JPH08250579A - Power source for electrostatic chuck of manufacture of semiconductor and manufacture of the semiconductor - Google Patents

Abstract

PURPOSE: To provide a power source for electrostatically chucking to effectively discharge the stored charge of an electrostatic chuck to effectively release a semiconductor wafer at the time of releasing even if there is a difference of small charging characteristics of semiconductor wafers. CONSTITUTION: At the time of releasing a semiconductor wafer, the characteristics of the wafer is considered, a desired vibration waveform signal from a vibration waveform signal generator 118 and a desired attenuation waveform signal from an attenuation waveform signal generator 120 are combined by a multiplier 117 to selectively generate a desired attenuating vibration waveform, the output of a power source for the chuck is fed back by an output divider 104 and a subtracter 111, controlled to be fed back by a closed loop between control input signal and the output, and the voltage of the accurate attenuation vibrating waveform is output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and more particularly to an electrostatic chuck power supply for an electrostatic chuck that electrostatically attracts and fixes a semiconductor wafer.

[0002]

2. Description of the Related Art As an example of this type of semiconductor manufacturing apparatus, there is a plasma processing apparatus. FIG. 9 shows the structure of the electrode provided with the electrostatic chuck of the plasma processing apparatus. FIG. 9 (a)
Shows a monopolar type electrostatic chuck, and (b) shows a bipolar type electrostatic chuck.

In FIG. 9, 50, 50a and 50b are equivalently shown electrostatic chuck power supplies, 51, 51a and 5
Reference numeral 1b represents a plasma discharge electrode in a vacuum chamber (not shown) of the plasma processing apparatus. Reference numeral 52 is a ceramic electrostatic chuck in which titanium oxide is added to alumina ceramic, 53 is a semiconductor wafer electrostatically attracted to the electrostatic chuck 52, and 54 is an equivalent resistance of plasma.
(Rp) is shown.

Next, the conventional operation will be described with reference to the waveform chart of FIG. In such a configuration, the plasma chuck electrodes 51, 51a, 51b provided with the electrostatic chuck 52 are connected to the electrostatic chuck power supplies 50, 50a, 50b as shown in FIG.
Applied voltage as shown in (a) (about -500 to -1000V)
Is given, an electrostatic force (Coulomb force) works between the semiconductor wafer 53 and the electrostatic chuck 52, and the semiconductor wafer 53 is attracted to the electrostatic chuck 52. As a result, the semiconductor wafer 53 is firmly and firmly fixed to the plasma discharge electrodes (lower electrodes) 51, 51a, 51b provided with the electrostatic chuck 52.

Usually, a thin groove is formed on the contact surface,
An inert gas such as He is flowed to uniformly cool the semiconductor wafer. In order to measure the uniformity of temperature distribution on the surface of the semiconductor wafer, it is also necessary to make the attraction force of the electrostatic chuck uniform. Usually, the electrostatic force (Coulomb force) is expressed by the following equation.

F = (1/2) ・ ε ・ (V / d) ² (1)

Here, F is the attractive force, ε is the dielectric constant, V is the applied voltage, and d is the interval. In addition to the Coulomb force, it is generally said that the electrostatic chuck has an attracting force due to the leak current of the electrostatic chuck (Johnson, Rahbeck force). Therefore, a larger suction force than that obtained by the equation (1) is obtained.

Next, the suction force is released to release the semiconductor wafer 53.
When disconnecting, the power supply output is first short-circuited as shown in FIG. 10B, and then the reverse polarity, as shown in FIG.
That is, a positive voltage is applied here. FIG. 10 (c)
Indicates a change in the suction force from the time when the semiconductor wafer 53 is sucked up to the time when the semiconductor wafer 53 is released.

At the time of disengagement, JP-A-62-44332, JP-A-1-112745 and JP-A-4-11432
As disclosed in Japanese Patent No. 246843, there is also a method of applying a voltage of damped oscillation. Further, JP-A-5-7492
Japanese Unexamined Patent Publication No. 0 (1999) describes a method in which a conductor is connected to a semiconductor wafer and an electrode, and these are drawn out of the chamber and connected via a resistor to discharge electric charges and facilitate separation.

