JP2011103762A - High voltage generation device for electrostatic chuck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high voltage generation device for an electrostatic chuck which the high voltage generation device requires an input power extremely smaller than an input power required by a conventional high voltage generator. <P>SOLUTION: The high voltage generation device includes a high voltage generation circuit 121 which amplifies a high-frequency signal output from an oscillation circuit 3 driven by a low-voltage power supply 2 and generates a high voltage using a high-frequency transformer, boosting/rectifying circuits 122 and 123 which raise the high voltage generated by the high voltage generating circuit 121 while rectifying the high voltage, an electrostatic chuck 22 serving as a capacitive load to which the high voltage raised and rectified by the boosting/rectifying circuits 122 and 123 is applied and discharge resistances R6 and R7 are connected in parallel, and a control circuit 110 which directly drives the oscillation circuit 3 with power from the low-voltage power supply 2 at the start of the generator, and drives the oscillation circuit 3 intermittently at a cycle shorter than a time constant determined by the capacitance of the electrostatic chuck 22 and the resistance values of the discharge resistances R6 and R7 with an elapse of a given time from the start of the generator. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrostatic chuck used for holding a substrate of a semiconductor manufacturing apparatus and a high voltage generator for an electrostatic chuck used in an exhibition / posting apparatus using an electrostatic chuck function, and more particularly to a solar cell. DC-DC conversion type electrostatic chuck that can generate high voltage in the order of kV using a low-voltage power source such as a battery or a secondary battery (storage battery) as an input power source. The present invention relates to a high voltage generator for use.

  An electrostatic chuck has, for example, a pair of suction electrodes, and accumulates positive and negative charges on the pair of suction electrodes to generate static electricity, thereby generating a dielectric substrate such as glass or plastic, silicon It is used for adsorbing and holding various substrates such as semiconductor substrates such as wafers and metal substrates such as iron, copper, aluminum, and stainless steel.

In addition, the electrostatic chuck can attract various substrates described above by utilizing the fact that a very strong electric field of about 1 × 10 ⁷ V / m can be easily created by adjusting the distance between the attracting electrodes. It can be applied not only to the function of holding, but also to devices such as sterilization and sterilization devices, dust collectors that collect dust and dirt in the air, and growth devices that promote the growth of vegetation such as plants and mushrooms. Hereinafter, these electrostatic chuck applied devices are also simply referred to as “electrostatic chuck”.

  In general, a high voltage power supply such as a direct current or an alternating current is used for the electrostatic chuck. However, in a relatively large apparatus such as a semiconductor manufacturing apparatus, it is possible to take a relatively large space and to ensure reliability. It is easy to avoid unexpected physical damage during maintenance, such as being covered with a sturdy housing, and there was no particular restriction on the size of the high-voltage power supply or the power consumption of the power supply itself. The power consumption of the high voltage power supply for the electrostatic chuck is, for example, ± 1 kV (potential difference 2 kV) bipolar voltage generation type. If the output current is 10 mA maximum, the power required for the input of this high voltage power supply is At least about 30W.

  Therefore, when using an electrostatic chuck, it is necessary to install a high-voltage power supply remotely outside the electrostatic chuck and supply power to the high-voltage power supply from, for example, an AC 100V outlet. The range of use will be affected by the installation position of the external power supply.

  Therefore, by reducing the size and power consumption of the high-voltage power supply for the electrostatic chuck, for example, it is possible to operate independently using solar cells, dry cells, or secondary batteries without removing power from an AC 100V outlet. A device using an electrostatic chuck is desired.

  However, the conventional high voltage power supply is large and consumes a large amount of power, so that it is difficult to put it into practical use.

  Then, as a technique regarding the high voltage generator which can be used as a power source of the electrostatic chuck utilizing device, for example, those disclosed in Patent Documents 1 to 4 have already been proposed.

  In the transformer type DC-DC converter according to Patent Document 1, a low-voltage DC power source such as a battery, a backflow prevention diode, and a switching element form a closed loop circuit for the primary winding of a high-frequency transformer, and the switching element is turned on. / OFF control circuit starter power supply is applied from the low-voltage DC power supply via a starter diode, and the energy stored in the inductance of the high-frequency transformer is connected in parallel to the primary winding In the transformer type DC-DC converter configured to be absorbed by the circuit, the energy absorbed by the snubber circuit is supplied to the control circuit as its drive power.

A high voltage generation circuit for an ion generator according to Patent Document 2 includes an oscillation circuit, a switching element that is switched by a pulse output of the oscillation circuit, and a current that flows through the primary coil is controlled by the switching element. A pulse transformer for outputting a high voltage pulse to the secondary side, a capacitor connected in parallel to the primary coil of the pulse transformer, a rectifier circuit for rectifying the high voltage pulse obtained on the secondary side of the pulse transformer, In a negative ion generator comprising a negative discharge electrode for applying a negative high voltage rectified by this rectifier circuit,
A driving power source for the oscillation circuit and the pulse transformer is a DC power source,
A diode is inserted in the forward direction in series with the primary coil of the pulse transformer.

