TWI486994B - Plasma processing device and plasma processing method - Google Patents

Description

Plasma processing device and plasma processing method

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

In the processing of etching, deposition, oxidation, sputtering, and the like in a semiconductor device or a FPD (Flat Panel Display) process, plasma is often used in order to allow a good reaction to be performed at a relatively low temperature in the processing gas. In the past, most of such plasma treatments used plasmas of high frequency discharge in the MHz field. The plasma of high-frequency discharge is roughly divided into a capacitively coupled plasma and an inductively coupled plasma as a more specific (device) plasma generation method.

In general, an inductively coupled plasma processing apparatus is configured to form at least a portion (for example, a ceiling) of a wall portion of a processing container by a dielectric window, and to supply a coil-shaped RF antenna provided outside the dielectric window. Frequency power. The processing container is a vacuum chamber that is decompressible, and a substrate to be processed (for example, a semiconductor wafer, a glass substrate, or the like) is disposed in a central portion of the chamber, and is introduced into a processing space set between the dielectric window and the substrate. Process the gas. The RF magnetic field flowing through the RF antenna through the RF current flowing through the RF antenna is generated around the RF antenna through an RF magnetic field such as a processing space in the chamber, and is processed by the temporal change of the RF magnetic field. An induced electric field is generated in the azimuthal direction in the space. Then, by inducing the electric field, the electrons accelerated in the azimuthal direction are ionized and collided with the molecules or atoms of the processing gas to generate a donut-shaped plasma.

By providing a large processing space in the chamber, the above-mentioned donut-shaped plasma can be efficiently diffused to the square (especially in the radial direction), and the density of the plasma on the substrate is relatively average. However, light using a conventional RF antenna, the uniformity of the plasma density that can be achieved on the substrate is insufficient in most plasma processes. In the inductively coupled plasma processing apparatus, the uniformity of the plasma density on the substrate is also one of the most important issues in terms of the uniformity of the left and right plasma processes, the reproducibility, and the manufacturing yield. So far, several techniques for this relationship have been proposed.

A conventional technique for uniformizing plasma density is to divide an RF antenna into a plurality of segments. The RF antenna division method includes a first mode in which individual high-frequency power is supplied to each antenna ‧ segment (for example, Patent Document 1), and an additional circuit such as a capacitor can change the impedance of each antenna ‧ segment, and the control is controlled by 1 The high-frequency power source is allocated to the second aspect of the division ratio of the RF power of all the antennas and the segments (for example, Patent Document 2).

Further, a technique in which a single RF antenna is used and a passive antenna is disposed in the vicinity of the RF antenna is known (Patent Document 3). The passive antenna is an independent coil that does not receive high-frequency power from a high-frequency power source, and the magnetic field generated by the RF antenna (inductive antenna) reduces the magnetic field strength in the loop of the passive antenna while making the passive antenna The strength of the magnetic field near the outside of the loop increases. Thereby, the radial direction distribution of the RF electromagnetic field in the plasma generation region in the chamber is changed.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] U.S. Patent No. 5,401,350

[Patent Document 2] U.S. Patent No. 5,906,221

[Patent Document 3] Special Table 2005-534150

However, in the above-described RF antenna division method, the first aspect requires not only a plurality of high-frequency power sources but also an integrator of the same number, and the high frequency power supply unit is complicated and the high cost is high, which poses a large bottleneck. Further, in the second aspect described above, not only the impedance of each antenna ‧ segment but also the impedance of the plasma is affected by the impedance of the other antenna ‧ segments. Therefore, the division ratio cannot be arbitrarily determined by the additional circuit, and the controllability is difficult, and it is not used.

Moreover, the conventional method of using the passive antenna disclosed in the above-mentioned Patent Document 3 is that the magnetic field generated by the RF antenna (inductive antenna) is affected by the presence of the passive antenna, whereby the plasma generation region in the chamber can be changed. The RF electromagnetic field is distributed in the radial direction, but the investigation of the role of the passive antenna is not sufficiently verified, and it is impossible to imagine a specific device configuration for controlling the plasma density distribution by using a passive antenna.

In today's plasma process, as the substrate is enlarged and the device is miniaturized, a plasma having a lower pressure, a higher density, and a larger diameter is required, and the uniformity of the process on the substrate is a more difficult problem than before.

In this point, the inductively coupled plasma processing device generates a donut shape on the inner side of the dielectric window close to the RF antenna, so that the donut-shaped plasma diffuses toward the substrate, but the plasma The diffusion pattern varies with the pressure in the chamber, and the plasma density distribution on the substrate is easily changed. Therefore, if the magnetic field generated by the RF antenna (inductive antenna) cannot be corrected, the pressure can be maintained even if the process recipe is changed, and the uniformity of the plasma density on the substrate can be maintained, so that the current plasma cannot be satisfied. The diverse and high process performance required for the processing equipment.

The present invention has been made in view of the above-described conventional techniques, and provides an RF antenna or a high-frequency power supply unit for plasma generation that does not require special work, and can be used to finely control the plasma density distribution using a simple correction coil. Inductively coupled plasma processing apparatus and plasma processing method.

A plasma processing apparatus according to a first aspect of the present invention includes: a processing container having a dielectric window; a coil-shaped RF antenna disposed outside the dielectric window; and a substrate holding portion The substrate to be processed is held in the processing container; the processing gas supply unit supplies the desired processing gas to the processing container for performing the desired plasma treatment on the substrate; and the high frequency power supply unit is for the aforementioned A high frequency electric power of a frequency suitable for high frequency discharge of the processing gas is supplied to the RF antenna by inductively coupling to generate plasma of the processing gas, and a correction coil for controlling the aforementioned inside the processing container The plasma density distribution on the substrate is disposed outside the processing container at a position that can be coupled to the RF antenna by electromagnetic induction; the switching element is disposed in the current path of the correction coil; and the switch control unit The ON/OFF control of the switching element is performed by a pulse width modulation at a desired load ratio.

In the plasma processing apparatus according to the first aspect of the invention, the RF coil is provided by the high frequency power supply unit, in particular, by the configuration including the correction coil, the switching element, and the switch control unit. When high-frequency power is supplied, the effect of the correction coil on the RF magnetic field generated around the antenna conductor by the high-frequency current flowing through the RF antenna can be fixedly and stably obtained (by sensing in the vicinity of the position overlapping the coil conductor) The plasma density of the core generated by the coupling is locally reduced. Moreover, the degree of such a correction coil effect (the effect of locally lowering the plasma density of the core) can be controlled substantially linearly. Thereby, the plasma density distribution can be arbitrarily and finely controlled in the vicinity of the substrate on the substrate holding portion, and the uniformity of the plasma process can be easily achieved.

A plasma processing apparatus according to a second aspect of the present invention includes a processing container which is a window having a dielectric in a ceiling, a coil-shaped RF antenna disposed on the dielectric window, and a substrate holding portion. Providing a substrate to be processed in the processing container; a processing gas supply unit for supplying a desired processing gas to the processing container for performing a desired plasma treatment on the substrate; and a high frequency power supply unit for Generating a plasma of a processing gas by inductive coupling in the processing container, and supplying high frequency power suitable for a frequency of high frequency discharge of the processing gas to the RF antenna; a correction coil having an annular coil conductor that is open at both ends via a gap for controlling the plasma density distribution on the substrate in the processing container, and is located between the inner circumference and the outer circumference of the RF antenna in the radial direction And being disposed on the RF antenna at a position that can be coupled by electromagnetic induction; the variable resistor is disposed in a gap of the correction coil; and the resistance control unit controls the resistance value of the variable resistor to The value expected.

In the plasma processing apparatus according to the second aspect of the invention, the RF coiling device, the variable resistor, and the resistor control unit are provided in the above-described configuration, and the RF power supply unit is used to RF. When the antenna supplies high-frequency power, the effect of the correction coil on the RF magnetic field generated around the antenna conductor by the high-frequency current flowing through the RF antenna can be fixed and stabilized (by the position overlapping the coil conductor) The effect of the local plasma density generated by the inductive coupling is locally reduced. Moreover, the degree of such a correction coil effect (the effect of locally lowering the plasma density of the core) can be controlled substantially linearly. Thereby, the plasma density distribution can be arbitrarily and finely controlled in the vicinity of the substrate on the substrate holding portion, and the uniformity of the plasma process can be easily achieved.

