JP5097074B2 - Plasma processing apparatus and plasma processing method - Google Patents

Description

  The present invention relates to a plasma processing apparatus and a plasma processing method for forming a plasma of a processing gas and performing a predetermined processing on a substrate to be processed.

  In order to carry out a submicron unit and sub-half micron ultrafine processing process required for ultrahigh integration of a substrate to be processed, such as a semiconductor wafer (hereinafter also simply referred to as “wafer”), by a plasma processing apparatus. For example, it is required to control a high-density plasma with high accuracy in a low-pressure atmosphere of 100 mTorr or less.

  As such a plasma processing apparatus, for example, a device that processes a wafer by generating high-frequency induction plasma using a high-frequency antenna is known (see, for example, Patent Document 1). In this type of plasma processing apparatus, for example, the ceiling wall of the processing chamber facing the mounting table on which the wafer is mounted is made of an insulator such as quartz glass, and a high frequency antenna made of a spiral coil is attached to the outside thereof. The When plasma processing is performed on a wafer, high frequency power is applied to a high frequency antenna to form a high frequency electromagnetic field in the processing chamber. As a result, electrons flowing in the electromagnetic field space collide with neutral particles of the processing gas, whereby the processing gas is ionized to generate plasma, and a predetermined process such as plasma etching is performed on the wafer.

Japanese Patent Application Laid-Open No. 07-122546 Japanese Unexamined Patent Publication No. 07-161695

However, in recent years, by processing a wafer with such a plasma processing apparatus, even if the semiconductor device is miniaturized, a problem associated with miniaturization has occurred, for example, the performance does not improve as expected. For example, a SiO ₂ film has been conventionally used for a gate insulating film of a CMOS device, but in recent years, the thickness of the gate oxide film has been reduced to 1 with the further demand for higher operating speed, higher integration, and thinner film. A value of ˜2 nm or less is required. Such a very thin gate oxide film has a problem that the tunnel current increases, and as a result, the gate leakage current increases.

For this reason, recently, a high dielectric material, so-called High-k material, has attracted attention as a material for realizing such a thin insulating film without increasing the gate leakage current as a material of the gate oxide film. Examples of such a high dielectric thin film include oxides of refractory metal materials such as HfO ₂ , HfSiO ₂ , ZrO ₂ , and ZrSiO ₄ . In the case of performing etching process by using plasma of these refractory metal material, typically, Cl, process gas mainly used a halogen-containing gas, such as Br, for example a single gas or BCl ₃ gas and O ₂ of BCl ₃ A mixed gas of gas is used.

However, when plasma processing of such a refractory metal material is performed in a high-pressure atmosphere, a vapor phase product (for example, B ₂ O ₃ ) is generated and adhered to the processing chamber, or a surface reaction by-product that is difficult to volatilize. things (such as HfCl _4, BOCl) occurs there are problems such as or not the etching progresses. Therefore, in the etching process of a refractory metal material, a plasma process in a lower pressure atmosphere, for example, an extremely low pressure atmosphere of 10 mTorr or less or several mTorr or less is required.

  However, in the plasma processing apparatus using the conventional high-frequency antenna as described above, the electron temperature of the plasma rapidly increases even in a slight pressure fluctuation in a very low pressure range of, for example, a few dozen mTorr or less ( For example, see Patent Document 2). That is, the lower the pressure in the processing chamber, the higher the probability that electrons in the plasma are accelerated without colliding with other particles, and for example, collide with the sidewall of the processing chamber and disappear. For this reason, the electron density in the plasma is lowered and the electron temperature is increased. As a result, ions in the plasma are accelerated and collide with the wafer with high energy, so that the wafer is easily damaged. is there.

  In addition, in a conventional plasma processing apparatus using a high-frequency antenna, the plasma electron density near the central portion on the wafer may be lower than the plasma electron density near the peripheral portion even in a low-pressure atmosphere of 100 mTorr or less. There is a case where the uniformity of the is reduced. Therefore, it is desired to improve the uniformity of the plasma electron density.

  In this regard, in order to improve the uniformity of the plasma electron density, for example, another high-frequency antenna may be provided on the center side of the ceiling wall so that plasma is generated on the center side. However, if this is done, a strong electromagnetic field energy is also applied to the center of the space where the plasma is formed, so that although the plasma electron density can be increased, the plasma electron temperature also rises.

  Therefore, the present invention has been made in view of such problems, and the object of the present invention is to achieve uniform plasma electron density while suppressing an increase in plasma electron temperature even when plasma is formed in a low-pressure atmosphere. It is an object of the present invention to provide a plasma processing apparatus and a plasma processing method that can improve performance.

  In order to solve the above problems, according to one aspect of the present invention, there is provided a plasma processing apparatus for performing a predetermined plasma process on a substrate to be processed by generating inductively coupled plasma of a processing gas in a decompressed processing chamber. , A mounting table provided in the processing chamber for mounting the substrate to be processed; a processing gas introduction portion for introducing the processing gas into the processing chamber; an exhaust portion for exhausting and depressurizing the processing chamber; A high frequency antenna disposed via a plate-like insulating member so as to face the table, and a high-frequency power for generating the inductively coupled plasma in a plasma generation space between the table and the plate-like insulating member Is disposed via the plate-like insulating member so as to face the high-frequency power source for applying to the high-frequency antenna and to return to the upper part of the plasma generation space. The plasma processing apparatus wherein a plurality of magnetic field lines which form has an upper moving magnetic field generator of the annular forming a moving magnetic field that rotates in the circumferential direction is provided.

  According to the present invention as described above, plasma is generated in the processing chamber by introducing the processing gas from the processing gas introduction section into the processing chamber whose pressure is reduced to a predetermined pressure by the exhaust section and applying high-frequency power to the high-frequency antenna. A process gas inductively coupled plasma is generated in the space. At that time, the moving magnetic field rotating in the upper region of the plasma generation space can be formed by the upper moving magnetic field forming unit. The cyclotron resonance effect of this moving magnetic field can confine the electrons of the inductively coupled plasma generated by the high-frequency antenna in the plasma generation space, so that the rise of the plasma electron temperature can be suppressed and the uniformity of the plasma electron density. Can be improved. Thereby, for example, in a low pressure atmosphere of 100 mTorr or less, and even in an extremely low pressure atmosphere of tens of mTorr or less, a more uniform process can be performed within the surface of the substrate to be processed without damaging the substrate to be processed. It can be performed.

  In this case, the upper moving magnetic field forming section is formed, for example, on the upper side of the plate-like insulating member, with an annular core disposed together with the high-frequency antenna, and on the lower surface of the annular core. A plurality of teeth portions arranged in a circumferential direction so as to extend radially, and a plurality of magnetic lines of force that form a path returning upward between the plurality of teeth portions are generated over the entire circumference of the annular core. And a coil composed of a plurality of windings wound between the plurality of teeth portions, and by passing the alternating currents having different phases through the windings of the coil to change the lines of magnetic force with time, An AC power source is provided that forms a moving magnetic field that rotates in the circumferential direction above the plasma generation space. For example, the coil includes three sets of windings, and a three-phase alternating current is supplied to each of the windings from the magnetic field forming power source.

  According to this, when an alternating current from the upper magnetic field forming power source is supplied to the coil, magnetic lines of force are formed below the annular core to form a downward path between the plurality of teeth portions. These lines of magnetic force change with time, and a moving magnetic field that rotates in the circumferential direction can be formed in the upper region of the plasma generation space.

  The high-frequency antenna is formed in a planar coil shape so as to surround the annular core, for example. According to this, since the moving magnetic field can be formed in the central plasma region of the inductively coupled plasma generated by the high frequency antenna, the electrons of the generated inductively coupled plasma can be confined in the central plasma region inside. As a result, the plasma electron density in the central plasma region can be controlled as compared with the peripheral plasma region, so that the uniformity of the plasma electron density can be further increased in the entire plasma region, and the processing uniformity of the substrate to be processed can be improved. Can do.

