JP4653395B2 - Plasma processing equipment - Google Patents

Description

The present invention relates to a plasma treatment MakotoSo location, to a suitable plasma treatment MakotoSo location for the surface treatment of a sample such as semiconductor devices, especially using plasma.

  When performing an etching process using plasma, the process gas is ionized and activated to speed up the process, and a high-frequency bias power is supplied to the material to be processed so that ions in the plasma are incident perpendicularly to the material to be processed. As a result, a highly accurate etching process such as an anisotropic shape is realized.

As a plasma processing apparatus for performing such processing, an air-core coil is provided on the outer peripheral portion outside the vacuum vessel, a circular conductor plate is provided facing a sample stage provided in the vacuum vessel, and a UHF band power source and a circular conductor plate are provided on the circular conductor plate. A first high-frequency power source is connected, a second high-frequency power source is connected to the sample stage, and an electric field having a frequency different from the frequency of the UHF band is superimposed on the circular conductor plate and supplied. A plasma is formed using an electron cyclotron resonance phenomenon caused by the interaction between an electromagnetic wave generated by a UHF band power supply and a magnetic field generated by an air core coil, and a bias applied to the circular conductor plate is increased by a high frequency voltage generated by the superimposed first high frequency power supply. The conductive plate reacts with the plasma so that more active species contributing to the etching can be generated, and the second high-frequency power source connected to the sample base It controls the incident energy on the sample have been proposed (e.g., see Patent Document 1).
JP-A-9-321031 (USP 5,891,252)

In such a conventional apparatus, the ion energy incident on the material to be processed is determined by the self-bias potential generated by the bias power supplied to the material to be processed, but with respect to the substrate electrode as the wafer size increases. Since the ratio of the ground area decreases, sufficient electrons cannot be supplied from the plasma to the substrate electrode.
For this reason, the ratio of Vdc / Vpp decreases and the plasma potential increases. As a result, the RF bias application efficiency decreases, the ground electrode and the side wall member are sputtered by ions in the plasma to cause metal contamination, or the plasma diffuses into the space below the processing chamber to increase foreign matter. There is a problem of doing.

  Further, a sinusoidal high-frequency electric field is applied to the sample stage, that is, the substrate electrode, and the ion energy distribution is fixed by a high-frequency bias with a fixed frequency. In the case of a material to be processed as typified by Aligned Contact), when the processing is performed while maintaining the etching rate, the selection ratio between the mask and the base material becomes small, and it is difficult to perform high-precision processing.

A first object of the present invention is to provide a plasma treatment MakotoSo location which can sufficiently secure a selection ratio between the mask and / or substrate material perform high-precision surface treatment.

A second object of the present invention is to suppress an increase in plasma potential is to provide a plasma treatment MakotoSo location capable of suppressing an increase in metal contamination and foreign matters.

  The object is to independently control plasma generation and bias voltage application to the sample, and in the method of plasma processing the sample, the bias voltage applied to the sample is given as a high frequency voltage, and the voltage waveform of the high frequency voltage is an arbitrary voltage. Achieved by flattening with.

  Further, the voltage waveform on the negative voltage side of the high frequency voltage applied to the substrate electrode is flattened.

  Further, the voltage waveform on the positive voltage side of the high-frequency voltage applied to the substrate electrode is flattened.

  Further, the voltage waveform on the positive and negative voltage sides of the high-frequency voltage applied to the substrate electrode is flattened.

  Further, an electrode facing the substrate electrode is provided, a high frequency voltage having the same frequency is applied to both electrodes, and the phase of the high frequency voltage is controlled.

  In order to achieve the above object, according to one aspect of the present invention, a plasma processing apparatus includes a processing chamber to which an evacuation apparatus is connected and whose inside can be decompressed, and a gas supply device that supplies gas into the processing chamber. A substrate electrode provided in the processing chamber on which a material to be processed can be placed, a high-frequency power source connected to the substrate electrode via a matching unit, plasma generating means for generating plasma in the processing chamber, and the matching A voltage waveform control circuit for flattening a voltage waveform provided in the chamber or between the substrate electrode and the matching unit;

  Further, the voltage waveform control circuit is a circuit for flattening the negative voltage side of the high-frequency voltage waveform applied to the substrate electrode with an arbitrary voltage.

