JP5301340B2 - Sputtering apparatus and film forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dual cathode type sputtering apparatus which can be downsized and can reduce production cost, and to provide a film deposition method. <P>SOLUTION: The sputtering apparatus 1A comprises a vacuum chamber 3, at least a pair of targets 4, 5 provided in the vacuum chamber 3 and arranged opposite to an object S1 for film deposition, an AC power source 6 for applying the AC voltage Vmf1, Vmf2 to the targets 4, 5 so that the cathode and the anode are alternately changed between the pair of targets 4, 5, a high frequency power source 10 for generating the high frequency voltage Vrf to be applied in a superposed manner on the AC voltage Vmf1, Vmf2, and a high-speed switching circuit 11 which is connected between the high frequency power source 10 and the pair of targets 4, 5 to alternately change the high frequency voltage Vrf to each of the pair of targets 4, 5, and apply it thereto. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a sputtering apparatus and a film forming method.

  In recent years, in order to reduce the discharge sustaining voltage of a DC sputtering apparatus and suppress damage to the film, a method of superposing a radio frequency (RF) on a target serving as a cathode is often used. However, in this method, when a high resistivity material or an insulating material is formed, the anode periphery and the inner wall of the chamber are covered with these materials and do not function as an anode. There is a problem that becomes unstable.

  In view of this, a method has been devised in which two targets are arranged in a chamber, and a cathode voltage and an anode voltage are alternately switched and applied to these targets (so-called dual cathode method). For example, Patent Document 1 discloses a sputtering apparatus including a pair of targets in a vacuum chamber.

  FIG. 7 is a block diagram schematically showing a configuration of a conventional dual cathode sputtering apparatus. As shown in FIG. 7, a conventional sputtering apparatus 100 applies two targets 111 and 121 arranged in a chamber 101, and applies an intermediate voltage (MF: Mid Frequency) AC voltage to these targets 111 and 121. AC power supply (MF power supply) 130 and low-pass filters (LPF) 112 and 122 disposed between the AC power supply 130 and the targets 111 and 121, respectively. The sputtering apparatus 100 further includes a high frequency power supply 113 for applying a high frequency voltage to the target 111 and a high frequency power supply 123 for applying a high frequency voltage to the target 112. A high-frequency matching circuit (matching box) 114 for impedance matching is provided between the target 111 and the high-frequency power source 113, and similarly, a high-frequency matching circuit 124 is provided between the target 121 and the high-frequency power source 123. . The high frequency power supply 113 (123) applies a high frequency voltage to the target 111 (121) when a negative voltage is applied to the target 111 (121) from the AC power supply 130 to serve as a cathode.

Japanese Patent Laid-Open No. 2004-27277

  As shown in FIG. 7, the conventional dual cathode sputtering apparatus uses one high-frequency power source for one target, which is one factor that hinders downsizing of the apparatus and suppression of production costs. The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a dual cathode type sputtering apparatus and a film forming method capable of reducing the size of the apparatus and reducing the production cost.

  In order to solve the above-described problems, a sputtering apparatus according to the present invention includes a vacuum chamber, at least a pair of targets provided in the vacuum chamber and arranged to face a film formation target, and between the pair of targets. An AC power supply that applies an AC voltage to each target so that the cathode and the anode are alternately switched, a high-frequency power supply that generates a high-frequency voltage that is superimposed on the AC voltage, and a connection between the high-frequency power supply and a pair of targets Switching means for alternately switching and applying the high-frequency voltage to each of the pair of targets.

  In addition, the film forming method according to the present invention uses at least a pair of targets disposed in a vacuum chamber so as to face a film formation target, and applies each target so that the cathode and the anode are alternately switched between the pair of targets. A film forming method for forming a film on an object to be formed by applying an alternating voltage, wherein a high frequency voltage generated by a high frequency power source shared by a pair of targets is alternately switched for each of the pair of targets. While being superimposed on the AC voltage, it is applied.