  Further, the storage unit stores processing conditions of the substrate to be processed, and the upper moving magnetic field forming unit controls the alternating current from the magnetic field forming power source according to the processing conditions stored in the storage unit. And a control unit that controls the moving magnetic field. According to this, the control unit controls the alternating current flowing from the magnetic field forming power source to the coil in accordance with the processing conditions of the substrate to be processed (for example, the pressure in the processing chamber). Can be controlled. As a result, an appropriate moving magnetic field can be formed according to processing conditions such as the pressure in the processing chamber, for example, so that an increase in plasma electron temperature can be efficiently suppressed and the distribution of plasma electron density can be controlled.

  Furthermore, a plurality of lines of magnetic force are disposed around the periphery of the plasma generation space via a cylindrical insulating member, and a plurality of lines of magnetic force are formed in the periphery of the plasma generation space to form a path returning inward toward the outside. A peripheral moving magnetic field forming unit that forms a rotating moving magnetic field may be provided. In this case, the peripheral moving magnetic field forming section is formed, for example, by an annular core disposed through a cylindrical insulating member so as to surround the plasma generation space, and projecting from an inner surface of the annular core. A plurality of teeth portions arranged in the circumferential direction so as to extend in the vertical direction of the core, and a magnetic line of force that forms a path returning to the outside toward the inside between the plurality of teeth portions extends over the entire circumference of the annular core. A coil composed of a plurality of windings wound between the plurality of tooth portions so as to generate a plurality, and by passing alternating currents having different phases through the windings of the coil to change the lines of magnetic force in time. An AC power supply for forming a moving magnetic field rotating in the circumferential direction is provided at the periphery of the plasma generation space.

  According to this, the moving magnetic field rotating in the upper region of the plasma generation space can be formed by the upper moving magnetic field forming unit, and the moving magnetic field rotating in the peripheral region in the peripheral region of the plasma generating space by the peripheral moving magnetic field forming unit. Can be formed. For this reason, plasma electrons generated by the high-frequency antenna can be confined not only in the upper part of the central plasma region but also in the peripheral plasma region. As a result, the increase in plasma electron temperature can be more effectively suppressed, and the uniformity of plasma electron density can be further improved.

  In order to solve the above problems, according to another aspect of the present invention, a high-frequency antenna provided via a plate-like insulating member is provided so as to face a mounting table disposed in a processing chamber, and the pressure is reduced to a predetermined pressure. In addition, by introducing a processing gas into the processing chamber and applying high-frequency power to the high-frequency antenna, inductively coupled plasma of the processing gas is generated in the processing chamber, and a predetermined processing is performed on the substrate to be processed on the mounting table. The plasma processing method of the plasma processing apparatus for applying an annular upper moving magnetic field forming portion disposed through the plate-like insulating member so as to face the mounting table is provided on the lower surface of the upper moving magnetic field forming portion. , Generate a plurality of magnetic lines that make U-turns in the upper region of the plasma generation space from the lower surface toward the plasma generation space, and these magnetic field lines rotate along the lower surface of the upper moving magnetic field forming unit A plasma processing method characterized by forming a moving magnetic field is provided that.

  According to the present invention, the processing gas is introduced into the processing chamber whose pressure is reduced to a predetermined pressure, and the high frequency power is applied to the high frequency antenna, whereby the inductively coupled plasma of the processing gas is generated in the plasma generation space in the processing chamber. Is generated. At that time, the moving magnetic field rotating in the upper region of the plasma generation space can be formed by the upper moving magnetic field forming unit. The cyclotron resonance effect of this moving magnetic field can confine the electrons of the inductively coupled plasma generated by the high-frequency antenna in the plasma generation space, so that the rise of the plasma electron temperature can be suppressed and the uniformity of the plasma electron density. Can be improved. Thereby, for example, in a low pressure atmosphere of 100 mTorr or less, and even in an extremely low pressure atmosphere of tens of mTorr or less, a more uniform process can be performed within the surface of the substrate to be processed without damaging the substrate to be processed. It can be performed.

  In this case, an annular peripheral moving magnetic field forming unit disposed via a cylindrical insulating member so as to surround the peripheral part of the plasma generation space is connected to the inner side surface of the peripheral moving magnetic field forming unit from the inner side surface thereof. A plurality of magnetic field lines that turn to the plasma generation space and make U-turns in the peripheral region of the plasma generation space are generated, and these magnetic field lines form a moving magnetic field that rotates along the inner surface of the peripheral moving magnetic field forming unit. It may be. According to this, the moving magnetic field rotating in the upper region of the plasma generation space can be formed by the upper moving magnetic field forming unit, and the moving magnetic field rotating in the peripheral region in the peripheral region of the plasma generating space by the peripheral moving magnetic field forming unit. Can be formed. For this reason, plasma electrons generated by the high-frequency antenna can be confined not only in the upper part of the central plasma region but also in the peripheral plasma region. As a result, the increase in plasma electron temperature can be more effectively suppressed, and the uniformity of plasma electron density can be further improved.

  According to the present invention, even if plasma is formed in a low-pressure atmosphere, plasma electrons can be confined in the plasma generation space, so that the rise in plasma electron temperature can be suppressed and the uniformity of plasma electron density is improved. Can be made. Thereby, even in a low pressure atmosphere, there is no damage to the substrate to be processed, and uniform plasma processing can be performed on the surface of the substrate to be processed.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(Configuration example of plasma processing equipment)
First, a configuration example of the plasma processing apparatus 100 according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of the plasma processing apparatus 100. The plasma processing apparatus 100 is configured as an inductively coupled plasma etching apparatus that performs an etching process on a substrate to be processed, such as a semiconductor wafer (hereinafter also simply referred to as “wafer”) W. The plasma processing apparatus 100 includes a processing chamber (chamber) 102 formed in a cylindrical or rectangular shape made of metal (for example, aluminum or stainless steel).

  A substantially cylindrical mounting table 104 for mounting the wafer W is housed in the bottom of the processing chamber 102 via an insulating plate 103 such as ceramic. The mounting table 104 mainly includes a susceptor support 104a formed in a cylindrical shape with aluminum or the like, and a susceptor 104c made of aluminum or the like detachably provided with a bolt 104b or the like thereon. In this way, by configuring the susceptor 104c to be detachable, maintenance and the like can be easily performed.

  The susceptor support 104a is provided with a temperature control medium flow path 109 as an example of temperature adjusting means. A temperature control medium from a temperature control medium supply source (not shown) is introduced into the temperature control medium flow path 109 through the introduction pipe 111, circulates through the temperature control medium flow path 109, and is discharged from the discharge pipe 112. The temperature control medium is selected according to the adjustment temperature of the wafer W. For example, when the wafer W is cooled, water or a refrigerant may be used as the temperature control medium, and when the wafer W is heated, the heating medium may be used as the temperature control medium. Here, for example, Galden or the like is used as the refrigerant. When such a coolant flows through the temperature control medium flow path 109, the wafer W can be cooled to a desired temperature (here, for example, about −50 ° C. to −150 ° C.) via the susceptor 104c.

  An electrostatic chuck 113 is formed on the wafer mounting portion on the upper surface of the susceptor 104c so as to have approximately the same area as the wafer area. The electrostatic chuck 113 is formed, for example, by sandwiching a conductive film 113a such as a copper foil between two polymer polyimide films in an insulating state, and the conductive film 113a is connected to a variable DC high voltage power source 114. Therefore, by applying a high voltage to the conductive film 113a, the wafer W can be attracted and held on the upper surface of the electrostatic chuck 113 by a Coulomb force.