A plasma processing apparatus according to a third aspect of the present invention includes: a processing container having a dielectric window; an RF antenna disposed outside the dielectric window; and a substrate holding portion being subjected to the processing The substrate to be processed is held in the container; and the processing gas supply unit is configured to perform the desired electricity on the substrate a slurry treatment for supplying a desired processing gas into the processing container; and a high frequency power feeding portion for generating a high frequency discharge suitable for the processing gas in order to generate a plasma of the processing gas by inductive coupling in the processing container The high frequency power of the frequency is supplied to the RF antenna; the correction coil is for controlling the plasma density distribution on the substrate in the processing container, and has a circuit independent of the RF antenna, and can be electromagnetically A position inductively coupled to the RF antenna is disposed outside the processing container; and a shutter is disposed in the circuit of the correction coil.

In the above-described configuration of the plasma processing apparatus according to the third aspect of the present invention, in particular, the configuration of the correction coil and the shutter is used to supply high-frequency power to the RF antenna by the high-frequency power supply unit. The effect of the correction coil on the RF magnetic field generated around the antenna conductor by the high-frequency current flowing through the RF antenna can be selectively obtained (the core generated by inductive coupling in the vicinity of the position overlapping the coil conductor) The effect of the plasma density is locally reduced.)

A plasma processing apparatus according to a fourth aspect of the present invention includes: a processing container having a dielectric window; an RF antenna disposed outside the dielectric window; and a substrate holding portion being processed by the processing The processing substrate is held in the container; the processing gas supply unit supplies the desired processing gas to the processing container for performing the desired plasma processing on the substrate; and the high-frequency power supply unit is for the processing container. Generating a plasma of a process gas by inductive coupling, and a high frequency discharge suitable for the process gas The high-frequency power of the frequency is supplied to the RF antenna; and the first and second correction coils are provided separately from the RF antenna in order to control the plasma density distribution on the substrate in the processing container. And being disposed outside the processing container at a position that can be coupled to the RF antenna by electromagnetic induction; and the first and second switches are respectively disposed in the circuits of the first and second correction coils.

In the plasma processing apparatus according to the fourth aspect of the present invention, the first and second correction coils and the first and second shutters are provided by the high frequency power supply unit. When the high-frequency power is supplied to the RF antenna, the action of each of the correction coils on the RF magnetic field generated around the antenna conductor by the high-frequency current flowing through the RF antenna can be selectively obtained (near the position overlapping the coil conductor) The effect of the total density of the core of the correction coil is reduced by the combination of the first correction coil and the second correction coil.

A plasma processing method according to a fifth aspect of the present invention is a plasma processing method for performing a desired plasma treatment on a substrate in a plasma processing apparatus, the plasma processing apparatus comprising: a processing container having a dielectric a coiled RF antenna disposed outside the dielectric window; a substrate holding portion holding the substrate to be processed in the processing container; and a processing gas supply portion for performing the substrate The desired plasma treatment, and the desired processing gas is supplied into the processing container; and a high frequency power feeding unit that supplies high frequency power suitable for a high frequency discharge of a processing gas to the RF antenna for generating a plasma of a processing gas by inductive coupling in the processing container; the plasma The processing method is: having a bypass circuit independent of the RF antenna, and a correction coil that can be combined with the RF antenna by electromagnetic induction in parallel with the processing container and the RF antenna are arranged in parallel, and the circuit of the correction coil is arranged A shutter is provided inside to control the opening and closing state of the shutter to control the plasma density on the substrate.

In the plasma processing method according to the above fifth aspect, the correction coil which is independent of the RF antenna, and which can be combined with the RF antenna by electromagnetic induction, by the above-described technique, in particular, outside the processing container It is arranged in parallel with the RF antenna, and a switch is provided in the circuit of the correction coil to control the opening/closing state of the switch. When the high-frequency power supply unit supplies high-frequency power to the RF antenna, it can be set and stabilized. The correction coil is obtained by the action of the RF magnetic field generated around the antenna conductor by the high-frequency current flowing through the RF antenna (the plasma density of the core generated by inductive coupling near the position overlapping the coil conductor is locally The effect of low ground reduction is). Thereby, the plasma density distribution can be arbitrarily controlled in the vicinity of the substrate on the substrate holding portion, and the uniformity of the plasma process can be easily achieved.

A plasma processing method according to a sixth aspect of the present invention is a plasma processing method for performing a desired plasma treatment on a substrate in a plasma processing apparatus, the plasma processing apparatus having: a processing container having a dielectric window; a coil-shaped RF antenna disposed outside the dielectric window; a substrate holding portion holding the substrate to be processed in the processing container; and a processing gas supply unit And supplying a desired processing gas to the processing container for performing a desired plasma treatment on the substrate; and a high-frequency power feeding unit for generating a processing gas by inductive coupling in the processing container. a high frequency electric power of a frequency suitable for processing a high frequency discharge of a gas to the aforementioned RF antenna; characterized by having a bypass circuit independent of the aforementioned RF antenna, and being external to the processing container The first and second correction coils that are coupled to the RF antenna are arranged in parallel with the RF antenna, and the first and second switches are provided in the circuits of the first and second correction coils, and the first and second switches are controlled. The plasma density on the substrate is controlled in each of the open and closed states of the second shutter.

In the plasma processing method according to the sixth aspect described above, the above-described technique, particularly in addition to the processing container, has a bypass circuit independent of the RF antenna, and can be combined with the RF antenna by electromagnetic induction. The first and second correction coils are arranged in parallel with each other, and the first and second shutters are provided in the circuits of the first and second correction coils, and the opening and closing of the first and second switches are controlled ( In the ON/OFF state, when high-frequency power is supplied to the RF antenna by the high-frequency power supply unit, the correction coil can be fixedly and stably obtained for the high-frequency current flowing through the RF antenna to be generated around the antenna conductor. The action of the RF magnetic field (the effect of locally lowering the plasma density of the core generated by inductive coupling near the position where the coil conductor overlaps). Thereby, the plasma density distribution can be arbitrarily controlled in the vicinity of the substrate on the substrate holding portion, and the uniformity of the plasma process can be easily achieved.

According to the plasma processing apparatus or the plasma processing method of the present invention, the RF antenna or the high-frequency power supply unit for plasma generation does not require special work, and a simple correction coil can be used. From and finely control the plasma density distribution.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

[First Embodiment]

A first embodiment of the present invention will be described with reference to Figs. 1 to 10 .

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

First, the configuration of each unit irrespective of plasma generation in the inductively coupled plasma etching apparatus will be described.

In the center of the lower portion of the chamber 10, the disk-shaped susceptor 12 on which the substrate to be processed, for example, the semiconductor wafer W, is placed is horizontally disposed as a substrate holding table having a high-frequency electrode. The susceptor 12 is made of, for example, aluminum and is supported by an insulating cylindrical support portion 14 that extends vertically from the bottom of the chamber 10 to the upper side.

An annular exhaust passage 18 is formed between the conductive cylindrical support portion 16 extending vertically from the bottom of the chamber 10 to the upper portion of the insulating cylindrical support portion 14 and the inner wall of the chamber 10, An annular baffle 20 is attached to the upper portion or the inlet of the exhaust passage 18, and an exhaust port 22 is provided at the bottom. In order to make the airflow in the chamber 10 uniform with respect to 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.

Each of the exhaust ports 22 is connected to the exhaust device 26 via an exhaust pipe 24. The exhaust device 26 is a vacuum pump having a turbo molecular pump or the like, and can decompress the plasma processing space in the chamber 10 to a desired degree of vacuum. A gate valve 28 that opens and closes the carry-out port 27 of the semiconductor wafer W is attached to the outside of the side wall of the chamber 10.

The high frequency power source 30 for RF bias is electrically connected to the susceptor 12 via the integrator 32 and the feed bar 34. The high frequency power source 30 can output a high frequency RF _L suitable for controlling a certain frequency (below 13.56 MHz) of ion energy introduced to the semiconductor wafer W with variable power. The integrator 32 is an integrated circuit having a variable reactance for integrating between the impedance of the high frequency power source 30 side and the impedance of the load (mainly the susceptor, plasma, chamber) side. A blocking capacitor for self-bias generation is included in the integrated circuit.

