JP2020074271A - Etching device - Google Patents

Abstract

To provide a device in which a plasma potential is independent of an inner surface condition of a vessel.SOLUTION: A plasma processing device comprises: a balun having a first unbalanced terminal, a second unbalanced terminal, a first balanced terminal, and a second balanced terminal; a grounded vacuum vessel; a first electrode electrically connected to the first balanced terminal; a second electrode electrically connected to the second balanced terminal; an impedance matching circuit; a first power source, connected to the balun via the impedance matching circuit, which supplies high-frequency waves to the first electrode via the impedance matching circuit and the balun; a low-pass filter; and a second power source which supplies a voltage to the first electrode via the low-pass filter.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a plasma processing device.

  There is a plasma processing apparatus that generates a plasma by applying a high frequency between two electrodes and processes a substrate with the plasma. Such a plasma processing apparatus may operate as a sputtering apparatus or an etching apparatus depending on the area ratio of two electrodes and / or the bias. A plasma processing apparatus configured as a sputtering apparatus has a first electrode holding a target and a second electrode holding a substrate, and is between the first electrode and the second electrode (between the target and the substrate). A high frequency is applied to the plasma and plasma is generated between the target and the anode. The plasma generation creates a self-bias voltage on the surface of the target, which causes the ions to strike the target and eject the particles of the material that make it up.

  Patent Document 1 discloses a plasma processing apparatus having a grounded chamber, a target electrode connected to an RF generation source via an impedance matching network, and a substrate holding electrode grounded via a substrate electrode tuning circuit. Have been described.

  In the sputtering apparatus described in Patent Document 1, the chamber may function as an anode in addition to the substrate holding electrode. The self-bias voltage may depend on the state of the part that can function as the cathode and the state of the part that can function as the anode. Therefore, when the chamber also functions as the anode in addition to the substrate holding electrode, the cell bias voltage may change depending on the state of the portion of the chamber that functions as the anode. Changes in the self-bias voltage cause changes in the plasma potential, and changes in the plasma potential can affect the characteristics of the film formed.

  When the film is formed on the substrate by the sputtering apparatus, the film may be formed on the inner surface of the chamber. This can change the state of the portion of the chamber that can function as the anode. Therefore, if the sputtering apparatus is continuously used, the self-bias voltage may change due to the film formed on the inner surface of the chamber, and the plasma potential may also change. Therefore, conventionally, it has been difficult to maintain constant characteristics of the film formed on the substrate when the sputtering apparatus is used for a long period of time.

  Similarly, even when the etching apparatus is used for a long period of time, the self-bias voltage may be changed by the film formed on the inner surface of the chamber, which may change the plasma potential, so that the etching characteristics of the substrate may be kept constant. It was difficult.

  Further, in the sputtering apparatus described in Patent Document 1, it is necessary to adjust the high frequency power in order to control the self bias voltage. However, when the high frequency power is changed to adjust the self-bias voltage, the plasma density also changes. Therefore, conventionally, it was not possible to individually adjust the self-bias voltage and the plasma density. Similarly, also in the etching apparatus, conventionally, the self-bias voltage and the plasma density could not be individually adjusted.

Japanese Patent Publication No. 55-35465

  The present invention has been made based on the above recognition of the problem, and provides an advantageous technique for stabilizing the plasma potential, and an advantageous technique for individually adjusting the voltage applied to the electrode and the plasma density. To aim.

  One aspect of the present invention relates to a plasma processing apparatus, which includes a balun having a first unbalanced terminal, a second unbalanced terminal, a first balanced terminal, and a second balanced terminal, and a grounded vacuum. A container, a first electrode electrically connected to the first balanced terminal, a second electrode electrically connected to the second balanced terminal, an impedance matching circuit, and the impedance matching circuit via the impedance matching circuit. A second power supply connected to a balun, supplying a high frequency to the first electrode via the impedance matching circuit and the balun, a low-pass filter, and supplying a voltage to the first electrode via the low-pass filter, And a power supply.

  According to the present invention, there is provided a technique that is advantageous for stabilizing the plasma potential and advantageous for individually adjusting the voltage applied to the electrodes and the plasma density.