  The susceptor support base 104a and the susceptor 104c penetrate through them to receive heat transfer gas (back cooling gas) such as He from a heat transfer gas supply source (not shown) and the members constituting the back surface of the wafer W and the susceptor 104c. A gas passage 116 is formed for supplying the gas to the joint portion. An annular focus ring 117 is disposed around the upper end of the susceptor 104c so as to surround the wafer W.

  Further, a high frequency power source 119 is connected to the susceptor 104c via a matching capacitor 118. During processing, a frequency of 1 to 15 MHz, for example, is applied to the susceptor 104c to generate a bias potential with the plasma. It is possible to effectively irradiate the plasma flow without causing damage to the surface to be processed.

  A temperature adjustment heater 132 housed in a heater fixing base 131 is provided below the susceptor 104 c between the electrostatic chuck 113 and the temperature adjustment medium flow path 109. By adjusting the electric power supplied from the heater power supply 133 to the temperature adjustment heater 132, the temperature of the wafer W can be adjusted by controlling the conduction of the cold heat from the temperature adjustment medium channel 109. ing.

  The ceiling wall 105 of the processing chamber 102 substantially opposite to the mounting surface of the mounting table 104 is made of a plate-like insulating member such as quartz glass or ceramic. The ceiling wall 105 of the processing chamber 102 has a gas introduction port 121 formed substantially at the center thereof, and a gas supply unit 120 is connected to the gas introduction port 121. The gas supply unit 120 includes a gas supply source 122 that supplies a processing gas such as an etching gas. The gas supply source 122 is connected to the gas inlet 121 via a gas supply pipe 123. A flow rate controller for controlling the flow rate of the processing gas, for example, a mass flow controller 124 is interposed in the middle of the gas supply pipe 123. In addition, an open / close valve may be provided in the gas supply pipe 123. According to such a gas supply unit 120, the processing gas from the gas supply source 122 is controlled to a predetermined flow rate by the mass flow controller (MFC) 124 and is supplied into the processing chamber 102 from the gas inlet 121.

  In FIG. 1, the gas supply unit 120 is represented by a single gas line for the sake of simplicity, but the gas supply unit 120 is not limited to supplying a processing gas of a single gas type. A plurality of gas species may be supplied as the processing gas. In this case, a plurality of gas supply sources may be provided to form a plurality of gas lines, and a mass flow controller may be provided in each gas line.

As a processing gas supplied into the processing chamber 102 by such a gas supply unit 120, for example, in etching an oxide film, a halogen-based gas containing Cl or the like is used. Specifically, when etching a silicon oxide film such as a SiO ₂ film, CHF ₃ gas or the like is used as a processing gas. Further, when etching a high dielectric thin film such as HfO ₂ , HfSiO ₂ , ZrO ₂ , ZrSiO ₄ , BCl ₃ gas is used as a processing gas, or a mixed gas of BCl ₃ gas and O ₂ gas is used as a processing gas. Used.

  On the outer side surface (upper side surface) of the ceiling wall 105, a high frequency antenna 106 for generating plasma of the processing gas is disposed in the processing chamber 102. The high-frequency antenna 106 is formed of a spiral coil of a conductor such as a copper plate, aluminum, or stainless steel. Between both terminals (inner terminal 106a and outer terminal 106b) of the high frequency antenna 106, a high frequency power of, for example, 13.56 MHz can be applied from a high frequency power source 107 for plasma generation via a matching unit 108.

  Further, an upper moving magnetic field forming unit 300 for confining electric charges (mainly electrons) in plasma generated by the high frequency antenna 106 is disposed inside the high frequency antenna 106 on the outer surface of the ceiling wall 105. . The upper moving magnetic field forming unit 300 is formed in, for example, an annular shape (for example, concentric shape) surrounding the gas inlet 121. The upper moving magnetic field forming unit 300 forms a moving magnetic field that rotates in the central plasma region by supplying an alternating current from an alternating current power source (upper moving magnetic field forming alternating current power source) 302. The upper moving magnetic field forming unit 300 and the AC power supply 302 constitute moving magnetic field forming means. The specific configuration of the upper moving magnetic field forming unit 300 and the details of the operation and effect will be described later.

  An exhaust pipe 130 is connected to the bottom wall of the processing chamber 102 so that the atmosphere in the processing chamber 102 can be exhausted by an exhaust unit 140 configured by a vacuum pump or the like. A wafer loading / unloading port is formed on the side wall of the processing chamber 102, and a gate valve 137 is provided at the wafer loading / unloading port. For example, when the wafer W is loaded, the gate valve 137 is opened, the wafer W is placed on the susceptor 104c in the processing chamber 102 by a transfer mechanism such as a transfer arm (not shown), the gate valve 137 is closed, and the wafer W is loaded. Process.

  Note that an optical sensor 136 that detects a signal related to an emission spectrum generated in the processing chamber 102 may be provided on the side wall of the processing chamber 102. Specifically, for example, a transmission window 134 made of a transparent material such as quartz glass is provided on the side wall of the processing chamber 102, and light in the processing chamber 102 that transmits the transmission window 134 is transmitted through the optical system 135 to the optical sensor. 136, and a signal related to the emission spectrum generated from the processing chamber 102 can be sent to the control unit 200 described later. Further, a pressure sensor 138 for detecting the pressure in the processing chamber 102 is attached to the processing chamber 102 so that a signal related to the pressure in the processing chamber 102 can be sent to the control unit 200.

  The plasma processing apparatus 100 is provided with a control unit 200 that controls the operation of the entire apparatus. The control unit 200 performs a predetermined process in a processing chamber such as etching, for example, by controlling each unit based on a predetermined processing condition by a predetermined program.

(Configuration example of control unit)
A specific configuration example of the control unit 200 will be described with reference to the drawings. As shown in FIG. 2, the control unit 200 includes a CPU (Central Processing Unit) 210 that constitutes the control unit main body, a ROM (Read Only Memory) 220 that stores data for controlling each unit, and the like. A random access memory (RAM) 230 provided with a memory area used for various data processing, a display unit 240 including a liquid crystal display for displaying an operation screen, a selection screen, etc., various operations by an operator And an operation panel 250 that can input information and the like, for example, a notification unit 260 including an alarm device such as a buzzer.

  In addition, the control unit 200 includes various controllers 270 for controlling each unit of the plasma processing apparatus 100. The various controllers 270 include a controller that controls the refrigerant source, the heat transfer gas supply source, etc., in addition to the high frequency power sources 107 and 119, the heater power source 133, the mass flow controller 124, the AC power source 302, and the exhaust unit 140.

  In addition, the control unit 200 stores a program data storage unit 280 that stores program data for performing the processing of the plasma processing apparatus 100, and a process that stores various processing conditions such as recipe data used when executing a process based on the program data. A condition storage unit 290 is provided. The processing conditions here include, for example, the type of processing gas, the flow rate of the processing gas, the high frequency power, the pressure in the processing chamber, and the like. The program data storage unit 280 and the processing condition storage unit 290 are composed of recording media such as a flash memory, a hard disk, and a CD-ROM, for example, and data is read by the CPU 210 as necessary.

  The CPU 210, ROM 220, RAM 230, display unit 240, operation panel 250, notification unit 260, various controllers 270, program data storage unit 280, and processing condition storage unit 290 are bus lines such as a control bus, a system bus, and a data bus. Are electrically connected.

  The control unit 200 controls each unit based on a predetermined processing condition read from the processing condition storage unit 290 by using a predetermined program read from the program data storage unit 280, so that, for example, in the processing chamber 102 such as etching. The predetermined processing is performed. At this time, for example, a control signal is sent based on feedback signals from various sensors such as the optical sensor 136 and the pressure sensor 138 or a preset set value to control each unit. Thereby, the operating environment of the plasma processing apparatus 100 can be optimally adjusted.

