JP2006080464A - Electrostatic chuck and processor using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic chuck which can attract a processing object such as a substrate by a simple constitution which does not require a dc power supply. <P>SOLUTION: The electrostatic chuck has a bias electrode 41, a negative pole 44 and a positive pole 45 which are disposed in opposition to the bias electrode and attract the processing object, a high frequency power supply 59 one terminal of which is connected to the bias electrode and the other terminal is subjected to ground connection, a first diode 46 whose anode terminal 46a is connected to a negative pole, a first variable capacitor 47 one terminal of which is connected to a cathode terminal 46b of the first diode and the other terminal is subjected to ground connection, a second diode 48 whose anode terminal 48a is connected to a positive pole and a second variable capacitor 49 one terminal of which is connected to a cathode terminal 48b of the second diode and the other terminal is subjected to ground connection. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrostatic chuck used for holding an object to be processed such as a substrate used in a manufacturing process of a semiconductor integrated circuit or a liquid crystal display device, and a processing apparatus using the same.

  In a manufacturing process of a semiconductor integrated circuit, a liquid crystal display device, or the like, an electrostatic chuck that fixes an object to be processed such as a substrate in a predetermined position using an electrostatic force may be used (for example, see Patent Document 1). ). The electrostatic chuck includes a bias electrode that applies a high-frequency voltage to an object to be processed, an insulating member that is provided on the bias electrode and insulates the bipolar electrode from the outside, and a predetermined distance from the bias electrode inside the insulating member. A bipolar electrode composed of a positive electrode and a negative electrode embedded in the open position is provided.

When a positive voltage and a negative voltage are respectively applied to the positive electrode and the negative electrode of the bipolar electrode, electrostatic induction is generated in the object to be processed due to the electric field generated from both electrodes, and an attractive force is generated between the electrostatic chuck and the object to be processed. Thus, the workpiece is attracted to the electrostatic chuck while the voltage is applied.
Japanese Patent Publication No. 5-87177

  However, since the conventional electrostatic chuck requires a DC power source for applying a DC voltage to the bipolar electrode, the apparatus configuration has become complicated and large.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrostatic chuck capable of adsorbing an object to be processed such as a substrate with a simple configuration that does not require a DC power supply, and the like. It is to provide a processing apparatus using the above.

  In order to solve the above problems and achieve the object, an electrostatic chuck and a processing apparatus using the same according to the present invention are configured as follows.

(1) A bias electrode, a first electrode and a second electrode for adsorbing an object to be processed, which are arranged opposite to the bias electrode, have two terminals, and one terminal is connected to the bias electrode. A first rectifier having a high-frequency power source having the other terminal connected to ground, a first anode terminal and a first cathode terminal, wherein the first anode terminal is connected to the first electrode And a first capacitor having one terminal connected to the first cathode terminal of the first rectifying terminal and the other terminal connected to the ground, a second anode terminal, and a second terminal A second rectifying means having two cathode terminals, the second anode terminal being connected to the second electrode, and two terminals, one terminal being the second rectifying means of the second rectifying means. 2 is connected to the cathode terminal and the other terminal is connected to the ground. Characterized by comprising a second capacitor that.

(2) The electrostatic chuck described in (1), wherein the first rectifying means and the second rectifying means are diodes.

(3) The electrostatic chuck described in (1), wherein the first capacitor and the second capacitor are variable capacitors.

(4) The electrostatic chuck described in (1), further comprising discharge means for discharging the charges stored in the first capacitor and the second capacitor. .

(5) The electrostatic chuck described in (1), further comprising an insulating member provided on the bias electrode and covering the first electrode and the second electrode.