  In the sputtering apparatus and the film forming method described above, a common high-frequency power source is used for the pair of targets, and a high-frequency voltage from the high-frequency power source is alternately switched and applied to each of the pair of targets. With such a configuration, since only one high-frequency power source is required for a pair of targets, the apparatus can be downsized and the production cost can be reduced as compared with a conventional dual cathode sputtering apparatus.

  Further, the sputtering apparatus and the film forming method may be characterized in that the switching means controls switching of the high-frequency voltage for the pair of targets based on the AC voltage. This makes it possible to easily and accurately switch the high-frequency voltage in accordance with the cycle in which the cathode and the anode are switched.

  In that case, the sputtering apparatus and the film forming method are configured so that the timing at which the switching means switches the high-frequency voltage for the pair of targets coincides with the timing at which the cathode and the anode are switched between the pair of targets by the AC voltage. It may be a feature. Alternatively, in the sputtering apparatus and the film forming method, the timing at which the switching means switches the high-frequency voltage for the pair of targets is shifted by a predetermined time from the timing at which the cathode and the anode are switched between the pair of targets by the AC voltage. This may be a feature. In particular, when the timing for switching the high-frequency voltage is shifted, for example, by superimposing the high-frequency voltage on the other target before one target changes from the cathode to the anode, the discharge is continued when the cathode / anode is switched. Therefore, impedance matching between the high frequency power source and the target can be facilitated.

  Further, the sputtering apparatus includes a switching element for switching the high-frequency voltage for the pair of targets, a delay circuit that delays a control signal that is generated based on the AC voltage and is input to the control terminal of the switching element. It is good also as having. Thereby, the structure for shifting the timing which switches a high frequency voltage only for predetermined time is easily realizable.

  Further, the sputtering apparatus may further include an operation unit for changing the predetermined time to an arbitrary time within a half cycle of the AC voltage. Thereby, adjustment of the said predetermined time by the difference in film-forming material can be made easy.

  Further, the sputtering apparatus may be characterized in that a plurality of pairs of targets are provided, and a high-frequency voltage is distributed from a common high-frequency power source to the plurality of pairs of targets via switching means. Thereby, it is possible to efficiently form a film on a large-area film formation target. In that case, it is preferable that the sputtering apparatus further includes a phase adjuster connected between the switching unit and the plurality of pairs of targets.

  According to the sputtering apparatus and the film forming method of the present invention, the apparatus can be miniaturized and the production cost can be reduced.

1 is a block diagram showing a configuration of a sputtering apparatus 1A according to a first embodiment of the present invention. (A) AC voltage applied to one target 4 when the timing of switching the high-frequency voltage with respect to the targets 4 and 5 is made coincident with the timing of switching the cathode and anode between the targets 4 and 5 by the AC voltage (B) A high-frequency voltage applied to one target 4, (c) an AC voltage applied to the other target 5, and (d) a high-frequency voltage applied to the other target 5. . In the case where the timing for switching the high-frequency voltage with respect to the targets 4 and 5 is shifted by a predetermined time Δt (2.5 microseconds) from the timing at which the cathode and the anode are switched between the targets 4 and 5 by the AC voltage, (A) AC voltage applied to one target 4, (b) high frequency voltage applied to one target 4, (c) AC voltage applied to the other target 5, and (d) other target 5 6 is a timing chart showing high-frequency voltages applied to the two. It is a figure which shows each internal structure of (a) low-pass filter 7, (b) high frequency matching circuit 12, and (c) high-speed switching circuit 11 with which sputtering apparatus 1A is provided. It is a block diagram which shows the structure of sputtering device 1B which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the structure of 1 C of sputtering devices as a modification of 2nd Embodiment. It is a block diagram which shows the structure of the conventional dual cathode type | mold sputtering apparatus.