The figure which shows typically the structure of the plasma processing apparatus of 1st Embodiment of this invention. The figure which shows the structural example of a balun. The figure which shows the other structural example of a balun. The figure explaining the function of the balun 103. The figure which illustrates the relationship of electric current I1 (= I2), I2 ', I3, ISO, and (= X / Rp). The figure which shows the result of having simulated the plasma potential and cathode potential in the case of satisfy | filling 1.5 <= X / Rp <5000. The figure which shows the result of having simulated the plasma potential and cathode potential in the case of satisfy | filling 1.5 <= X / Rp <5000. The figure which shows the result of having simulated the plasma potential and cathode potential in the case of satisfy | filling 1.5 <= X / Rp <5000. The figure which shows the result of having simulated the plasma potential and cathode potential in the case of satisfy | filling 1.5 <= X / Rp <5000. The figure which shows the result of having simulated the plasma electric potential and the cathode electric potential when not satisfy | filling 1.5 <= X / Rp <5000. The figure which shows the result of having simulated the plasma electric potential and the cathode electric potential when not satisfy | filling 1.5 <= X / Rp <5000. The figure which shows the result of having simulated the plasma electric potential and the cathode electric potential when not satisfy | filling 1.5 <= X / Rp <5000. The figure which shows the result of having simulated the plasma electric potential and the cathode electric potential when not satisfy | filling 1.5 <= X / Rp <5000. The figure which illustrates the confirmation method of Rp-jXp. The figure which shows typically the structure of the plasma processing apparatus of 2nd Embodiment of this invention. The figure which shows typically the structure of the plasma processing apparatus of 3rd Embodiment of this invention. The figure which shows typically the structure of the plasma processing apparatus of 4th Embodiment of this invention. The figure which shows typically the structure of the plasma processing apparatus of 5th Embodiment of this invention. The figure which shows typically the structure of the plasma processing apparatus of 6th Embodiment of this invention.

  Hereinafter, the present invention will be described through exemplary embodiments thereof with reference to the accompanying drawings.

  FIG. 1 schematically shows the configuration of a plasma processing apparatus 1 according to the first embodiment of the present invention. The plasma processing apparatus 1 includes a balun (balance / unbalance conversion circuit) 103, a vacuum container 110, a first electrode 106, a second electrode 111, a low pass filter 115, and a power supply 116 (second power supply). There is. Alternatively, the plasma processing apparatus 1 includes a balun 103 and a main body 10, and the main body 10 includes a vacuum container 110, a first electrode 106, a second electrode 111, a low-pass filter 115, and a power supply 116 (second power supply). ), May be understood as comprising. The main body 10 has a first terminal 251 and a second terminal 252. The power supply 116 may be, for example, a DC power supply or an AC power supply. The DC power supply may generate a DC voltage including an AC component. The main body 10 may have a third terminal 253 connected to the vacuum container 110. The plasma processing apparatus 1 may further include an impedance matching circuit 102 and a high frequency power supply 101 (first power supply).

  The balun 103 has a first unbalanced terminal 201, a second unbalanced terminal 202, a first balanced terminal 211, and a second balanced terminal 212. An unbalanced circuit is connected to the first unbalanced terminal 201 and the second unbalanced terminal 202 of the balun 103, and a balanced circuit is connected to the first balanced terminal 211 and the second balanced terminal 212 of the balun 103. It The vacuum container 110 is made of a conductor and is grounded. The balun 103 may further include a midpoint terminal 213. The balun 103 may be configured such that the voltage at the midpoint terminal 213 is at the midpoint between the voltage at the first balanced terminal 211 and the voltage at the second balanced terminal 212. The midpoint terminal 213 may be electrically connected to the third terminal 253 of the main body 10.

  In the first embodiment, the first electrode 106 is a cathode and holds the target 109. The target 109 can be, for example, an insulator material or a conductor material. In addition, in the first embodiment, the second electrode 111 is an anode and holds the substrate 112. The plasma processing apparatus 1 of the first embodiment can operate as a sputtering apparatus that forms a film on the substrate 112 by sputtering the target 109. The first electrode 106 is electrically connected to the first balanced terminal 211, and the second electrode 111 is electrically connected to the second balanced terminal 212. The fact that the first electrode 106 and the first balanced terminal 211 are electrically connected means that the first electrode 106 and the first balanced terminal 211 are connected so that a current flows between the first electrode 106 and the first balanced terminal 211. This means that a current path is formed between the current path and the point 211. Similarly, in this specification, “a and b are electrically connected” means that a current path is formed between a and b so that a current flows between a and b. means.

  In the above structure, the first electrode 106 is electrically connected to the first terminal 251, the second electrode 111 is electrically connected to the second terminal 252, and the first terminal 251 is electrically connected to the first balanced terminal 211. And the second terminal 252 is electrically connected to the second balanced terminal 212.

  In the first embodiment, the first electrode 106 and the first balanced terminal 211 (first terminal 251) are electrically connected via the blocking capacitor 104. The blocking capacitor 104 blocks a direct current between the first balanced terminal 211 and the first electrode 106 (or between the first balanced terminal 211 and the second balanced terminal 212). Instead of providing the blocking capacitor 104, an impedance matching circuit 102, which will be described later, may be configured to block a direct current flowing between the first unbalanced terminal 201 and the second unbalanced terminal 202. The first electrode 106 may be supported by the vacuum container 110 via the insulator 107. The second electrode 111 may be supported by the vacuum container 110 via the insulator 108. Alternatively, the insulator 108 may be disposed between the second electrode 111 and the vacuum container 110.

  The high frequency power supply 101 (first power supply) supplies a high frequency (high frequency current, high frequency voltage, high frequency power) between the first unbalanced terminal 201 and the second unbalanced terminal 202 of the balun 103 via the impedance matching circuit 102. To do. In other words, the high frequency power supply 101 supplies a high frequency (high frequency current, high frequency voltage, high frequency power) between the first electrode 106 and the second electrode 111 via the impedance matching circuit 102, the balun 103 and the blocking capacitor 104. .. Alternatively, the high frequency power supply 101 can also be understood as a high frequency power supply between the first terminal 251 and the second terminal 252 of the main body 10 via the impedance matching circuit 102 and the balun 103.