(6) A chamber, an introduction port for introducing gas into the chamber, plasma means for converting the gas in the chamber into plasma, and an electrostatic chuck provided in the chamber for holding an object to be processed. The electrostatic chuck includes a bias electrode, a first electrode and a second electrode that are disposed opposite to the bias electrode, and holds and holds a workpiece, and two terminals. Is connected to the bias electrode, the other terminal is grounded, a first anode terminal and a first cathode terminal, and the first anode terminal is connected to the first electrode. A first capacitor having two terminals, one terminal connected to the first cathode terminal of the first rectifier terminal and the other terminal connected to ground, Second anode terminal and second Having a cathode terminal, the second anode terminal being connected to the second electrode, and two terminals, one terminal being the second of the second rectifier means. And a second capacitor connected to the ground terminal of the other terminal.

  According to the present invention, an object to be processed such as a substrate can be adsorbed with a simple configuration that does not require a DC power supply.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing a plasma CVD apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, this plasma CVD apparatus has a chamber 1 serving as a reaction chamber. In the side wall of the chamber 1, an introduction port 2 for introducing a processing gas into the chamber 1 and an exhaust port 3 for exhausting unreacted processing gas, generated gas and the like in the chamber 1 are formed.

  Further, an electrostatic chuck 4 for holding the workpiece W is provided inside the chamber 1, and the processing in the chamber 1 is located at a position facing the workpiece W held on the electrostatic chuck 4. A counter electrode 5 (plasma means) for applying a high-frequency voltage to the gas is provided.

  2 is a configuration diagram showing the electrostatic chuck 4 according to the embodiment, FIG. 3 is a plan view showing the bipolar electrode 43 according to the embodiment, and FIG. 4 is an equivalent of the electrostatic chuck 4 according to the embodiment. It is a circuit diagram which shows a circuit.

  As shown in FIG. 2, the electrostatic chuck 4 is provided on a bias electrode 41 that applies a high-frequency voltage V to a processing gas in the chamber 1 via a workpiece W, and an upper surface of the bias electrode 41. An insulating member 42 that insulates (described later) from the outside, and a bipolar electrode 43 embedded in the insulating member 42 at a position spaced from the upper surface of the bias electrode 41 by a predetermined distance.

  The bias electrode 41 has a disk shape, and a high frequency power supply 59 for applying a high frequency voltage V is connected to a predetermined position thereof. As the material of the bias electrode 41, a metal such as copper or aluminum is used.

  The insulating member 42 has substantially the same shape as the bias electrode 41 in plan view, and a flat suction surface 42a that sucks the workpiece W is formed on the upper surface thereof. As a material of the insulating member 42, polyimide or the like is used.

  As shown in FIG. 3, the bipolar electrode 43 includes a negative electrode 44 (first electrode) and a positive electrode 45 (second electrode). Thus, the negative electrode 44 and the positive electrode 45 constitute a first capacitor 50a and a second capacitor 50b together with the bias electrode 41, as shown in FIG. In addition, as a material of the negative electrode 44 and the positive electrode 45, metals, such as copper and aluminum, are used.

  A first diode 46 (first rectifier), a first variable capacitor 47, and a ground 60 are connected to a predetermined position of the negative electrode 44 in order from the negative electrode 44 side. What is important here is that the forward direction of the first diode 46 is directed from the negative electrode 44 side to the ground 60 side. In other words, the negative electrode 44 is connected to the anode terminal 46 a of the first diode 46, and the first variable capacitor 47 is connected to the cathode terminal 46 b of the first diode 46.

  For this reason, the first diode 46 is energized when the first capacitor 50a side is at a higher potential than the ground 60 side, and is cut off when the ground 60 side is at a higher potential than the first capacitor 50a side. The first variable capacitor 47 includes a discharge short-circuit switch 47a (discharge means).

  A second diode 48 (second rectifier), a second variable capacitor 49, and a ground 60 are connected to a predetermined position of the positive electrode 45 in order from the positive electrode 45 side. What is important here is that the forward direction of the second diode 48 is directed from the ground 60 side to the positive electrode 45 side. In other words, the positive electrode 45 is connected to the cathode terminal 48 b of the second diode 48, and the second variable capacitor 49 is connected to the anode terminal 48 a of the second diode 48.