[0010]

SUMMARY OF THE INVENTION In the conventional electrostatic chuck power source as described above, -500 to -1000 during adsorption.
A voltage of V (the polarity may be positive or negative, but a negative polarity is often used in plasma processing apparatuses) is applied to cause adsorption, and after etching or the like is completed, the power supply output is short-circuited and the reverse The polarity, in this case positive polarity, is applied to cancel the charge charge in the electrostatic chuck.
This is because it is difficult to set the reverse polarity application time, and if it is too long, the attraction force will be generated again. The part A of the characteristic curve in FIG. 10C shows this. As described above, there is a problem that it is difficult to control the reverse polarity application time at the time of detachment due to the minute difference in the characteristics of the adsorbate (here, the semiconductor wafer).

Further, as in JP-A-5-74920, when a semiconductor wafer and an electrode are connected to a conductive wire and these are drawn out of the chamber and connected to discharge electric charges, an electric wire is placed in the chamber. There is a problem that it is necessary to pull in the wire, the noise may be picked up by this conducting wire, and a malfunction may occur, and the structure of the semiconductor manufacturing apparatus becomes complicated.

The present invention has been made in order to solve the above-mentioned problems, so that even if there is a slight difference in the charging characteristics between the adsorbed material, that is, the semiconductor wafer, the separation can be reliably performed at the time of separation. An object of the present invention is to provide a power supply for an electrostatic chuck that discharges the charge of the electrostatic chuck.
Another object of the present invention is to provide a semiconductor manufacturing apparatus capable of controlling the charge from the outside of the chamber without extracting an electric charge from the electrostatic chuck without using an electric wire.

[0013]

In view of the above-mentioned object, the first invention of the present invention provides a dielectric material among a pair of upper and lower electrodes provided facing each other in a vacuum chamber of a semiconductor manufacturing apparatus. A voltage is applied to the lower electrode provided so as to intervene between the electrostatic chuck consisting of
A power supply for an electrostatic chuck of a semiconductor manufacturing apparatus, which attracts and separates a semiconductor wafer by charging and discharging the electrostatic chuck, which is a DC main power supply and switching power for opening and closing the DC main power supply. A transistor, a step-up transformer that steps up the input of the power transistor, a rectifying / polarity switching section that rectifies the output of the step-up transformer and switches the polarity, and a filter circuit section that smoothes the rectified output of the rectifying / polarity switching section. And a power supply circuit section for applying the output voltage of the filter circuit section to the upper electrode and the lower electrode, an output short circuit section for short-circuiting the output of the power supply circuit section, and on / off control of the switching power transistor. A PWM control amplifier for performing the above, and a vibration waveform signal generator that selectively generates a plurality of vibration waveform signals,
A damping waveform signal generation unit that selectively generates a plurality of damping waveform signals, a multiplication unit that multiplies the vibration waveform signal and the damping waveform signal to generate a damping vibration signal, and a predetermined suction for suction during the suction. A time control signal and a damping vibration signal of the multiplying unit at the time of the separation, respectively, and a polarity for performing polarity switching of the rectification / polarity switching unit according to the output of the signal switching unit and the signal switching unit. The electrostatic chuck power supply for a semiconductor manufacturing apparatus includes a switching control unit and a negative feedback circuit unit that negatively feeds back the output of the power feeding circuit unit as an input of the PWM control amplifier.

The second invention of the present invention is characterized by further comprising a dead zone generating section for keeping the output at zero potential for a predetermined time at the output polarity switching point of the step-up transformer. It is in the power supply for the electrostatic chuck of the semiconductor manufacturing apparatus described.

According to a third aspect of the present invention, an upper electrode and a lower electrode are provided so as to face each other, and a semiconductor wafer is electrostatically attracted to the lower electrode by being charged and discharged. , An electrostatic chuck to be detached, an optical switching element that electrically short-circuits the lower electrode and the electrostatic chuck, a chamber that houses each of the parts, and on / off control of the optical switching element from outside the chamber. The semiconductor manufacturing apparatus is provided with a transparent window portion provided in the chamber for supplying a light control signal to be generated and a light emitting portion provided outside the chamber for generating the light control signal.

According to a fourth aspect of the present invention, the electrostatic chuck is electrically connected to the optical switching element.
4. The semiconductor manufacturing apparatus according to claim 3, wherein the surface of the electrostatic chuck is provided with a discharge electrode having a shape that spreads uniformly.