An electrostatic chuck 36 for holding the semiconductor wafer W by electrostatic attraction force is provided on the upper surface of the susceptor 12, and a focus ring 38 surrounding the periphery of the semiconductor wafer W is provided on the outer side in the radial direction of the electrostatic chuck 36. The electrostatic chuck 36 is such that an electrode 36a made of a conductive film is interposed between a pair of insulating films 36b and 36c, and a high-voltage DC power source 40 is electrically connected to the electrode 36a via a switch 42 and a covered wire 43. The semiconductor wafer W can be adsorbed and held on the electrostatic chuck 36 by electrostatic force by a high-voltage DC voltage applied from the DC power source 40.

An annular refrigerant chamber or a refrigerant flow path 44, for example, along the circumferential direction is provided inside the susceptor 12. The refrigerant chamber 44 is a refrigerant such as cooling water cw that is circulated and supplied to a predetermined temperature from a cooling unit (not shown) via pipes 46 and 48. The temperature in the process of the semiconductor wafer W on the electrostatic chuck 36 can be controlled by the temperature of the refrigerant. In connection with this, 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 tube 50. Further, a lift pin that can move up and down through the susceptor 12 in the vertical direction for loading/unloading of the semiconductor wafer W, an elevating mechanism (not shown), and the like are also provided.

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

The ceiling of the chamber 10 is spaced apart from the base 12 by a large distance, and a circular dielectric window 52 composed of, for example, a quartz plate is hermetically mounted. In the dielectric window 52, a coil-shaped RF antenna 54 is generally disposed horizontally coaxially with the chamber 10 or the susceptor 12. Preferably, the RF antenna 54 is a body having, for example, a spiral coil (Fig. 2A) or a concentric coil having a constant radius in one week (Fig. 2B), and is fixed to the antenna fixing member (not shown) formed of an insulator. On the dielectric window 52.

At one end of the RF antenna 54, the output terminal of the high frequency power source 56 for plasma generation is electrically connected via the integrator 58 and the feed line 60. Although the other end of the RF antenna 54 is omitted, it is actually electrically connected to the ground potential via a ground line.

The high-frequency power source 56 can output a high-frequency RF _H suitable for a certain frequency (13.56 MHz or more) suitable for plasma generation by high-frequency discharge with variable power. The integrator 58 is an integrated circuit having a variable reactance for integrating the impedance on the side of the high-frequency power source 56 with the impedance on the side of the load (mainly the RF antenna, the plasma, and the correction coil).

The processing gas supply unit for supplying the processing gas to the processing space in the chamber 10 has an annular manifold or buffer portion 62 which is provided in the chamber 10 at a position slightly lower than the dielectric window 52. Among the side walls (or outside); a plurality of side wall gas discharge holes 64 which face the plasma generation space from the buffer portion 62 at equal intervals in the circumferential direction; and a gas supply pipe 68 from the process gas supply source 66 It extends to the buffer portion 62.

Further, the processing gas supply source 66 includes a flow rate controller and an on-off valve (not shown).

The inductively coupled plasma etching apparatus includes a correction coil 70 for variably controlling the density distribution of the inductively coupled plasma generated in the processing space in the chamber 10 in the radial direction, and is provided in the chamber 10 The antenna room of the atmospheric pressure space on the top plate can be combined with the RF antenna 54 by electromagnetic induction; and the switch mechanism 110 is for variably controlling the load ratio of energization of the current induced current flowing through the correction coil 70.

The configuration and operation of the correction coil 70 and the switch mechanism 110 will be described in detail later.

The main control unit 74 is, for example, a microcomputer, and controls each unit in the plasma etching apparatus such as the exhaust unit 26, the high-frequency power sources 30 and 56, the integrators 32 and 58 , the switch 42 for the electrostatic chuck, the processing gas supply source 66, The operation of each of the switching mechanism 110, the cooling unit (not shown), the heat transfer gas supply unit (not shown), and the entire operation (sequence) of the apparatus.

In the inductively coupled plasma etching apparatus, first, the gate valve 28 is opened, and the semiconductor wafer W to be processed is carried into the chamber 10 and placed on the electrostatic chuck 36. Then, after the gate valve 28 is closed, the etching gas (generally a mixed gas) is introduced into the chamber from the processing gas supply source 66 via the gas supply pipe 68, the buffer portion 62, and the side wall gas discharge hole 64 at a predetermined flow rate and flow rate ratio. In 10, the pressure in the chamber 10 is set to a set value by the exhaust device 26. The high-frequency power source 56 is turned on (ON) to output the high-frequency RF _H for plasma generation at a predetermined RF power, and the current of the high-frequency RF _H is supplied to the RF antenna 54 via the integrator 58 via the integrator 58. On the other hand, the high frequency power source 30 is turned on to cause the high frequency RF _L for ion introduction control to be output at a predetermined RF power, and the high frequency RF _L is applied to the susceptor 12 via the integrator 32 and the power feeding rod 34. . Further, the heat transfer gas supply unit supplies a heat transfer gas (He gas) to the contact interface between the electrostatic chuck 36 and the semiconductor wafer W, and the ON switch 42 is electrostatically adsorbed by the electrostatic chuck 36. The heat transfer gas is closed at the above contact interface.

The etching gas discharged from the side wall gas discharge holes 64 is a processing space uniformly diffused under the dielectric window 52. By the current of the high-frequency RF _H flowing through the RF antenna 54, the magnetic field passing through the dielectric window 52 and passing through the plasma generating space in the chamber is generated around the RF antenna 54 by the RF magnetic field. The temporal change produces an RF induced electric field in the azimuthal direction of the processing space. Then, by inducing the electric field, the electrons accelerated in the azimuthal direction collide with the molecules or atoms of the etching gas to form a donut-shaped plasma. The free radicals or ions of the donut-shaped plasma diffuse in the square in a wide processing space, and the radicals are equally dropped, and the ions are attracted by the DC bias and supplied to the upper surface of the semiconductor wafer W (processed surface). As described above, on the surface to be processed of the wafer W, the active species of the plasma brings about a chemical reaction and a physical reaction, and the processed film is etched into a desired pattern.

The inductively coupled plasma etching apparatus is formed as described above under the dielectric window 52 of the RF antenna 54 to form an inductively coupled plasma in a doughnut shape, so that the donut-shaped plasma is dispersed in a wide area. Within the processing space, the density of the plasma is averaged near the susceptor 12 (i.e., on the semiconductor wafer W). Here, the density of the donut-shaped plasma depends on the intensity of the induced electric field, and even depends on the power of the high-frequency RF _H supplied to the RF antenna 54 (more correctly, the current flowing through the RF antenna 54). That is, the higher the power of the high-frequency RF _H , the higher the density of the donut-shaped plasma, and the plasma density near the susceptor 12 is increased by the diffusion of the plasma. On the other hand, the form in which the donut-shaped plasma diffuses in the square (especially in the radial direction) mainly depends on the pressure in the chamber 10. The lower the pressure, the more plasma is concentrated in the center of the chamber 10, There is a tendency for the plasma density distribution near the susceptor 12 to rise at the center. Further, the plasma density distribution in the donut-shaped plasma changes depending on the power of the high-frequency RF _H supplied to the RF antenna 54 or the flow rate of the processing gas introduced into the chamber 10.

Here, the "doughnut-shaped plasma" is not limited to a plasma that does not cause plasma in the radial direction inner side (center portion) of the chamber 10, but only a plasma ring that is plasma-like on the outer side in the radial direction, and also means a diameter. The volume or density of the plasma on the outer side is larger than the inner diameter in the radial direction of the chamber 10. Further, depending on the type of the gas used for the processing gas or the pressure value in the chamber 10, the so-called "doughnut-shaped plasma" may not be formed.

In the plasma etching apparatus, the plasma density distribution in the vicinity of the susceptor 12 is uniformized in the radial direction, and the electromagnetic field generated by the RF antenna 54 is corrected by the correction ring 70, and in accordance with the process conditions (chamber) The pressure in 10, etc., is made variable by the switching mechanism 110 in the energization load ratio of the correction coil 70.

Hereinafter, the configuration and operation of the correction ring 70 and the switching mechanism 110, which are the main features of the inductively coupled plasma etching apparatus, will be described.