  Hereinafter, embodiments of a sputtering apparatus and a film forming method according to the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
Referring to FIG. 1, a sputtering apparatus 1A according to the first embodiment is a so-called dual cathode type sputtering apparatus, and includes a vacuum chamber 3, a pair of targets 4 and 5 provided in the vacuum chamber 3, and a pair AC power supply 6 for applying AC voltages Vmf1 and Vmf2 to the targets 4 and 5, and low-pass filters 7 and 8 provided between the AC power supply 6 and the pair of targets 4 and 5. Further, the sputtering apparatus 1A alternately switches and applies the high-frequency power source 10 that generates the high-frequency voltage Vrf applied to the AC voltages Vmf1 and Vmf2 and the pair of targets 4 and 5 alternately. A high-speed switching circuit 11 and high-frequency matching circuits 12 and 13 provided between the high-speed switching circuit 11 and the pair of targets 4 and 5 are provided.

  In the vacuum chamber 3, a film formation target S1 is accommodated. Examples of the material to be deposited on the surface of the deposition target S1 include semiconductor layers such as zinc oxide (ZnO) and SiC, and amorphous silicon. The targets 4 and 5 are flat plate members made of such a film forming material, but a cylindrical target may be used. The targets 4 and 5 are disposed in the vacuum chamber 3 so as to face the film formation target S1 and are arranged side by side in a direction along the film formation target surface of the film formation target S1.

  The AC power source 6 is electrically connected to each of the pair of targets 4 and 5, and the AC voltage Vmf 1 is applied to each target 4 and 5 so that the cathode and the anode are alternately switched between the pair of targets 4 and 5. Vmf2 is applied. The frequency of the AC voltage generated by the AC power source 6 is, for example, a medium frequency (MF) such as 10 [kHz] to 40 [kHz], and is 20 [kHz] as an example. The rated output of the AC power supply 6 is, for example, 10 [kW] to 30 [kW]. The AC power supply 6 applies AC voltages Vmf1 and Vmf2 having opposite phases to the targets 4 and 5. That is, when the potential of the target 4 becomes negative (cathode) by the AC voltage Vmf1, the potential of the target 5 becomes positive (anode) by the AC voltage Vmf2, and when the potential of the target 4 is positive (anode) by the AC voltage Vmf1 The potential of the target 5 becomes negative (cathode) by the voltage Vmf2.

  The low-pass filter 7 has one end connected to the AC power source 6 and the other end connected to the target 4. The low-pass filter 8 has one end connected to the AC power source 6 and the other end connected to the target 5. The low-pass filters 7 and 8 are provided to prevent the high-frequency voltage Vrf output from the high-frequency power source 10 from reaching the AC power source 6 via the target 4 or 5. That is, the low-pass filters 7 and 8 pass the frequencies (10 to 40 [kHz]) of the AC voltages Vmf1 and Vmf2 output from the AC power supply 6 described above, and set the frequency of the high-frequency voltage Vrf output from the high-frequency power supply 10. Designed to block.

  The high-frequency power source 10 continuously generates a high-frequency voltage Vrf that is applied by being superimposed on the AC voltages Vmf1 and Vmf2 that are applied from the AC power source 6 to the targets 4 and 5, respectively. The frequency of the high frequency voltage Vrf generated by the high frequency power supply 10 is a high frequency (RF) such as 13.56 [MHz], for example. Only one high-frequency power source 10 is provided for the pair of targets 4 and 5. The rated output of the high frequency power supply 10 is several hundred watts, for example.

  The high-speed switching circuit 11 is a switching means in the present embodiment, and is connected between the high-frequency power source 10 and the pair of targets 4 and 5. The input terminal of the high-speed switching circuit 11 is connected to the output terminal of the high frequency power supply 10, and the high frequency voltage Vrf is input from the high frequency power supply 10. The switching circuit 11 periodically and alternately outputs the high-frequency voltage Vrf to each of the pair of targets 4 and 5. That is, the switching circuit 11 changes the path of the high-frequency voltage so that the high-frequency voltage Vrf is output to the target 4 in a half cycle of a certain cycle and the high-frequency voltage Vrf is output to the target 5 in the remaining half cycle. (Switching). The high-frequency voltages Vrf1 and Vrf2 thus generated from the high-frequency voltage Vrf are output from the high-speed switching circuit 11 toward the targets 4 and 5, respectively.