  Furthermore, the electrostatic coating apparatus according to Patent Document 3 includes (A) a DC power supply circuit, (B) a first high-frequency oscillation circuit capable of stopping oscillation by an external signal, a first step-up transformer, A negative voltage high voltage generating circuit that generates a negative DC high voltage with respect to the ground, including a voltage doubler rectifier circuit and a first discharge resistor connected between output terminals of the voltage doubler rectifier circuit; A first current limiting resistor connected between the output terminal of the negative high voltage generating circuit and the nozzle; and (C) a switch capable of switching between high output voltage oscillation and low output voltage oscillation and stopping oscillation by an external signal. The second high-frequency oscillator, a second step-up transformer, a second voltage doubler rectifier circuit, and a second discharge resistor connected between the output terminals of the voltage doubler rectifier circuit. When high output voltage oscillates, the positive DC high voltage with respect to ground (D) a second current limiting resistor connected between the output terminal of the positive high voltage generation circuit and the nozzle; and (E) an output current of the negative high voltage generation circuit. An output current detection circuit for detecting the output current, and (F) a safety circuit, which is low in the second high-frequency oscillation circuit as long as the output current detected by the output current detection circuit is normal. When a command signal for oscillating at an output voltage is transmitted and an abnormality is detected in the output current, an oscillation stop command signal is transmitted to the first high-frequency oscillation circuit, and at the same time, a high-frequency signal is supplied to the second high-frequency oscillation circuit. A command signal for oscillating at the output voltage is transmitted for a predetermined time, and then a command signal for stopping oscillation is transmitted to the second high-frequency transmission circuit.

In addition, the high voltage generator according to Patent Document 4 includes a generator housed in an electrostatic coating device (15), on the one hand, a voltage booster transformer (2) on the one hand, and an output from the transformer (2) on the other hand. A high voltage generator for an electrostatic coating device (15), comprising a high voltage “cascade” (16) with a high voltage amplifier (3) arranged in
Said transformer (2) consists of a double or double transformer formed by at least two basic transformers, the individual primary windings (8A, 8B, 8C) being mounted electrically in parallel. The individual secondary windings (9A, 9B, 9C) are electrically connected in series, and the series arrangement of the secondary windings (9A, 9B, 9C) provides the output voltage (Vs), and the total voltage (Vs / N) crosses each terminal of the secondary winding, and is configured to be the input voltage of the voltage amplifier (3).

JP 05-176533 A JP 2004-31158 A JP 2003-164777 A JP 2005-200594 A

  However, Patent Document 1 uses general blocking oscillation, and when the current supplied to the inductor of the high-frequency transformer is instantaneously cut off by the switching element, the electric power stored in the inductor of the high-frequency transformer is stored. The voltage is boosted by generating a high voltage in the secondary winding of the high-frequency transformer by energy, and in order to obtain a desired high voltage, it is necessary to pass a certain amount of current through the primary winding of the high-frequency transformer. There is a large power loss in the circuit itself. In the case of Patent Document 1, if the output voltage of the battery is 5 V, for example, the current must be supplied from 200 to 500 mA regardless of the load, and requires a total power of about 1 W (= 5 V × 200 mA), A large battery is required.

  Patent Document 1 requires about 1 W of electric power as a whole as described above, and a relatively low power power source such as a storage battery or a solar battery generates a high voltage of kV order and It is difficult to operate such a capacitive load.

  Further, in Patent Document 2, a driving power source for an oscillation circuit and a pulse transformer is a DC power source, and a diode is inserted in a forward direction in series with a primary side coil of the pulse transformer. Although a forward diode inserted in series with the diode suppresses the influence of noise, it is necessary to always apply a DC voltage to the oscillation circuit with a DC power supply, and there is a limit in reducing power consumption accordingly. is doing.

  Furthermore, in Patent Document 3, a DC power supply circuit uses a commercial power supply as a power supply, and a low-voltage DC power supply such as a battery cannot be used as a power supply.

  Further, Patent Document 4 uses a generator housed in the electrostatic coating device (15) as a power source, and cannot use a low-voltage DC power source such as a battery as a power source. .

  Accordingly, a first problem to be solved by the present invention is to provide a high voltage generator for an electrostatic chuck that requires very little input power compared to a conventional high voltage generator.

  In addition, the second problem to be solved by the present invention is that a charge from a high voltage generator is efficiently allowed to flow into a capacitive load such as an electrostatic chuck, and a predetermined voltage is applied to the electrode of the electrostatic chuck. It is an object of the present invention to provide a high voltage generator for an electrostatic chuck that can be developed between the two.

  That is, the present invention provides a self-excited oscillation circuit driven by a low-voltage power supply, an amplifying circuit composed of a plurality of Darlington-connected transistors for amplifying a high-frequency signal output from the self-excited oscillation circuit, and the amplifying circuit A high-voltage generator comprising: a high-frequency transformer that applies a high-frequency signal amplified by a primary winding; and a rectifier circuit that includes a diode and a capacitor connected to a secondary winding of the high-frequency transformer. Is the basic configuration.

The present invention amplifies a high-frequency signal output from an oscillation circuit driven by a low-voltage power supply, and generates a high voltage using a high-frequency transformer,
A boost rectifier circuit that boosts the high voltage generated by the high voltage generator circuit while rectifying the high voltage;
An electrostatic chuck as a capacitive load to which a high voltage boosted while being rectified by the boost rectifier circuit is applied and a discharge resistor is connected in parallel;
At the time of start-up, the oscillation circuit is directly driven by the low-voltage power supply, and after a predetermined time has elapsed since the start-up, the oscillation circuit is made to have a capacitance of the electrostatic chuck and a resistance of the discharge resistor. A control circuit that controls to drive intermittently at a cycle shorter than the time constant determined by the value;
A high voltage generator for an electrostatic chuck.

A conventional high voltage generator requires an input power of about 1 W to 30 W. When this level of power is generated by a solar cell, the current output of the solar cell is still small, and the power obtained under sunlight per unit area is as small as about 0.013 W / cm ² at most. In addition, when using accumulated electrical energy such as dry batteries as an input power source, it is necessary to have a long life, but the power capacity of a commercially available dry battery is approximately independent of the battery voltage. It is about 1000 mAh. For example, in the case of a high voltage generator that requires an input power of 100 mA at 10 V, that is, 1 W, the lifetime of the dry battery will have only 10 hours. Therefore, a high voltage generator that requires a small input power is required.