  The power supply 116 (second power supply) may be configured to supply a negative DC voltage (bias voltage) or an AC voltage to the first electrode 106 via the low pass filter 115. The low-pass filter 115 blocks the high frequency supplied from the balun 103 so that the high frequency is not transmitted to the power supply 116. By supplying a negative DC voltage or AC voltage from the power supply 116 to the first electrode 106, the voltage on the surface of the target 109 or the ion energy impinging on the surface of the target 109 can be controlled (determined). When the target 109 is made of a conductive material, the voltage on the surface of the target 109 can be controlled by supplying a negative DC voltage from the power supply 116 to the first electrode 106. When the target 109 is made of an insulating material, it is possible to control the ion energy that collides with the surface of the target 109 by supplying an AC voltage from the power supply 116 to the first electrode 106.

  When the target 109 is made of an insulating material and the power supply 116 (second power supply) supplies an AC voltage to the first electrode 106, the frequency of the voltage supplied by the power supply 116 to the first electrode 106 is the high frequency power supply 101 (first It can be set lower than the frequency of the high frequency generated by the power supply. In this case, the frequency of the voltage supplied from the power supply 116 to the first electrode 106 is preferably set within the range of several 100 KHz to several MHz.

  Gas (for example, Ar, Kr, or Xe gas) is supplied to the internal space of the vacuum container 110 through a gas supply unit (not shown) provided in the vacuum container 110. Further, a high frequency is supplied between the first electrode 106 and the second electrode 111 by the high frequency power supply 101 (first power supply) via the impedance matching circuit 102, the balun 103 and the blocking capacitor 104. A negative DC voltage or AC voltage is supplied to the first electrode 106 from the DC power supply 116 via the low pass filter 115. Thereby, plasma is generated between the first electrode 106 and the second electrode 111, the surface of the target 109 is controlled to a negative voltage, or the ion energy that collides with the surface of the target 109 is controlled. Then, the ions in the plasma collide with the surface of the target 109, and the particles of the material forming the target 109 are emitted from the target 109, and the particles form a film on the substrate 112.

  FIG. 2A shows a configuration example of the balun 103. The balun 103 shown in FIG. 2A includes a first coil 221 that connects the first unbalanced terminal 201 and the first balanced terminal 211, and a second coil 221 that connects the second unbalanced terminal 202 and the second balanced terminal 212. And a coil 222. The first coil 221 and the second coil 222 are coils having the same number of turns and share the iron core.

  FIG. 2B shows another configuration example of the balun 103. The balun 103 shown in FIG. 2B includes a first coil 221 connecting the first unbalanced terminal 201 and the first balanced terminal 211, and a second coil 221 connecting the second unbalanced terminal 202 and the second balanced terminal 212. And a coil 222. The first coil 221 and the second coil 222 are coils having the same number of turns and share the iron core. Further, the balun 103 shown in FIG. 2B further includes a third coil 223 and a fourth coil 224 connected between the first balanced terminal 211 and the second balanced terminal 212, and the third coil 223 and the fourth coil 223 are connected to each other. The 4-coil 224 is configured so that the connection node between the third coil 223 and the fourth coil 224 is at the midpoint between the voltage of the first balanced terminal 211 and the voltage of the second balanced terminal 212. The connection node is connected to the midpoint terminal 213. The third coil 223 and the fourth coil 224 are coils having the same number of turns and share the iron core. The midpoint terminal 213 may be grounded, may be connected to the vacuum container 110, or may be floating.

The function of the balun 103 will be described with reference to FIG. It is assumed that the current flowing through the first unbalanced terminal 201 is I1, the current flowing through the first balanced terminal 211 is I2, the current flowing through the second unbalanced terminal 202 is I2 ′, and the current flowing out of the current I2 to ground is I3. When I3 = 0, that is, when no current flows to the ground on the side of the balance circuit, the isolation performance of the balance circuit with respect to the ground is the best. When I3 = I2, that is, when all of the current I2 flowing through the first balanced terminal 211 flows with respect to the ground, the isolation performance of the balanced circuit with respect to the ground is the worst. The index ISO indicating the degree of such isolation performance can be given by the following formula. Under this definition, the larger the absolute value of ISO, the better the isolation performance.
ISO [dB] = 20 log (I3 / I2 ')

  In FIG. 3, Rp-jXp is the side of the first electrode 106 and the second electrode 111 (from the side of the first balanced terminal 211 and the second balanced terminal 212 in the state where plasma is generated in the internal space of the vacuum container 110). The impedance (including the reactance of the blocking capacitor 104) when looking at the main body 10 side is shown. It should be noted that this impedance is an impedance at a high frequency generated by the high frequency power supply 101, and the impedances of the low pass filter 115 and the DC power supply 116 can be ignored. Rp represents a resistance component and -Xp represents a reactance component. Further, in FIG. 3, X represents the reactance component (inductance component) of the impedance of the first coil 221 of the balun 103. ISO has a correlation to X / Rp.