  Further, the control signal Sc is provided from the AC power supply 6 to the high-speed switching circuit 11 of the present embodiment. The control signal Sc is a signal for controlling switching of the high-frequency voltage Vrf for the pair of targets 4 and 5 in the high-speed switching circuit 11 based on the AC voltage Vmf1 or Vmf2. The control signal Sc may be the AC voltage Vmf1 or Vmf2 itself, or may be a periodic signal generated based on the AC voltage Vmf1 or Vmf2. Whether the high-speed switching circuit 11 matches the timing of switching the high-frequency voltage Vrf with respect to the targets 4 and 5 based on the control signal Sc to the timing of switching the cathode and anode between the targets 4 and 5 by the AC voltages Vmf1 and Vmf2. Alternatively, the shift is performed for a predetermined time.

  The high-frequency matching circuits 12 and 13 are circuits (matching boxes) for matching impedance between the high-frequency power supply 10 and the high-speed switching circuit 11 and the targets 4 and 5. The high frequency matching circuit 12 has one end connected to the high speed switching circuit 11 and the other end connected to the target 4. The high-frequency matching circuit 13 has one end connected to the high-speed switching circuit 11 and the other end connected to the target 5.

  2 and 3, (a) an AC voltage Vmf1 applied to one target 4, (b) a high-frequency voltage Vrf1 applied to one target 4, and (c) applied to the other target 5. 6 is a timing chart illustrating an AC voltage Vmf2 and (d) a high-frequency voltage Vrf2 applied to the other target 5.

  In the example shown in FIG. 2, the high-speed switching circuit 11 applies the high-frequency voltage Vrf1 to the target 4 while the AC voltage Vmf1 to the target 4 is negative (that is, while the target 4 is a cathode), The high-frequency voltage Vrf2 is applied to the target 5 while the AC voltage Vmf2 to the target 5 is negative (that is, while the target 5 is the cathode). In FIG. 2, the timing Ta at which the high-frequency voltage Vrf is switched with respect to the targets 4 and 5 is made coincident with the timing Tb at which the cathode and the anode are switched between the targets 4 and 5 by the AC voltage Vmf1 (or Vmf2). As a result, the period during which the AC voltage Vmf1 to the target 4 is negative (that is, the period during which the target 4 is a cathode) and the period during which the high-frequency voltage Vrf1 is applied completely coincide. When the frequency of the AC voltages Vmf1 and Vmf2 is 20 [kHz], the time (ΔT in the figure) from when the cathode is switched between the targets 4 and 5 to when it is switched again is 25 microseconds.

  In the example shown in FIG. 3, the high-speed switching circuit 11 applies the high-frequency voltage Vrf1 to the target 4 while the AC voltage Vmf1 to the target 4 is mainly negative, and the AC voltage Vmf2 to the target 5 is The high frequency voltage Vrf2 is applied to the target 5 while it is mainly negative. However, the high-speed switching circuit 11 precedes the timing Ta at which the high frequency voltage is switched with respect to the targets 4 and 5 by a predetermined time Δt from the timing Tb at which the cathode and the anode are switched between the targets 4 and 5 by the AC voltage Vmf1 (or Vmf2). It is shifted to. The predetermined time Δt is, for example, 1/10 of ΔT, and when ΔT is 25 microseconds, Δt is, for example, 2.5 microseconds. Note that since Δt has an optimum value depending on the type of film forming material and film forming conditions, it is desirable that an operator can adjust the sputtering apparatus 1A. Further, when switching the high-frequency voltage to the targets 4 and 5, the high-frequency voltage is instantaneously simultaneously applied to the two targets 4 and 5 by slightly delaying the application time of the high-frequency voltage to the target on the application end side. It may be applied. In this case, the application time of the high frequency voltage to the targets 4 and 5 is slightly longer than ΔT described above.