  The voltage waveform control circuit is a circuit that flattens the positive voltage side of the high-frequency voltage waveform applied to the substrate electrode with an arbitrary voltage.

  The voltage waveform control circuit is a circuit for flattening the positive and negative voltage sides of the high-frequency voltage waveform applied to the substrate electrode with an arbitrary voltage.

  The voltage waveform control circuit includes a semiconductor element and a DC power source.

  An electrode facing the substrate electrode was provided, and a high frequency power source was connected to the electrode.

  Further, a phase controller is provided that controls the phase difference between the high-frequency voltages that have the same frequency applied to the two electrodes.

  According to another aspect of the present invention, the method of independently controlling plasma generation and bias voltage application to the sample, and the method of plasma processing the sample, the bias voltage applied to the sample is given as a high frequency voltage, the high frequency Flattening the voltage waveform of the voltage to an arbitrary voltage on the positive voltage side and the negative voltage side.

  Further, in the above method, an electrode facing the substrate electrode is provided, a high frequency voltage having the same frequency is applied to both electrodes, and the phase of the high frequency voltage is controlled.

  Further, the phase of the high-frequency voltage has a phase difference within a range of 180 ° ± 30 °.

  According to another aspect of the present invention, a plasma processing apparatus includes a processing chamber to which an evacuation device is connected and whose inside can be decompressed, a gas supply device that supplies gas into the processing chamber, and a chamber provided in the processing chamber. A substrate electrode on which a processing material can be placed, a high-frequency power source connected to the substrate electrode via a matching unit, plasma generating means for generating plasma in the processing chamber, the matching unit or the substrate electrode, and the substrate electrode A voltage waveform control circuit is provided between the matching unit and flattenes the high-frequency voltage waveform to an arbitrary voltage on the positive voltage side and the negative voltage side.

  In the above apparatus, the voltage waveform control circuit includes a diode and a DC power source.

  An electrode facing the substrate electrode was provided, and a high frequency power source was connected to the electrode.

  Further, a phase controller is provided for controlling the phase of the high-frequency voltage by making the frequency of the high-frequency voltage applied to the two electrodes the same.

  Further, the phase controller can control the phase difference within a range of 180 ° ± 30 °.

  According to another aspect of the present invention, there is provided a method for plasma processing a sample in a processing chamber in which plasma is generated, wherein a high frequency voltage is applied to a sample stage on which the sample is arranged, and the voltage waveform of the high frequency voltage is changed to an arbitrary voltage. Flattening step.

  In the above method, the voltage waveform of at least one of the positive and negative voltages applied to the substrate electrode is flattened.

  A plasma processing apparatus according to another aspect of the present invention includes a processing chamber to which an evacuation apparatus is connected and whose inside can be decompressed, a gas supply device that supplies gas to the processing chamber, and a material to be processed that is provided in the processing chamber. A substrate electrode that can be placed, a high-frequency power source connected to the substrate electrode via a matching device, and a voltage for flattening a voltage waveform provided in the matching device or between the substrate electrode and the matching device Includes a waveform control circuit.

  In the above apparatus, the voltage waveform control circuit can flatten at least one of the positive and negative voltage waveforms of the high-frequency voltage applied to the substrate electrode.

  As described above, by controlling the high-frequency voltage waveform applied to the substrate electrode, the distribution of ion energy incident on the sample can be controlled, and the ion energy mainly contributes to the etching of the material to be etched. Since the distribution of ion energy that does not contribute to the etching of the material can be made, it is possible to ensure a sufficient selection ratio between the mask and the underlying material and perform highly accurate surface treatment without greatly changing the speed. it can.

  Also, by flattening the negative voltage of the high-frequency voltage applied to the substrate electrode, the width of the ion energy distribution that spreads high and low can be narrowed, and a large amount of ion energy useful for processing can be distributed. And the efficiency of the plasma treatment can be improved.