  Here, in order to clarify the advantage of the configuration in which a high frequency is supplied from the high frequency power supply 101 to the first electrode 106 and the second electrode 111 via the balun 103, the power supply 116 (and the low pass filter 115) is subjected to plasma treatment. The operation of the plasma processing apparatus 1 when it is detached from the apparatus 1 (main body 10) will be described. FIG. 4 shows the relationship among the currents I1 (= I2), I2 ′, I3, ISO, and α (= X / Rp) when the power supply 116 (and the low-pass filter 115) is removed from the plasma processing apparatus 1 (main body 10). Is illustrated.

  The present inventor has found that the potential (plasma potential) of plasma formed in the internal space of the vacuum container 110 (the space between the first electrode 106 and the second electrode 111) when 1.5 ≦ X / Rp ≦ 5000 is satisfied. ) Is insensitive to the state of the inner surface of the vacuum container 110. Here, the fact that the plasma potential is insensitive to the state of the inner surface of the vacuum container 110 means that the plasma potential can be stabilized even when the plasma processing apparatus 1 is used for a long period of time. 1.5 ≦ X / Rp ≦ 5000 corresponds to −10.0 dB ≧ ISO ≧ −80 dB.

  5A to 5D show the results of simulating the plasma potential and the potential (cathode potential) of the first electrode 106 when 1.5 ≦ X / Rp ≦ 5000 is satisfied. FIG. 5A shows the plasma potential and the cathode potential in the state where the film is not formed on the inner surface of the vacuum container 110. FIG. 5B shows the plasma potential and the cathode potential in the state where the resistive film (1000Ω) is formed on the inner surface of the vacuum container 110. FIG. 5C shows the plasma potential and the cathode potential in the state where the inductive film (0.6 μH) is formed on the inner surface of the vacuum container 110. FIG. 5D shows the plasma potential and the cathode potential when the capacitive film (0.1 nF) is formed on the inner surface of the vacuum container 110. From FIGS. 5A to 5D, it is understood that when 1.5 ≦ X / Rp ≦ 5000 is satisfied, the plasma potential is stable in various states on the inner surface of the vacuum container 110.

  6A to 6D show the results of simulating the plasma potential and the potential (cathode potential) of the first electrode 116 when 1.5 ≦ X / Rp ≦ 5000 is not satisfied. FIG. 6A shows the plasma potential and the cathode potential in the state where the film is not formed on the inner surface of the vacuum container 110. FIG. 6B shows the plasma potential and the cathode potential in the state where the resistive film (1000Ω) is formed on the inner surface of the vacuum container 110. FIG. 6C shows the plasma potential and the cathode potential when an inductive film (0.6 μH) is formed on the inner surface of the vacuum container 110. FIG. 6D shows the plasma potential and the cathode potential when the capacitive film (0.1 nF) is formed on the inner surface of the vacuum container 110. From FIGS. 6A to 6D, it is understood that when 1.5 ≦ X / Rp ≦ 5000 is not satisfied, the plasma potential changes depending on the state of the inner surface of the vacuum container 110.

  Here, X / Rp> 5000 (for example, X / Rp = ∞) and X / Rp <1.5 (for example, X / Rp = 1.0, X / Rp = 0.5) In both cases, the plasma potential is likely to change depending on the state of the inner surface of the vacuum container 110. When X / Rp> 5000, electric discharge occurs only between the first electrode 106 and the second electrode 111 in the state where the film is not formed on the inner surface of the vacuum container 110. However, in the case of X / Rp> 5000, when a film starts to be formed on the inner surface of the vacuum container 110, the plasma potential reacts sensitively to it, resulting in the results illustrated in FIGS. On the other hand, in the case of X / Rp <1.5, the current flowing into the ground through the vacuum container 110 is large, so that the influence of the state of the inner surface of the vacuum container 110 (electrical characteristics of the film formed on the inner surface) is affected. Becomes remarkable, and the plasma potential changes depending on the film formation. Therefore, as described above, the plasma processing apparatus 1 should be configured so as to satisfy 1.5 ≦ X / Rp ≦ 5000.

  An example of a method of determining Rp-jXp (only Rp is the one that one actually wants to know) will be described with reference to FIG. 7. First, the balun 103 is removed from the plasma processing apparatus 1, and the output terminal 230 of the impedance matching circuit 102 is connected to the first terminal 251 (blocking capacitor 104) of the main body 10. In addition, the second terminal 252 (second electrode 111) of the main body 10 is grounded. In this state, high frequency power is supplied from the high frequency power supply 101 to the first terminal 251 of the main body 10 through the impedance matching circuit 102. In the example shown in FIG. 7, the impedance matching circuit 102 is equivalently composed of coils L1 and L2 and variable capacitors VC1 and VC2. Plasma can be generated by adjusting the capacitance values of the variable capacitors VC1 and VC2. When the plasma is stable, the impedance of the impedance matching circuit 102 matches the impedance Rp-jXp of the body 10 side (the first electrode 106 and the second electrode 111 side) when the plasma is generated. .. The impedance of the impedance matching circuit 102 at this time is Rp + jXp. Therefore, based on the impedance Rp + jXp of the impedance matching circuit 102 when the impedances match, Rp−jXp (only Rp is the one that one actually wants to know) can be obtained. Besides, Rp-jXp can be obtained by simulation based on design data, for example.