More specifically, as shown in FIG. 6, the correction coil 70 is constituted by an annular single-coil coil or a rewinding coil which is opened by sandwiching an appropriate gap g at both ends, so that the coil conductor in the radial direction can be located in the RF antenna 54. The RF antenna 54 is coaxially disposed between the inner circumference and the outer circumference (preferably in the vicinity of the center), and is horizontally held by an insulating coil holding member (not shown) at a certain height position close to the RF antenna 54. The material of the correction coil 70 has a high electrical conductivity, and is preferably a copper-based metal.

Further, in the present invention, "coaxial" refers to a positional relationship in which the central axes of a plurality of coils or antennas overlap each other, and not only when the respective coil faces or antenna faces are offset from each other in the axial direction or the longitudinal direction, but also include the same When the faces are consistent (concentric positional relationship).

Here, the configuration in which the correction coil 70 has no gap g is referred to as a completely endless type correction coil 70', and the action when changing the height position of the completely endless type correction coil 70' will be described.

First, as shown in FIG. 3A, when the height position of the completely endless type correction coil 70' is set to the vicinity of the upper limit value, the RF around the antenna conductor is generated by the current of the high frequency RF _H flowing through the RF antenna 54. The magnetic field H is not affected by any of the completely endless type correction coils 70', and forms a loop-like magnetic line of force passing through the processing space under the dielectric window 52 in the radial direction.

The radial direction (horizontal) component Br of the magnetic flux density of the processing space is such that the current of the high frequency RF _H is not zero at the center (O) and the peripheral portion of the chamber 10, and is in the radial direction and the inner circumference and the outer circumference of the RF antenna 54. The position where the vicinity of the middle (hereinafter referred to as "antenna intermediate portion") overlaps is extremely large, and the current of the high-frequency RF _H is larger, and the maximum value thereof is higher. The intensity distribution of the induced electric field in the azimuthal direction generated by the RF magnetic field H also forms the same contour as the magnetic flux density Br in the radial direction. Thus, a donut-shaped plasma is formed coaxially with the RF antenna 54 in the vicinity of the dielectric window 52.

This donut-shaped plasma then spreads to the square (especially in the radial direction) in the processing space. As described above, the diffusion pattern depends on the pressure in the chamber 10. However, as shown in FIG. 3A, for example, in the radial direction near the susceptor 12, the electron density (plasma density) is relatively opposite to the antenna. The position corresponding to the intermediate portion is increased (maintained extremely) and the contour is lowered at the center portion and the peripheral portion.

In such a case, as shown in FIG. 3B, if the height position of the completely endless type correction coil 70' is lowered to, for example, the vicinity of the lower limit value, the high frequency RF _H flowing through the RF antenna 54 is as shown in the figure. The RF magnetic field H generated by the current around the antenna conductor is affected by the reaction of the electromagnetic induction due to the completely endless type correction coil 70'. The reaction of this electromagnetic induction is to resist the change of the magnetic flux (magnetic flux) in the loop through the completely endless correction coil 70', and the induced current is generated in the loop of the completely endless correction coil 70' and the current flows.

Thus, by the reaction of the electromagnetic induction from the completely endless type correction coil 70', the position near the dielectric window 52 is substantially directly below the coil conductor (particularly the intermediate portion of the antenna) of the completely endless type correction coil 70'. The radial direction (horizontal) component Br of the magnetic flux density of the processing space is locally weakened, so that the intensity of the induced electric field in the azimuthal direction is also locally weakened at the position corresponding to the intermediate portion of the antenna, similarly to the magnetic flux density Br. As a result, in the vicinity of the susceptor 12, the electron density (plasma density) is moderately uniform in the radial direction.

The diffusion form of the plasma as shown in Fig. 3A is an example. For example, when the pressure is low, the plasma is excessively concentrated in the central portion of the chamber 10. As shown in Fig. 4A, the electron density in the vicinity of the susceptor 12 is sometimes displayed. (The plasma density) will become a mountain-like outline that is extremely large at the center.

In such a case, as shown in FIG. 4B, once the completely endless type correction coil 70' is lowered to the vicinity of the lower limit value, for example, as shown in the figure, the intermediate portion overlapping the coil conductor of the completely endless type correction coil 70' is shown. The position, the radial direction (horizontal) component Br of the magnetic flux density of the processing space near the dielectric window 52 is locally weakened, whereby the concentration of plasma toward the center of the chamber is weakened, and the electricity near the susceptor 12 is weakened. The pulp density is moderately normalized in the radial direction.

The inventors have verified the action of the completely endless type correction coil 70' as described above by electromagnetic field simulation. In other words, the relative height position (distance interval) of the RF antenna 54 by the completely endless type correction coil 70' is used as a parameter, and the value of the parameter is selected as 4 types of 5 mm, 10 m, 20 mm, and infinity (no correction coil). When the current density distribution (corresponding to the plasma density distribution) in the radial direction of the doughnut-shaped plasma (the position of 5 mm from the upper surface) is taken, the verification result as shown in FIG. 5 can be obtained.

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

As can be seen from FIG. 5, when the completely endless type correction coil 70' is disposed at a height position where the RF antenna 54 is coupled by electromagnetic induction, the plasma density in the donut-shaped plasma is overlapped with the coil conductor of the correction coil 70. The position (the example shown in the figure is a position overlapping the intermediate portion of the antenna) is locally lowered, and the more the endless type correction coil 70' approaches the RF antenna 54, the more the local reduction degree becomes substantially linear.

The inductively coupled plasma etching apparatus (Fig. 1) of this embodiment is a single-coil coil that is opened by using an appropriate gap g at both ends instead of using the completely endless type correction coil 70' as described above. The correction coil 70 formed of (or rewinding coil) is connected to the switching element 112 between the open ends of the correction coil 70.

The switching mechanism 110 has a switching control circuit 114 that controls the switching element 112 by a wide frequency modulation (PWM) at a certain frequency (for example, 1 to 100 kHz) ON/OFF control or switching.

A specific configuration example of the switch mechanism 110 is shown in FIG. In this configuration example, the switching element 112 is a pair of transistors (for example, IGBT or MOS transistor) 112A, 112B that are reversely connected in parallel with each other, and the diodes 116A, 116B for reverse bias protection are connected in series with the respective transistors 112A, 112B. .

The two transistors 112A, 112B are simultaneously turned ON/OFF in accordance with the PWM control signal SW from the switch control circuit 114. In the ON period, the positive induced current i+ flowing in the positive direction of the correction coil 70 in the positive half cycle of the high frequency flows through the first transistor 112A and the first diode 116A, and the second half of the high frequency The negative induced current i- flowing through the correction coil 70 in the reverse direction flows through the second transistor 112B and the second diode 116B.

Although not shown in the drawings, the switch control circuit 114 actually includes a triangular wave generating circuit that generates, for example, a triangular wave signal of a predetermined frequency, and a variable voltage signal generating circuit that corresponds to a desired duty ratio (ON period of a pulse of one cycle) a variable voltage level to generate a voltage signal; a comparator that compares the voltage levels of the triangular wave signal and the variable voltage signal to generate a 2-value PWM control signal SW according to its magnitude relationship And a driving circuit that drives the two transistors 112A, 112B with a PWM control signal SW.

Here, the expected duty ratio is given from the main control unit 74 to the switch control circuit 114 via the predetermined control signal S _D .

According to this embodiment, the switching mechanism 110 configured as described above can control the energization load ratio of the correction coil 70 by the PWM control in the plasma process, as shown in FIG. 8, which can be 0% to 100%. The electric load ratio is controlled to be arbitrarily changed within the range.

What is important here is that the load ratio of the energization current i flowing through the correction coil 70 can be arbitrarily changed in the range of 0% to 100% by the PWM control as described above, and the original position H _P near the upper limit position. It is functionally equivalent to arbitrarily change the height position of the completely endless type correction coil 70' as described above between the lower limit position of the proximity RF antenna 54. In other words, the correction coil 70 is fixed to the height position near the RF antenna 54 by the switch mechanism 110, and the characteristics of FIG. 5 can be realized by means of the device, thereby making it easy to achieve the control of the plasma density distribution control. Degree and precision improvement.