  Therefore, the second diode 48 is energized when the second capacitor 50b side is at a lower potential than the ground 60 side, and is cut off when the ground 60 side is at a lower potential than the second capacitor 50b side. The second variable capacitor 49 includes a discharge short-circuit switch 49a (discharge means).

  Next, the operation of the electrostatic chuck 4 will be described with reference to FIG.

  FIG. 5 is an explanatory diagram illustrating a process in which the first and second capacitors 50a and 50b of the electrostatic chuck 4 according to the embodiment are charged.

  As shown in FIG. 5A, when the high frequency voltage V is generated from the high frequency power supply 59, the first capacitor 50a side has a higher potential than the ground 60 side in the first region R1 in which the high frequency voltage has a positive value. Therefore, the first diode 46 is energized, and a predetermined amount of charge is charged in the first capacitor 50a and the first variable capacitor 47 as shown in FIG. 5B (step S1).

  At this time, since the second capacitor 50b side has a higher potential than the ground 60 side, the second diode 48 is cut off and the second capacitor 50b and the second variable capacitor 49 are not charged. .

  In the second region R2 where the high-frequency voltage V has a negative value, the second capacitor 50b side is at a lower potential than the ground 60 side, so that the second capacitor 50b is in a normal state, as shown in FIG. As shown, a predetermined amount of charge is charged in the second capacitor 50b and the second variable capacitor 49 (step S2).

  At this time, since the first capacitor 50a side has a lower potential than the ground 60 side, the first diode 46 is cut off, and the first capacitor 50a and the first variable capacitor 47 are further charged. Absent. That is, the charge amount of the first capacitor 50a and the first variable capacitor 47 charged in step S1 is maintained.

  In the third region where the value of the high-frequency voltage V is a positive value, the first capacitor 50a side is at a higher potential than the ground 60 side, so that the first diode 46 is energized again, and FIG. ), A predetermined amount of electric charge is further charged in the first capacitor 50a and the first variable capacitor 47 (step S3).

  At this time, since the second capacitor 50b side is at a higher potential than the ground 60 side, the second diode 48 is cut off and the second capacitor 50b and the second variable capacitor 49 are not further charged. . That is, the charge amount of the second capacitor 50b and the second variable capacitor 49 charged in step S2 is maintained.

  In the fourth region R4 in which the value of the high frequency voltage is negative, the second capacitor 50b side is at a lower potential than the ground 60 side, so that the second capacitor 50b is energized again, and FIG. ), A predetermined amount of charge is charged in the second capacitor 50b and the second variable capacitor 49 (step S4).

  At this time, since the first capacitor 50a side has a lower potential than the ground 60 side, the first diode 46 is cut off and the first capacitor 50a and the first variable capacitor 47 are not charged. That is, the charge amount of the first capacitor 50a and the first variable capacitor 47 charged in step S3 is maintained.

  As described above, when the above steps S1 to S4 are repeated, the charge amounts of the first and second capacitors 50a and 50b gradually increase, and the voltage Va of the negative electrode 44 and the voltage of the positive electrode 45 after a predetermined time elapses. Each Vb reaches a desired value.

  Next, a processing method of the workpiece W by the plasma CVD apparatus equipped with the electrostatic chuck 4 will be briefly described.

  First, the workpiece W is placed on the attracting surface 42 a of the electrostatic chuck 4, and a high frequency voltage V is applied from the high frequency power supply 59 to the bias electrode 41. Thus, the voltages Va and Vb of the negative electrode 44 and the positive electrode 45 of the bipolar electrode 43 reach a predetermined voltage value through the above process, and an attracting force due to electrostatic induction is generated on the attracting surface 42a. The workpiece W placed on the attracting surface 42a is firmly attracted to the electrostatic chuck 4 by this attracting force.