  Based on the Rp thus obtained, the reactance component (inductance component) X of the impedance of the first coil 221 of the balun 103 may be determined so as to satisfy 1.5 ≦ X / Rp ≦ 5000. By determining the reactance component of the balun 103 as described above, the plasma potential (and the self-bias voltage (the surface voltage of the target 109)) can be stabilized even when the power supply 116 is not provided.

  Further, according to the configuration in which the negative DC voltage is supplied from the power supply 116 to the first electrode 106 via the low pass filter 115, the surface voltage of the target 109 can be controlled by this DC voltage. On the other hand, according to the configuration in which the AC voltage is supplied from the power supply 116 to the first electrode 106 via the low-pass filter 115, the ion energy colliding with the surface of the target 109 can be controlled by this AC voltage. Therefore, the high frequency power supplied from the high frequency power supply 101 between the first electrode 106 and the second electrode 111 can be adjusted independently of the surface voltage of the target 109. Further, according to the configuration in which the negative DC voltage or AC voltage is supplied from the power supply 116 to the first electrode 106 via the low-pass filter 115, the plasma potential can be made insensitive to the state of the inner surface of the vacuum container 110. .. Therefore, it is not always necessary to satisfy 1.5 ≦ X / Rp ≦ 5000, and practical performance can be provided even when 1.5 ≦ X / Rp ≦ 5000 is not satisfied.

  The size relationship between the first electrode 106 and the second electrode 111 is not limited, but it is preferable that the first electrode 106 and the second electrode 111 have approximately the same size. In this case, the self-bias voltage can be reduced, and the surface voltage of the target 109 or the energy of ions that strike the surface of the target 109 can be freely controlled by the power supply 116.

  FIG. 8 schematically shows the configuration of the plasma processing apparatus 1 according to the second embodiment of the present invention. The plasma processing apparatus 1 of the second embodiment can operate as an etching apparatus that etches the substrate 112. In the second embodiment, the first electrode 106 is a cathode and holds the substrate 112. In addition, in the second embodiment, the second electrode 111 is an anode. In the plasma processing apparatus 1 of the second embodiment, the first electrode 106 and the first balanced terminal 211 are electrically connected via the blocking capacitor 104. In other words, in the plasma processing apparatus 1 of the second embodiment, the blocking capacitor 104 is arranged in the electrical connection path between the first electrode 106 and the first balanced terminal 211.

  FIG. 9 schematically shows the configuration of the plasma processing apparatus 1 according to the third embodiment of the present invention. The plasma processing apparatus 1 of the third embodiment is a modification of the plasma processing apparatus 1 of the first embodiment, and further includes at least one of a mechanism for moving the second electrode 111 up and down and a mechanism for rotating the second electrode 111. In the example shown in FIG. 9, the plasma processing apparatus 1 includes a drive mechanism 114 including both a mechanism for moving the second electrode 111 up and down and a mechanism for rotating the second electrode 111. A bellows 113 forming a vacuum partition may be provided between the vacuum container 110 and the driving mechanism 114. Similarly, the plasma processing apparatus 1 of the second embodiment may further include at least one of a mechanism for moving the second electrode 111 up and down and a mechanism for rotating the second electrode 111.

  Also in the third embodiment, the size relationship between the first electrode 106 and the second electrode 111 is not limited, but it is preferable that the first electrode 106 and the second electrode 111 have the same size.

  FIG. 10 schematically shows the configuration of the plasma processing apparatus 1 according to the fourth embodiment of the present invention. Matters not mentioned as the plasma processing apparatus 1 of the fourth embodiment can be according to the first to third embodiments. The plasma processing apparatus 1 includes a balun 103, a vacuum container 110, a first electrode 106, a second electrode 135, a third electrode 151, low pass filters 115 and 303, a power supply 116, and a DC power supply 304. ing. Alternatively, the plasma processing apparatus 1 includes the balun 103 and the main body 10, and the main body 10 includes the vacuum container 110, the first electrode 106, the second electrode 135, the third electrode 151, and the low-pass filters 115 and 303. May be understood to include a power supply 116 and a DC power supply 304. The main body 10 has a first terminal 251 and a second terminal 252. The plasma processing apparatus 1 may further include impedance matching circuits 102 and 302 and high frequency power supplies 101 and 301. The power supply 116 may be, for example, a DC power supply or an AC power supply. The DC power supply may generate a DC voltage including an AC component.