A fifth aspect of the present invention is a DC main power source,
A switching power transistor that opens and closes the DC main power source, a step-up transformer that steps up the input of the power transistor, a rectification / polarity switching unit that rectifies the output of the step-up transformer and switches the polarity, and the rectification / polarity switching. A filter circuit unit that smoothes the rectified output of the unit, a power supply circuit unit that applies the output voltage of the filter circuit unit to the upper electrode and the lower electrode, and an output short-circuit unit that short-circuits the output of the power supply circuit unit, A PWM control amplifier that performs on / off control of the switching power transistor, a vibration waveform signal generation unit that selectively generates a plurality of vibration waveform signals, and an attenuation waveform signal that selectively generates a plurality of attenuation waveform signals. A generation unit, a multiplication unit that multiplies the vibration waveform signal and the damping waveform signal to generate a damping vibration signal, and a predetermined adsorption unit for adsorption during the adsorption. A signal switching unit that supplies the arrival control signal and the damping vibration signal of the multiplication unit to the PWM control amplifier at the time of departure and polarity switching of the rectification / polarity switching unit according to the output of the signal switching unit. 5. An electrostatic chuck power supply comprising: a polarity switching control unit; and a negative feedback circuit unit that negatively feeds back the output of the power feeding circuit unit as an input of the PWM control amplifier. The semiconductor manufacturing apparatus described in 1.

[0018]

According to the first aspect of the present invention, it is possible to select and generate an output of a desired damping vibration waveform in consideration of the characteristics of the semiconductor wafer when the semiconductor wafer is detached, and to output the output of the electrostatic chuck power supply. Is fed back to form a closed loop with the control input signal and feedback control is performed, whereby a more accurate voltage having a damped oscillation waveform can be output.

According to the second aspect of the present invention, a dead zone is provided at the point where the vibration of the damping vibration signal switches between positive and negative at the time of leaving, and the polarity on the output side is switched at the time of this dead zone, so that the transient occurs. The control of the period can be stabilized.

In the third aspect of the present invention, since an optical switching element which can be controlled by light is used as an element for forcibly short-circuiting the electrostatic chuck and the lower power source, light is incident from the outside of the chamber. By doing so, it is possible to control the discharge of the electrostatic chuck without pulling an electric wire into the chamber, thus preventing malfunction of the short-circuit element, and the structure of the semiconductor manufacturing apparatus. Is never complicated.

According to a fourth aspect of the present invention, the surface of the electrostatic chuck on which the semiconductor wafer is adsorbed is provided with a discharge electrode which spreads uniformly on this surface, and an optical switching element is connected to this to form an optical switching element. Since the electrostatic chuck and the lower electrode are forcibly short-circuited by making the conductive state, the charged charges of the electrostatic chuck can be efficiently and uniformly discharged, and the semiconductor wafer can be reliably removed. .

According to a fifth aspect of the present invention, in a semiconductor manufacturing apparatus provided with an optical switching element for short-circuiting an electrostatic chuck and a lower power source, the electrostatic chuck power source is according to the present invention, and after the semiconductor wafer is attracted, When the power supply is short-circuited, the short-circuiting contact is closed to short-circuit the power output of the electrostatic chuck power supply, and at the same time, the optical switching element is also turned on to short-circuit the electrostatic chuck and the lower electrode, so that electrostatic charging can be performed more efficiently and accurately. Let the electric chuck discharge.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. Example 1. FIG. 1 is a diagram showing the configuration of a semiconductor manufacturing apparatus equipped with a power supply for an electrostatic chuck according to an embodiment of the present invention. Here, a plasma processing apparatus will be described as an example.
In FIG. 1, 1 is a semiconductor manufacturing apparatus, 2 is a vacuum chamber, 3 is an upper electrode that also serves as a reaction gas supply port 8, 4 is a lower electrode, 5 is an electrostatic chuck provided on a lower electrode 4, and 6 is a semiconductor. Wafer, 7 is bellows, 9 is an exhaust port, 10 is a power source for electrostatic chuck, 11 is a matching unit, and 12 is a coaxial gable.

FIG. 2 shows the electrostatic chuck power supply 1 of FIG.
1 shows an example of the configuration of No. 0, in particular, it is possible to generate an output of a desired damping vibration waveform in consideration of the characteristics of the semiconductor wafer when the semiconductor wafer is separated, and feedback control the output of the electrostatic chuck power supply 10. It is characterized by outputting a more accurate damped oscillation waveform voltage. These are basically all configured by hardware (not controlled by a program such as a microcomputer described later).