  In addition, by flattening the voltage on the positive voltage side in accordance with the flattening of the voltage on the negative voltage side, a stable plasma potential can be obtained, the plasma processing can be stabilized, and the plasma characteristics can be improved. Since the influence of the in-plane distribution of the plasma sheath characteristics due to the in-plane distribution is reduced, charging damage can be suppressed, and high-precision etching processing can be performed with low damage.

  Furthermore, an electrode is provided opposite to the substrate electrode, a high frequency voltage of the same frequency is applied to both electrodes, and the phase difference of the high frequency voltage is set within a range of 180 ° ± 30 °, so that the positive voltage side of the high frequency voltage is Since the potential increase can be suppressed, a stable plasma potential can be obtained, and the plasma treatment can be stabilized.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a longitudinal sectional view of an etching apparatus which is an example of a plasma processing apparatus to which the present invention is applied. In the upper opening of the vacuum vessel 101, a cylindrical processing vessel 102, a flat antenna electrode 103 made of a conductor, and a dielectric window 104 capable of transmitting electromagnetic waves are provided in an airtight manner, and a processing chamber is formed inside. Yes. A magnetic field generating coil 105 is provided on the outer periphery of the processing container 102 so as to surround the processing chamber. The antenna electrode 103 has a porous structure for flowing an etching gas, and a gas supply device 107 is connected thereto. A vacuum exhaust device (not shown) is connected to the lower portion of the vacuum vessel 101 via a vacuum exhaust port 106.

  A coaxial line 108 is provided on the antenna electrode 103, and a plasma generating high frequency power supply 111 (for example, a frequency of 450 MHz) is connected through the coaxial line 108, the filter 109, and the matching unit 110. An antenna bias power source 114 (for example, a frequency of 13.56 kHz) is connected to the antenna electrode 103 via a coaxial line 108, a filter 112, and a matching unit 113. Here, the filter 109 allows high-frequency power from the high-frequency power source 111 to pass and effectively cuts bias power from the antenna bias power source 114. The filter 112 passes the bias power from the antenna bias power source 114 and effectively cuts the high frequency power from the high frequency power source 111.

  A substrate electrode 115 on which a material to be processed 116 can be placed is provided in the lower part of the vacuum vessel 101. A substrate bias power source 119 (for example, a frequency of 800 kHz) is connected to the substrate electrode 115 via a filter 117 and a matching unit 118. In this case, the matching unit 118 includes a matching unit 200 on the power source side and a clip circuit 201 on the load side. Note that the clip circuit 201 may be provided separately from the matching unit 118. The clip circuit 201 flattens the high-frequency voltage waveform from the substrate bias power supply 119 with an arbitrary voltage value. The clip circuit 201 has a function of an embodiment described later. The substrate electrode 115 is connected to an electrostatic chuck power source 121 for electrostatically attracting the material 116 to be processed through a filter 120.

  Here, the filter 117 passes the bias power from the substrate bias power source 119 and effectively cuts the high frequency power from the high frequency power source 111 and the bias power from the antenna bias power source 114. Normally, the high frequency power is absorbed in the plasma and therefore does not flow to the substrate electrode 115 side. However, for safety, the filter 117 is also used to cut the high frequency power. The filter 120 allows the DC power from the electrostatic chuck power supply 121 to pass and effectively cuts the power from the high frequency power supply 111, the antenna bias power supply 114, and the substrate bias power supply 119.

FIG. 2 shows a circuit configuration example of the matching unit 118. A diode (D1) and a DC power supply (Vb1) are connected in series between the active line 202 on the load side and the ground line 203 with respect to the matching unit 200 including the inductors (L1, L2) and the capacitor (C1). A clip circuit (flattening circuit) 201a is connected. In this case, the diode (D1) cuts the negative side of the high-frequency voltage and gives a negative potential by the DC power supply (Vb1). Thus, the operating voltage of the diode (D1) is set according to the set value of the DC power supply (Vb1). With this circuit configuration, the voltage waveform can be clipped (flattened or cut) at an arbitrary voltage value, and a voltage waveform 301 of a high frequency voltage as shown in FIG. 3 can be obtained.