  When the workpiece W is firmly adsorbed on the adsorption surface 42 a of the electrostatic chuck 4, the gas in the chamber 1 is discharged from the exhaust port 3 and the processing gas is introduced into the chamber 1 from the introduction port 2. The inside is adjusted to a predetermined pressure. Then, a high frequency voltage is applied to the processing gas from the counter electrode 5 to generate plasma in the chamber 1. As a result, the workpiece W is exposed to plasma, and the surface thereof is subjected to plasma processing such as etching and gas layer growth.

  When the surface of the workpiece W is subjected to plasma processing, unreacted processing gas or generated gas filled in the chamber 1 is exhausted from the exhaust port 3 and the discharge short-circuit switches 47a and 49a are closed. The charges stored in the first and second capacitors 50a and 50b and the first and second variable capacitors 47 and 49 are released, and the adsorption of the electrostatic chuck 4 to the workpiece W is released.

  Thus, the processing of the workpiece W by the plasma CVD apparatus equipped with the electrostatic chuck 4 is completed.

  Next, the effect of the plasma CVD having the above configuration will be described.

  According to the plasma CVD of the above configuration, the electrostatic chuck 4 of the type that applies the high frequency voltage V from the high frequency power source 59 to the bias electrode 41 and generates electrostatic induction between the insulating member 42 and attracts the workpiece W. , The negative electrode 44 and the ground 60 are connected through the first diode 46 and the first variable capacitor 47, and the positive electrode 45 and the ground 60 are connected through the second diode 48 and the second variable capacitor 49. ing.

  Therefore, only by applying a high frequency voltage from the high frequency power supply 59 to the bias electrode 41, the first and second capacitors 50a and 50b are charged to a desired charge amount after a predetermined time has elapsed. A DC power supply only for adsorbing is no longer necessary, and the apparatus configuration can be simplified and miniaturized.

  In addition, when a conventional DC power supply is used, since the charge amounts of the first and second capacitors 50a and 50b are fixed, there is a limit to the adsorption force for adsorbing the workpiece W. If the electrostatic chuck 4 is used, the adsorption force for adsorbing the workpiece W can be varied by adjusting the capacities of the first and second capacitors 50a and 50b.

  As a method of adjusting the capacitance of the first and second capacitors 50a and 50b, for example, the distance between the bias electrode 41 and the bipolar electrode 43, the size of the positive and negative electrodes 44 and 45 of the bipolar electrode 43, and the insulating member 42 are adjusted. It is conceivable to change the material type.

  The first and second variable capacitors 47 and 49 include discharge short-circuit switches 47a and 49a. Therefore, if the frequency of the high-frequency voltage applied to the bias electrode 41 is changed, the time required for the first and second capacitors 50a and 50b to reach a desired charge amount, that is, the time required for the adsorption of the workpiece W is increased. The processing efficiency of the workpiece W can be improved.

  Further, by adjusting the capacities of the first and second variable capacitors 47 and 49, the charge amounts of the first and second capacitors 50a and 50b, that is, the voltage values applied to the negative electrode 44 and the positive electrode 45 can be changed. Therefore, it is possible to set an optimum attractive force according to the type of the workpiece W and the type of processing without changing the voltage value applied to the bias electrode 41.

  Here, the experiment of the attractive force performed by the inventor will be described with reference to [Table 1] and [Table 2].

  [Table 1] shows the adsorption force of the workpiece when the voltage value of the high-frequency voltage is changed variously using the same method as that of the electrostatic chuck 4 according to the present embodiment, and [Table 2] shows the conventional technique. The chucking force of the object to be processed when the voltage value of the DC power supply is variously changed using the same method as that of the electrostatic chuck 4 is shown.

  The experimental conditions are as follows.

Workpiece: silicon wafer,
Distance between internal electrode and bias electrode: 0.225 [mm],
Environment: room temperature and vacuum,
Frequency of the high frequency voltage: 50 [Hz].

  Comparing [Table 1] and [Table 2], when the method of the electrostatic chuck 4 according to the present embodiment is used, a predetermined attracting force is obtained as compared with the case of using the method of the conventional electrostatic chuck 4. It can be seen that the voltage value required to obtain the value is less than half. From this experimental result, it can be seen that the workpiece W can be efficiently adsorbed by using the electrostatic chuck 4 according to the present embodiment.