In FIG. 2, 101 is a DC main power source, 10
Reference numeral 2 is a switching power transistor, 103 is a step-up transformer, 104 is an output division circuit including two voltage dividing resistors 104a and 104b for feeding back a high voltage output voltage, 105 is a resistor 105a for smoothing a switching frequency and two capacitors. Reference numeral 106b denotes a filter circuit, 106 denotes a short-circuit contact for short-circuiting the output terminal 130 of the electrostatic chuck power supply 10, and 10
Reference numerals 7, 108a and 108b denote a switch and a diode for rectifying the output of the step-up transformer 103 and switching the polarity. The switch 107 that switches the polarity on the output side can be realized by a semiconductor switch, a reed relay, a mercury relay, or the like. If the vibration cycle can be delayed, a normal relay may be used.

Reference numeral 110 denotes a PWM control amplifier for performing on / off control of the switching power transistor 102,
Reference numeral 111 is a subtraction element for performing subtraction between the control signal and the feedback signal from the output division circuit 104, and 112 is a control input for stabilizing the polarity switching transition period, which includes a pair of diodes 112a and 112b connected in antiparallel. A dead band generation circuit for creating a dead band of the above, and 113 is a high voltage side polarity switching controller for switching and controlling the switch 107 in accordance with a control signal from a buffer amplifier 114 described later.

Reference numeral 114 is a buffer amplifier for input control of the high-voltage power supply, 115 is a switching gate section for switching between the suction-time control signal C at the time of suction and the damping vibration signal D at the time of separation, 116a,
Reference numeral 116b is an analog switch that performs switching under the control of the switching gate unit 115, 116c and 116d are resistors, and 117 is a multiplier. Reference numeral 118 is a vibration waveform signal generator for generating various vibration waveform signals, 119 is a selection switch for selecting these vibration waveform signals, 120 is an attenuation waveform signal generator for generating various attenuation waveform signals, and 121 is these attenuation waveform signals. Is a selection switch.

The damped vibration signal D is the vibration waveform signal generator 1
The vibration waveform signal of 18 and the attenuation waveform signal of the attenuation waveform signal generator 120 can be obtained by passing through the multiplier 117. At the time of disengagement, this damping vibration signal D becomes a control input signal to the switching power supply of the electrostatic chuck. The damping vibration signal D selected as the control input signal by the switching gate unit 115 is subtracted from the subtraction element 111 via the buffer amplifier 114 and the like.
Is input to

In the subtraction element 111, feedback control is performed, and the damping vibration signal D is subtracted from the signal fed back from the output side. Then, the PWM control amplifier 110 supplies the power module (power module) to the power transistor 102. It is output as a signal for PWM). Thereby, the pulse width is controlled by the power transistor 102, and the output voltage from the output terminal 130 is controlled to be the same as the damping vibration signal D.

The switch 107 and the diode 1
08a and 108b configure a rectification / polarity switching unit, the filter circuit 105 configures a filter circuit unit, and the output terminal 13
0, the matching device 11 and the coaxial gable 12 of FIG. 1 form a power supply circuit unit, the short-circuiting contact 106 forms an output short-circuiting unit, the vibration waveform signal generator 118 and the selection switch 11
Reference numeral 9 constitutes a vibration waveform signal generator.

Further, the decay waveform signal generator 120 and the selection switch 121 constitute a decay waveform signal generation section, the multiplier 117 constitutes a multiplication section, and the switching gate section 115, analog switches 116a and 116b, resistors 116c and 11 are provided.
6d and the buffer amplifier 114 configure a signal switching unit, the polarity switching controller 113 configures a polarity switching control unit,
The output division circuit 104 and the attenuation element 111 constitute a negative feedback circuit section.

Next, the operation will be described with reference to the waveforms shown in FIG. (a) is an output voltage waveform of the electrostatic chuck power supply 10. The rise at the time of adsorption is shown in two stages,
This is because the charging current to the electrostatic chuck 5 is suppressed.
(b) shows the waveform of the adsorption control signal C, and the output of the electrostatic chuck power supply 10 during adsorption follows this waveform.

(C) shows the short-circuit contact 1 in order to quickly discharge the charge of the electrostatic chuck 5 after the adsorption is completed.
This is a power output short circuit signal for closing 06 to short the power output. This is effective when used in combination with the one that directly short-circuits the electrostatic chuck body described in the third embodiment.