  In the plasma processing apparatus 100 configured as described above, when etching the wafer W in the processing chamber 102, first, the gate valve 137 is first opened and the wafer W is moved into the processing chamber 102 by a transfer arm (not shown). Carry in, place on the mounting table 104, and close the gate valve 137. At this time, the wafer W is electrostatically held by the electrostatic chuck 113 and, for example, a coolant is supplied to the temperature control medium channel 109 while supplying the heat transfer gas toward the back surface of the wafer W. (For example, -50 degreeC thru | or -150 degreeC).

  Thereafter, a predetermined processing gas is introduced into the processing chamber 102 from the gas supply unit 120 at a predetermined flow rate while being evacuated and reduced to a predetermined pressure by the exhaust unit 140. Then, a high frequency power of 13.56 MHz, for example, is applied from the high frequency power source 107 to the high frequency antenna 106 via the matching unit 108, and a bias potential having a frequency of 1 to 15 MHz is applied to the mounting table 104 as necessary. Thus, an induction electromagnetic field is generated in the processing chamber 102 by the high frequency from the high frequency antenna 106, and inductively coupled plasma of the processing gas is excited in the plasma generation space S. The surface of the wafer W is physically or chemically etched by radicals and ions in the plasma.

  Here, the plasma generation space S is a space in which plasma is mainly generated between the ceiling wall 105 and the susceptor 104c in the processing chamber 102, and is a space on the wafer W placed on the susceptor 104c. It is not limited, and extends to the space outside in the radial direction and extends to the vicinity of the inner wall or side wall of the processing chamber 102. Here, in the plasma generation space S, a space on the central region on the center side of the wafer W that is directly below the upper moving magnetic field forming unit 300 is referred to as a “central plasma region”, and the surrounding space (the edge of the wafer W) The space on the peripheral region on the side and the space near the inner wall or side wall of the processing chamber 102 on the outside thereof are referred to as “peripheral plasma region”.

  When such an etching process is completed, the gate valve 137 is opened and the processed wafer W is unloaded from the process chamber 102. In this way, a series of processes are completed after the etching process for one lot (for example, 25 wafers) of wafers W is successively performed one by one.

  In the plasma processing apparatus 100 according to the first embodiment, when the plasma is formed by the high-frequency antenna 106 as described above, the moving magnetic field rotating in the upper region of the plasma generation space S is driven by driving the upper moving magnetic field forming unit 300. Can be formed. With this moving magnetic field, electric charges (mainly electrons) in the plasma generated by the high-frequency antenna 106 can be confined in the upper region of the plasma generation space S. As a result, an increase in plasma electron temperature can be suppressed, and the uniformity of plasma electron density can be improved. As a result, for example, even in a low pressure atmosphere of 100 mTorr or less, and in an extremely low pressure atmosphere of 10 mTorr or less, a more uniform process is performed in the plane of the wafer W without damaging the wafer W. be able to.

(Specific configuration example of the moving magnetic field generator)
A specific configuration example of the upper moving magnetic field forming unit 300 will be described with reference to the drawings. FIG. 3 is a diagram illustrating an appearance of the upper moving magnetic field forming unit 300, and FIG. 4 is a diagram illustrating a part of an internal configuration of the upper moving magnetic field forming unit 300. For simplicity of explanation, the coil is omitted in FIG. 3, and the coil is cut at the inner peripheral surface of the annular core in FIG.

  As shown in FIGS. 3 and 4, the upper moving magnetic field forming unit 300 is configured by covering an annular core 310 around which a coil 320 is wound with a casing 330. The annular core 310 is made of a magnetic material such as metal, ferrite, or ceramic. Here, the case where the cyclic | annular core 310 is comprised with the cyclic | annular iron core is mentioned as an example. The casing 330 is made of, for example, ceramics or quartz so that the lines of magnetic force generated on the lower surface of the annular core 310 are transmitted. Further, the material of the casing 330 is not limited to the above, and for example, only the lower surface of the casing 330 may be made of ceramics or quartz, and the other parts may be made of stainless steel. The lower surface of the casing 330 may open over the circumferential direction.

  A plurality of teeth portions 312 are formed on the lower surface of the annular core 310 at regular intervals in the circumferential direction. A groove portion 314 is formed between each tooth portion 312, and the coil 320 is inserted into the groove portion 314 and wound around each tooth portion 312. In the coil 320, for example, as shown in FIG. 4, a U-shaped magnetic field line that forms a path returning downward from the lower surface between the plurality of tooth portions 312 extends over the entire circumference of the annular core 310. It is wound so as to generate a plurality. Specific examples of the winding state of the coil 320 are shown in FIGS. FIG. 5 is a view of the annular core 310 as viewed from below, and the coil 320 is schematically shown as a straight line for the sake of simplicity. FIG. 5 is a connection diagram showing the entire coil winding state, and FIG. 6 is a connection diagram showing a part of the coil winding state. In FIG. 6, the lower side is the inside of the annular core 310, and the upper side is the outside of the annular core 310.

  As shown in FIG. 5, the coil 320 includes three windings 320A, 320B, and 320C. One of the windings 320A, 320B, and 320C is inserted into the groove portion 314 of the annular core 310, and the windings 320A, 320C, and 320B are inserted into the groove portions 314 in that order from the inside to the outside and outside. It is wound in different directions, such as from the inside. That is, as shown in FIG. 6, when the groove portion 314 of the annular core 310 is first to sixth in order from the left, the winding 320A is respectively connected to the first and fourth groove portions 314 from the inside to the outside and from the outside. It is wound so as to be inserted inside. The winding 320B is wound around the third and sixth grooves 314 so as to be inserted from the inside to the outside and from the outside to the inside, respectively. The winding 320C is wound around the second and fifth grooves 314 so as to be inserted from the outside to the inside and from the inside to the outside, respectively.

  Each winding 320A, 320B, 320C of the coil 320 is in a closed loop. Each of the windings 320A, 320B, and 320C has three-phase AC currents A, B, and C shifted from each other by 120 degrees as shown in FIG. By flowing in this manner, a synthetic magnetic field can be generated in the tooth portion 312.

For example a three-phase alternating currents A, B, and C, _{respectively, I 0 cosωt, I 0 cos} (ωt-2 / 3π), and I 0 cos (ωt-4 / 3π). At this time, in the windings 320A, 320B, and 320C inserted through the grooves 314, currents flowing from the inside to the outside of the annular core 310 are a, b, and c as shown in FIG. if the current flowing Te -a, -b, and -c, current a, b, respectively c _{is, I 0 cosωt, I 0 cos} (ωt-2 / 3π), I 0 cos (ωt-4 / 3π) next, each current -a, -b, -c _{is, -I 0 cosωt, -I 0 cos} (ωt-2 / 3π), - a I 0 cos (ωt-4 / 3π).

  In this case, when the annular core 310 shown in FIG. 6 is viewed from the outside, the currents flowing through the windings 320A, 320B, and 320C inserted through the grooves 314 are a, −c, b, -A, c, -b. At this time, a magnetic field is generated around the windings 320A, 320B, and 320C (around the groove portion 314) according to the direction and magnitude of the flowing current. For example, a magnetic field as indicated by an arrow in FIG. Then, a synthetic magnetic field as shown in FIG. For this reason, as shown in FIG. 10 as a whole, U-shaped magnetic field lines that form a path that goes downward from the lower surface of one tooth portion 312 and returns to the lower surface of another tooth portion 312 in the circumferential direction. Multiple occurrences along.

  Since the three-phase alternating currents A, B, and C continuously change in magnitude as time passes as shown in FIG. 7, the strength of the magnetic field lines generated on the lower surface of the annular core 310 also changes continuously. . As a result, a moving magnetic field that rotates in the circumferential direction along the lower surface of the annular core 310 is formed in the central plasma region immediately below the upper moving magnetic field forming unit 300.