  The balun 103 has a first unbalanced terminal 201, a second unbalanced terminal 202, a first balanced terminal 211, and a second balanced terminal 212. An unbalanced circuit is connected to the first unbalanced terminal 201 and the second unbalanced terminal 202 of the balun 103, and a balanced circuit is connected to the first balanced terminal 211 and the second balanced terminal 212 of the balun 103. It The balun 103 may further have the midpoint terminal as described above. The midpoint terminal may be electrically connected to the vacuum container 110.

  The first electrode 106 holds the target 109. The target 109 can be, for example, an insulator material or a conductor material. The second electrode 135 is arranged around the first electrode 106. The first electrode 106 is electrically connected to the first balanced terminal 211 of the balun 103, and the second electrode 135 is electrically connected to the second balanced terminal 212 of the balun 103. The third electrode 151 holds the substrate 112. A high frequency can be supplied to the third electrode 151 from the high frequency power supply 301 via the impedance matching circuit 302.

  In the above configuration, the first electrode 106 is electrically connected to the first terminal 251, the second electrode 135 is electrically connected to the second terminal 252, and the first terminal 251 is the first balanced terminal 211 of the balun 103. Can also be understood as a configuration in which the second terminal 252 is electrically connected to the second balanced terminal 212 of the balun 103.

  The first electrode 106 and the first balanced terminal 211 (first terminal 251) may be electrically connected via the blocking capacitor 104. The blocking capacitor 104 is provided between the first balanced terminal 211 of the balun 103 and the first electrode 106 (or between the first balanced terminal 211 and the second balanced terminal 212 of the balun 103), and receives a direct current from the power source 116. Or cut off the alternating current. Instead of providing the blocking capacitor 104, the impedance matching circuit 102 is configured to block a direct current or an alternating current from the power source 116 that flows between the first unbalanced terminal 201 and the second unbalanced terminal 202. Good. Alternatively, the blocking capacitor 104 may be arranged between the second electrode 135 and the second balanced terminal 212 (second terminal 252). The first electrode 106 and the second electrode 135 may be supported by the vacuum container 110 via the insulator 132.

  The high frequency power supply 101 supplies a high frequency between the first unbalanced terminal 201 and the second unbalanced terminal 202 of the balun 103 via the impedance matching circuit 102. In other words, the high frequency power supply 101 supplies a high frequency between the first electrode 106 and the second electrode 135 via the first impedance matching circuit 102, the balun 103 and the blocking capacitor 104. Alternatively, the high frequency power supply 101 supplies a high frequency between the first terminal 251 and the second terminal 252 of the main body 10 via the impedance matching circuit 102 and the balun 103. The high frequency power supply 301 supplies a high frequency to the third electrode 151 via the impedance matching circuit 302.

  The power supply 116 supplies a negative DC voltage (bias voltage) or an AC voltage to the first electrode 106 via the low pass filter 115. The low-pass filter 115 blocks the high frequency supplied from the balun 103 so that the high frequency is not transmitted to the power supply 116. By supplying a negative DC voltage from the power supply 116 to the first electrode 106, the voltage on the surface of the target 109 can be controlled. By supplying an AC voltage from the power supply 116 to the first electrode 106, the energy of ions that strike the surface of the target 109 can be controlled. The DC power supply 304 supplies a DC voltage (bias voltage) to the third electrode 151 via the low pass filter 303. The low pass filter 303 blocks the high frequency supplied from the high frequency power supply 301 so that the high frequency is not transmitted to the DC power supply 304. By supplying a DC voltage to the third electrode 151 by the DC power supply 304, the surface potential of the substrate 112 can be controlled.

  Also in the fourth embodiment, a negative DC voltage or an AC voltage is supplied from the power supply 116 to the first electrode 106 to control the surface voltage of the target 109 or the ion energy that collides with the target 109, and the high frequency power supply 101 and The high frequency power source 301 can control the plasma density. Also in the fourth embodiment, it is advantageous to satisfy 1.5 ≦ X / Rp ≦ 5000 in order to further stabilize the plasma potential.

  Also in the fourth embodiment, the size relationship between the first electrode 106 and the second electrode 135 is not limited, but it is preferable that the first electrode 106 and the second electrode 135 have approximately the same size.

  FIG. 11 schematically shows the configuration of the plasma processing apparatus 1 according to the fifth embodiment of the present invention. The plasma processing apparatus 1 of the fifth embodiment has a configuration in which a driving mechanism 114 is added to the plasma processing apparatus 1 of the fourth embodiment. The drive mechanism 114 may include at least one of a mechanism for moving the third electrode 151 up and down and a mechanism for rotating the third electrode 151.

  Also in the fifth embodiment, the size relationship between the first electrode 106 and the second electrode 135 is not limited, but it is preferable that the first electrode 106 and the second electrode 135 have approximately the same size.

  FIG. 12 schematically shows the configuration of the plasma processing apparatus 1 according to the sixth embodiment of the present invention. Matters not mentioned as the sixth embodiment can comply with the first to fifth embodiments. The plasma processing apparatus 1 of the sixth embodiment includes a plurality of first high frequency supply units and at least one second high frequency supply unit. Here, an example will be described in which the plurality of first high-frequency supply units are composed of two high-frequency supply units. Further, the two high-frequency supply units and the components related thereto are distinguished from each other by subscripts a and b. Similarly, the two targets are also distinguished from each other by the subscripts a and b.