  In addition, an electrostatic chuck as a load of a high voltage generator has an electrode through an electrically insulating layer such as synthetic resin or ceramic, and the electrode is also covered with an insulating layer of synthetic resin or ceramic. Seen from the side of the voltage generator, it is considered to be an extremely high resistance and capacitive load. The capacitance value is about 1 nF to 50 nF, although it depends on the arrangement and area of the electrodes. The capacitance formed between the electrodes does not require a large current as an input power source, and can be charged efficiently. If this is not transferred, a necessary voltage cannot be developed in the electrode, and the original attractive force or strong electric field cannot be generated.

  In the present invention, a high-frequency signal is output from a self-excited oscillation circuit driven by a low-voltage power source, and the high-frequency signal is amplified in a primary winding of a high-frequency transformer in a state where the high-frequency signal is current-amplified by an amplifier circuit including a plurality of Darlington-connected transistors. When applied, the electric energy determined by the current flowing in the primary winding and the inductance on the primary winding side is accumulated in the high-frequency transformer, and the transistor is turned off by the high-frequency signal applied to the transistor constituting the amplifier circuit. Since the current instantaneously becomes zero, a high voltage is generated on the primary winding side of the high-frequency transformer due to the electrical energy accumulated in the primary winding of the high-frequency transformer. The generated high voltage is further boosted by the secondary winding and then rectified by the rectifier circuit. Since the DC high voltage is obtained, a low voltage power source can be used as a power source, and the current flowing to the primary side of the high frequency transformer is a high frequency signal output from the self-excited oscillation circuit. Is amplified by an amplifier circuit, the input current supplied from the low-voltage power supply is about several tens of mA, and can be driven for a long time by a combination of solar cells, secondary batteries, or dry cells. It becomes possible.

  Further, in the present invention, the oscillation circuit is directly driven by a low voltage power source at the time of startup, but after a predetermined time has elapsed from the time of startup, the oscillation circuit is connected to the electrostatic capacity and discharge resistance of the electrostatic chuck. By controlling to drive intermittently with a cycle shorter than the time constant determined by the resistance value, the input current supplied from the low-voltage power supply can be further reduced, and further power saving can be achieved. Become.

  According to the high voltage generator of the present invention, it is possible to provide a high voltage generator that requires very little input power as compared with the conventional high voltage generator.

  Further, according to the high voltage generator of the present invention, the electric charge from the high voltage generator is efficiently allowed to flow into a capacitive load such as an electrostatic chuck, and a predetermined voltage is applied between the electrodes of the electrostatic chuck. It is possible to provide a high voltage generator capable of being expressed.

1 is a circuit diagram showing a high voltage generator according to Embodiment 1 of the present invention. FIG. 2 is a chart showing parameters when the high voltage generator according to Embodiment 1 of the present invention is actually driven. FIG. 3 is a schematic perspective sectional view showing a state in which a silicon wafer is sucked and held using an electrostatic chuck to which the high voltage generator of the present invention is applied in a parallel plate type plasma etching apparatus, and the silicon wafer is etched. FIG. 4 is a circuit diagram showing an electrostatic chuck to which the high voltage generator 1 is applied. FIG. 5 is a block diagram showing a high voltage generator according to Embodiment 2 of the present invention. FIG. 6 is a circuit diagram showing a high voltage generator according to Embodiment 2 of the present invention. FIG. 7 is a waveform diagram showing the operation of the high voltage generator according to Embodiment 2 of the present invention.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the accompanying drawings. The present invention is not limited to the following description.

Embodiment 1
FIG. 1 is a circuit diagram showing a high voltage generator according to Embodiment 1 of the present invention.
In the figure, reference numeral 1 denotes a high voltage generator. The high voltage generator 1 includes a secondary battery (storage battery) BAT as a low voltage power source 2 and a Schottky barrier diode for preventing backflow in the secondary battery BAT. And a solar cell SC as a low-voltage power supply connected in parallel via D100. The low voltage power source 2 is not limited to the combination of the secondary battery BAT and the solar battery SC, and may include at least one of a solar battery, a dry battery, a secondary battery, and a fuel cell. Any two or more of secondary batteries and fuel cells may be used in any combination. The supply voltage of the low voltage power supply 2 is set to 3 to 15 V, for example, and the supply average current is set to 10 to 100 mA, for example.

As the secondary battery BAT, any battery can be used. For example, a battery in which three lithium secondary batteries PB3048 with a capacity of 11 V / 300 mAh manufactured by Micro Vehicle are connected in series is used. Any solar cell SC can be used. For example, two amorphous silicon solar cells BCS0906P manufactured by TDK are connected in parallel, or an amorphous silicon solar cell manufactured by SANYO. AM-5815 having a total light receiving area of about 3 cm ² connected in parallel (for example, 8) is used.

  As the capacity of the secondary battery BAT, for example, a capacity of 300 mAh is used. Therefore, when the low-voltage power supply 2 is operated at a voltage of 9 V, it can be continuously operated for about 10 hours without sunlight. When there is sunlight, the secondary battery BAT is charged by the current that has been in the booster circuit composed of first and second high-frequency transformers TR1 and TR2, which will be described later.