In the apparatus configured as described above, the inside of the processing chamber is depressurized by a vacuum exhaust device (not shown), and then a process gas, in this case, an etching gas is introduced into the processing chamber by the gas supply device 107 and adjusted to a desired pressure. . For example, high-frequency power having a frequency of 450 MHz oscillated from the high-frequency power source 111 propagates through the coaxial line 108 and is introduced into the processing chamber via the upper electrode 103 and the dielectric window 104. The electric field generated by the high-frequency power introduced into the processing chamber generates high-density plasma in the processing chamber by interaction with the magnetic field generated in the processing chamber by the magnetic field generating coil 105, for example, a solenoid coil. In particular, when a magnetic field intensity (for example, 160 G) that causes electron cyclotron resonance is formed in the processing chamber, high-density plasma can be generated efficiently.

Further, high frequency power (for example, frequency 13.56 MHz) is supplied from the antenna bias power supply 114 to the antenna electrode 103 via the coaxial line 108. By applying a high frequency voltage to the antenna electrode 103 by the antenna bias power supply 114, when a desired material is used for the antenna electrode, the material and radicals in the plasma react to control the composition of the generated plasma. For example, in the case of oxide film etching, by using Si as the material of the antenna electrode 103, the amount of F radicals in the plasma that affects the etching characteristics of the oxide film, particularly the SiO ₂ / SiN selection ratio in the case of the SAC structure can be reduced. It becomes possible to decrease.

  Further, the material to be processed 116 placed on the substrate electrode 115 is supplied with high frequency power (for example, a frequency of 800 kHz) from the substrate bias power source 119, and the material to be processed 116 on the substrate electrode 115 is surface-treated. In this case, etching is performed. It is processed.

  In the apparatus of this configuration, plasma is mainly generated by the high frequency power supply 111 of 450 MHz, the plasma composition or the plasma distribution is controlled by the antenna bias power supply 114, and the incident energy of ions in the plasma to the material 116 is controlled by the substrate bias power supply 119. Is controlling. Such an apparatus has an advantage that plasma generation (ion amount) and plasma composition (radical concentration ratio) can be controlled independently.

  By arbitrarily setting the DC power supply (Vb) in the clip circuit 201a of this apparatus, Vb of the voltage waveform 301 shown in FIG. 3 can be arbitrarily set. For example, the negative side of the voltage waveform of a sine wave having a frequency of 800 kHz can be arbitrarily set. Can be clipped at a voltage of.

  FIG. 4A shows the energy of ions incident on the workpiece 116 when the output of the substrate bias power source 119 is kept constant and the DC voltage (Vb1) is changed to control the clip voltage (Vb) of the voltage waveform 301. Show the distribution. FIG. 4B shows the energy of ions incident on the workpiece 116 when the value of the clip voltage (Vb) of the voltage waveform 301 is made constant by the DC power supply (Vb1) and the output of the substrate bias power supply 119 is changed. Show the distribution. The vertical axis represents the amount of ions, and the horizontal axis represents the ion energy. In general, the ion energy distribution when high frequency power is applied to a wafer is M.P. J. et al. Kushner, J. et al. Appl. Phys. 58, 4024 (1985), it is known that the distribution has peaks at two locations on the high energy side and the low energy side. 4A shows an ion energy distribution waveform 401 when a sinusoidal voltage waveform is applied to the substrate electrode 115, an ion energy distribution waveform 402 when the clip voltage (Vb) is set to −500 V, and a clip voltage. An ion energy distribution waveform 403 when (Vb) is set to −250 V is shown three-dimensionally. As shown in the figure, by making the output of the substrate bias power source 119 constant and changing the clip voltage (Vb) to -500 V and -250 V, the potential value of ion energy distributed more on the high energy side is gradually increased. It can be shifted to a lower potential value. In addition, the amount of ions distributed on the high energy side can be gradually increased.