Therefore, the energization load ratio of the control correction coil 70 can be changed via the switching mechanism 110 each time the process recipe changes all or part of the process conditions, whereby the correction coil 70 can be arbitrarily and finely adjusted by flowing through the RF The current of the high frequency RF _H of the antenna 54 is generated by the RF magnetic field H around the antenna conductor, that is, the plasma density in the donut-shaped plasma is locally near the position where the coil conductor of the correction coil 70 overlaps. The degree of the effect of low ground reduction (strong or weak).

The inductively coupled plasma etching apparatus of this embodiment is, for example, an application applicable to a multilayer film in which a surface of a substrate is continuously etched in a plurality of steps. Hereinafter, an embodiment of the present invention relating to the multilayer mask method (Multilayer Resist) as shown in Fig. 9 will be described.

In FIG. 9, on the main surface of the semiconductor wafer W to be processed, the SiN layer 102 as the lowermost layer (final mask) is formed on the original processed film (for example, the Si film for gate) 100, and An organic film (for example, carbon) 104 as an intermediate layer is formed thereon, and an uppermost photoresist 108 is formed thereon via a Si-containing anti-reflection film (BARC) 106. The film formation of the SiN layer 102, the organic film 104, and the anti-reflection film 106 is a coating film formed by CVD (Chemical Vacuum Evaporation) or spin coating, and the patterning of the photoresist 108 is by using light micro- Photolithography.

First, in the etching process of the first step, as shown in FIG. 9(A), the Si-containing anti-reflection film 106 is etched using the patterned photoresist 108 as a mask. In this case, the etching gas is a mixed gas of CF ₄ /O ₂ , and the pressure in the chamber 10 is set to be relatively low, for example, 10 mTorr.

Next, in the etching process of the second step, as shown in FIG. 9(B), the organic film 104 is etched by using the photoresist 108 and the anti-reflection film 106 as a mask. In this case, the etching gas is a single gas using O ₂ , and the pressure in the chamber 10 is set to be lower, for example, 5 mTorr.

Finally, in the etching process of the third step, as shown in (C) and (D) of FIG. 9, the SiN film 102 is etched by using the patterned anti-reflection film 106 and the organic film 104 as a mask. In this case, the etching gas is a mixed gas of CHF ₃ /CF ₄ /Ar/O ₂ , and the pressure in the chamber 10 is set to be relatively high, for example, 50 mTorr.

In the multi-step etching process as described above, all or a part of the process conditions (especially the pressure in the chamber 10) are switched in each step, whereby the diffusion pattern of the donut-shaped plasma changes in the processing space. . Here, when the correction coil 70 is completely incapable of functioning (energization), in the processes of the first and second steps (pressure 10 mTorr or less), the electron density (plasma density) in the vicinity of the susceptor 12 as shown in FIG. 4A is relatively In the center portion, a steep mountain-shaped contour is formed which is significantly swelled, and the process (pressure 50 mTorr) in the third step is a mountain-shaped contour in which the center portion is slightly raised.

According to this embodiment, for example, in the process recipe, the energization of the correction coil 70 is set by adding a normal process condition (high-frequency power, pressure, gas type, gas flow rate, etc.) or by relating to such a process. The load ratio is one of the prescription information or process parameters. Further, when the etching process of the above-described multi-step is performed, the main control unit 74 reads out the data indicating the energization load ratio from the memory, and the energization load of the correction coil 70 is compared with the set value by the switching mechanism 110 at each step.

For example, when using the embodiment of FIG. 9 as much as the etching process step a multilayer resist method shown in Figure 10, in the first step (10 mTorr) is switched to a relatively large duty ratio D _1, in the second step ( 5mTorr) is switched to a larger duty ratio D ₂ , and in the third step (50 mTorr) is switched to a relatively small duty ratio D ₃ , and the energization load ratio of the correction coil 70 is switched at each step.

Further, from the viewpoint of plasma ignitability, immediately after the start of the process of each step, the energization of the correction coil 70 is forcibly held in the (OFF) state to cause the plasma to be surely ignited, and the plasma is ignited. The power-on load ratio of the post-control set value is also valid.

[Second Embodiment]

Next, a second embodiment of the present invention will be described with reference to Figs. 11 to 14 .

Fig. 11 shows the configuration of the inductively coupled plasma etching apparatus of the second embodiment. In the drawings, the same components or functions as those of the device (Fig. 1) of the first embodiment are denoted by the same reference numerals.

The feature of the second embodiment is a configuration in which the resistance variable mechanism 120 is provided instead of the switch mechanism 110 as compared with the first embodiment.

More specifically, the correction coil 70 is constituted by an annular single-coil coil or a rewinding coil that is opened by sandwiching an appropriate gap g at both ends, so that the coil conductor in the radial direction can be located between the inner circumference and the outer circumference of the RF antenna 54. The method (preferably in the vicinity of the center) is coaxially arranged with respect to the RF antenna 54, and is horizontally held by an insulating coil holding member (not shown) at a position close to the height of the RF antenna 54.

As shown in FIG. 12, the variable resistance mechanism 120 has a variable resistor 122 connected to both open ends of the correction coil 70, and a resistance control portion 124 for controlling the resistance value of the variable resistor 122. The value that is expected.

A specific configuration example of the resistance variable mechanism 120 is shown in FIG.

The variable resistor 122 of this configuration example has a metal-based or carbon-based resistor 128 having a high specific resistance, and is inserted through the insulator 126 so as to block the gap g between the open ends of the correction coil 70; And the bridge type short-circuit conductor 130 is short-circuited between the two points at a predetermined distance interval on the correction coil 70.

The material of the bridge type short-circuit conductor 130 is high in electrical conductivity, and is preferably a copper-based metal.

The resistance control unit 124 includes a slide mechanism 132 for sliding the bridge type short-circuit conductor 130 while sliding on the correction coil 70, and a resistance position control unit 134 for bridging via the slide mechanism 132. The position of the shorted conductor 130 is aligned with the desired resistance position.

More specifically, the slide mechanism 132 is constituted by a ball screw mechanism, and rotates the stepping motor 138 of the horizontally extending conveying screw 136 at a predetermined position, and has a nut portion (not shown) screwed to the conveying screw 136. a slider body 140 horizontally moving in the axial direction by the rotation of the conveying screw 136, a compression coil spring 142 coupled to the slider body 140 and the bridge type short-circuit conductor 130, and a slidably fitted in the vertical direction The cylindrical bodies 144, 146 are formed. Here, the outer cylindrical body 144 is fixed to the slider body 140, and the inner cylindrical body 146 is fixed to the bridge type short-circuit conductor 130. The compression coil spring 142 pushes the bridge type short-circuit conductor 130 to the correction coil 70 by an elastic force.

The resistance position control unit 134 controls the position of the bridge type short-circuit conductor 130 via the rotation direction and the rotation amount of the stepping motor 138. The target position of the bridge type short-circuit conductor 130 is given from the main control unit 74 (FIG. 11) to the resistance position control unit 134 via the predetermined control signal S _R .

Here, the action of the variable resistance mechanism 120 will be described with reference to FIGS. 13 and 14A to 14C.

First, when the bridge type short-circuit conductor 130 is set to the position shown in FIG. 13, both ends of the coil conductor of the correction coil 70 are bypassed by the bridge type short-circuit conductor 130 via the resistor body 128. Thereby, the resistance value of the variable resistor 122 forms the lowest value (substantially zero), whereby the coil resistance value of the entire coil 70 is corrected to form the lowest value.

From the state of Fig. 13, the bridge type short-circuit conductor 130 is slid to the right of the figure and positioned at the position shown in Fig. 14A. This position is that the contact portion 130R of one end (right end) of the bridge type short-circuit conductor 130 is connected to the one end (right end) portion of the coil conductor as it is, but the contact portion 130L of the other end (left end) is beyond the other end (left end) of the coil conductor. It enters the section of the resistor body 128. Thereby, the resistance value of the variable resistor 122 is not zero, and a meaningful value is formed, and the coil resistance value of the entire correction coil 70 is higher than that in FIG.

When the bridge type short-circuit conductor 130 is further slid to the right in the state of FIG. 14A, the section length of the resistor body 128 occupied by the current path of the correction coil 70 is increased, and the resistance value of the variable resistor 122 is increased. The coil resistance value of the entire correction coil 70 is higher than that in Fig. 14A.