  A general-purpose timer IC3 as a self-excited oscillation circuit is connected to the secondary battery BAT via a switch SW. As the general-purpose timer IC3, for example, an LMC555 type oscillation IC is used, but other types may be used as a matter of course. The general-purpose timer IC3 outputs a high-frequency signal having a frequency of 6.5 kHz with astable oscillation. The self-excited oscillation circuit 3 is not limited to the general-purpose timer IC, and may be any circuit that can output a high-frequency voltage of about 1 to 10 kHz, and the waveform of the output signal is a rectangular wave. In the general-purpose timer IC3, the positive electrode of the secondary battery BAT is connected to the VCC terminal and the RESET terminal, and the GND terminal is connected to the negative electrode (ground potential) of the secondary battery BAT. The DISC terminal of the general-purpose timer IC3 is connected to the positive electrode side of the secondary battery BAT via the first resistor R1, and the THRES terminal and the TRIG terminal are connected in series to the positive electrode side of the secondary battery BAT. Are connected via the first resistor C1 and the second resistor R2, and are connected to the negative electrode of the secondary battery BAT via the first capacitor C1. The first and second resistors R1 and R2 and the first capacitor C1 are for driving the general-purpose timer IC3 by the low-voltage power supply 2, and are not limited to these resistors and capacitors. Absent.

  The high-frequency output signal 4 output from the OUT terminal, which is the output terminal of the general-purpose timer IC 3, is a plurality (two in the illustrated example) of first (two in the illustrated example) that are Darlington-connected via a third resistor R 3 for current adjustment. And an amplifier circuit 5 composed of the second transistors T1 and T2. The high-frequency output signal 4 output from the general-purpose timer IC3 is input to the base terminal of the first transistor T1 constituting the amplifier circuit 5, and the collector terminals of the first and second transistors T1 and T2 will be described later. The first and second high-frequency transformers TR1 and TR2 are connected in parallel to one end of the primary windings N1 and N1. The emitter terminal of the first transistor T1 is connected to the base terminal of the second transistor T2, and the emitter terminal of the second transistor T2 is connected to the negative electrode (ground potential) of the secondary battery BAT. The amplifier circuit 5 current-amplifies the high-frequency output signal 4 output from the general-purpose timer IC3 with an amplification factor according to the relationship between the amplification factor of the first transistor T1 and the amplification factor of the second transistor T2.

  The collector terminals of the first and second transistors T1 and T2 are connected in parallel to one ends of the primary windings N1 and N1 of the first and second high-frequency transformers TR1 and TR2, and the first and second transistors The other ends of the primary windings N1 and N1 of the high-frequency transformers TR1 and TR2 are connected to the positive electrode of the secondary battery BAT via the voltage adjustment volume P1 and the switch SW, respectively. As the first and second high-frequency transformers TR1 and TR2, for example, a high-frequency transformer ST-14 (1k: 500k) manufactured by SANSUI is used. The first high-frequency transformer TR1 is for positive-polarity DC high-voltage output, and the second high-frequency transformer TR2 is for negative-polarity DC high-voltage output. The high-frequency transformers TR1 and TR2 do not necessarily need to be used, and only need to have one of positive polarity or negative polarity.

  Connected to the secondary winding N2 of the first high-frequency transformer TR1 is a first Cockcroft-Walton circuit 6 as a positive voltage boosting rectifier circuit. The first Cockcroft-Walton circuit 6 is configured by connecting five capacitors C2, C3, C4, C5, C6 and five diodes D1, D2, D3, D4, D5, D6 in five stages. A sixth resistor R6 (about 100 MΩ) is connected in parallel with the ground potential on the output side of the first Cockcroft-Walton circuit 6, and 1 MΩ is connected between the positive output terminal 7. A fourth resistor R4 for current limiting with a high resistance set to a degree is connected in series.

  For example, a fast recovery diode is used as the rectifying diode, but a normal rectifying diode IN4007 (withstand voltage of 1 kV) or the like may be used.

  Further, a second cockcroft-Walton circuit 8 as a negative-polarity step-up rectifier circuit is connected to the secondary winding N2 of the second high-frequency transformer TR2. The second Cockcroft-Walton circuit 8 is configured by connecting five capacitors C7, C8, C9, C10, C11 and five diodes D6, D7, D8, D9, D10, D11 in five stages. A seventh resistor R7 (about 100 MΩ) is connected in parallel with the ground potential on the output side of the second Cockcroft-Walton circuit 8, and 1 MΩ between the negative output terminal 9 A high resistance current limiting fifth resistor R5 set to a degree is connected in series.

  Resistors R6 and R7 of about 100 MΩ connected in parallel to the output terminal are for self-discharging and for quickly reducing the output voltage when the power switch SW is turned off to ensure safety. . The resistors R4 and R5 of about 1 MΩ connected in series with the output terminal are for limiting the current of the load, and charges the capacitor such as the load consisting of the chucking electrode of the electrostatic chuck smoothly. (= Pressure increase).

  In the above configuration, the high voltage generator according to this embodiment can provide a high voltage generator that requires very little input power as compared with the conventional high voltage generator as follows. It is possible.

  That is, as shown in FIG. 1, in the high voltage generator 1, the secondary battery BAT is charged with the electric power generated when the solar battery SC is receiving light. In the present embodiment, two amorphous silicon solar cells BCS0906P manufactured by TDK are connected in parallel. As shown in FIG. 2, the generated voltage is about 9.0 V at the maximum by natural light. The current average value is about 35 mA, and the current peak value is about 48 mA. Therefore, the total power (W) is about 0.32 W on average and about 0.43 W on peak.

