JPH11111830A - Electrostatic sucking device and method, and method and device for treatment apparatus using them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic sucking device for sucking an insulating substrate like an LCD substrate surely to a supporting stage. SOLUTION: An electrostatic sucking device 10 for sucking an insulating substrate (S) is provided in a plasma formed space. The electrostatic sucking device 10 includes an insulating body 12 with an inner electrode 13, sucking member 11 for sucking the insulating substrate (S), and a DC power supply 21 for applying a DC voltage to an electrode 13. In a plasma formed space, the DC voltage is applied to the electrode 13. Then, the substrate (S) is sucked by the sucking member 11 through electrostatic force between the electrode 13 and charges generated from the plasma and accumulated on the substrate (S).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic attraction device and an electrostatic attraction method applied when performing a predetermined process on an insulating substrate such as an LCD substrate, and a processing apparatus and a processing method using the same. About.

[0002]

2. Description of the Related Art Conventionally, dry etching performed under a high vacuum has been adopted for etching a semiconductor wafer or an LCD substrate as a substrate to be processed. In dry etching, a substrate to be processed is placed in a chamber, plasma is formed in the chamber, and etching is performed by the plasma. In such a dry etching method, the etching characteristics greatly depend on the substrate temperature. Therefore, a coolant is passed through a substrate supporting member that supports the substrate to control the substrate temperature. A heat transfer gas such as He gas flows between the substrate and the substrate support member in order to improve the heat transfer efficiency of the refrigerant.

Meanwhile, the substrate must be fixedly supported on a substrate support member. For example, when the substrate to be processed is a semiconductor wafer, the semiconductor wafer is supported by an electrostatic force such as Coulomb force. 2. Description of the Related Art An electrostatic attraction device that is attracted and supported on a top is often used. On the other hand, in the case of an LCD substrate, since the substrate is an insulator, it cannot be electrostatically adsorbed on the same principle as a semiconductor wafer which is a conductor. Has been adopted.

[0004]

[0005] In recent years, demands for larger LCD substrates have been increasing, and there has been a demand for LCD substrates which are significantly larger than conventional LCD substrates. When the size of the LCD substrate is increased, the following problems occur. That is, since He gas flows between the substrate and the substrate support member in order to increase the transmission efficiency, when the peripheral edge of the substrate is held by the clamp member, the flowing He gas causes the central portion of the substrate to flow. It swells. As a result, uniform cooling is not performed on the substrate, and the etching characteristics and the like may vary.

[0005] Therefore, there is a demand for a technique capable of securely holding the entire LCD substrate even on such a large-sized insulating LCD substrate on a substrate supporting member.

The present invention has been made in view of the above circumstances, and an electrostatic suction device and an electrostatic suction device capable of reliably sucking and supporting the entirety of an insulating substrate such as an LCD substrate. It is an object to provide a method, and a processing apparatus and a processing method using the same.

[0007]

The present inventor has conducted experiments and studies to solve the above-mentioned problems. As a result, the present inventor has found that even an insulating substrate such as an LCD substrate can be adsorbed by electrostatic attraction. Clarified. In other words, since an insulating substrate such as an LCD substrate is insulative, it cannot be electrostatically attracted by the same principle as a semiconductor wafer as a conductor. It has been found that it is possible to perform electrostatic attraction of an insulating substrate.
Hereinafter, this principle will be described based on the findings of the inventor.

That is, an insulating substrate such as an LCD substrate is placed on an electrostatic attraction sheet having an insulator and electrodes provided therein, similar to an electrostatic attraction device used for a semiconductor wafer. When a predetermined DC voltage is applied from a DC power source to the substrate and plasma is formed around the substrate, mutually opposite charges are generated in the substrate and the electrodes, and an electrostatic force such as Coulomb force is generated. The substrate is attracted by the electric power.

That is, as shown in FIG.
The charge accumulated on the insulating substrate from the plasma by the application of the DC voltage to the electrode and the electrode to which the DC voltage is applied act as a capacitor, forming a closed circuit through the plasma as shown in FIG. Therefore, the principle is that a suction force is generated. Therefore, even an insulating substrate such as an LCD substrate can be electrostatically attracted. According to the experiments performed by the inventor, application of a DC voltage to the substrate support member does not adversely affect the etch rate and the uniformity of the etching.

