height position of the coil 70 is also possible.

  Alternatively, as another embodiment for variably adjusting the height position of the correction coil 70 in the antenna-coil spacing control unit 72, a non-rotating lifting shaft such as a rack and pinion or a piston can be used for the lifting mechanism. is there. In addition to the motor, for example, an air cylinder may be used as a drive source for the lifting mechanism. When a motor is used as the drive source, it is not limited to a stepping motor, and may be an AC motor, a DC motor, a linear motor, or the like.

As a means for measuring or feeding back an arbitrary height position of the correction coil 70, for example, an encoder can be used in addition to the linear scale 84 in the above embodiment. Further, when the correction coil 70 is moved and positioned at a predetermined height position, a position sensor such as a photo sensor or a limit switch can be preferably used.

[Embodiment 2]

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  In the plasma etching apparatus of the second embodiment, the plasma density distribution in the vicinity of the susceptor 12 is made uniform in the radial direction, and the RF coil generated by the RF antenna 54 is electromagnetically corrected by the correction coil 90 with a capacitor. In addition, the height position of the correction coil 90 with a capacitor can be variably controlled by the antenna-coil interval control unit 72.

  Hereinafter, the configuration and operation of the correction coil 90 with a capacitor, which is a main characteristic part of the inductively coupled plasma etching apparatus, will be described.

  As shown in FIG. 9, the correction coil 90 is composed of a single-winding coil or a multi-winding coil whose both ends are opened with a gap (gap) G interposed therebetween, and a fixed capacitor 94 is provided in the gap G. As will be described later, the fixed capacitor 94 may be a commercially available general-purpose type such as a film capacitor or a ceramic capacitor, or may be a custom-made product or a one-piece product integrally formed in the correction coil 90.

  The correction coil 90 is preferably arranged coaxially with the RF antenna 54 and has a coil diameter such that the coil conductor is located between the inner periphery and the outer periphery of the RF antenna 54 (for example, just in the middle) in the radial direction. Have. With respect to the orientation of the correction coil 90 in the azimuth direction, for example, as shown in the figure, the position of the fixed capacitor 94 (that is, the position of the cut G) overlaps the position of the RF input / output cut G for the RF antenna 54. The material of the coil conductor of the correction coil 90 is preferably a metal having high conductivity, such as silver-plated copper.

  Here, the operation of the correction coil 90 with the fixed capacitor 94 will be described. The inventor conducted the following electromagnetic field simulation for the inductively coupled plasma etching apparatus of this embodiment.

  That is, the relative height position (distance interval) h of the correction coil 90 with respect to the RF antenna 54 is used as a parameter, and the value of the parameter h is selected from four types of 5 mm, 10 m, 20 mm, and infinity (no correction coil). When the current density distribution in the radial direction (corresponding to the plasma density distribution) inside the donut-shaped plasma in 10 (position 5 mm from the upper surface) was obtained, profiles as shown in FIG. 10 were obtained at each coil height position. .

In this electromagnetic field simulation, the outer diameter (radius) of the RF antenna 54 is set to 250 mm, the inner diameter (radius) and outer diameter (radius) of the correction coil 90 are set to 100 mm and 130 mm, respectively, and the capacitance ( The capacitance of the fixed capacitor 94) was set to 600 pF. The doughnut-shaped plasma generated by inductive coupling in the processing space in the chamber below the RF antenna 54 is simulated by a disk-shaped resistor 95 as shown in FIG. Was set to 100 Ωcm, and the skin thickness was set to 10 mm. The frequency of the high frequency RF _H for plasma generation was 13.56 MHz.

  The capacitance of the correction coil 90 is set to infinity (corresponding to the case where the fixed capacitor 94 is removed and both ends of the correction coil 90 are short-circuited). As shown in FIG. 5, a profile as shown in FIG. 5 is obtained at each coil height position.

  As shown in FIG. 10A, the closer the correction coil 90 is to the RF antenna 54, the more the plasma density distribution of the donut-shaped plasma is near the position (r = 110 to 130 mm) that overlaps the coil conductor of the correction coil 90. It tends to be locally higher and lower than that when there is no correction coil 90 at the radially inner and outer positions. Then, as shown in FIG. 10B, it can be seen that this tendency becomes weaker as the correction coil 90 is moved away from the RF antenna 54. Further, as shown in FIG. 10C, when the correction coil 90 is moved away from the RF antenna 54 by an appropriate distance (h = 20 mm), a position (r = 110 to 130 mm) overlapping with the coil conductor of the correction coil 90 is obtained. It can also be seen that the plasma density is several steps higher in the outer region (r = 130-250 mm) than in the radially inner region (r = 0-110 mm).