  With such a moving magnetic field, it acts only on the upper part of the plasma generation space S and does not act on the lower part thereof. Accordingly, it is possible to avoid or reduce the possibility that a magnetic field acts on the wafer W on the mounting table 104 to cause damage or stress to the device on the wafer W. Here, the non-magnetic field state that does not damage or stress the devices on the wafer W is preferably a state below the geomagnetic level (for example, 0.5 G) in terms of magnetic field strength, but even about 5 G is not a problem ( It may be said that it is a substantially no magnetic field state.

In the upper moving magnetic field forming unit 300 according to the first embodiment, the control unit 200 controls the AC power supply 302, and the magnitude (I ₀ ), frequency, and phase of the three-phase AC currents A, B, and C that flow through the coil 320. By changing the above, it is possible to easily change the strength and rotation speed of the moving magnetic field. For example, the strength of the moving magnetic field can be varied by changing the magnitude and frequency of the three-phase alternating currents A, B, and C. The rotational speed of the moving magnetic field can be changed by changing the frequency of the three-phase alternating currents A, B, and C. For this reason, for example, when changing the strength of the magnetic field, it becomes unnecessary to replace the magnet as in the case of using a segment magnet as in the prior art, and vibration that tends to occur when the segment magnet is rotated is eliminated. be able to.

  Note that the strength and rotational speed of the moving magnetic field vary depending on the pitch between the tooth portions 312 and the number of the tooth portions 312, and therefore, for example, the pitch between the tooth portions 312 and the number of the tooth portions 312 for each plasma processing apparatus 100. It is possible to easily adjust the strength of the moving magnetic field and the rotational speed by controlling the AC power supply 302 by the control unit 200 after mounting it after designing it appropriately.

  An arrangement example of such an upper moving magnetic field forming unit 300 is shown in FIG. In the plasma processing apparatus 100 according to the first embodiment, the case where the upper moving magnetic field forming unit 300 is provided on the outer side surface (upper side surface) of the ceiling wall 105 is taken as an example. For example, as shown in FIG. 11, the upper moving magnetic field forming unit 300 is disposed inside the high-frequency antenna 106 formed in a spiral coil shape.

  Next, the operation of the upper moving magnetic field forming unit 300 arranged as described above will be described in more detail while comparing the case where the moving magnetic field is formed with the case where the moving magnetic field is not formed. 12 and 13 are diagrams for explaining the action of the moving magnetic field by the upper moving magnetic field forming unit 300. In order to easily understand the action of the moving magnetic field, the configuration of the plasma processing apparatus shown in FIG. 1 is further simplified. ing. FIG. 12 shows a case where a moving magnetic field is not formed, and FIG. 13 shows a case where a moving magnetic field is formed. The plasma formed in each case is schematically shown.

FIG. 14 is a graph showing the tendency of the in-plane uniformity of the plasma electron temperature (eV) and the plasma electron density (Ne) when the moving magnetic field is not formed in the processing chamber pressure. FIG. 14 shows the experimental results when the SiO ₂ film on the wafer W is etched by the plasma of CHF ₃ gas. The plasma electron temperature (eV) in FIG. 14 is a graph obtained by measuring the electron temperature in the processing chamber 102 with a Langmuir probe each time plasma is generated in the processing chamber 102 and the pressure in the processing chamber 102 is changed. It is a thing. The in-plane uniformity of the plasma electron density (Ne) is a graph obtained by measuring the electron density Ne _center near the _center of the plasma and the electron density Ne _edge near the edge of the plasma to determine the in-plane uniformity. .

  First, in the case where plasma is generated by the high frequency antenna 106 without forming the moving magnetic field by the upper moving magnetic field forming unit 300, as shown in FIG. 12, the central plasma on the wafer center side with respect to the peripheral plasma region on the wafer edge side is shown. In the region, the plasma electron density tends to be relatively low. Looking at this in relation to the pressure in the processing chamber 102, as shown in FIG. 14, in a low pressure atmosphere of 100 mTorr or less, the processing chamber 102 is in a relatively low pressure range (for example, 20 to 10 mTorr or less). The lower the internal pressure, the greater the possibility that the wafer W will be damaged because the electron temperature fluctuates greatly with a slight pressure fluctuation.

  On the other hand, in the range where the pressure in the processing chamber 102 is higher than 20 to 10 mTorr (shown up to 50 mTorr in the figure), the electron temperature gradually decreases from 4 eV to 2 eV even if the pressure increases. It can be seen that the higher the value is, the more stable the plasma electron temperature is, so that a stable plasma can be obtained and the possibility of damaging the wafer W is low. However, in the range where the pressure in the processing chamber 102 is relatively high (for example, 70 to 80 mTorr or more), the uniformity of plasma electron density is greatly reduced, so that the in-plane uniformity of processing on the wafer W is likely to be reduced. End up.

  This is because, as the pressure in the processing chamber 102 is lower, the electrons in the plasma are accelerated without colliding with other particles, and for example, there is a higher probability that the electrons collide with the sidewall of the processing chamber and disappear. In this case, the electron density in the plasma is lowered and the electron temperature is increased, and as a result, ions in the plasma are accelerated and collide with the wafer with high energy, so that the wafer is easily damaged. In addition, the higher the pressure in the processing chamber 102, the greater the acceleration of electrons in the plasma, and there is a higher possibility of diffusion from the peripheral part to the outside without staying at the central part. For this reason, the plasma electron density is also relatively lowered on the wafer center side as compared to the wafer edge side, so that in-plane uniformity of processing on the wafer W is lowered.

  In this regard, when plasma is generated by the high-frequency antenna 106 while forming the moving magnetic field by the upper moving magnetic field forming unit 300, the central plasma region immediately below the upper moving magnetic field forming unit 300 is as shown in FIG. A plurality of magnetic field lines are generated in the circumferential direction from the lower surface of the upper moving magnetic field forming unit 300 toward the plasma region and making U-turns in the upper region of the plasma region. A moving magnetic field GC that rotates in one circumferential direction is formed along the lower surface of the upper moving magnetic field forming unit 300 as a whole while increasing or decreasing the strength of these lines of magnetic force.

  As a result, charges (mainly electrons) that drift in the plasma under a high-frequency electric field receive a force (Lorentz force) by the moving magnetic field in the central plasma region, and are confined by the cyclotron resonance effect, and the ceiling wall from the central plasma region. It is possible to prevent accelerating and diffusing to 105 and the side wall. As a result, it is possible to prevent a rapid decrease in the electron density of the plasma due to the diffusion and extinction of the plasma, and to suppress an increase in the plasma electron temperature. For example, in the case shown in FIG. 14, the plasma can be suppressed to a range where the plasma electron temperature can be obtained stably (for example, a range of about 4 eV to 2 eV). If it is suppressed to such a range, the possibility of damaging the wafer W is reduced.

  Moreover, since the upper moving magnetic field forming unit 300 in the first embodiment is disposed on the central plasma region, electric charges (mainly electrons) in the plasma can be confined in the central plasma region immediately below the upper moving magnetic field forming unit 300. It is possible to control the distribution of the plasma electron density of the plasma, thereby controlling the distribution of the entire plasma region.

  Therefore, for example, by forming a moving magnetic field by the upper moving magnetic field forming unit 300 in a low pressure atmosphere of 100 mTorr or less, the pressure in the processing chamber 102 is relatively low, for example, as shown by an arrow shown in FIG. It is possible to prevent an increase in the electron temperature which is a problem in the following extremely low pressure atmosphere, and it is possible to prevent a decrease in the in-plane uniformity of the electron density which is a problem in a pressure atmosphere having a relatively high pressure in the processing chamber of several tens mTorr or more. As a result, the wafer W can be uniformly processed within the surface of the wafer W without damaging the wafer W in any pressure range of 100 mTorr or less.