  FIG. 4 shows an example of internal configurations of (a) the low-pass filter 7, (b) the high-frequency matching circuit 12, and (c) the high-speed switching circuit 11 included in the sputtering apparatus 1 </ b> A. In the present embodiment, the configuration of the low-pass filter 8 is the same as the configuration of the low-pass filter 7, and the configuration of the high-frequency matching circuit 13 is the same as the configuration of the high-frequency matching circuit 12.

  Referring to FIG. 4A, the low-pass filter 7 includes an input end 7a, an output end 7b, inductors 14 and 15, and a capacitor 16, and has a so-called T-type low-pass filter configuration. Specifically, inductors 14 and 15 are connected in series between the input terminal 7a and the output terminal 7b, one electrode of the capacitor 16 is a contact between the inductor 14 and the inductor 15, and the other electrode is grounded. Each is connected to a potential. The input terminal 7 a is connected to the output terminal of the AC power source 6, and the output terminal 7 b is connected to the target 4.

  4B, the high-frequency matching circuit 12 includes an input terminal 12a, an output terminal 12b, variable capacitance capacitors 17 and 18, and an inductor 19. Specifically, one electrode of the variable capacitance capacitor 17 is connected to the input end 12a via the inductor 19, and the other electrode is connected to the output end 12b. Also, one electrode of the variable capacitance capacitor 18 is connected to the input terminal 12a, and the other electrode is connected to the ground potential. The input terminal 12 a is connected to the high speed switching circuit 11, and the output terminal 12 b is connected to the target 4.

  4C, the high-speed switching circuit 11 operates the input terminals 11a and 11b and the output terminals 11c and 11d, a pair of switching elements 20, 21 such as transistors, and the operation of the switching elements 20, 21. A control circuit 22 for controlling and a delay circuit 23 are included. The pair of switching elements 20 and 21 are elements for switching the high-frequency voltage Vrf with respect to the pair of targets 4 and 5. The switching elements 20 and 21 have one current terminals connected to each other, and these current terminals are further connected to the input end 11a. A high frequency voltage Vrf is input from the high frequency power supply 10 to the input end 11a. The other current terminals of the switching elements 20 and 21 are connected to the output terminals 11c and 11d, respectively. Control terminals of the switching elements 20 and 21 are connected to the control circuit 22. The control circuit 22 inputs a control signal Sc from the AC power supply 6 through the input terminal 11b. Based on the control signal Sc, the control circuit 22 generates two control signals Sc1 and Sc2 having the same period as the control signal Sc and having opposite phases to each other, and outputs these control signals Sc1 and Sc2 to the control terminals (typically bases) of the switching elements 20 and 21. Terminal).

  The delay circuit 23 is connected between the input terminal 11b and the control circuit 22, and is a circuit for delaying the control signal Sc (and thus delaying the control signals Sc1 and Sc2). For example, when the delay circuit 23 delays the control signal Sc by a predetermined time (ΔT−Δt), the switching operation of the switching elements 20 and 21 is delayed by (ΔT−Δt), and the timing as shown in FIG. It is synonymous with Ta being delayed by (ΔT−Δt) from timing Tb, that is, shifted forward by a predetermined time Δt.

  The delay circuit 23 is preferably connected to an operating means 24 for changing the predetermined time Δt to an arbitrary time within the half cycle (ΔT) of the AC voltages Vmf1 and Vmf2. The operating means 24 is operated by an operator, and an optimum Δt is set depending on the type of film forming material and film forming conditions. Thereby, the delay circuit 23 can control the delay time (ΔT−Δt) so that the optimum Δt is realized. The predetermined time Δt may be a negative value depending on conditions.