  In this embodiment, the antenna-coil spacing control unit 72 keeps the correction coil 90 parallel to the horizontal RF antenna 54 (horizontal), while maintaining the relative height position of the correction coil 90 with respect to the RF antenna 54 constant. Since it can be varied arbitrarily and finely within a range (for example, 1 mm to 50 mm), the characteristics shown in FIG. 10 verified by electromagnetic field simulation are realized as a device, and the degree of freedom and accuracy of plasma density distribution control are greatly improved. Can be made.

  In the second embodiment, a configuration in which the fixed capacitor 94 is replaced with a variable capacitor 96 is also possible. In that case, as shown in FIG. 11, a capacitance variable mechanism 98 for variably controlling the capacitance of the variable capacitor 96 is also provided. The variable capacitor 96 may be a commercially available general-purpose type such as a variable capacitor or a varicap, or may be a custom-made product or a one-piece product integrally formed in the correction coil 90.

  The capacitance variable mechanism 98 is a capacitance that variably controls the variable capacitor 96 provided in the loop of the correction coil 90 and the capacitance of the variable capacitor 96 typically by a mechanical drive mechanism or an electric drive circuit. It is comprised with the control part 100.

The capacitance control unit 100 receives, from the main control unit 74, the capacitance setting value or recipe information or process parameter that is the basis of the capacitance setting value through the control signal S _C regarding the capacitance of the variable capacitor 96. Furthermore, the capacity control unit 100 represents the _peak value V _PP of the high-frequency voltage immediately before being input from the V _PP detector 102 (FIG. 1) to the RF antenna 54 as a monitor signal or feedback signal for variable coil capacity control. The signal SV _PP is received, and the signal SI _IND representing the current value (effective value) of the induced current I _IND flowing through the correction coil 90 is received from the coil current measuring device 104. Furthermore, the current value (effective value) of the antenna current (RF current) I _RF flowing through the RF antenna 54 may be measured by the RF ammeter 105 and the measured value SI _RF may be given to the capacitance control unit 100. As the V _PP detector 102, the one provided in the matching unit 58 in order to measure the _peak value V _PP of the output voltage of the matching unit 58 can be used. As an example, the coil current measuring device 104 includes a current sensor 106 and a coil current measuring circuit 108 that calculates a current value (effective value) of the coil current I _IND based on an output signal of the current sensor 106.

The capacity control unit 100 preferably includes a microcomputer, and for example, the coil capacity-dependent characteristics of the current ratio I _IND / I _RF or V _PP can be mapped to the table memory, and is sent from the main control unit 74. Based on the information such as the capacity setting value (target value) or the process recipe or process parameter that comes, and further by the feedback control using the current monitor unit or the V _PP monitor unit, the variable capacitor 74 most suitable for the process. The capacitance can be selected or can be dynamically varied.

  As described above, by independently variably controlling the height position and the capacitance of the correction coil 90 with the variable capacitor 96, the degree of freedom and accuracy of plasma density distribution control can be further improved.

  12 and 13 show an example of the configuration of the correction coil 90 with a capacitor. In the configuration example shown in FIG. 12, one cut G is formed in the correction coil 90, and a commercially available two-terminal capacitor (94, 96) is attached to this place. The configuration example shown in FIG. 13 is an example in which the gap G of the correction coil 90 is used as it is as the interelectrode gap of the fixed capacitor 94. A dielectric film (not shown) may be inserted into the cut line G. In this configuration example, the pair of open ends of the coil conductors facing each other through the cut G constitute a capacitor electrode. As shown in FIG. 15B, the capacitor electrode can be adjusted to have an arbitrary electrode area by integrally attaching an extension 120 extending upward (or laterally).

  It is also possible to provide a plurality of correction coils 90. For example, as shown in FIG. 14, two independent correction coils 90A and 90B having different coil diameters may be arranged concentrically.

As another configuration example, although not shown, it is also possible to arrange a plurality of independent correction coils 90A, 90B,...