As described above, according to the present embodiment, by forming the moving magnetic field by the upper moving magnetic field forming unit 300, an increase in electron temperature can be effectively prevented in an extremely low pressure atmosphere of tens of mTorr or less to several mTorr or less. In addition to the SiO ₂ film conventionally used as a material for the gate oxide film, the present invention exerts a great effect on the etching of a refractory metal material which has been attracting attention in recent years. That is, when etching a refractory metal material such as HfO ₂ , HfSiO ₂ , ZrO ₂ , ZrSiO _4, etc., plasma processing in an extremely low pressure atmosphere in which the plasma electron temperature is likely to rise is required.

For example, FIG. 15 and FIG. 16 are graphs showing the pressure dependence of the etching rate when an HfO ₂ film or SiO ₂ film is etched, and FIG. 15 is a case where etching is performed by plasma of BCl ₃ gas. FIG. 16 shows a case where etching is performed by plasma of a mixed gas of BCl ₃ gas and O ₂ gas. FIG. 17 shows the relationship between the electron temperature and pressure of plasma using BCl ₃ gas when the moving magnetic field is not formed in this embodiment.

According to this, in order to proceed effectively etching when etching the HfO ₂ film, it is preferably a pressure range of about 6~12mTorr as shown in FIG. 15 is a plasma BCl ₃ gas and BCl ₃ gas and O _In the mixed gas plasma of _two gases, a pressure range of 12 mTorr or less is preferable as shown in FIG. Moreover, towards the plasma BCl ₃ gas and a mixed gas of _{O 2} gas in comparison with the plasma of BCl ₃ gas is higher etching rate. However, it can be seen that in the pressure range used in the plasma using such BCl ₃ gas (for example, an extremely low pressure atmosphere of 12 mTorr or less), the plasma electron temperature rapidly increases as shown in FIG.

  Therefore, when performing a plasma treatment in an extremely low pressure atmosphere as in the case of etching a refractory metal material having such a so-called difficult-to-etch characteristic, a plasma is generated by forming a moving magnetic field by the upper moving magnetic field forming unit 300. Since plasma electrons can be confined in the generation space, an increase in plasma electron temperature can be suppressed and uniformity of plasma electron density can be improved. Thereby, there is no damage to the wafer W, and uniform plasma processing can be performed within the wafer surface. Further, since there is no risk of damage to the wafer W, etching can be performed at a lower pressure. Thereby, the etching rate of the refractory metal material can be increased more than before without damaging the wafer W.

As shown in FIG. 15, the SiO ₂ film is hardly etched in the BCl ₃ gas plasma as shown in FIG. 15. However, in the plasma of the mixed gas of BCl ₃ gas and O ₂ gas as shown in FIG. In a low pressure atmosphere, the lower the pressure, the higher the etching rate. Therefore, in this case as well, by forming the moving magnetic field by the upper moving magnetic field forming unit 300, the wafer W is not damaged and uniform plasma processing can be performed within the wafer surface.

  Further, as shown in FIGS. 14 and 17, it can be seen that the rate of increase in plasma electron temperature tends to increase as the pressure decreases. Therefore, the control unit 200 controls the alternating current flowing from the AC power source 302 to the coil 320 of the upper moving magnetic field forming unit 300 according to the pressure in the processing chamber 102 when performing the plasma processing of the wafer W, thereby moving the magnetic field. You may make it increase the intensity of or increase the rotational speed. In this way, it is possible to effectively suppress an increase in plasma electron temperature by forming an optimum moving magnetic field according to the pressure.

  Further, for example, the uniformity of plasma processing can be controlled by controlling the strength and rotation speed of the moving magnetic field in accordance with the type of plasma processing and processing conditions (for example, the type and flow rate of processing gas, the pressure in the processing chamber, etc.). . For example, paying attention to any one or a combination of two or more of the types of processing gas, the pressure in the processing chamber 102, the flow rate of the processing gas, and the high-frequency power, In some cases, the strength and rotational speed of the moving magnetic field are finely adjusted according to the processing conditions. Even if the plasma distribution is changed by changing these processing conditions, it is possible to control the alternating current flowing from the AC power supply 302 to the coil 320 so that the plasma distribution is always optimal.

  Under such processing conditions, it is easy to influence the plasma distribution in the central region on the center side of the wafer W and the peripheral region on the edge side of the wafer W. The order is pressure, flow rate of processing gas, and high-frequency power. The higher the frequency, the more likely the influence is higher. For this reason, when adjusting the plasma distribution between the wafer center side and the wafer edge side, it is preferable to control the AC power supply 302 by the control unit 200 according to at least the type of processing gas. In addition, if any of the type of processing gas that easily affects the plasma distribution, the pressure in the processing chamber 102, or the flow rate of the processing gas changes, the control unit 200 controls the AC power supply 302 accordingly, thereby making the plasma finer. The distribution can be controlled.

  By the way, in order to improve the uniformity of the plasma electron density, instead of the upper moving magnetic field forming unit 300, for example, another high-frequency antenna is provided also on the center side of the ceiling wall, and the plasma is also formed on the center side. It is also possible to generate. However, if this is done, a strong electromagnetic field energy is also applied to the center of the space where the plasma is formed, so that although the plasma electron density can be increased, the plasma electron temperature is also increased to, for example, 10 to 20 eV or more. It will be high. This increases the possibility of damaging the wafer W.

  On the other hand, when the moving magnetic field is formed by the upper moving magnetic field forming unit 300 as in the present embodiment, the plasma is not formed immediately below, but the electrons of the plasma formed in another place move. Since it is attracted by the magnetic field and only confined by the weak magnetic field, the plasma electron density can be increased while the plasma electron temperature is kept low, for example, 2-4 eV or lower. Thereby, uniform plasma processing can be performed while suppressing damage to the wafer W.

  In the first embodiment, the case where the upper moving magnetic field forming unit 300 is arranged inside the high frequency antenna 106 to form the moving magnetic field in the upper region of the central plasma region has been described. The arrangement of the magnetic field forming unit 300 is not limited to this. For example, as shown in FIG. 18, the upper moving magnetic field forming unit 300 may be arranged outside the high frequency antenna 106 so as to form a moving magnetic field in the upper region of the peripheral plasma region.

  According to this, when the above-described three-phase AC current is supplied from the AC power supply 302 to the upper moving magnetic field forming unit 300, as schematically shown in FIG. , A plurality of magnetic field lines are generated in the circumferential direction from the lower surface of the upper moving magnetic field forming unit 300 toward the plasma region and making U-turns in the upper region of the plasma region. A moving magnetic field GC that rotates in one circumferential direction is formed along the lower surface of the upper moving magnetic field forming unit 300 as a whole while increasing or decreasing the strength of these lines of magnetic force.

  That is, in the peripheral plasma region, a vertical magnetic field (magnetic field perpendicular to the plasma diffusion direction) that surrounds while rotating like a curtain can be formed from the vicinity of the peripheral region of the wafer W to the outer region. Thus, for example, when high-frequency power is applied from the high-frequency power source 107 to the high-frequency antenna 106 to form plasma, the upper moving magnetic field forming unit 300 is further driven to form a moving magnetic field immediately below it. Charges (mainly electrons) that drift in a high-frequency electric field in the plasma receive a force (Lorentz force) by the moving magnetic field in the peripheral plasma region, and are confined by the cyclotron resonance effect and accelerated outward. It can prevent spreading. As a result, it is possible to prevent a rapid decrease in the electron density of the plasma due to the diffusion and extinction of the plasma, and to suppress an increase in the plasma electron temperature.

  In addition, since the upper moving magnetic field forming unit 300 shown in FIG. 18 is disposed on the peripheral plasma region, electric charges (mainly electrons) in the plasma can be confined in the peripheral plasma region immediately below it. The distribution of plasma electron density can be controlled, and the distribution of the entire plasma region can be controlled.