  The film forming method using the sputtering apparatus 1A of the present embodiment described above is as follows. That is, the film forming method according to the present embodiment uses a pair of targets 4 and 5 disposed in the vacuum chamber 3 so as to face the film forming object S1, and a cathode and an anode between the pair of targets 4 and 5. A film is formed on the film formation target S1 by applying AC voltages Vmf1 and Vmf2 to the targets 4 and 5 so that are alternately switched. During the film formation, the high frequency voltage Vrf generated by the high frequency power supply 10 shared with the targets 4 and 5 is applied to the targets 4 and 5 while being alternately switched to the alternating voltages Vmf1 and Vmf2. To do.

  In the film forming method according to this embodiment, switching of the high-frequency voltage Vrf with respect to the targets 4 and 5 is controlled based on the AC voltage Vmf1 or Vmf2. Then, the timing Ta for switching the high-frequency voltage Vrf with respect to the targets 4 and 5 is made to coincide with the timing Tb at which the cathode and the anode are switched between the targets 4 and 5 by the AC voltages Vmf1 and Vmf2, or shifted by a predetermined time Δt.

  According to the sputtering apparatus 1A and the film forming method according to the present embodiment, since only one high-frequency power source 10 is required for the pair of targets 4 and 5, the apparatus is compared with the conventional high-frequency superimposed dual-cathode sputtering apparatus. Can be reduced in size and the production cost can be reduced.

  Further, as in this embodiment, the high-speed switching circuit 11 preferably controls switching of the high-frequency voltage Vrf with respect to the targets 4 and 5 based on the AC voltages Vmf1 and Vmf2. This makes it possible to easily and accurately switch the high-frequency voltage Vrf in accordance with the cycle in which the cathode and the anode are switched.

  In this case, the high-speed switching circuit 11 uses the timing Ta at which the high-frequency voltage Vrf is switched with respect to the targets 4 and 5 as in the present embodiment, and the timing at which the cathode and anode are switched between the targets 4 and 5 by the AC voltages Vmf1 and Vmf2. It is further preferable to shift from Tb by a predetermined time Δt (where 0 <| Δt | <ΔT). Thus, for example, the high frequency voltage Vrf can be superimposed on the other target 5 before the one target 4 changes from the cathode to the anode, so that the discharge (plasma) can be continued when the cathode / anode is switched. It becomes. In general, the impedance matching condition between the high frequency power source and the target is greatly different between discharging and non-discharging. Therefore, by continuing the discharge in this way, the high frequency power source 10 and the targets 4 and 5 are not affected. Impedance matching by the high-frequency matching circuits 12 and 13 can be facilitated, and discharge can be started by omitting a so-called trigger operation when switching between the cathode and the anode.

  Further, as in the present embodiment, the high-speed switching circuit 11 is generated based on the switching elements 20 and 21 for switching the high-frequency voltage Vrf with respect to the pair of targets 4 and 5, and the alternating voltages Vmf1 and Vmf2. It is preferable to have a delay circuit 23 that delays the control signals Sc1 and Sc2 input to the control terminals 20 and 21. Thereby, the structure for shifting the timing Ta which switches the high frequency voltage Vrf by predetermined time (DELTA) t is easily realizable.

(Second Embodiment)
Referring to FIG. 5, the sputtering apparatus 1 </ b> B according to the second embodiment includes a plurality of pairs (three pairs in the figure) of targets 4 and 5 in a vacuum chamber 33 in which the film formation target S <b> 2 is accommodated. The high-frequency voltage Vrf is distributed from the high-frequency power supply 10 to a plurality of pairs of targets 4 and 5 via the high-speed switching circuit 31.