After that, in the release sequence, the vibration waveform signal of the vibration waveform signal generator 118 of (d) and the attenuation waveform signal of the attenuation waveform signal generator 120 of (e) are multiplied by the multiplier 117, The damped vibration signal D of (f) can be produced. At this time, the vibration waveform signal of the vibration waveform signal generator 118 and the attenuation waveform signal of the attenuation waveform signal generator 120 are respectively selected by the selection switches 119 and 121.
For example, a desired one can be selected in consideration of the charging characteristics of the semiconductor wafer 6.

The vibration waveform signal generator 118 generates a plurality of kinds of vibration signals such as a sine wave, a rectangular wave, and a triangular wave, and the attenuation waveform signal generator 120 also includes a plurality of kinds such as linear damping and exponential damping. Generated attenuated signals and can be selected from these combinations.

(G) relates to the dead zone generating circuit 112, which will be described in the second embodiment. (h) is a polarity switching signal for switching the polarity on the output side, which is obtained by determining the positive or negative polarity of the damping vibration signal, and the polarity switching controller 113 determines the polarity of the damping vibration signal. The signal as shown is output to the switch 107.

In FIG. 4, when the vehicle is disengaged as in this embodiment,
The waveform diagram at the time of applying the applied voltage of a desired damping vibration signal waveform to a lower electrode is shown. (a) shows the applied voltage, (b) shows the timing of the power supply output short circuit, and (c) shows the attraction force. By applying the applied voltage of the damping vibration signal waveform of the desired waveform,
As shown in (c), the suction force will not be generated again.

The electrostatic chuck power source 10 shown in FIG.
Is basically composed of hardware, but the portions of the vibration waveform signal generator 118, the damping waveform signal generator 120, the selection switches 119 and 121, and the multiplier 117 are generated as shown in FIG. 5, for example. It may be configured by a microcomputer 30 with a built-in program and a D / A converter 31 which converts a digital signal output from the microcomputer 30 into an analog signal.

An algorithm equivalent to an arbitrary function generator commonly called a function generator may be realized by software of the microcomputer 30 and the digital value may be output via the bipolar type D / A converter 31.

As described above, in this embodiment, when the semiconductor wafer is detached, a desired damping vibration waveform output can be selected and generated in consideration of the characteristics of the semiconductor wafer, and the electrostatic chuck power supply Feed back the output,
By performing a feedback control by forming a closed loop with the control input signal, it is possible to output a voltage with a more accurate damping vibration waveform, so that the attracting force does not occur again and the desorption can be performed reliably. .

Example 2. This embodiment particularly relates to the dead zone generating circuit 112 of FIG. A dead band is provided at the positive / negative switching point of the damping vibration signal D by the dead band generation circuit 112 including the diodes 112a and 112b connected in anti-parallel. The signal is shown in FIG. This requires polarity switching on the output side by the polarity switching controller 113, the switch 107, and the diodes 108a and 108b. During this polarity switching, the control input signal is set to zero, and the polarity switching on the output side is surely completed. After that, by inputting the control input signal, the reliability and safety of the operation are ensured.

As described above, in this embodiment, at the time of separation,
By providing a dead zone at the point where the vibration switches to positive and negative, and switching the polarity of the output side at the time of this dead zone,
It is possible to stabilize the control during the transition period.

Example 3. FIG. 6 shows an equivalent circuit for the electrostatic chuck in the vacuum chamber of the plasma processing apparatus. C
c and Rc are the capacitance and resistance of the electrostatic chuck 52, Cw,
Rw represents the capacity and resistance of the adsorbate (here, the semiconductor wafer 53). Rp is the equivalent resistance of plasma discharge.

As shown in this circuit, if the output of the electrostatic chuck power supply 50 is short-circuited by the short-circuiting contact 106 after charging, it takes time to discharge the charge at both ends of the capacitance Cc of the electrostatic chuck 52. Takes. Further, the resistance Rc of the electrostatic chuck 52 is required to have a large value (about 100 MΩ).
This is because it is necessary to make the resistance Rc larger than the resistance Rw of the semiconductor wafer 53, reduce the voltage applied to the resistance Rw, and suppress the charge-up of the semiconductor wafer 53.