  As shown in FIG. 1, when the switch SW is turned on, the high voltage generator 1 supplies an average power of about 0.32 W from at least one of the secondary battery BAT and the solar battery SC to the downstream side of the circuit. Then, the general-purpose timer IC3 is driven, and the high-frequency signal 4 having a frequency of 6.5 kHz is output from the output terminal OUT by the astable oscillation from the general-purpose timer IC3. The high-frequency output signal 4 output from the general-purpose timer IC3 is input to the base terminal of the first transistor T1 connected in Darlington via the third resistor R3, and the first and second transistors T1 connected in Darlington connection. , T2 is current amplified.

  The high-frequency signal 10 amplified by the first and second transistors T1, T2 connected in Darlington is applied to the primary windings N1, N1 of the first and second high-frequency transformers TR1, TR2, and the high-frequency transformer TR1, Electric energy determined by the current flowing through the primary windings N1 and N1 and the inductance of the primary winding side is stored in TR2, and the high-frequency signal 10 applied to the first transistor T1 of the transistor constituting the amplifier circuit Since the current instantaneously becomes zero when the transistor T1 is turned off, the primary windings N1, N1 of the high-frequency transformers TR1, TR2 are generated by the electrical energy accumulated in the primary windings N1, N1 of the high-frequency transformers TR1, TR2. A high voltage is generated on the side, and the primary windings N1, N1 of the high-frequency transformers TR1, TR2 Is generated by the secondary windings N2 and N2, and the secondary windings N2 and N2 of the first and second high-frequency transformers TR1 and TR2 are connected to the primary winding N1. A high voltage boosted in synchronism with the applied high-frequency signal 10 is generated.

  The high voltage generated in the secondary windings N2 and N2 of the first and second high-frequency transformers TR1 and TR2 is rectified and boosted and output by the first and second Cockcroft-Walton circuits 6 and 8. .

  The DC high voltage output from the first Cockcroft-Walton circuit 6 is output as a positive DC high voltage (for example, +900 V) from the output terminal 7 via the fourth resistor R4 for current limiting. On the other hand, the DC high voltage output from the second Cockcroft-Walton circuit 8 is output as a negative DC high voltage (for example, -900 V) from the output terminal 9 via the sixth resistor R5 for current limiting. Is done. Further, the output voltage can be adjusted over 1 to 900 V by controlling the current flowing through the primary windings N1 and N1 of the first and second high-frequency transformers TR1 and TR2 by the voltage adjustment volume P1.

  The inventor made a prototype of the high voltage generator 1 shown in FIG. 1 and examined the characteristics of the high voltage generator 1. As a result, the results shown in FIG. 2 were obtained.

  When the input voltage supplied from at least one of the secondary battery BAT or the solar battery SC is 9 V, the average value of the input current is 35 mA, the peak value of the input current is 48 mA, the maximum output voltage is ± 850 V, and the input power The average value was 0.32 W, and the peak value of input power was 0.43 W.

  Also, when the input voltage is 5.5V, the average value of the input current is 23mA, the peak value of the input current is 28mA, the maximum output voltage is ± 480V, the average value of the input power is 0.13W, the peak of the input power The value was 0.15W.

  As described above, in the high voltage generator 1, the low voltage power source 2 has the input voltage of 9V and the average value of the input current of about 35 mA, and the current and the fourth and the current limiting currents from the output terminals 7 and 9. A positive DC high voltage (for example, +900 V) and a negative DC high voltage (for example, -900 V) can be output via the fifth resistors R4 and R5, and are connected to the output terminals 7 and 9. Even when a capacitive load having an electrostatic capacity of about 20 nF, such as an adsorption electrode of an electrostatic chuck, is connected as a load, a high voltage of about +900 V and −900 V close to the kV order is output, and the substrate, etc. Can be stably adsorbed and held.

  FIG. 3 is a perspective view showing a state in which the silicon wafer w is sucked and held using the electrostatic chuck 22 to which the high voltage generator 1 of the present invention is applied in the parallel plate type plasma etching apparatus 21 and the etching process of the silicon wafer w is performed. FIG. 4 is a circuit diagram showing an electrostatic chuck to which the high voltage generator 1 is applied.

  The electrostatic chuck 22 has an electrode sheet 24 attached to the upper surface side of an aluminum metal base 23 having a thickness of 12 mm and a diameter of 340 mm. The electrode sheet 24 is formed by laminating a lower insulating layer 26 and an upper insulating layer 27 made of a polyimide film having a thickness of 100 μm and a diameter of 298 mm on the upper and lower surfaces of the adsorption electrode 25, respectively. The electrode sheet 24 is attached with a solar cell SC made of amorphous silicon at a peripheral portion of the substrate adsorption surface that adsorbs the substrate w and does not adsorb the substrate, and the metal substrate 23 has a high voltage. The generator 1 is incorporated. As the high voltage generator 1, the one shown in FIG. 1 is used. The solar cell SC generates power using the plasma of the plasma etching device 21. However, the solar cell SC may be arranged outside the plasma etching device 21 so as to take in sunlight or the like from the outside.

  In FIG. 3, reference numeral 28 denotes an upper electrode of the plasma etching apparatus 21, and a high frequency power supply 29 is connected to the upper electrode 28.

Embodiment 2
FIG. 5 is a block diagram showing a high voltage generator according to Embodiment 2 of the present invention. The same reference numerals are given to the same parts as those in Embodiment 1, and in this Embodiment 2, A high-frequency signal output from an oscillation circuit driven by a low-voltage power supply is amplified and a high voltage is generated using a high-frequency transformer, and the high voltage generated by the high-voltage generation circuit is rectified A boost rectifier circuit that boosts the voltage, an electrostatic chuck as a capacitive load to which a high voltage boosted while rectified by the boost rectifier circuit is applied and a discharge resistor is connected in parallel; The oscillation circuit is directly driven by the low-voltage power supply, and after a predetermined time has elapsed from the start-up, the oscillation circuit is connected to the electrostatic chuck capacitance and the discharge resistance. It is configured to include a control circuit for controlling to intermittently driven in a shorter period than the time constant determined by the resistance value.