  In the present embodiment, an example in which the electrostatic chuck 4 according to the present invention is mounted on a plasma CVD apparatus is described. However, any apparatus that processes a workpiece W such as a substrate by fixing it on a surface can be used. It is not particularly limited.

  In the present embodiment, in order to charge the negative electrode 44 and the positive electrode 45, the direction of charge movement is controlled using the first and second diodes 46 and 48. However, it is not limited to this.

  The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the spirit of the invention in the stage of implementation. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment.

The block diagram which shows the plasma CVD apparatus which concerns on one embodiment of this invention. The block diagram which shows the electrostatic chuck which concerns on the same embodiment. The top view which shows the bipolar electrode which concerns on the same embodiment. The circuit diagram which shows the equivalent circuit of the electrostatic chuck which concerns on the same embodiment. Explanatory drawing explaining the process in which the 1st, 2nd capacitor | condenser of the electrostatic chuck which concerns on the same embodiment charges.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Chamber, 2 ... Inlet, 4 ... Electrostatic chuck, 5 ... Counter electrode (plasma means), 41 ... Bias electrode, 42 ... Insulating member, 44 ... Negative electrode (1st electrode), 45 ... Positive electrode (2nd) ), 46... First diode (first rectification means), 46 a... Anode terminal (first anode terminal), 46 b... Cathode terminal (first cathode terminal), 47. 47a ... short-circuit switch (discharge means), 48 ... second diode (second rectification means), 48a ... anode terminal (second anode terminal), 48b ... cathode terminal (second cathode terminal), 49 ... first 2 variable capacitors, 49a ... short circuit switch (discharge means), 59 ... high frequency power supply, W ... workpiece.

Claims (6)

A bias electrode;
A first electrode and a second electrode disposed opposite to the bias electrode for adsorbing a workpiece;
A high frequency power source having two terminals, one terminal connected to the bias electrode and the other terminal connected to ground;
A first rectifier having a first anode terminal and a first cathode terminal, wherein the first anode terminal is connected to the first electrode;
A first capacitor having two terminals, one terminal connected to the first cathode terminal of the first rectifying terminal and the other terminal connected to ground;
A second rectifying means having a second anode terminal and a second cathode terminal, wherein the second anode terminal is connected to the second electrode;
A second capacitor having two terminals, one terminal connected to the second cathode terminal of the second rectifying means and the other terminal connected to ground;
An electrostatic chuck comprising:   2. The electrostatic chuck according to claim 1, wherein the first rectifying means and the second rectifying means are diodes.   2. The electrostatic chuck according to claim 1, wherein the first capacitor and the second capacitor are variable capacitors.   2. The electrostatic chuck according to claim 1, further comprising discharging means for discharging the charges stored in the first capacitor and the second capacitor.   The electrostatic chuck according to claim 1, further comprising an insulating member provided on the bias electrode and covering the first electrode and the second electrode. A chamber;
An inlet for introducing gas into the chamber;
Plasma means for converting the gas in the chamber into plasma,
An electrostatic chuck provided in the chamber and holding an object to be processed;
Comprising
The electrostatic chuck is
A bias electrode;
A first electrode and a second electrode disposed opposite to the bias electrode for adsorbing a workpiece;
A high frequency power source having two terminals, one terminal connected to the bias electrode and the other terminal connected to ground;
A first rectifier having a first anode terminal and a first cathode terminal, wherein the first anode terminal is connected to the first electrode;
A first capacitor having two terminals, one terminal connected to the first cathode terminal of the first rectifying terminal and the other terminal connected to ground;
A second rectifying means having a second anode terminal and a second cathode terminal, wherein the second anode terminal is connected to the second electrode;
A second capacitor having two terminals, one terminal connected to the second cathode terminal of the second rectifying means and the other terminal connected to ground;
A processing apparatus comprising:

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