Since charging / discharging is performed through the electrostatic chuck power supply 50, the semiconductor wafer 53, and the equivalent resistance Rp of plasma discharge, it is difficult to shorten the discharge time only by short-circuiting the power supply during discharging. Therefore, a semiconductor manufacturing apparatus that improves this will be described below.

FIG. 7 is a diagram showing the structure of a semiconductor manufacturing apparatus according to another embodiment of the present invention. 7, parts that are the same as or correspond to those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. In the semiconductor manufacturing apparatus 1a of this embodiment,
An optical switching element 13 for electrically short-circuiting the electrostatic chuck 5 and the lower electrode 4 is provided in the vacuum chamber 2. When the optical switching element 13 is installed in the vacuum chamber 2 for plasma processing, it must be covered with a plasma-resistant ceramic cover 14 or the like.

Further, the vacuum chamber 2 is provided with a transparent window portion 2a for guiding an optical control signal for controlling ON / OFF of the optical switching element 13 from the outside of the chamber. Then, by generating a light control signal from the light emitting element 15 which is a light emitting section provided outside the vacuum chamber 2, this is sent to the optical switching element 13 through the window 2a, and the optical switching element 13 is electrostatically charged. The chuck 6 and the lower electrode 4 are short-circuited, and the electrostatic chuck 6 is forcibly discharged.

A resistor may be inserted in the optical switching element 13 in order to limit the inrush current of the discharge current.
Further, FIG. 7 shows the electrostatic chuck power supply 10 according to the present invention described in the previous embodiment as the electrostatic chuck power supply, but is not limited to this.

As described above, in this embodiment, since the optical switching element which can be controlled by light is used as the element for forcibly short-circuiting the electrostatic chuck and the lower electrode, the light is emitted from the outside of the chamber. It is possible to perform control by making it incident, and thereby it is possible to control the discharge of the electrostatic chuck without pulling an electric wire into the chamber, and thus it is possible to prevent malfunction of the element for short circuit, and the structure of the semiconductor manufacturing apparatus. Is never complicated.

Example 4. This embodiment relates to the electrostatic chuck of the semiconductor manufacturing apparatus of the above-mentioned fourth embodiment, and particularly to a structure for more efficient discharge. 8A and 8B show the structures of the electrostatic chuck 5a and the lower electrode 4 according to this embodiment. FIG. 8A is a partial sectional view and FIG. 8B is a perspective view. As can be seen from the figure, a discharge electrode is formed on the surface of the electrostatic chuck 5a on which the semiconductor wafer is adsorbed, by forming a thin conductor of carbon or stainless steel whose coefficient of thermal expansion is close to that of the electrostatic chuck 5a by vapor deposition or the like. 57 is formed,
One of the optical switching elements 13 is connected to this.

The discharge electrode 57 is of a mesh type in which conductors extend radially and annularly from the center of the electrostatic chuck 5a so as to spread uniformly on the surface of the electrostatic chuck 5a. Then, if the optical switching element 13 is turned on,
The electrostatic chuck 5a is efficiently and uniformly discharged at once.

The discharge electrodes are shown in FIGS. 8 (c) and 8 (d).
It may be one that covers the entire surface of the electrostatic chuck 5a, like the discharge electrode 58 shown in FIG. Further, the discharge electrode is not limited to this shape, and may be any shape as long as it uniformly spreads on the surface of the electrostatic chuck 5a for attracting the semiconductor wafer.

As described above, according to this embodiment, on the surface of the electrostatic chuck 5a on which the semiconductor wafer is adsorbed, the discharge electrodes 57 and 58 that are uniformly spread on this surface are provided, and the optical switching element 13 is attached thereto. Connect the optical switching element 1
Since the electrostatic chuck 5a and the lower electrode 4 are forcibly short-circuited by making 3 electrically conductive, the charged charges of the electrostatic chuck 5a can be discharged efficiently and uniformly, and by extension, a reliable semiconductor. The wafer can be detached.

Example 5. In this embodiment, in the semiconductor manufacturing apparatus 1a shown in FIG. 7 provided with the optical switching element 13 for short-circuiting the electrostatic chuck 5 and the lower power source 4, the electrostatic chuck power source 10 shown in FIG. To do. When the power supply is short-circuited after the semiconductor wafer is sucked as shown in FIGS. 3 and 4, the short-circuit contact 106 shown in FIG.
Is also turned on (conduction state), and electrostatic chucks 5 and 5a and lower electrode 4 are turned on.
By short-circuiting, the electrostatic chucks 5 and 5a can be discharged more efficiently and accurately.