Then, as shown in FIG. 14B, when the contact portion 130L at the left end of the bridge type short-circuit conductor 130 is moved to the other end of the resistor 126 side of the resistor 128, the section length of the resistor body 128 occupied by the current path of the correction coil 70 is formed. maximum. Therefore, the resistance value of the variable resistor 122 is maximized, and the coil resistance value of the entire correction coil 70 is maximized.

Further, when the bridge type short-circuit conductor 130 is further slid to the right in the figure from the state of FIG. 14B, as shown in FIG. 14C, the contact portion 130L of the left end of the bridge type short-circuit conductor 130 is moved beyond the insulator 126 to the right side. In the coil conductor, the correction coil 70 is electrically cut by the insulator 126, and is substantially open at both ends. Another point of view is that the resistance value of the variable resistor 122 will be infinitely large.

As described above, in this embodiment, the resistance value of the variable resistor 122 is variably controlled by the resistance variable mechanism 120, and as described above, the minimum resistance value (Fig. 13) equivalent to the coil closed at both ends can be included. The maximum resistance value of the entire section of the resistor 128 (FIG. 14A, FIG. 14B) can continuously change the coil resistance of the entire correction coil 70, and the coil cut state equivalent to the uncorrected coil 70 can be selected (FIG. 14C).

Thereby, when the RF antenna 54 flows a high-frequency RF _H current, the current value (amplitude value or tip value) of the current flowing to the correction coil 70 by electromagnetic induction can be arbitrarily changed to 0% to ～ 100% range. Here, the current value 100% corresponds to the current value when the coil is in the short-circuited state (FIG. 13), and the current value 0% corresponds to the current value when the coil is in the cut-off state (FIG. 14C).

It is important here that the current value of the current flowing through the correction coil 70 can be arbitrarily changed in the range of 0% to 100% by the variable resistance control of the correction coil 70 as described above, and the original can be near the upper limit position. It is functionally equivalent to arbitrarily change the height position of the completely endless type correction coil 70' between the position H _P and the lower limit position of the proximity RF antenna 54 as described above. In addition, the resistance variable mechanism 120 can fix the correction coil 70 to the height position in the vicinity of the RF antenna 54 as it is, and can realize the characteristics of FIG. 5 in an apparatus manner, and can be more easily achieved in the same manner as in the first embodiment. The degree of freedom and accuracy of plasma density distribution control.

Therefore, each time the process recipe changes the value of the process parameter, the amplitude value of the current flowing through the correction coil 70 can be changed via the resistance variable mechanism 120, whereby the correction coil 70 can be arbitrarily and finely adjusted. The RF magnetic field H generated around the antenna conductor by the current flowing through the high frequency RF _H of the RF antenna 54 acts, that is, in the donut-shaped plasma near the position where the coil conductor of the correction coil 70 overlaps. The degree to which the plasma density is locally reduced (strength). Thereby, the plasma density in the vicinity of the susceptor 12 can be uniformly maintained in the radial direction through the entire step, and the uniformity of the etching process of the multilayer photoresist method can be improved.

For example, when the etching process of the multi-step photoresist method as shown in FIG. 9 is performed, the illustration is omitted, but in actuality, the first step (10 mTorr) is switched to a relatively low resistance value (resistance position) R ₁ . The second step (5mTorr) is switched to a lower resistance value (resistance position) R ₂ , and in the third step (50mTorr) is switched to a relatively high resistance value (resistance position) R ₃ as long as it is switched at each step. The resistance value (resistance position) of the variable resistor 122 may be sufficient.

Further, from the viewpoint of plasma ignitability, immediately after the start of the process of each step, the correction coil 70 is held in an electrically cut state (Fig. 14C) to reliably ignite the plasma, and the plasma is ignited. It is also effective to apply the variable resistor 122 to a predetermined resistance value (resistance position).

[Modification]

Fig. 15 shows a modification of the correction coil 70 and the switching mechanism 110 of the first embodiment. In this embodiment, a plurality of (for example, two) correction coils 70A and 70B having different coil diameters are arranged concentrically (or coaxially), and switching elements 112A are provided in the circuits of the correction coils 70A and 70B, respectively. , 112B. Then, the switching elements 112A and 112B are controlled to be turned ON/OFF according to the PWM control by the individual switch control circuits 114A and 114B, respectively, at an arbitrary arbitrary energization load ratio.

A modification of the correction coil 70 and the resistance variable mechanism 120 of the second embodiment described above is shown in Fig. 16 . In this embodiment, a plurality of (for example, two) correction coils 70A and 70B having different coil diameters are arranged concentrically (or coaxially), and are respectively provided in the circuits of the correction coils 70A and 70B. Resistors 122A, 122B. Then, the resistance values of the variable resistors 122A and 122B are independently and arbitrarily variably controlled by the individual resistance control units 124A and 124B.

In the switching mechanism 110 of FIG. 15 and in the resistance variable mechanism 120 of FIG. 16, the combination of the values of the induced currents (the energization load ratio or the tip value) flowing to the two correction coils 70A, 70B is arbitrary. A wide variety of choices can increase the freedom of plasma density distribution control.

Further, as shown in FIG. 17A, the correction coil 70B may be held in a non-actuated (non-energized) state, and only the correction coil 70A may be activated (energized). Alternatively, as shown in Fig. 17B, the correction coil 70A may be held in a non-actuated (non-energized) state, and only the correction coil 70B may be actuated (energized). Further, as shown in Fig. 17C, the two correction coils 70A, 70B may be simultaneously operated (energized).

[Third embodiment]

In the first embodiment described above, the switching mechanism 110 may be replaced with the opening and closing mechanism 150 as shown in Fig. 18 as another embodiment.

The opening and closing mechanism 150 has a shutter 152 that is connected to both open ends of the correction coil 70 via a conductor, and an opening and closing control circuit 154 that switches and controls opening and closing of the shutter 152 according to an instruction from the main control unit 74. (ON/OFF) status.

In the opening and closing mechanism 150, when the shutter 152 is switched to the OFF state, since the induced current does not flow to the correction coil 70, it is equivalent to the case where the correction coil 70 is not formed. When the shutter 152 is switched to the ON state, the correction coil 70 is equivalent to a coil that is closed at both ends. When a current of a high frequency RF _H flows in the RF antenna 54, the induced current flows to the correction coil 70.

As shown in FIG. 19, such an opening and closing mechanism 150 may be applied to a configuration in which a plurality of correction coils 70A, 70B are arranged concentrically. That is, a plurality of (for example, two) correction coils 70A and 70B having different coil diameters are arranged concentrically, and the correction coils 70A and 70B are inserted into the connection switches 152A and 152B, respectively. Then, the control switches 152A, 152B can be independently opened and closed by the individual opening and closing control circuits 154A, 154B. In such a shutter method, although the degree of freedom of control is limited to some extent, variable control of the current density (density of the donut-shaped plasma) as shown in FIGS. 17A to 17C can be performed.

Further, when the above-described opening and closing mechanism 150 is provided, it is possible to appropriately control the shutters 150 (152A, 152B) in accordance with the change, change, or switching of the process conditions in the plasma processing of one of the substrates to be processed. The method of opening and closing the state.

For example, in the multi-step etching process (FIG. 9) of the multilayer photoresist method described above, when the single type correction coil 70 (the shutter 152) as shown in FIG. 18 is used, as shown in FIG. 20, in the first step. The shutter 152 is switched to the ON state. In the second step, the shutter 152 is switched to the ON state, and in the third step, the shutter 152 is switched to the ON state.

Further, in the twin type correction coils 70A, 70B (the shutters 152A, 152B) as shown in Fig. 19, in the first step, the shutters 152A, 152B are switched to the ON state together. In the second step, the shutters 152A and 152B are switched to the ON state. In the third step, the shutter 152A is switched to the ON state, and the shutter 152B is switched to the ON state.

Further, as shown in FIG. 22, the plurality of (for example, three) correction coils 70A, 70B, and 70c are arranged in the vertical direction and arranged coaxially. The same switches 152A, 152B, and 152C and the opening and closing can be applied. Control circuits 154A, 154B, 154C (not shown).