  4B shows the ion energy distribution waveform 404 when the clip voltage (Vb) of the substrate electrode 115 is set to −500 V and the output of the substrate bias power source 119 is 500 W, and the substrate bias power source 119. An ion energy distribution waveform 405 when the output is 1000 W and an ion energy distribution waveform 406 when the output of the substrate bias power supply 119 is 1500 W are shown three-dimensionally. As shown in the figure, the value of the clip voltage (Vb) is kept constant, and the output of the substrate bias power supply 119 is gradually increased, thereby gradually increasing the amount of ions of ion energy distributed on the high energy side. be able to.

Thus, by adjusting the bias voltage waveform applied to the substrate electrode 115, it is possible to control the ion energy distribution, and by controlling it together with the output of the substrate bias power source, finer ion energy can be controlled. The distribution can be controlled. As a result, ions having an arbitrary ion energy can be efficiently incident on the material 116 to be processed. Therefore, by using a distribution with a large amount of ions with high ion energy, for example, as shown in FIG. Processing of HARC (High Aspect Ratio Contact) formed in SiO ₂ that is a deep hole (a deep hole having a diameter of 0.1 μm and a depth of 2 μm and an aspect ratio of 20) and a deep trench formed in Si are facilitated. .

  In addition, it is possible to select and control ion energy that is effective for the material to be processed but not effective for the mask or the base material, so the selection ratio for the mask or the base material It is possible to perform an etching process with improved resistance. Thereby, there is an effect that a high-quality etching process can be performed.

  In the case of oxide film etching, since high energy ions are incident, there is a possibility of causing lattice defects in the underlying film and causing damage. However, according to the ion energy control of this embodiment, the etching rate is adjusted. An etching process that ensures and does not cause damage is possible, and a surface treatment with high quality, high throughput, and high yield is possible.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 6 shows a circuit configuration example of the matching unit 118. 2 is different from FIG. 2 in that the diode (D1) and the DC power supply (Vb1) in the clip circuit 201a of FIG. This is a point as (flattening circuit) 201b. In this case, the diode (D2) cuts the positive side of the high frequency voltage and gives a positive potential by the DC power supply (Vb2). Thus, the operating voltage of the diode (D2) is set according to the set value of the DC power supply (Vb2). With this circuit configuration, the voltage waveform can be clipped (flattened or cut) at an arbitrary voltage value, and a voltage waveform 302 of a high frequency voltage as shown in FIG. 7 can be obtained.

  By setting the DC power supply (Vb2) in the clip circuit 201b of this apparatus to an arbitrary clip voltage, the voltage Vb of the voltage waveform 302 shown in FIG. 7 can be set arbitrarily. For example, the voltage waveform of a sine wave with a frequency of 800 kHz The positive side can be clipped with an arbitrary voltage.

  FIG. 8 shows the energy distribution of ions incident on the workpiece 116 when the voltage waveform 302 is controlled by changing the DC power supply (Vb2). The vertical axis represents the amount of ions, and the horizontal axis represents the ion energy. FIG. 8 shows an ion energy distribution waveform 401 when a sinusoidal voltage waveform is applied to the substrate electrode 115, an ion energy distribution waveform 407 when the positive voltage side clip voltage (Vb) is set to 50V, and a negative voltage. An ion energy distribution waveform 408 when the side clip voltage (Vb) is set to −600 V is shown. As shown in the figure, by setting the clip voltage (Vb) to 50 V and keeping the plasma potential low, the potential value of ion energy distributed more on the high energy side is lowered and the amount of ions distributed on the lower energy side. Can be increased. Further, as can be seen from FIG. 8, if the negative voltage side of the voltage waveform is clipped, the distribution of a large amount of ions of high ion energy can be obtained, and if the positive voltage side of the voltage waveform is clipped, the ion amount of low ion energy is reduced. Many distributions can be obtained.

  Therefore, the ion energy distribution can be controlled by adjusting the bias voltage waveform applied to the substrate electrode 115. As a result, ions having an arbitrary ion energy can be efficiently incident on the material 116 to be processed. Therefore, by using a distribution with a large amount of ions with low ion energy, for example, as shown in FIG. This is effective for the etching process of SAC that requires a selection ratio with the base material.