  One of the plurality of first high frequency supply units includes a first electrode 106a, a second electrode 135a, a balun 103a, a power supply 116a, a low pass filter 115a, a high frequency power supply 101a, and an impedance matching circuit 102a. The blocking capacitor 104a may be included. The other one of the plurality of first high frequency power supply units includes a first electrode 106b, a second electrode 135b, a balun 103b, a power supply 116b, a low pass filter 115b, a high frequency power supply 101b, and an impedance matching circuit 102b. , A blocking capacitor 104b. The second high frequency power supply unit may include a high frequency power supply 301, an impedance matching circuit 302, a DC power supply 304, and a low pass filter 303. The power supplies 116a and 116b may be, for example, a DC power supply or an AC power supply. The DC power supply may generate a DC voltage including an AC component.

  In another aspect, the plasma processing apparatus 1 includes the baluns 103a and 103b, the vacuum container 110, the first electrodes 106a and 106b, the second electrodes 135a and 135b, the third electrode 151, and the low pass filters 115a and 115b. 303, power supplies 116a and 116b, a DC power supply 304, and high frequency power supplies 101a, 101b and 301.

  The balun 103a has a first unbalanced terminal 201a, a second unbalanced terminal 202a, a first balanced terminal 211a, and a second balanced terminal 212a. An unbalanced circuit is connected to the first unbalanced terminal 201a and the second unbalanced terminal 202a of the balun 103a, and a balanced circuit is connected to the first balanced terminal 211a and the second balanced terminal 212a of the balun 103a. It The balun 103b has a first unbalanced terminal 201b, a second unbalanced terminal 202b, a first balanced terminal 211b, and a second balanced terminal 212b. An unbalanced circuit is connected to the first unbalanced terminal 201b and the second unbalanced terminal 202b of the balun 103b, and a balanced circuit is connected to the first balanced terminal 211b and the second balanced terminal 212b of the first balun 103b. Connected.

  The first electrodes 106a and 106b hold targets 109a and 109b, respectively. The targets 109a and 109b can be, for example, an insulator material or a conductor material. The second electrodes 135a and 135b are arranged around the first electrodes 106a and 106b, respectively. The first electrodes 106a and 106b are electrically connected to the first balanced terminals 211a and 211b of the baluns 103a and 103b, respectively, and the second electrodes 135a and 135b are the second balanced terminals 212a of the first baluns 103a and 103b, respectively. It is electrically connected to 212b. The high frequency power supply 101a supplies a high frequency (high frequency current, high frequency voltage, high frequency power) between the first unbalanced terminal 201a and the second unbalanced terminal 202a of the balun 103a via the impedance matching circuit 102a. The high frequency power supply 101b supplies a high frequency (high frequency current, high frequency voltage, high frequency power) between the first unbalanced terminal 201b and the second unbalanced terminal 202b of the balun 103b via the impedance matching circuit 102b. The third electrode 151 holds the substrate 112. A high frequency can be supplied to the third electrode 151 from the high frequency power supply 301 via the impedance matching circuit 302.

  The power supplies 116a and 116b supply negative DC voltage (bias voltage) or AC voltage to the first electrodes 106a and 106b via the low-pass filters 115a and 115b, respectively. The low-pass filters 115a and 115b block the high frequencies supplied from the baluns 103a and 103b, respectively, so that the high frequencies are not transmitted to the power supplies 116a and 116b. By supplying a negative DC voltage from the power supplies 116a and 116b to the first electrodes 106a and 106b, the voltage on the surface of the targets 109a and 109b can be controlled. By supplying an AC voltage from the power supplies 116a and 116b to the first electrodes 106a and 106b, it is possible to control the ion energy that collides with the surfaces of the targets 109a and 109b. The DC power supply 304 supplies a DC voltage (bias voltage) to the third electrode 151 via the low pass filter 303. The low pass filter 303 blocks the high frequency supplied from the high frequency power supply 301 so that the high frequency is not transmitted to the DC power supply 304. By supplying a DC voltage to the third electrode 151 by the DC power supply 304, the surface potential of the substrate 112 can be controlled.

  The first high-frequency supply unit and the second high-frequency supply unit can be represented by equivalent circuits similar to those in FIG. Also in the sixth embodiment, it is preferable that 1.5 ≦ X / Rp ≦ 5000 is satisfied.

  Also in the sixth embodiment, the size relationship between the first electrode 106a and the second electrode 135a is not limited, but it is preferable that the first electrode 106a and the second electrode 135a have approximately the same size. Similarly, the size relationship between the first electrode 106b and the second electrode 135b is not limited, but it is preferable that the first electrode 106b and the second electrode 135b have the same size.

  The present invention is not limited to the above embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, in order to make the scope of the present invention public, the following claims are attached.