  More specifically, the sputtering apparatus 1B includes a vacuum chamber 33, N pairs (where N ≧ 2) targets 4 and 5 provided in the vacuum chamber 33, and an AC voltage Vmf1 across the N pairs of targets 4 and 5. , Vmf2 and N AC power sources 6 and N sets of low-pass filters 7 and 8 provided between the AC power sources 6 and the targets 4 and 5, respectively. Further, the sputtering apparatus 1B distributes the high-frequency voltage Vrf to one high-frequency power source 10 that generates the high-frequency voltage Vrf and the N pairs of targets 4 and 5, and alternately outputs the high-frequency voltage Vrf to each pair of targets 4 and 5. A high-speed switching circuit 31 for switching and applying, and N sets of high-frequency matching circuits 12 and 13 provided between the high-speed switching circuit 31 and the targets 4 and 5 are provided. Of these components, the configurations of the AC power supply 6, the low-pass filters 7 and 8, the high-frequency power supply 10, and the high-frequency matching circuits 12 and 13 are the same as those in the first embodiment described above, and thus the description thereof is omitted. To do.

  In the vacuum chamber 33, the film formation target S2 is accommodated. The plurality of targets 4 and 5 are disposed in the vacuum chamber 33 so as to face the film formation target S2, and are arranged side by side in a direction along the film formation target surface of the film formation target S2.

  The high-speed switching circuit 31 is a switching means in this embodiment, and is connected between the high-frequency power supply 10 and the N pairs of targets 4 and 5. The input terminal of the high-speed switching circuit 31 is connected to the output terminal of the high frequency power supply 10, and the high frequency voltage Vrf is input from the high frequency power supply 10. The switching circuit 31 distributes the high-frequency voltage Vrf to each of the N pairs of targets 4 and 5, and periodically switches the high-frequency voltage Vrf to the paired (adjacent) targets 4 and 5 alternately. Output. The high-frequency voltages Vrf1 and Vrf2 thus generated from the high-frequency voltage Vrf are output from the high-speed switching circuit 31 toward each of the N pairs of targets 4 and 5.

  The high-speed switching circuit 31 is provided with a control signal Sc from each of the N AC power supplies 6. These control signals Sc are signals for controlling switching of the high-frequency voltage Vrf for the targets 4 and 5 connected to each AC power source 6 based on the AC voltage Vmf1 or Vmf2 applied to the targets 4 and 5. is there. As in the first embodiment, the high-speed switching circuit 31 sets the timing Ta for switching the high-frequency voltage Vrf to the targets 4 and 5 based on the control signal Sc between the targets 4 and 5 by the AC voltages Vmf1 and Vmf2. And it is made to coincide with the timing Tb at which the anode is switched or shifted by a predetermined time Δt. When the phases of the outputs of the N AC power supplies 6 are not synchronized with each other, the nth target is used by using the control signal Sc of the nth (n is an integer of 1 to N) AC power supply 6. The switching of the high-frequency voltage Vrf input to the pair 4 and 5 is controlled.

  According to the sputtering apparatus 1B of the present embodiment having the above configuration, a plurality of pairs of targets 4 and 5 are provided, and the high frequency voltage Vrf is distributed from the common high frequency power supply 10 to the targets 4 and 5 via the high speed switching circuit 31. Therefore, it is possible to efficiently form a film even on the film-forming object S2 having a large area.

(Modification)
FIG. 6 is a block diagram showing a configuration of a sputtering apparatus 1C as a modification of the sputtering apparatus 1B according to the second embodiment described above. The difference between the sputtering apparatus 1C according to this modification and the sputtering apparatus 1B according to the second embodiment is that the sputtering apparatus 1C according to this modification includes phase adjusters (phase shifters) 34 and 35. . N sets of phase adjusters 34 and 35 are provided corresponding to N pairs of targets 4 and 5, and the phase adjusters 34 are connected between the high-speed switching circuit 31 and the high-frequency matching circuit 12. 35 is connected between the high-speed switching circuit 31 and the high-frequency matching circuit 13. The phase adjusters 34 and 35 make it possible to individually adjust the phases of the high-frequency voltages Vrf1 and Vrf2 output from the high-speed switching circuit 31 and provided to the targets 4 and 5 in each of the N pairs of targets 4 and 5. .