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 10 shows a circuit configuration example of the embodiment in addition to the matching unit 118. A diode (D1, D2) and a DC power supply (Vb1, Vb2) are connected between the active line 202 on the load side and the ground line 203 with respect to the matching unit 200 including the inductors (L1, L2) and the capacitor (C1). A clip circuit (flattening circuit) 201c connected in series is connected. The diode (D1) cuts the negative voltage side of the high frequency voltage and applies a negative potential by the DC power supply (Vb1), and sets the operating voltage of the diode (D1) according to the set value of the DC power supply (Vb1). The diode (D2) cuts the positive voltage side of the high frequency voltage and applies a positive potential by the DC power supply (Vb2), and sets the operating voltage of the diode (D2) according to the set value of the DC power supply (Vb2). With this circuit configuration, the voltage waveform can be clipped (flattened or cut) with an arbitrary voltage value on the positive voltage side and the negative voltage side, and a voltage waveform 303 of a high frequency voltage as shown in FIG. 12 can be obtained. . FIG. 12 shows a voltage waveform 303 applied to the substrate electrode 115 output using the clip circuit 201 c of the matching unit 118. The vertical axis is voltage and the horizontal axis is time.

  FIG. 11 shows another example of the matching unit 118. In this matching device, a switching circuit, for example, transistors Tr1 and Tr2 are installed on the active line 202 on the load side of the matching unit 200, and a clip circuit 201d in which DC power sources Vb1 and Vb2 are connected to base electrodes of the transistors Tr1 and Tr2. Is provided. The clip circuit 201d performs switching operation of the transistors according to the set values of the DC power supplies Vb1 and Vb2, thereby allowing the positive voltage side and the negative voltage side of the voltage waveform to be set to arbitrary voltage values as in the matching unit shown in FIG. It is possible to clip with.

  In the clip circuit 201c shown in FIG. 10, when the amount of direct current passing through the diode is large, a voltage drop may occur due to the internal resistance of the direct current power source, and the operating voltage of the diode may fluctuate. However, when the transistor shown in FIG. 11 is used, the voltage fluctuation due to the internal resistance of the DC power supply can be ignored, so that the clipping operation can be performed with high accuracy.

  By arbitrarily setting the DC power supplies (Vb1, Vb2) in the clip circuits 201c and 201d in FIGS. 10 and 11, for example, a voltage waveform of a sine wave with a frequency of 800 kHz can be clipped with an arbitrary voltage. Thus, by changing the DC power supply (Vb) and controlling the voltage waveform 303, the energy distribution of ions incident on the workpiece 116 can be changed to the energy distribution shown in FIGS. 4 and 8 described above. .

  By using a clip circuit capable of clipping the positive voltage side and the negative voltage side of the voltage waveform with an arbitrary voltage value, the same operation and effect as those of the first and second embodiments can be obtained. In addition, since both characteristics can be provided, the process window can be further widened.

  As described above, according to these embodiments, the voltage waveform of the high-frequency voltage applied to the substrate electrode can be flattened, so that a bias voltage with an optimum ion energy distribution can be applied to the substrate electrode for each process in various processes. And there is an effect that a highly accurate surface treatment can be performed.

  Further, since the positive voltage side of the voltage waveform of the high-frequency voltage applied to the substrate electrode is flattened, it is possible to suppress an increase in the plasma potential, so that ions in the plasma do not sputter the processing chamber wall and the metal Contamination can be reduced, and plasma diffusion to the space below the processing chamber can be prevented, so that an increase in foreign matter can be suppressed.

  The clip circuits shown in the first to third embodiments are not limited to the configuration described above, and the configuration of a clip circuit generally used in an electronic circuit can be used.

  In these embodiments, the magnetic field UHF plasma processing apparatus having the antenna electrode in the vacuum vessel is described as an example. However, the magnetic field UHF plasma processing apparatus having the antenna electrode outside the vacuum vessel as shown in FIG. It can also be applied to. The apparatus of this figure is different from the apparatus of FIG. 1 in that the processing chamber is hermetically configured by the processing container 102 and the dielectric window 123, and the antenna electrode 103 is provided on the upper side of the dielectric window 123. The antenna electrode 103 is provided only with a circuit for the high-frequency power source 111 for plasma generation.