  Next, a plasma processing apparatus according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 19 is a schematic configuration diagram of a plasma processing apparatus according to the second embodiment. In FIG. 19, the configuration of the processing chamber 102 is simplified for easy understanding of the action of the moving magnetic field. FIG. 20 is a diagram illustrating an external appearance of the peripheral moving magnetic field forming unit 340.

  In the second embodiment, in addition to the configuration of the first embodiment (for example, the upper moving magnetic field forming unit 300 provided outside the ceiling wall 105 of the processing chamber 102), the periphery of the side wall of the processing chamber 102 is also surrounded. As an example, the peripheral moving magnetic field forming unit 340 is provided. In the second embodiment, not only the ceiling wall 105 of the processing chamber 102 but also the side wall of the processing chamber 102 may be formed of an insulating member such as quartz. In this case, as shown in FIG. 19, the portion surrounded by the peripheral moving magnetic field forming portion 340 in the entire side wall may be formed of quartz or the like as the cylindrical insulating member 344, and the entire side wall of the processing chamber 102 may be formed as a cylinder. The shaped insulating member may be made of quartz or the like.

  The peripheral moving magnetic field forming unit 340 shown in FIG. 19 generates a plurality of lines of magnetic force that make U-turns on the inner side surface from the inner side surface toward the plasma generation space S in the peripheral region of the plasma generation space S. These magnetic lines of force form a moving magnetic field that rotates along the inner surface of the peripheral moving magnetic field forming unit 340.

  Specifically, as shown in FIG. 20, the peripheral moving magnetic field forming unit 340 is configured such that the inner surface thereof corresponds to the lower surface of the upper moving magnetic field forming unit 300 shown in FIG. That is, the peripheral moving magnetic field forming unit 340 includes an annular core 310 disposed via the cylindrical insulating member 344 so as to surround the plasma generation space S. A coil 320 (not shown) is wound around the annular core 310 and covered with a casing 330.

  The annular core 310 has a plurality of teeth portions 312 formed on the inner surface thereof at regular intervals in the circumferential direction. A groove portion 314 is formed between the teeth portions 312. The coil 320 is inserted into the groove portion 314 and wound around each tooth portion 312. The coil 320 is wound between the plurality of tooth portions 312 so that a plurality of magnetic lines of force that form a path returning to the inside outward between the plurality of tooth portions 312 are generated over the entire circumference of the annular core 310. Consists of multiple windings. Specifically, for example, the winding is performed in the same manner as shown in FIGS. In the case of the second embodiment, the inner surface of the peripheral moving magnetic field forming unit 340 corresponds to the lower surface of the upper moving magnetic field forming unit 300 shown in FIG. The outer side and the inner side correspond to the upper side and the lower side of the peripheral moving magnetic field forming unit 340. Accordingly, the coil 320 of the peripheral moving magnetic field forming unit 340 is also configured by, for example, three windings 320A, 320B, and 320C similar to those in FIG. That is, it is almost the same as the method of winding the coil 320 when FIG. 6 is considered as a view seen from the inside of the peripheral moving magnetic field forming unit 340.

  Three-phase AC currents A, B, and C whose phases are shifted from each other by 120 degrees as shown in FIG. 7, for example, from an AC power source (AC power source for forming a peripheral moving magnetic field) 342 to the windings 320A, 320B, and 320C of the coil 320, respectively. Is caused to flow as shown by the arrow in FIG. The AC power supply 342 of the peripheral moving magnetic field forming unit 340 can be controlled separately by being provided in a separate system from the AC power supply 302 of the upper moving magnetic field forming unit 300.

  In the plasma processing apparatus according to the second embodiment configured as described above, when the inductively coupled plasma of the processing gas is generated by the high-frequency antenna 106 and the wafer W is processed, predetermined AC power sources 302 and 342 are used. The three-phase alternating current is supplied to the upper moving magnetic field forming unit 300 and the peripheral moving magnetic field forming unit 340, respectively. As a result, as shown in FIG. 19, a moving magnetic field GC is formed in the upper region of the plasma region, and a moving magnetic field GE is formed so as to surround the peripheral region of the plasma region.

  That is, a plurality of magnetic lines that make U-turns in the peripheral plasma region are generated in the peripheral direction from the inner surface toward the plasma region on the inner surface of the peripheral moving magnetic field forming unit 340, and the strength of these magnetic force lines increases. A moving magnetic field GE that rotates in one circumferential direction along the inner peripheral surface of the peripheral moving magnetic field forming unit 340 is formed as a whole while decreasing.

  According to this, the plasma electrons generated by the high-frequency antenna 106 can be confined not only in the upper part of the central plasma region but also in the peripheral plasma region. In addition, since the moving magnetic field rotating around the side wall of the processing chamber 102 is formed by the peripheral moving magnetic field forming unit 340, the diffusion and extinction of plasma in the vicinity of the side wall of the processing chamber 102 can be more effectively suppressed. As a result, the increase in plasma electron temperature can be more effectively suppressed, and the uniformity of plasma electron density can be further improved.

  In the first and second embodiments described above, the case where the plasma processing of the wafer W is mainly performed in a low-pressure atmosphere of 100 mTorr or less has been described as an example. However, the plasma of the wafer W in a pressure range exceeding 100 mTorr is described. Even when processing is performed, the uniformity of the plasma electron density between the central side and the peripheral side can be controlled by forming the moving magnetic field by the upper moving magnetic field forming unit 300.

  The present invention described in detail with reference to the first and second embodiments may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. A medium such as a storage medium storing a software program for realizing the functions of the above-described embodiments is supplied to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus is stored in the medium such as the storage medium. The present invention can also be achieved by reading and executing the program.

  In this case, the program itself read from the medium such as a storage medium realizes the functions of the above-described embodiment, and the medium such as the storage medium storing the program constitutes the present invention. Examples of the medium such as a storage medium for supplying the program include a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, and a DVD-RAM. DVD-RW, DVD + RW, magnetic tape, nonvolatile memory card, ROM, and the like. It is also possible to provide a program downloaded to a medium via a network.

  Note that by executing the program read by the computer, not only the functions of the above-described embodiments are realized, but also an OS or the like running on the computer is part of the actual processing based on the instructions of the program. Alternatively, the case where the functions of the above-described embodiment are realized by performing all the processing and the processing is included in the present invention.

  Furthermore, after a program read from a medium such as a storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function is determined based on the instructions of the program. The present invention also includes a case where the CPU or the like provided in the expansion board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, the present invention can be applied to other plasma processing apparatuses 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 may be various substrates for flat panel displays, photomasks, CD substrates, printed substrates, and the like.

  The present invention can be applied to a plasma processing apparatus and a plasma processing method for forming a processing gas plasma and performing a predetermined processing on a substrate to be processed.