[0055]

As described above, in the first aspect of the present invention, it is possible to select and generate a desired damping vibration waveform output in consideration of the characteristics of the semiconductor wafer when the semiconductor wafer is separated. By feeding back the output of the electrostatic chuck power supply and forming a closed loop with the control input signal to perform feedback control, it is possible to output a more accurate voltage of the damping vibration waveform. It is possible to provide an electrostatic chuck power supply capable of more reliable and stable detachment without variation in the detachment time.

Further, in the second aspect of the present invention, at the time of departure, a dead zone is provided at the point where the vibration of the damping vibration signal switches between positive and negative, and the polarity on the output side is switched at the time of this dead zone, so that the transient occurs. It is possible to provide a stable power supply for the electrostatic chuck, and to provide a more reliable and stable power supply for the electrostatic chuck without variation in the separation time.

Further, in the third aspect of the present invention, as an element for forcibly short-circuiting the electrostatic chuck and the lower power source,
Since an optical switching element that can be controlled by light is used, it can be controlled by entering light from the outside of the chamber, which controls the discharge of the electrostatic chuck without pulling an electric wire into the chamber. It is possible,
Therefore, it is possible to prevent the malfunction of the short-circuit element and to provide the semiconductor manufacturing apparatus having a simple structure.

According to the fourth aspect of the present invention, the surface of the electrostatic chuck on which the semiconductor wafer is adsorbed is provided with a discharge electrode which spreads uniformly on this surface, and an optical switching element is connected to this electrode for optical switching. Since the electrostatic chuck and the lower electrode are forcibly short-circuited by making the element conductive, it is possible to discharge the electrostatic chuck charge efficiently and evenly, and to reliably separate the semiconductor wafer. It is possible to obtain effects such as providing a semiconductor manufacturing apparatus capable of performing the above.

According to a fifth aspect of the present invention, in a semiconductor manufacturing apparatus provided with an optical switching element for short-circuiting an electrostatic chuck and a lower power source, the electrostatic chuck power source is according to the present invention, and after chucking a semiconductor wafer. When the power supply is short-circuited, the short-circuiting contact is closed to short-circuit the power output of the electrostatic chuck power supply, and at the same time, the optical switching element is also brought into the conducting state to short-circuit the electrostatic chuck and the lower electrode, thereby further improving efficiency and reliability. It is possible to obtain effects such as providing a semiconductor manufacturing apparatus capable of causing the electrostatic chuck to discharge.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a semiconductor manufacturing apparatus including an electrostatic chuck power supply according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of the configuration of the electrostatic chuck power supply of FIG.

FIG. 3 is a waveform diagram for explaining the operation of the electrostatic chuck power supply in FIG.

FIG. 4 is a waveform diagram for explaining a suction force of the electrostatic chuck power supply of FIG.

FIG. 5 is a diagram showing a configuration when a part of the electrostatic chuck power supply in FIG. 2 is configured by software.

FIG. 6 is a diagram showing an equivalent circuit for an electrostatic chuck in a vacuum chamber of a plasma processing apparatus.

FIG. 7 is a diagram showing a configuration of a semiconductor manufacturing apparatus according to another embodiment of the present invention.

FIG. 8 is a diagram showing a structure of an electrostatic chuck and a lower electrode according to another embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of an electrode provided with an electrostatic chuck of a plasma processing apparatus.

FIG. 10 is a waveform diagram for explaining the operation of the conventional electrostatic chuck power supply.

[Explanation of symbols]

1, 1a Semiconductor manufacturing equipment, 2 Vacuum chambers, 2a
Window part, 3 upper electrode, 4 lower electrode, 5, 5a electrostatic chuck, 6 semiconductor wafer, 7 bellows, 8 supply port, 9
Exhaust port, 10 Power supply for electrostatic chuck, 11 Matching device,
12 coaxial cable, 13 optical switching element, 14
Cover, 15 light emitting element, 30 microcomputer with built-in waveform generation program, 31 D / A converter, 5
7, 58 short-circuit electrode, 101 DC main power supply, 102 switching power transistor, 103 step-up transformer, 104 output dividing circuit, 105 filter circuit, 1
06 short-circuit contact, 107 switch, 108a, 10
8b diode, 110 PWM control amplifier, 111
Subtraction element, 112 dead zone generation circuit, 113 polarity switching controller, 114 buffer amplifier, 115 switching gate section, 116a, 116b analog switch, 116
c, 116d resistance, 117 multiplier, 118 vibration waveform signal generator, 119, 121 selection switch, 120
Attenuated waveform signal generator, 130 output terminal.