  The sputtering apparatus and film forming method according to the present invention are not limited to the above-described embodiments, and various other modifications are possible. For example, in each of the above embodiments, the case where the AC voltages Vmf1 and Vmf2 and the high-frequency voltage Vrf are sine waves is illustrated, but even if the AC voltage or the high-frequency voltage is a rectangular wave, a triangular wave, or an arbitrary waveform, The effects of the present invention can be suitably obtained.

  In the second embodiment, an example in which N AC power sources 6 are provided corresponding to N pairs of targets has been described. However, the AC power source may be smaller than the number of target pairs, and a plurality of AC power sources may be provided. May be used for paired targets.

  DESCRIPTION OF SYMBOLS 1A, 1B, 1C ... Sputtering device, 3,33 ... Vacuum chamber, 4, 5 ... Target, 6 ... AC power supply, 7, 8 ... Low pass filter, 10 ... High frequency power supply, 11, 31 ... High-speed switching circuit, 12, 13 ... high frequency matching circuit, 34, 35 ... phase adjuster, S1, S2 ... film formation target, Sc, Sc1, Sc2 ... control signal, Vmf1, Vmf2 ... AC voltage, Vrf, Vrf1, Vrf2 ... high frequency voltage.

Claims (12)

A vacuum chamber;
At least a pair of targets provided in the vacuum chamber and arranged to face the film formation target;
An AC power supply for applying an AC voltage to each target so that the cathode and the anode are alternately switched between the pair of targets;
A high-frequency power source for generating a high-frequency voltage to be applied superimposed on the AC voltage;
A sputtering apparatus comprising: switching means connected between the high-frequency power source and the pair of targets, and alternately switching and applying the high-frequency voltage to each of the pair of targets.   The sputtering apparatus according to claim 1, wherein the switching unit controls switching of the high-frequency voltage with respect to the pair of targets based on the AC voltage.   3. The switching unit according to claim 2, wherein the switching unit matches the timing of switching the high-frequency voltage with respect to the pair of targets with the timing of switching the cathode and the anode between the pair of targets by the AC voltage. Sputtering equipment.   The switching means shifts the timing at which the high-frequency voltage is switched for the pair of targets by a predetermined time from the timing at which the cathode and anode are switched between the pair of targets by the AC voltage. 2. The sputtering apparatus according to 2. The switching means includes
A switching element for switching the high-frequency voltage with respect to the pair of targets;
The sputtering apparatus according to claim 4, further comprising: a delay circuit that delays a control signal generated based on the AC voltage and input to a control terminal of the switching element.   The sputtering apparatus according to claim 4, further comprising operation means for changing the predetermined time to an arbitrary time within a half cycle of the AC voltage.   The said target is provided with multiple pairs, The said high frequency voltage is distributed to the said multiple pairs of target via the said switching means from the said common high frequency power supply, The Claim 1 characterized by the above-mentioned. The sputtering apparatus as described.   The sputtering apparatus according to claim 7, further comprising a phase adjuster connected between the switching unit and the plurality of pairs of targets. The film formation is performed by using an at least one pair of targets disposed in a vacuum chamber facing a film formation target and applying an alternating voltage to each target so that the cathode and the anode are alternately switched between the pair of targets. A film forming method for forming a film on an object,
A film forming method, wherein a high frequency voltage generated by a common high frequency power source is applied to the pair of targets while being alternately switched to each of the pair of targets and superimposed on the AC voltage.   The film forming method according to claim 9, wherein switching of the high-frequency voltage with respect to the pair of targets is controlled based on the AC voltage.   The film forming method according to claim 10, wherein a timing at which the high-frequency voltage is switched with respect to the pair of targets is made to coincide with a timing at which a cathode and an anode are switched between the pair of targets by the AC voltage.   The timing at which the high-frequency voltage is switched with respect to the pair of targets is shifted by a predetermined time from the timing at which the cathode and the anode are switched between the pair of targets by the AC voltage. Membrane method.

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