[Other Embodiments]

  As another embodiment of the configuration or function around the correction coil of the present invention, as shown in FIG. 15, the coil rotation for rotating or displacing the correction coil 90 with a capacitor at a position coaxial with the RF antenna 54 is performed. The mechanism 180 can be suitably provided. The coil rotation mechanism 180 is coupled to, for example, an insulating substrate holding plate 182 that holds the correction coil 90 coaxially and horizontally with the RF antenna 54, and a central portion of the substrate holding plate 182 via a vertical rotation shaft 184. And a rotation control unit 188 for controlling the rotation direction, rotation speed, or rotation angle of the correction coil 90 through the stepping motor 186. A reduction mechanism (not shown) may be provided between the stepping motor 186 and the rotating shaft 184. The ground wire 55 electrically connects the other end (high frequency outlet end) of the RF antenna 54 to the ground potential.

  According to this embodiment, by providing the coil rotation mechanism 180 having the above-described configuration, for example, as shown in FIGS. 16A and 16B, the correction coil 90 is rotated around its central axis N, and the rotation direction, The rotational speed, rotational angle, reciprocating motion, etc. can be arbitrarily controlled or selected.

  For example, when the vicinity of the cut G forms a spatial singular point on the electromagnetic field of the correction coil 90 with respect to the plasma in the RF antenna 54 or the chamber 10, the correction coil 90 is moved at a constant speed by the coil rotation mechanism 180. By rotating continuously at, the positions of the singular points can be leveled in the circumferential direction so that the correction coils are closed at both ends without any breaks.

  In addition, a large induction current (sometimes a current greater than the current flowing through the RF antenna) may flow through the correction coil of the present invention, and it is important to pay attention to the heat generated by the correction coil.

  From this point of view, as shown in FIG. 17A, a coil cooling unit that cools by an air cooling method by installing an air cooling fan in the vicinity of the correction coil 90 can be suitably provided. Alternatively, as shown in FIG. 17B, a coil cooling section in which the correction coil 90 is configured by a hollow copper tube and a refrigerant is supplied therein to prevent the correction coil 90 from being overheated is also preferable.

  Although the embodiment shown in FIGS. 14 to 17B relates to the correction coil 90 with a capacitor, the same configuration can be applied to the correction coil 70 without a capacitor.

  As another embodiment relating to the configuration or function around the correction coil of the present invention, as shown in FIG. 18, the correction coil 70 (90) is raised and lowered in the antenna chamber above the top plate (dielectric window) 52 of the chamber 10. The coil handling mechanism 200 that enables not only the movement but also a horizontal posture, an arbitrary inclined posture, and a periodic waving motion can be suitably provided.

  The coil handling mechanism 200 includes rod-like coil support shafts 202A, 202B, and 202C that are coupled to the correction coil 70 (90) via insulating joints 202A, 202B, and 202C at a predetermined interval in the circumferential direction. These coil support shafts 204A, 204B, and 204C have direct-acting electric actuators 206A, 206B, and 206C that extend or retract in the vertical direction.

  The electric actuators 206A, 206B, and 206C are attached to an annular support plate 208 horizontally installed above the top plate (dielectric window) 52 at intervals of 120 °. Here, the support plate 208 includes, for example, an annular flange portion 210 coupled to the chamber 10, four column members 212 attached to the flange portion 210 on the circumference at intervals of 90 °, for example. It is fixed to the chamber 10 by a horizontal beam portion 214 that connects the column member 212 and the support plate 208.

  The electric actuators 206A, 206B, and 206C can independently move the coil support shafts 202A, 202B, and 202C at arbitrary timings, speeds, and strokes under the control of the main control unit 74. The joints 202A, 202B, and 202C have a joint function that can follow the inclination posture of the correction coil 70 (90), and reduce stress applied when the correction coil 70 (90) changes its posture.

  In this coil handling mechanism 200, the correction coil 70 (90) can be placed in a parallel posture with respect to the RF antenna 54 by adjusting the stroke amount (lifting amount) of the coil support shafts 204A, 204B, 204C. It is also possible to adopt an inclined posture at an angle and an arbitrary direction.