As another embodiment of the correction coil 70, as shown in FIG. 23, it is also possible to selectively switch: a plurality of (for example, three) coil conductors 70(1), 70(2), 70(3) are respectively used as A separate mode of the individual correction coils and a connection mode of one correction coil that is electrically connected in series.

In Fig. 23, each of the coil conductors 70 (1), 70 (2), and 70 (3) is constituted by an annular single-coil coil (or a rewinding coil) which is opened by sandwiching a moderate gap therebetween. These gaps can be electrically connected in a plurality of types by means of three switching switches 160, 162, 164 and one open/close switch 166.

The first changeover switch 160 has a first fixed contact 160a that is connected to one end of the innermost coil conductor 70(1), and a movable contact 160b that is connected to the other of the coil conductor 70(1). One end; and a second fixed contact 160c are connected to one end of the adjacent intermediate coil conductor 70(2).

The second changeover switch 162 has a first fixed contact 162a connected to one end of the intermediate coil conductor 70 (2) and a movable contact 162b connected to the other end of the coil conductor 70 (2); And a second fixed contact 162c connected to one end of the outer adjacent coil conductor 70 (3).

The third changeover switch 164 has a first fixed contact 164a connected to one end of the outer coil conductor 70 (3), and a movable contact 164b connected to the other end of the coil conductor 70 (3); And a second fixed contact 164c that is connected to the movable contact 166d of the open/close switch 166.

The fixed contact 166e of the open/close switch 166 is connected to one end of the inner coil conductor 70(1).

In this configuration, when the individual mode is selected, the movable contact 160b of the first changeover switch 160 is switched to the first fixed contact 160a, and the movable contact 162b of the second changeover switch 162 is switched to the first fixed contact. 162a, the movable contact 164b of the third changeover switch 164 is switched to the first fixed contact 164a, and the open/close switch 166 is switched to the open state.

When the connection mode is selected, the movable contact 160b of the first changeover switch 160 is switched to the second fixed contact 160c, and the movable contact 162b of the second changeover switch 162 is switched to the second fixed contact 162c, and the third connection is made. The movable contact 164b of the changeover switch 164 is switched to the second fixed contact 164c, and the open/close switch 166 is switched to the closed state.

In a modification of this embodiment, for example, any two of the three coil conductors 70 (1), 70 (2), and 70 (3) may be selected in a connection mode, and the remaining one may be selected. The configuration of the switching circuit network selected as a separate mode.

Further, in the case where the correction coil of the present invention has a large induced current (sometimes a current flowing to the RF antenna or more), it is important to pay attention to the heat generation of the correction coil.

From this point of view, as shown in FIG. 24A, a coil cooling portion that is provided with an air-cooling fan in the vicinity of the correction coil 70 to be air-cooled can be provided. Alternatively, as shown in FIG. 24B, a coil winding portion in which a correction coil 70 is formed by a hollow copper tube and a refrigerant is supplied therein to prevent overheating of the correction coil 70 may be provided.

The configuration of the inductively coupled plasma etching apparatus of the above-described embodiment is an example of the configuration. Of course, the configuration in which the respective portions of the plasma generating mechanism are not directly related to the plasma generation can be variously modified.

For example, in the above embodiment, the correction coil 70 is fixedly disposed at one position. However, a configuration in which the position of the correction coil 70 can be changed may be employed, and in particular, the height position of the correction coil 70 may be arbitrarily changed.

Further, in the current path or circuit of the correction coil 70, a capacitor (not shown) may be provided in addition to the above-described switching element 112, resistor 122, or shutter 152 (152A, 152B, 152C).

Further, the basic form of the RF antenna 54 and the correction antenna 70 may be a form other than a planar shape, for example, a dome shape or the like. Further, it may be a form provided outside the ceiling of the chamber 10, for example, a spiral shape provided outside the side wall of the chamber 10.

Further, it may be a chamber structure for a rectangular substrate to be processed, a rectangular RF antenna structure, and a rectangular correction coil structure.

Further, the processing gas supply unit may be configured to introduce the processing gas into the chamber 10 from the ceiling, or may be in a form in which the high frequency RF _L for DC bias control is not applied to the susceptor 12. On the other hand, the present invention is also applicable to the use of a plurality of RF antennas or antennas ‧ segments, which are individually supplied with plasma by a plurality of high frequency power sources or high frequency power feeding systems for the plurality of RF antennas (or antenna ‧ segments) A plasma device of a high frequency power generation method.

Moreover, the inductively coupled plasma processing apparatus or plasma processing method of the present invention is not limited to the technical field of plasma etching, and can also be applied to plasma CVD, plasma oxidation, plasma nitridation, sputtering, and the like. Slurry process. Further, the substrate to be processed of the present invention is not limited to a semiconductor wafer, and may be various substrates for a planar right-angle display, a photomask, a CD substrate, a printed substrate, and the like.

10. . . Chamber

12. . . Pedestal

56. . . High frequency power supply

66. . . Process gas supply

70. . . Correction coil

110. . . Switch mechanism

112. . . Switching element

120. . . Resistance variable mechanism

122. . . Variable resistance

124. . . Resistance variable mechanism

150. . . Opening and closing mechanism

152, 152A, 152B, 152C. . . Switch

1 is a longitudinal cross-sectional view showing a configuration of an inductively coupled plasma processing apparatus according to a first embodiment of the present invention.

2A is a perspective view showing an example of a helical coil-shaped RF antenna.

2B is a perspective view showing an example of a concentric circular coil-shaped RF antenna.

Fig. 3A is a view schematically showing an example of an action of an electromagnetic field when the completely endless type correction coil is disposed away from the RF antenna.

3B is a view schematically showing an example of the action of an electromagnetic field when a completely endless type correction coil is disposed in the vicinity of an RF antenna.

4A is a view showing another example of the action of an electromagnetic field when the completely endless type correction coil is disposed away from the RF antenna.

FIG. 4B schematically shows another example of the action of the electromagnetic field when the completely endless type correction coil is disposed in the vicinity of the RF antenna.

Fig. 5 is a view showing changes in the current density distribution in the processing space in the vicinity of the dielectric window when the distance between the completely endless type correction coil and the RF antenna is changed.

Fig. 6 is a view showing an example of the configuration of a correction coil and a switch mechanism according to the first embodiment;

Fig. 7 is a view showing an example of a specific configuration of the above-described switch mechanism.

Fig. 8 is a view showing a PWM control chart using the above-described switching mechanism.

Fig. 9 is a view showing the construction of the multilayer photoresist method in stages.

Fig. 10 is a view showing a method of variably controlling the energization load ratio of the correction coil in a multi-step etching process using a multilayer photoresist method.

FIG. 11 is a longitudinal cross-sectional view showing a configuration of an inductively coupled plasma etching apparatus according to a second embodiment.

Fig. 12 is a view showing an example of the configuration of a correction coil and a resistance variable mechanism according to the second embodiment;

Fig. 13 is a view showing an example of a specific configuration of the variable resistance mechanism;

Fig. 14A is a view showing a resistance position of one of the variable resistance mechanisms.

Fig. 14B is a view showing another resistance position of the variable resistance mechanism.

Fig. 14C is a view showing another resistance position of the variable resistance mechanism.

Fig. 15 is a view showing an example of the configuration of a correction coil and a switch mechanism according to a modification of the first embodiment.

Fig. 16 is a view showing an example of the configuration of a correction coil and a resistance variable mechanism according to a modification of the second embodiment.

Fig. 17A is a view showing an example of the operation of the configuration example of Fig. 15 or Fig. 16;

Fig. 17B is a view showing an example of the operation of the configuration example of Fig. 15 or Fig. 16;

Fig. 17C is a view showing an example of the operation of the configuration example of Fig. 15 or Fig. 16;

FIG. 18 is a view showing an example of the configuration of a correction coil and an opening and closing mechanism according to the third embodiment.

19 is a view showing an example of a configuration of a correction coil and an opening and closing mechanism according to a modification.

Fig. 20 is a view showing a method of controlling the opening and closing state of the shutter provided in the single type correction coil in the multi-step etching process using the multilayer photoresist method.

Fig. 21 is a view showing a method of controlling the opening and closing states of two shutters provided in the twin type correction coil in a multi-step etching process using a multilayer photoresist method.