  Also, devices other than UHF plasma devices, such as CCP (capacitively coupled plasma), dual-frequency excitation (SWF), SWW (surface wave excised plasma), magnetron device, VHF plasma, VHF plasma, etc. The same applies to. 14 to 16 show some of these devices. In the apparatus shown in FIG. 14, a dielectric chamber 603 is installed and sealed on the upper part of the processing container 102 whose upper part is opened to form a processing chamber. A magnetron 601 is connected to the upper part of the dielectric window 603 via a waveguide 602. For example, a 2.45 GHz microwave oscillated from the magnetron 601 propagates through the waveguide 602, is introduced into the processing chamber via the dielectric window 603, and is generated by the magnetic field generating coil 105. It is a device that efficiently ionizes gas and generates plasma by interaction with an 875 G magnetic field. In this figure, the same reference numerals as those in FIG.

  In the apparatus shown in FIG. 15, a dielectric chamber 603 is installed and sealed on the upper part of the processing container 102 whose upper part is opened to form a processing chamber. A loop antenna 701 is installed above the dielectric window 603. The loop antenna 701 is connected to an antenna power source 702 of 13.56 MHz, for example. A high-frequency power is supplied from a loop antenna 701 through a dielectric window 603 into a processing chamber to generate plasma. In this figure, the same reference numerals as those in FIG.

  The apparatus shown in FIG. 16 installs and seals a dielectric window 104 (for example, made of quartz) and an upper electrode 103 on the upper part of a processing vessel 102 whose upper part is sealed. The upper electrode 103 is connected to a high frequency power source 801 of 27 MHz or 60 MHz, for example. In this apparatus, plasma is generated by high-frequency power supplied from the upper electrode 103 into the processing chamber. In this figure, the same reference numerals as those in FIG.

  A fourth embodiment of the present invention will be described with reference to FIG. In this figure, the same reference numerals as those in FIG. The difference between FIG. 1 and FIG. 1 will be described below. The antenna bias power source 114 and the substrate bias power source 119 are connected to the phase controller 122 so that the phase of the high frequency output from the antenna bias power source 114 and the substrate bias power source 119 can be controlled. In this case, the frequency of the antenna bias power supply 114 and the substrate bias power supply 119 is, for example, 800 kHz and the same frequency.

  The phase controller 122 takes in power signals from between the filter 112 and the matching unit 113 on the antenna bias power source 114 side and between the filter 117 and the matching unit 118 on the substrate bias power source 119 side. A small-amplitude signal whose phase is shifted is output to the antenna bias power supply 114 and the substrate bias power supply 119 so that the phases of the respective electric powers are opposite in phase, in this case, a desired phase difference within 180 ° ± 45 °. . In this case, the antenna bias power supply 114 and the substrate bias power supply 119 need only have an amplifier function.

  In addition, the phase controller 122 takes in power signals from between the filter 112 and the matching unit 113 on the antenna bias power source 114 side and between the filter 117 and the matching unit 118 on the substrate bias power source 119 side, respectively, and outputs the power output timing. In the case where only the trigger signal for instructing is output, the antenna bias power source 114 and the substrate bias power source 119 are assumed to have an oscillator function.

  When the high-frequency voltage applied to the antenna electrode 103 and the substrate electrode 115 is in reverse phase (preferably within a range of 180 ° ± 30 °), for example, when a positive voltage is applied to the substrate electrode 115, the antenna electrode 103 Since a negative voltage is applied to the antenna electrode 103, ions are incident but electrons are not incident, and the vicinity of the antenna electrode 103 is in an electron-rich state, and the opposing electrode functions efficiently as a ground. Therefore, if the plasma potential is determined from the peak voltage value of the high-frequency voltage regardless of the high-frequency power, it is fixed to a voltage value of about 20 to 30 V, which is close to 0 V. Therefore, the matching unit 118 shown in the first embodiment is used. Thus, the ion energy control effect on the substrate electrode 115 side can be realized with higher accuracy. This also has the effect of reducing charging damage.