It is sectional drawing which shows the structural example of the plasma processing apparatus concerning 1st Embodiment of this invention. It is a block diagram which shows the structural example of the control part shown in FIG. It is a perspective view which shows the general | schematic external appearance structure of the upper moving magnetic field formation part in the embodiment. It is a perspective view which shows a part of schematic internal structure of the upper moving magnetic field formation part in the embodiment. It is a connection diagram which shows the whole winding state of the coil in the embodiment. It is a connection diagram which shows a part of winding state of the coil in the embodiment. It is a wave form diagram which shows the three-phase alternating current sent through the coil in the same embodiment. It is a figure which shows typically the magnetic field which generate | occur | produces around the coil in the same embodiment. It is a figure which shows typically direction of the magnetic field which generate | occur | produces on the surface of the teeth part in the embodiment. It is a figure which shows typically the magnetic force line which generate | occur | produces on the surface of the teeth part in the embodiment. It is a top view which shows the example of arrangement | positioning of a high frequency antenna and an upper moving magnetic field formation part. It is a schematic block diagram of the plasma processing apparatus in the same embodiment, and is a figure for demonstrating the effect | action when not forming a moving magnetic field. It is a schematic block diagram of the plasma processing apparatus in the same embodiment, and is a figure for demonstrating the effect | action at the time of forming a moving magnetic field. It is the figure which showed the pressure dependence about the uniformity of plasma electron temperature and plasma electron density in the case where a moving magnetic field is not formed. BCl ₃ is a view showing a graph of pressure dependency of the etching rate by plasma etching gas. BCl ₃ is a view showing a graph of pressure dependence of the gas and the etching rate by plasma etching of a mixed gas of O ₂ gas. The pressure dependence of the plasma electron temperature in the plasma using BCl ₃ gas is a diagram showing the graph. It is a schematic block diagram which shows the modification of the plasma processing apparatus concerning the embodiment. It is a schematic block diagram of the plasma processing apparatus concerning 2nd Embodiment of this invention. It is a perspective view which shows the schematic external appearance structure of the peripheral part movement magnetic field formation part in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Plasma processing apparatus 102 Processing chamber 103 Insulating plate 104 Mounting base 104a Susceptor support base 104b Bolt 104c Susceptor 105 Ceiling wall (plate-shaped insulating member)
106 High-frequency antenna 106a Inner terminal 106b Outer terminal 107, 119 High-frequency power supply 108 Matching device 109 Temperature control medium flow path 111 Inlet pipe 112 Discharge pipe 113 Electrostatic chuck 113a Conductive film 114 Variable DC high-voltage power supply 116 Gas path 117 Focus ring 118 For matching Capacitor 119 High-frequency power source 120 Gas supply part 121 Gas inlet 122 Gas supply source 123 Gas supply pipe 124 Mass flow controller 130 Exhaust pipe 131 Heater fixing base 132 Heating heater 133 Heater power supply 134 Transmission window 135 Optical system 136 Optical sensor 137 Gate valve 138 Pressure sensor 140 Exhaust unit 200 Control unit 210 CPU
220 ROM
230 RAM
240 Display unit 250 Operation panel 260 Notification unit 270 Various controllers 280 Program data storage unit 290 Processing condition storage unit 300 Upper moving magnetic field forming units 302 and 342 AC power supply 310 Annular core 312 Teeth unit 314 Groove 320 Coil 320A, 320B, 320C Winding 330 Casing 340 Peripheral Moving Magnetic Field Forming Unit 344 Tubular Insulating Member W Wafer

Claims (9)

A plasma processing apparatus for performing predetermined plasma processing on a substrate to be processed by generating inductively coupled plasma of a processing gas in a decompressed processing chamber,
A mounting table provided in the processing chamber for mounting the substrate to be processed;
A processing gas introduction part for introducing the processing gas into the processing chamber;
An exhaust section for exhausting and depressurizing the processing chamber;
A high-frequency antenna disposed through a plate-like insulating member so as to face the mounting table,
A high frequency power source for applying high frequency power to the high frequency antenna for generating the inductively coupled plasma in a plasma generation space between the mounting table and the plate-like insulating member;
A moving magnetic field in which a plurality of magnetic lines of force that are arranged via the plate-like insulating member so as to face the mounting table and that form a path returning upward in the upper part of the plasma generation space rotate in the circumferential direction. An annular upper moving magnetic field forming section that forms
The upper moving magnetic field forming unit is
An annular core disposed with the high-frequency antenna on the upper side of the plate-like insulating member;
A plurality of teeth formed to protrude from the lower surface of the annular core and arranged in a circumferential direction so as to extend radially from the inside to the outside of the annular core;
The annular core is sequentially inserted into the grooves between the teeth portions so that a plurality of magnetic lines of force that form a path returning downward to the lower side of the teeth portions are generated over the entire circumference of the annular core. A coil comprising a plurality of windings wound around
An AC power source is provided that forms a moving magnetic field that rotates in the circumferential direction above the plasma generation space by passing alternating currents having different phases through the windings of the coil and temporally changing the lines of magnetic force. A plasma processing apparatus. The plasma processing apparatus according to claim 1 , wherein the high-frequency antenna is formed in a planar coil shape so as to surround the annular core. The coil consists of three sets of windings, a plasma processing apparatus according to claim 1 or 2, characterized in that to supply the three-phase alternating currents to each of the windings from the magnetic field power source. Formed by the upper moving magnetic field forming unit by controlling the alternating current from the magnetic field forming power source according to the processing condition stored in the storage unit, and a storage unit that stores the processing conditions of the substrate to be processed The plasma processing apparatus according to claim 1, further comprising a control unit that controls the moving magnetic field. The control unit is configured to control the alternating current from the magnetic field forming power source based on the pressure in the processing chamber among the processing conditions stored in the storage unit, thereby moving the movement formed by the upper moving magnetic field forming unit. The plasma processing apparatus according to claim 4 , wherein the magnetic field is controlled. A plurality of lines of magnetic force that are arranged through a cylindrical insulating member so as to surround the periphery of the plasma generation space, and that form a path that returns to the inside toward the outside in the periphery of the plasma generation space rotate in the circumferential direction. The plasma processing apparatus according to claim 1, further comprising a peripheral moving magnetic field forming unit that forms a moving magnetic field. The peripheral moving magnetic field forming unit is:
An annular core disposed through a cylindrical insulating member so as to surround the plasma generation space;
A plurality of teeth formed on the inner surface of the annular core and arranged in the circumferential direction so as to extend in the vertical direction of the annular core;
A plurality of windings wound between the plurality of tooth portions so that a plurality of magnetic lines of force that form a path returning inward toward the inside between the plurality of tooth portions are generated over the entire circumference in the circumferential direction of the annular core. A coil consisting of
An alternating current power source is provided for forming a moving magnetic field that rotates in the circumferential direction at the periphery of the plasma generation space by passing alternating currents having different phases through the windings of the coil and temporally changing the lines of magnetic force. The plasma processing apparatus according to claim 6 . A high-frequency antenna provided via a plate-like insulating member is provided opposite to the mounting table disposed in the processing chamber, and a processing gas is introduced into the processing chamber that has been decompressed to a predetermined pressure to supply high-frequency power to the high-frequency antenna. A plasma processing method of a plasma processing apparatus for generating inductively coupled plasma of a processing gas in the processing chamber by applying a predetermined processing to a substrate to be processed on the mounting table,
Through the plate-shaped insulating member so as to face arranged upper moving magnetic field generator of the ring-shaped prior to mounting table,
The upper moving magnetic field forming part is formed on the upper side of the plate-like insulating member with an annular core disposed with the high frequency antenna, and protrudes on the lower surface of the annular core, and extends radially from the inside to the outside of the annular core. The plurality of teeth portions arranged in the circumferential direction as described above, and a plurality of lines of magnetic force that form a path returning downward toward the lower side below the teeth portions are generated over the entire circumference in the circumferential direction of the annular core. A coil composed of a plurality of windings that are sequentially inserted in the groove between the teeth and wound around the annular core, and the magnetic field lines are temporally changed by passing alternating currents of different phases through the windings of the coil. An AC power source that forms a moving magnetic field that rotates in the circumferential direction above the plasma generation space,
The lower surface of the upper moving magnetic field generator, to generate a plurality of lines of magnetic force U-turn in the upper region of the plasma generating space directed from the lower surface to the plasma generation space, these field lines of the upper moving magnetic field generator A plasma processing method comprising forming a moving magnetic field rotating along a lower surface. The plasma generation is performed from the inner surface to the inner surface of the peripheral moving magnetic field forming portion by an annular peripheral moving magnetic field forming portion disposed through a cylindrical insulating member so as to surround the peripheral portion of the plasma generating space. characterized by forming a moving magnetic field by generating a plurality of lines of magnetic force U-turn in the peripheral area of the plasma generating space toward the space, these magnetic field lines is rotated along the inner surface of the peripheral portion moving magnetic field generator The plasma processing method according to claim 8 .

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