Claims (5)

[Claims] 1. An electrostatic chuck made of a dielectric is provided between a pair of upper and lower electrodes facing each other in a vacuum chamber of a semiconductor manufacturing apparatus so as to be interposed between the electrostatic chuck and the semiconductor wafer. A power supply for an electrostatic chuck of a semiconductor manufacturing apparatus, which applies a voltage to a lower electrode to charge and discharge the electrostatic chuck to attract and separate a semiconductor wafer to and from the electrostatic chuck. A switching power transistor that opens and closes a DC main power supply, a step-up transformer that steps up the input of the power transistor, a rectifying / polarity switching unit that rectifies the output of the step-up transformer and switches the polarity, and the rectifying / polarity switching unit. A filter circuit unit for smoothing the rectified output of the power supply unit, a power supply circuit unit for applying an output voltage of the filter circuit unit to the upper electrode and the lower electrode, An output short circuit section for short-circuiting the output of the electric circuit section, a PWM control amplifier for on / off control of the switching power transistor, a vibration waveform signal generation section for selectively generating a plurality of vibration waveform signals, A damping waveform signal generating section for selectively generating the damping waveform signal, a multiplication section for multiplying the vibration waveform signal and the damping waveform signal to generate a damping vibration signal, When the control signal is released, the damping vibration signal of the multiplication unit is supplied to the PWM control amplifier, and the polarity switching of the rectification / polarity switching unit is performed according to the output of the signal switching unit. A power supply for an electrostatic chuck of a semiconductor manufacturing apparatus, comprising: a control unit; and a negative feedback circuit unit that negatively feeds back the output of the power feeding circuit unit as an input of the PWM control amplifier. 2. The semiconductor manufacturing apparatus according to claim 1, further comprising a dead zone generating unit that keeps the output at zero potential for a predetermined time at the output polarity switching point of the step-up transformer. Power supply for electric chuck. 3. An upper electrode and a lower electrode which are provided to face each other, and by being charged and discharged by being provided on the lower electrode,
An electrostatic chuck that electrostatically adsorbs and detaches a semiconductor wafer to and from this, an optical switching element that electrically short-circuits the lower electrode and the electrostatic chuck, a chamber that houses each of the above parts, and an external chamber ON / OFF of the optical switching element
A semiconductor manufacturing apparatus including: a transparent window portion provided in the chamber for supplying a light control signal for controlling off; and a light emitting portion provided outside the chamber for generating the light control signal. . 4. The electrostatic chuck comprises a discharge electrode electrically connected to the optical switching element, the discharge electrode having a shape that spreads uniformly on the surface of the electrostatic chuck. The semiconductor manufacturing apparatus described. 5. A DC main power supply, a switching power transistor that opens and closes the DC main power supply, a step-up transformer that steps up the input of the power transistor, and a rectifying / switching polarity of the output of the step-up transformer. A polarity switching unit, a filter circuit unit that smoothes the rectified output of the rectification / polarity switching unit, a power supply circuit unit that applies the output voltage of the filter circuit unit to the upper electrode and the lower electrode, and the power supply circuit unit. Output short-circuiting section for short-circuiting the output of, a PWM control amplifier for performing on / off control of the switching power transistor, a vibration waveform signal generating section for selectively generating a plurality of vibration waveform signals, and a plurality of damping waveforms A damping waveform signal generator that selectively generates a signal; a multiplier that multiplies the vibration waveform signal and the damping waveform signal to generate a damped vibration signal; In the case of adsorption, a predetermined adsorption control signal for adsorption, and a damping vibration signal of the multiplication unit during detachment are supplied to the PWM control amplifier, respectively, and the rectification / commutation according to the output of the signal switching unit. An electrostatic chuck power supply including a polarity switching control unit that switches the polarity of the polarity switching unit and a negative feedback circuit unit that negatively feeds back the output of the power feeding circuit unit as an input of the PWM control amplifier is provided. The semiconductor manufacturing apparatus according to claim 3 or 4, characterized in that.