  Further, for example, as shown in FIG. 20, the electric actuators 206A, 206B, and 206C and the coil support shafts 204A, 204B, and 204C periodically move back and forth with a constant phase interval and the same amplitude, so that the correction coil 70 ( 90) can perform periodic undulation movements as shown in FIGS. 21A and 21B. In the figure, [A], [B], and [C] schematically represent the coil support shafts 202A, 202B, and 202C, respectively. In the illustrated example, the phase interval between the coil support shafts 204A, 204B, and 204C is 120 °, and the amplitude is ± 15 mm. Normally, three-phase driving may be used as in this example, but in the case of four-phase driving, for example, the phase interval is 90 °.

  In this periodic undulation movement, the center +0 of the correction coil 70 (90) is fixed or stationary at the same position of the height reference value (zero), and the top position HP and the top position HP of +15 mm, which is the highest of the correction coil 70 (90). It moves continuously at a constant speed in the circumferential direction while facing a low -15 mm bottom position LP at a point-symmetrical position, and appears to rotate in a wavy shape while maintaining a constant inclination posture. A straight line BL in FIGS. 21A and 21B indicates a horizontal line passing through the bottom position LP of the correction coil 70 (90), and rotates and moves periodically in the same plane. In the figure, the numerical values attached to [A], [B], and [C] represent the amplitude values of the support shafts 202A, 202B, and 202C at that time. For example, “+7.5” is +7.5 mm, and “−15” is −15 mm.

  In the periodic undulation motion as described above, the center O, the top position HP, and the bottom position of the correction coil 70 (90) are made different by varying the stroke amounts (lifting amounts) of the coil support shafts 202A, 202B, 202C. It is also possible to change the height of the HP.

  By causing the correction coil 70 (90) to perform the above-described periodic undulation motion, the degree of the correction coil effect (the effect of locally reducing the density of the core plasma) or the plasma density distribution in the vicinity of the substrate can be determined as the azimuth angle. It can be made easier and finer in the direction and can be controlled arbitrarily.

  Although the RF antenna 54 is fixed in the configuration example of FIG. 18, the RF antenna 54 is also moved up and down by providing an antenna handling mechanism (not shown) having the same configuration as the coil handling mechanism 200. , Horizontal postures, arbitrary tilting postures or periodic undulation movements can also be performed.

  The configuration of the inductively coupled plasma etching apparatus in the above-described embodiment is an example, and various modifications can be made to the configuration of each part not directly related to plasma generation as well as each part of the plasma generation mechanism.

  For example, as a basic form of the RF antenna 54 and the correction antenna 70, a type other than the planar form, such as a dome shape, is possible. Furthermore, the type installed in places other than the ceiling of the chamber 10 is also possible, for example, the helical type installed outside the side wall of the chamber 10 is also possible.

  Also, a chamber structure for a rectangular substrate, a rectangular RF antenna structure, and a rectangular correction coil structure are possible.

Further, the processing gas supply unit may be configured to introduce the processing gas into the chamber 10 from the ceiling, and may be configured such that the high frequency RF _L for DC bias control is not applied to the susceptor 12. On the other hand, a plasma using a plurality of RF antennas or antenna segments and individually supplying high-frequency power for generating plasma to the plurality of RF antennas (or antenna segments) from a plurality of high-frequency power sources or high-frequency power supply systems. The present invention can also be applied to an apparatus.

  Furthermore, the inductively coupled plasma processing apparatus or plasma processing method according to the present invention is not limited to the technical field of plasma etching, and can be applied to other plasma processes such as plasma CVD, plasma oxidation, plasma nitridation, and sputtering. . Further, the substrate to be processed in the present invention is not limited to a semiconductor wafer, and various substrates for flat panel displays, photomasks, CD substrates, printed substrates, and the like are also possible.

DESCRIPTION OF SYMBOLS 10 Chamber 12 Susceptor 26 Exhaust apparatus 56 High frequency power supply 66 Processing gas supply source 70 Correction coil 72 Antenna-coil space | interval control part 90 Correction coil with a capacitor 200 Coil handling mechanism

Claims (12)