Fig. 22 is a view showing a correction coil and a switching switch circuit network according to another embodiment.

Fig. 23 is a view showing a correction coil and a switch circuit network of another embodiment.

Fig. 24A shows an embodiment in which the correction coil is cooled by an air cooling type.

Fig. 24B is an embodiment in which a correction coil is cooled via a refrigerant.

56. . . High frequency power supply

58. . . Integrator

66. . . Process gas supply

68. . . Gas supply pipe

62. . . Buffer section

27. . . Move out of the entrance

28. . . gate

20. . . Baffle

18. . . Exhaust road

twenty two. . . exhaust vent

twenty four. . . exhaust pipe

26. . . Exhaust

64. . . Side wall gas discharge hole

110. . . Switch mechanism

70. . . Correction coil

60. . . wire

54. . . RF antenna

52. . . Dielectric window

38. . . Focus ring

36. . . Electrostatic chuck

36a. . . electrode

36b, 36c. . . Insulating film

W. . . Semiconductor wafer

44. . . Refrigerant flow path

46, 48. . . Piping

Cw. . . Cooling water

50. . . Gas supply pipe

43. . . Covered line

34. . . Electric bar

32. . . Integrator

30. . . High frequency power supply

74. . . Main control department

42. . . Switch for electrostatic chuck

40. . . DC power supply

14. . . Cylindrical support

16. . . Conductive cylindrical support

12. . . Circular plate base

10. . . Chamber

Claims (14)

A plasma processing apparatus characterized by comprising: a processing container having a dielectric window; a coil-shaped RF antenna disposed outside the dielectric window; and a substrate holding portion attached to the processing The processing substrate is held in the container; the processing gas supply unit supplies the desired processing gas to the processing container for performing the desired plasma processing on the substrate; and the high-frequency power supply unit is for the processing container. Generating a plasma of the processing gas by inductive coupling, and supplying high frequency power suitable for the frequency of the high frequency discharge of the processing gas to the RF antenna; and correcting the coil for controlling the substrate on the substrate in the processing container a plasma density distribution disposed outside the processing container at a position that can be coupled to the RF antenna by electromagnetic induction; a switching element disposed in a loop of the correction coil; and a switch control unit The expected load is ON/OFF controlled by the pulse width modulation to the aforementioned switching elements. A plasma processing apparatus characterized by comprising: a processing container having a dielectric window in a ceiling; a coil-shaped RF antenna disposed on the dielectric window; and a substrate holding portion being attached to the foregoing a processing substrate is held in the processing container; and a processing gas supply unit is configured to supply the desired processing gas to the processing container in order to perform a desired plasma treatment on the substrate; a high frequency power feeding unit that supplies high frequency power suitable for a high frequency discharge of a processing gas to the RF antenna in order to generate a plasma of a processing gas by inductive coupling in the processing container; In order to control the plasma density distribution on the substrate in the processing container, the RF antenna is coaxially disposed, and has a radial direction between the inner circumference and the outer circumference of the RF antenna, and both ends are open via a gap. a ring-shaped coil conductor disposed on the RF antenna at a height position that can be coupled to the RF antenna by electromagnetic induction; a variable resistor disposed in a gap of the correction coil; and a resistance control unit The resistance value of the variable resistor is controlled to a desired value. The plasma processing apparatus according to the second aspect of the invention, wherein the variable resistor includes a resistor, a gap provided in series with the coil conductor in the correction coil, and a bridge type short-circuit conductor The coil conductor and the resistor body are movable in the circumferential direction of the correction coil, and the desired resistance value can be selected by the position of the short-circuit conductor. A plasma processing apparatus characterized by comprising: a processing container having a dielectric window; an RF antenna disposed outside the dielectric window; and a substrate holding portion retained in the processing container a substrate to be processed; a processing gas supply unit for supplying a desired processing gas to the processing chamber in order to perform a desired plasma treatment on the substrate; a high frequency power feeding unit that supplies high frequency power suitable for a high frequency discharge of a processing gas to the RF antenna in order to generate a plasma of a processing gas by inductive coupling in the processing container; In order to control the plasma density distribution on the substrate in the processing container, the device has a circuit independent of the RF antenna, and is disposed in the processing container at a position that can be coupled to the RF antenna by electromagnetic induction. And a shutter that is disposed in the circuit of the correction coil. The plasma processing apparatus according to claim 4, wherein the dielectric window is a ceiling constituting the processing container, and the RF antenna is disposed on the dielectric window, and the correction coil is coupled to the RF antenna. Parallel configuration. The plasma processing apparatus of claim 4, wherein the correction coil is composed of a single-coil coil or a rewinding coil that is closed at both ends, and the RF antenna is coaxially disposed, and the coil conductor in the radial direction is located in the foregoing The coil diameter between the inner circumference and the outer circumference of the RF antenna. A plasma processing apparatus characterized by comprising: a processing container having a dielectric window and being vacuum ventilable; an RF antenna disposed outside the dielectric window; and a substrate holding portion attached to the substrate The processing substrate is held in the processing container, and the processing gas supply unit supplies the desired processing gas to the processing container in order to perform the desired plasma processing on the substrate, and the high-frequency power supply unit is configured to perform the foregoing processing. Inductive coupling And generating a plasma of the processing gas, and supplying high frequency power suitable for the frequency of the high frequency discharge of the processing gas to the RF antenna; and the first and second correction coils for controlling the substrate in the processing container The upper plasma density distribution has a split circuit independent of the RF antenna, and is disposed outside the processing container at a position that can be coupled to the RF antenna by electromagnetic induction; and the first and second shutters These are respectively provided in the circuits of the first and second correction coils. The plasma processing apparatus according to claim 7, wherein the dielectric window is a ceiling constituting the processing container, and the RF antenna is disposed on the dielectric window, and the first and second correction coils are provided. It is arranged in parallel with the aforementioned RF antenna. The plasma processing apparatus of claim 8, wherein the first and second correction coils are arranged concentrically. The plasma processing apparatus of claim 8, wherein the first and second correction coils are coaxially arranged at different height positions. A plasma processing method is a plasma processing method for performing a desired plasma treatment on a substrate in a plasma processing apparatus, the plasma processing apparatus having: a processing container having a dielectric window; a coil shape The RF antenna is disposed outside the dielectric window; the substrate holding portion holds the substrate to be processed in the processing container; and the processing gas supply portion is configured to perform the desired electricity on the substrate a slurry treatment to supply a desired processing gas to the processing container; and a high frequency power feeding portion for generating a high frequency of the processing gas by inductively coupling the plasma in the processing container to generate a processing gas The high frequency power of the frequency of the discharge is supplied to the RF antenna; the plasma processing method is: having a circuit independent of the RF antenna, and being combined with the RF antenna by electromagnetic induction outside the processing container The correction coil and the RF antenna are arranged in parallel, and a shutter is provided in the circuit of the correction coil to control the opening and closing state of the shutter to control the plasma density on the substrate. The plasma processing method according to claim 11, wherein in the plasma processing of the one substrate to be processed, the opening and closing state of the shutter is controlled in accordance with the change, change or switching of the process conditions. A plasma processing method is a plasma processing method for performing a desired plasma treatment on a substrate in a plasma processing apparatus, the plasma processing apparatus having: a processing container having a dielectric window; a coil shape The RF antenna is disposed outside the dielectric window; the substrate holding portion holds the substrate to be processed in the processing container; and the processing gas supply portion is configured to perform desired plasma processing on the substrate. And supplying the desired processing gas to the processing container; and the high frequency power feeding portion for inductive coupling in the processing container Combining to generate a plasma of the processing gas, and supplying high frequency power suitable for the frequency of the high frequency discharge of the processing gas to the RF antenna; the plasma processing method is: having a bypass circuit independent of the RF antenna, respectively The first and second correction coils that can be coupled to the RF antenna by electromagnetic induction are arranged in parallel with the RF antenna, and the first and second correction coils are respectively provided in the circuit of the first and second correction coils. And the second shutter controls the opening and closing states of the first and second shutters to control the plasma density on the substrate. The plasma processing method according to claim 13, wherein in the plasma processing of one of the substrates to be processed, each of the first and second shutters is controlled in accordance with a change, a change, or a switching of a process condition. Open and close state.