  Further, by providing a clip circuit similar to the clip circuit 201 of the matching unit 118 provided on the substrate electrode 115 side also in the matching unit 113 provided on the antenna electrode 103 side, the voltage waveform of the bias voltage of the antenna electrode 103 can be further increased. Since it can be controlled, the window of further process processing can be expanded.

  As described above, according to the present invention, by adjusting the high-frequency voltage waveform applied to the substrate electrode, the energy potential and amount of ions in the ion energy distribution can be controlled, and high-precision plasma processing and plasma processing with little charging damage can be performed. There is an effect that it becomes possible.

  In the above-described embodiments, the etching apparatus has been described. However, the present invention can be similarly applied to other plasma processing apparatuses that supply high-frequency power to the substrate electrode, such as an ashing apparatus and a plasma CVD apparatus.

1 is a longitudinal sectional view showing a plasma processing apparatus according to a first embodiment of the present invention. The circuit diagram which shows an example of the matching device of the apparatus of FIG. The figure which shows the voltage waveform example controlled using the matching device of FIG. The figure which shows the relationship between the value of DC voltage (Vb) of FIG. 3, and ion energy distribution. The longitudinal cross-sectional view which shows an example of the to-be-processed material etched using the apparatus of FIG. FIG. 3 is a circuit diagram showing an example of a matching device of the apparatus of FIG. 1 according to the second embodiment of the present invention. The figure which shows the voltage waveform example controlled using the matching device of FIG. The figure which shows the relationship between the value of DC voltage (Vb) of FIG. 7, and ion energy distribution. The longitudinal cross-sectional view which shows an example of the to-be-processed material etched by the apparatus using the matching device of FIG. FIG. 4 is a circuit diagram showing an example of a matching unit of the apparatus of FIG. 1 according to the third embodiment of the present invention. FIG. 11 is a circuit diagram showing another example of the matching device of FIG. 10. The figure which shows the voltage waveform example controlled using the matching device of FIG. 10 and FIG. The longitudinal cross-sectional view which shows the plasma processing apparatus which is the 4th Example of this invention. The longitudinal cross-sectional view which shows the plasma processing apparatus which is the 5th Example of this invention. The longitudinal cross-sectional view which shows the plasma processing apparatus which is the 6th Example of this invention. The longitudinal cross-sectional view which shows the plasma processing apparatus which is the 7th Example of this invention. The longitudinal cross-sectional view which shows the plasma processing apparatus which is the 8th Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 101 ... Vacuum container, 102 ... Processing container, 103 ... Antenna electrode, 104 ... Dielectric window, 105 ... Coil for magnetic field generation, 106 ... Vacuum exhaust port, 107 ... Gas supply device, 108 ... Coaxial line, 109, 112, 117 , 120 ... Filter, 110, 113, 118 ... Matching unit, 111 ... High frequency power supply, 114 ... Antenna bias power supply, 115 ... Substrate electrode, 116 ... Material to be processed, 119 ... Substrate bias power supply, 121 ... Electrostatic chuck power supply, 122 ... Phase controller, 200 ... Matching unit, 201, 201a, 201b, 201c, 201d ... Clip circuit, 202 ... Active line, 203 ... Ground line.

Claims (2)

A processing chamber to which an evacuation apparatus is connected and whose inside can be decompressed; a gas supply device that supplies gas into the processing chamber; a substrate electrode that is provided in the processing chamber and on which a material to be processed can be placed; and the substrate electrode characterized in that it comprises a high-frequency power supply connected via a matching unit, and a voltage waveform control circuit for flattening the voltage waveform provided between the matching unit and the matching unit in or the substrate electrode Plasma processing equipment . The plasma processing apparatus according to claim 1, wherein the voltage waveform control circuit is a plasma processing apparatus which is a possible flattening at least one voltage waveform of the positive and negative voltages of the high frequency voltage that will be applied to the substrate electrode.

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