  That is, as shown in FIG. 5, the high voltage generator 1 is roughly composed of a DC low voltage power supply 2, a controller 110, and a high voltage generator 120, and the high voltage generator 120. Is connected to an electrostatic chuck 22 as a capacitive load.

  The control unit 110 includes a timer circuit 111, a modulation signal generation circuit 112, and a logic circuit (AND circuit) 113.

  The timer circuit 111 changes the output voltage of the timer circuit 111 from 0 to high (output voltage of the DC power supply 2) after a predetermined time T of about 1 second elapses when the DC power supply 2 is turned on. It is a circuit for switching to. As shown in FIG. 6, the timer circuit 111 includes a series-connected resistor R12 and a capacitor C16 that constitute a CR circuit to which an output voltage is applied from the DC power source 2 via a ninth resistor R9. A base terminal of the third transistor Q3 is connected to a connection point between the series-connected resistor R12 and the capacitor C16. An output voltage is applied to the collector terminal of the third transistor Q3 via the resistor R13, and its emitter terminal is grounded. Furthermore, the base terminal of the fourth transistor Q4 is connected to the collector terminal of the third transistor Q3, and the output voltage is applied to the collector terminal of the fourth transistor Q4 via the resistor R13. And its emitter terminal is grounded. The collector terminal of the fourth transistor Q4 is connected to the reverse diode D15 of the logic circuit 113.

  In the timer circuit 111, immediately after the DC power supply 2 is turned on, the third transistor Q3 is turned off and the fourth transistor Q4 is turned on, and the output voltage of the timer circuit 111 becomes 0. The third transistor Q3 is turned on according to a time constant [= R (resistance value of R12) × C (capacitance of the capacitor C16)] determined by the series-connected resistor R12 and the capacitor C16, and the fourth transistor Q4 Is turned off, and the output voltage of the timer circuit 111 becomes high. Here, the time from when the DC power supply 2 is turned on until the output voltage of the timer circuit 111 becomes high is set to about 1 second, for example.

  The time until the output voltage of the timer circuit 111 becomes high, as shown in FIG. 7, which will be described later, the output voltage of the high voltage generator 120 rises to a predetermined high voltage after the power switch SW is turned on. In this embodiment, as described above, the time is set to about 1 second.

  The modulation signal generator 112 is configured in the same manner as the self-excited oscillation circuit of the high voltage generator 1 described above, for example, and a general-purpose timer IC 114 is used. For example, an LMC555 type oscillation IC is used as the general-purpose timer IC 114, but other types may be used. For example, the general-purpose timer IC 114 outputs a low-frequency signal having a rectangular wave shape with a frequency of about 10.0 to 20.0 Hz by astable oscillation. The self-excited oscillation circuit is not limited to the general-purpose timer IC, and may be any circuit that can output a rectangular wave-shaped low frequency signal having a frequency of about 10.0 to 20.0 Hz.

  As shown in FIG. 6, the general-purpose timer IC 114 includes a resistor R10, a resistor R11, a variable resistor X3, a capacitor C15, a capacitor C14, and diodes D13 and D14 for driving the general-purpose timer IC 114. Similarly, they are connected to the corresponding terminals. The variable resistor X3 is used to adjust the duty ratio of the output voltage output from the general-purpose timer IC 114.

  Further, as shown in FIG. 6, the logic circuit (AND circuit) 113 includes a reverse diode D15 and a reverse diode D16 to which the output voltage of the DC power supply 2 is applied via a resistor R15. The base terminal of the fifth transistor Q5 is connected to the connection point between the diode D15 and the reverse diode D16. The output voltage of the DC power supply 2 is applied to the collector terminal of the fifth transistor Q5 via the resistor R16, and the control signal output from the collector terminal is the general-purpose timer IC3 of the high voltage generator 120. Is input to the RESET terminal.

  The logic circuit (AND circuit) 113 receives an output signal from the timer circuit 111 input to one reverse diode D15 and an output signal from the modulation signal generator 112 input to the other reverse diode D16. Only when both are "high", the fifth emitter-grounded transistor Q5 is turned on to output a "0" signal.

  Therefore, the logic circuit (AND circuit) 113 does not output a signal when the output signal from the timer circuit 111 is “0”, and after the output signal from the timer circuit 111 becomes “high”, When the rectangular wave low frequency signal output from the modulation signal generation unit 112 is “high”, “0” is obtained. When the rectangular wave low frequency signal output from the modulation signal generation unit 112 is “0”, Is “high”, that is, a rectangular low frequency signal output from the modulation signal generator 112 is inverted and output.

  On the other hand, the high voltage generator 120 is basically configured in the same manner as the high voltage generator according to the first embodiment described above.

  That is, as shown in FIG. 5, the high voltage generator 120 is roughly divided into an oscillation circuit 3, a flyback converter circuit 121, a positive boost rectifier circuit 122, a negative boost rectifier circuit 123, and a positive discharge. The resistor R6, the discharge resistor R7 on the negative electrode side, the fourth resistor R4 for limiting current, and the fifth resistor R5 for limiting current are also included.