A processing vessel having a dielectric window on the ceiling;
A coiled RF antenna disposed on the dielectric window;
A substrate holding unit for holding a substrate to be processed in the processing container;
A processing gas supply unit for supplying a desired processing gas into the processing container in order to perform a desired plasma processing on the substrate;
A high-frequency power feeding unit that supplies high-frequency power having a frequency suitable for high-frequency discharge of the processing gas to the RF antenna in order to generate plasma of the processing gas by inductive coupling in the processing container;
In order to control the plasma density distribution on the substrate in the processing container, a correction coil disposed outside the processing container at a position that can be coupled to the RF antenna by electromagnetic induction;
A plasma processing apparatus, comprising: an antenna-coil interval control unit that variably controls a distance interval between the RF antenna and the correction coil while keeping the correction coil parallel to the RF antenna. The RF antenna is disposed on the dielectric window;
The antenna-coil spacing control unit moves up and down at least one of the RF antenna or the correction coil to change its height position.
The plasma processing apparatus according to claim 1. The antenna-coil spacing controller is
An insulating coil holder for holding the correction coil in parallel with the RF antenna;
A motor coupled to the coil holder via a ball screw mechanism, and rotating the feed screw of the ball screw mechanism to vary the height position of the correction coil;
The plasma processing apparatus according to claim 2, further comprising: a coil height control unit that controls a height position of the correction coil by controlling a rotation direction and a rotation amount of the motor. The antenna-coil spacing controller is
An insulating coil holder for holding the correction coil in parallel with the RF antenna;
A motor coupled to the coil holder via a three-dimensional cam mechanism having a rotating body, and rotating the rotating body of the three-dimensional cam mechanism to vary the height position of the correction coil;
The plasma processing apparatus according to claim 2, further comprising: a coil height control unit that controls a height position of the correction coil by controlling a rotation direction and a rotation amount of the motor. A processing vessel having a dielectric window on the ceiling;
A coiled RF antenna disposed on the dielectric window;
A substrate holding unit for holding a substrate to be processed in the processing container;
A processing gas supply unit for supplying a desired processing gas into the processing container in order to perform a desired plasma processing on the substrate;
A high-frequency power feeding unit that supplies high-frequency power having a frequency suitable for high-frequency discharge of the processing gas to the RF antenna in order to generate plasma of the processing gas by inductive coupling in the processing container;
In order to control the plasma density distribution on the substrate in the processing container, a correction coil disposed outside the processing container at a position that can be coupled to the RF antenna by electromagnetic induction;
A plasma processing apparatus, comprising: a handling mechanism that performs a relative up / down movement, a parallel posture, a tilt posture, or a periodic undulation motion between the RF antenna and the correction coil.   The correction coil is composed of a single-turn coil or a multi-turn coil closed at both ends, and is arranged coaxially with respect to the RF antenna, and the coil conductor is positioned between the inner periphery and the outer periphery of the RF antenna in the radial direction. The plasma processing apparatus as described in any one of Claims 1-5 which has such a coil diameter. The correction coil is composed of a single-turn coil or a multi-turn coil that is open at both ends,
A capacitor is provided between both open ends of the correction coil,
The plasma processing apparatus as described in any one of Claims 1-5.   The plasma according to claim 7, wherein the correction coil is disposed coaxially with the RF antenna and has a coil diameter such that a coil conductor is positioned between an inner periphery and an outer periphery of the RF antenna in a radial direction. Processing equipment.   The plasma processing apparatus as described in any one of Claims 1-8 which has a coil cooling part for cooling the said correction | amendment coil. A processing container having a dielectric window on the ceiling; a coiled RF antenna disposed on the dielectric window; a substrate holding unit for holding a substrate to be processed in the processing container; Suitable for high-frequency discharge of processing gas to generate plasma of processing gas by inductive coupling in the processing container and processing gas supply section for supplying a desired processing gas into the processing container to perform plasma processing A plasma processing method for performing a desired plasma process on the substrate in a plasma processing apparatus having a high-frequency power supply unit that supplies high-frequency power of a predetermined frequency to the RF antenna,
A correction coil that can be coupled to the RF antenna by electromagnetic induction outside the processing container is disposed in parallel with the RF antenna,
A plasma processing method for controlling a plasma density distribution on the substrate by variably controlling a distance interval between the RF antenna and the correction coil while keeping the correction coil parallel to the RF antenna.   11. The plasma according to claim 10, wherein a distance interval between the RF antenna and the correction coil is variably controlled in accordance with a change, change, or switching of a process condition during a plasma process on one substrate to be processed. Processing method.   Before starting plasma processing, the correction coil is sufficiently separated from the RF antenna, and after a predetermined time has elapsed since the plasma was ignited in the processing container, the correction coil is moved relative to the RF antenna. The plasma processing method according to claim 11, wherein the distance interval is adjusted to a preset value by moving at least one of the two so as to approach each other.

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