1: Plasma processing apparatus, 10: Main body, 101: High frequency power supply, 102: Impedance matching circuit, 103: Balun, 104: Blocking capacitor, 106: First electrode, 107, 108: Insulator, 109: Target, 110: Vacuum Container: 111: second electrode, 112: substrate, 115: low-pass filter, 116: power supply, 201: first unbalanced terminal, 202: second unbalanced terminal, 211: first balanced terminal, 212: second balanced terminal 213: midpoint terminal, 251: first terminal, 252: second terminal, 253: third terminal, 221: first coil, 222: second coil, 223: third coil, 224: fourth coil

The present invention relates to an etching device.

One aspect of the present invention relates to an etching apparatus, the etching apparatus, first unbalanced terminal, the second unbalanced terminals, a first balanced terminal not grounded, a second balanced terminals not grounded, the first 1. A balun having a first coil connecting the unbalanced terminal and the first balanced terminal, and a second coil connecting the second unbalanced terminal and the second balanced terminal, and a vacuum container grounded , electrically connected to the first balanced terminal, via a first electrode for holding a substrate, a second electrode electrically connected to the second balanced terminal, and an impedance matching circuit, the impedance matching circuit Connected to the first unbalanced terminal of the balun, supplying a high frequency to the first electrode via the impedance matching circuit and the balun, a low-pass filter, and the low-pass filter. A second power source for supplying a voltage to the first electrode via the second balanced terminal, the first balanced terminal and the first electrode being electrically connected via a blocking capacitor. The second electrode is electrically connected without a blocking capacitor.

Claims (20)

A balun having a first unbalanced terminal, a second unbalanced terminal, a first balanced terminal and a second balanced terminal;
A grounded vacuum container,
A first electrode electrically connected to the first balanced terminal;
A second electrode electrically connected to the second balanced terminal;
An impedance matching circuit,
A first power supply connected to the balun via the impedance matching circuit, and supplying a high frequency wave to the first electrode via the impedance matching circuit and the balun;
Low-pass filter,
A second power supply for supplying a voltage to the first electrode through the low pass filter;
A plasma processing apparatus comprising: The first electrode holds a target and the second electrode holds a substrate;
The plasma processing apparatus according to claim 1, wherein: The balun has a first coil that connects the first unbalanced terminal and the first balanced terminal, and a second coil that connects the second unbalanced terminal and the second balanced terminal.
The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus. The balun further has a third coil and a fourth coil connected between the first balanced terminal and the second balanced terminal, and the third coil and the fourth coil are connected to the third coil. The voltage at the connection node with the fourth coil is set to the midpoint between the voltage at the first balanced terminal and the voltage at the second balanced terminal,
The plasma processing apparatus according to claim 3, wherein the plasma processing apparatus is a plasma processing apparatus. The connection node is connected to the vacuum container,
The plasma processing apparatus according to claim 4, wherein The second power source includes an AC power source,
The frequency of the voltage supplied to the first electrode by the AC power source is lower than the frequency,
The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus. The first electrode is supported by the vacuum container via an insulator,
The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus. An insulator is disposed between the second electrode and the vacuum container,
The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus. At least one of a mechanism for moving up and down the second electrode and a mechanism for rotating the second electrode is further provided.
The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus. The first electrode holds a substrate, and the plasma processing apparatus is configured as an etching apparatus,
The plasma processing apparatus according to claim 1, wherein: The first electrode holds a target, and the second electrode is arranged around the first electrode,
The plasma processing apparatus according to claim 1, wherein: A plurality of high frequency supplying parts, each of the plurality of high frequency supplying parts includes the balun, the first electrode and the second electrode,
The first electrode of each of the plurality of high frequency supply parts holds a target, and in each of the plurality of high frequency supply parts, the second electrode is arranged around the first electrode.
The plasma processing apparatus according to claim 1, wherein: The first electrode and the second electrode are supported by the vacuum container via an insulator,
The plasma processing apparatus according to claim 11, wherein the plasma processing apparatus is a plasma processing apparatus. A third electrode holding the substrate,
A second high frequency power supply for supplying a high frequency to the third electrode via a second impedance matching circuit;
14. The plasma processing apparatus according to claim 11, further comprising:   The plasma processing apparatus of claim 14, further comprising a second DC power supply that supplies a DC voltage to the third electrode via a second low pass filter. An insulator is disposed between the third electrode and the vacuum container,
The plasma processing apparatus according to claim 14 or 15, characterized in that. At least one of a mechanism for moving up and down the third electrode and a mechanism for rotating the third electrode,
17. The plasma processing apparatus according to claim 14, wherein the plasma processing apparatus is a plasma processing apparatus. The first balanced terminal and the first electrode are electrically connected via a blocking capacitor,
18. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus. The second balanced terminal and the second electrode are electrically connected via a blocking capacitor,
The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus. Rp is a resistance component between the first balanced terminal and the second balanced terminal when the first electrode and the second electrode are viewed from the first balanced terminal and the second balanced terminal. , 1.5 ≦ X / Rp ≦ 5000, where X is the inductance between the first unbalanced terminal and the first balanced terminal,
20. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus.

Images