  In the second embodiment, as shown in FIG. 6, an eighth resistor R8 and a thirteenth capacitor C13 are respectively connected in parallel to the DC power source 2, and between the resistor R8 and the capacitor C13, A ninth resistor R9 is connected in series. Further, in the self-excited oscillation circuit 3 of the high voltage generator 120, the VCC terminal connected to the DC power supply 2 is grounded via a twelfth capacitor C12. Further, in the self-excited oscillation circuit 3 of the high voltage generator 120, a diode D12 is connected in the reverse direction between the positive electrode side of the DC power supply 2 and the output terminal, and the output terminal and the negative electrode of the DC power supply 2 are connected. The diode D11 is also connected in the reverse direction to the side (ground potential). In FIG. 6, the DC power source 2 is omitted. The resistor R8 added this time is for flowing a dummy current, R9 is a limiting resistor for the inflow current, and is for preventing an overcurrent from flowing when the power switch SW is turned on, capacitors C12, C13. , C14 represents a bypass capacitor, and diodes D11, D12, D13, and D14 represent protective diodes, respectively.

  In the above configuration, the high voltage generator according to the second embodiment can further reduce the input power as compared with the conventional high voltage generator as follows.

  That is, in the high voltage generator 1 according to the second embodiment, as shown in FIG. 6, when the switch SW (not shown) is turned on, a DC voltage of about 9 V is supplied from the low voltage DC power supply 2. Then, the general-purpose timer IC3 is driven. From the general-purpose timer IC3, a high-frequency signal 4 having a frequency of 15.1 kHz is output from the output terminal OUT by astable oscillation. The high-frequency output signal 4 output from the general-purpose timer IC 3 is converted into a relatively high AC voltage of about several tens to 100 V by the flyback converter circuit 120.

  Further, the AC voltage converted into a relatively high voltage by the flyback converter circuit 120 is converted into a positive DC high voltage of about ± 1.8 kV by the positive boost rectifier 122 and the negative boost rectifier 123. And converted to a negative DC high voltage, and then applied to a positive suction electrode 25 and a negative suction electrode 25 of an electrostatic chuck 22 (see FIGS. 3 and 4) as a capacitive load, respectively. Is done.

  At that time, a control signal 130 is input from the control unit 110 to the high voltage generation unit 120 of the high voltage generator 1 as shown in FIGS. As shown in FIG. 5, the control signal 130 output from the control unit 110 is a state in which the timer circuit 111 is activated immediately after the switch SW is turned on, and the output from the timer circuit 111 is It is “0”. Therefore, the high voltage generator 120 of the high voltage generator 1 is driven as described above by the DC voltage supplied from the low voltage DC power supply 2.

  Next, as shown in FIG. 5, when a predetermined time T elapses after the switch SW is turned on, the control unit 110 changes the output from the timer circuit 111 to the “high” state, A control signal 130 obtained by inverting the rectangular wave low-frequency signal from the modulation signal generation circuit 112 input to the other of 113 is input to the RESET terminal of the general-purpose timer IC 3 of the high-voltage generation unit 120.

  Then, the general-purpose timer IC3 of the high voltage generation unit 120 is modulated in accordance with the rectangular wave-like modulation signal from the modulation signal generation circuit 112 input to the RESET terminal, and the output voltage output from the output terminal of the general-purpose timer IC3. Is on / off modulated in accordance with the frequency of the modulation signal, and the flyback converter circuit 121 is driven intermittently. The modulation signal output from the output terminal of the general-purpose timer IC3 has a variable duty ratio. For example, the duty ratio is set to about 50 to 75%.

  The positive high voltage and the negative high voltage output from the high voltage generator 120 are connected to the current limiting fourth resistor R4 and the current limiting fifth resistor R5. The electrostatic chuck 22 (see FIG. 3 and FIG. 4) as a capacitive load is applied to the positive suction electrode 25 and the negative suction electrode 25, respectively.

  At this time, the frequency of the modulation signal that is output from the output terminal of the general-purpose timer IC3 and intermittently drives the flyback converter circuit 121 is attached between the output of the high voltage generator 120 and the ground (ground potential). The resistance value R (about 100 MΩ) of the discharge resistors R6 and R7 and the capacitance C (about 10 to 1000 nF) between the positive electrode 25 and the negative electrode 25 of the electrostatic chuck 22 as a capacitive load. The period is set sufficiently smaller than the time constant represented by the product of (1/10 to 1/20).

  As described above, the frequency of the modulation signal for intermittently driving the flyback converter circuit 121 includes the resistance value R of the discharge resistor R6 and the discharge resistor R7, and the positive electrode 25 and the negative electrode of the electrostatic chuck 22 as a capacitive load. By setting the frequency to be determined with a period sufficiently smaller than the time constant represented by the product of the capacitance C between the positive electrode 25 and the negative electrode 25, the positive electrode 25 and the negative electrode 25 of the electrostatic chuck 22 It is possible to reduce the average current required for input while taking a sufficiently high voltage of the applied high voltage output.

  Now, the resistance value R (about 100 MΩ) of the discharge resistors R6 and R7 and the capacitance C (10 to 1000 nF) between the positive electrode 25 and the negative electrode 25 of the electrostatic chuck 22 as a capacitive load. When the time constant RC expressed by the product of the degree is RC = 1 second, the period of the modulation signal generation circuit 112 is set to 0.1 second, that is, the frequency is set to about 10 Hz, and the output of the modulation signal generation circuit 112 is If the duty ratio of the waveform is set to 50%, the power consumption can be halved.

  Therefore, the AC voltage output from the general-purpose timer IC 3 of the high voltage generator 120 consumes power according to the duty ratio as compared with the case where it is directly driven by the DC voltage supplied from the low-voltage DC power supply 2. It becomes possible to reduce. Therefore, in the high voltage generator 1, if the duty ratio of the modulation signal output from the output terminal of the general-purpose timer IC 114 is set to 50%, the power consumption is halved compared to the case where it is directly driven by the DC power supply 2. Can be reduced.

  FIG. 7 shows a waveform when the inventor made a prototype of the high voltage generator 1 according to Embodiment 2 and observed the output voltage of the high voltage generator 1 with an oscilloscope. Here, the oscillation frequency of the timer IC 3 of the high voltage generation unit 120 is 15.1 kHz, the oscillation frequency of the timer IC 114 of the control unit is 13.6 Hz, the duty ratio of the timer IC 114 of the control unit is 72% (ON state), Each power supply voltage is set to 9V.

  As is apparent from FIG. 7, the control signal 130 output from the control unit 110 is “high” immediately after the switch SW is turned on until a predetermined time elapses, and the output voltage Immediately rises immediately after the switch SW is turned on and rises to about 1.8 kV. When a predetermined time set by the timer circuit 111 elapses immediately after the switch SW is turned on, the control signal 130 becomes a modulation signal output from the modulation signal generation circuit 112, and the output voltage is the control signal. The signal becomes an on / off modulated signal according to 130, and a DC high voltage of about 1.8 kV can be obtained.

  Further, when the current consumption and power consumption of the high voltage generator 1 were measured, they were 92 mA / 0.80 W and 48 mA / 0.42 W, respectively, during the continuous operation at the start-up and during the intermittent operation, which is the normal operation. It was found that the electric power was almost halved. In the second embodiment, although the output voltage can be increased to about 1.8 kV which is twice that of the first embodiment, the power consumption can be greatly reduced. The current consumption of the high voltage generator 1 was measured by inserting a shunt resistor of about 2.2Ω between the positive side of the DC power supply 2 and this circuit and observing the potential difference with two probes of an oscilloscope.

  In the high voltage generator 1 according to the first embodiment, the output voltage is about 0.9 kV, whereas in the second embodiment, the output voltage is as high as about 1.8 kV. The reason is that the oscillation frequency of the general-purpose timer IC3 of the high voltage generator 120 is increased from 6.5 kH in the first embodiment to 15.1 kH. By increasing the oscillation frequency of the general-purpose timer IC3 of the high voltage generator 120, the boosting rate is improved by about 17%, and the oscillation called Keen that was heard when the oscillation frequency of the general-purpose timer IC3 was 6.5 kHz. I can no longer hear the sound.

  Since other configurations and operations are the same as those of the first embodiment, description thereof is omitted.

  The electrostatic chuck of the present invention can be used in various substrate processing apparatuses used in a semiconductor manufacturing process, a liquid crystal manufacturing process or the like as long as it is an apparatus that emits light energy when processing a predetermined substrate. In particular, since the electrostatic chuck of the present invention can attract and hold a substrate without using an external power source, for example, it can be moved and transported while the substrate is attracted, and is conventionally used in a substrate processing apparatus. There is a possibility of creating a new usage mode without being limited to the use of the electrostatic chuck.

  The present invention relates to an electrostatic chuck used for holding a substrate of a semiconductor manufacturing apparatus, an exhibition / posting apparatus using a function of electrostatic chuck, a sterilization / sterilization apparatus, a dust collector that collects dust and dirt in the air, or The present invention relates to a high-voltage generator that generates a high voltage to be supplied to various devices, such as a growth device that promotes the growth of vegetation such as plants and mushrooms. In particular, a high voltage of the order of several kV using a solar cell or battery as an input power source The present invention relates to a DC-DC conversion high voltage generator that is small, light, and consumes very little power.

  1: high voltage generator, 2: low voltage power supply, 3: self-excited oscillation circuit, 5: amplifier circuit, 6, 8: rectifier circuit, 7, 9: output terminal.

Claims (5)

A high voltage generation circuit for amplifying a high frequency signal output from an oscillation circuit driven by a low voltage power source and generating a high voltage using a high frequency transformer;
A boost rectifier circuit that boosts the high voltage generated by the high voltage generator circuit while rectifying the high voltage;
An electrostatic chuck as a capacitive load to which a high voltage boosted while being rectified by the boost rectifier circuit is applied and a discharge resistor is connected in parallel;
At the time of start-up, the oscillation circuit is directly driven by the low-voltage power supply, and after a predetermined time has elapsed since the start-up, the oscillation circuit is made to have a capacitance of the electrostatic chuck and a resistance of the discharge resistor. A control circuit that controls to drive intermittently at a cycle shorter than the time constant determined by the value;
A high voltage generator for an electrostatic chuck, comprising:   The high voltage generator for an electrostatic chuck according to claim 1, further comprising a resistor for applying a predetermined high voltage to a load connected in series between the rectifier circuit and the output terminal.   The low voltage power source includes at least one of a solar cell, a dry cell, a secondary battery, and a fuel cell, and the supply voltage of the low voltage power source is 3 to 15 V and the average supply current is 10 to 100 mA. The high voltage generator for electrostatic chucks according to claim 1 or 2.   4. The high voltage generator for an electrostatic chuck according to claim 1, wherein an oscillation frequency of the oscillation circuit is 1 to 20 kHz.   At least one first high-frequency transformer for generating a positive high voltage and one second high-frequency transformer for generating a negative high voltage, the first and second high-frequency transformers One of the primary side windings is connected in parallel to the collectors of a plurality of Darlington-connected transistors constituting the amplifier circuit, and the other of the secondary side windings of the first and second high-frequency transformers is common. The high voltage generator for an electrostatic chuck according to claim 1, wherein the high voltage generator is connected to a ground potential of the electrostatic chuck.

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