The present invention has been made based on such knowledge, and a first invention is an electrostatic attraction device provided in a space where plasma is formed, for attracting an insulating substrate. An adsorbing member for adsorbing the insulating substrate, the electrode having a body and an electrode provided therein;
DC voltage applying means for applying a C voltage, and applying a DC voltage to the electrode in a state where plasma is formed, thereby generating a charge between the electrode and charges accumulated on the substrate from the plasma. An electrostatic attraction device characterized in that the insulating substrate is attracted to the attraction member by electrostatic force.

According to a second aspect of the present invention, there is provided a method for mounting an insulating substrate on a suction member having an insulator and electrodes provided therein, applying a DC voltage to the electrodes, Having a step of forming a plasma, the electrostatic force generated between the electrode to which a voltage is applied and the electric charge accumulated on the substrate from the plasma due to the voltage,
An electrostatic attraction method is provided, wherein the insulating substrate is attracted to the attraction member.

According to a third aspect of the present invention, there is provided a processing chamber for performing a predetermined processing on an insulating substrate, processing gas introducing means for introducing a processing gas into the processing chamber, and a plasma for forming a plasma of the processing gas in the processing chamber. Forming means, a substrate supporting member for supporting the insulating substrate in the processing chamber, and an electrostatic chucking device for electrostatically holding the insulating substrate, wherein a predetermined amount of plasma is applied to the insulating substrate by plasma of the processing gas. A processing apparatus for performing a process, wherein the electrostatic suction device has an insulator and an electrode provided therein, and has a suction member for suctioning the insulating substrate, and applies a DC voltage to the electrode. DC voltage applying means, and by applying a DC voltage to the electrode in a state where plasma is formed, an electrostatic force generated between the electrode and the electric charge accumulated on the substrate from the plasma. Providing a processing device, wherein the insulating substrate is adsorbed to the adsorption member.

A fourth invention provides the processing apparatus according to the third invention, further comprising a heat transfer gas supply means for supplying a heat transfer gas between the insulating substrate and the adsorption member. .

According to a fifth aspect of the present invention, there is provided a process for mounting an insulating substrate on a suction member provided on a substrate support member in a processing chamber and having an insulator and electrodes provided therein, A step of introducing a gas, a step of applying a DC voltage to the adsorption member, and a step of forming a plasma of a processing gas in the processing chamber, wherein a predetermined processing is performed on the insulating substrate by the plasma of the processing gas. Processing method to be applied,
A process method comprising: adsorbing the insulating substrate to the adsorbing member by electrostatic force generated between the electrode to which power is applied and electric charge accumulated on the substrate from plasma by the voltage. I do.

A sixth invention provides the processing method according to the fifth invention, further comprising a step of supplying a heat transfer gas between the insulating substrate and the suction sheet.

In the present invention, since the charges in the plasma are accumulated on the substrate, even an insulating substrate can be adsorbed by electrostatic adsorption, and the entire substrate can be reliably supported. Therefore, even in the case of a large-sized insulating substrate such as an LCD substrate, it is possible to avoid such a problem that the central portion of the substrate swells due to the heat transfer gas and the temperature uniformity is impaired. In addition, since the temperature of the substrate can be made uniform, variations in the etching rate can be eliminated.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a sectional view showing an etching apparatus to which the electrostatic chuck according to the embodiment of the present invention is applied. This etching apparatus has a chamber 1 configured to be airtight. This chamber 1
A support table (substrate support member) 2 for horizontally supporting an LCD substrate S, which is a processing target, is provided substantially at the center of the substrate. A coolant channel 3 is provided inside the support table 2, and the support table 2 can be cooled by the coolant flowing through the coolant channel 3. The support table 2 is grounded via the chamber 1.

The support table 2 is provided with an electrostatic suction device 10 for sucking the LCD substrate S.
The electrostatic suction device 10 is provided on the upper surface of the support table 2,
Adsorbing member 1 having insulating layer 12 of polyimide or ceramic and electrode 13 made of copper or the like embedded therein.
1 and a DC power supply 2 for applying a DC voltage to the electrode 13
And 1. Note that the suction member 11 is fixed to the support table 2.

The electrode 13 and the DC power source 21 are connected to a cable 19
Connected by A switch 20 is provided on the ground side of the cable 19, and power is supplied to the electrode 13 by connecting the switch 20 to a terminal a on the power supply 21 side. Also,
By connecting the switch 20 to the terminal b on the ground side,
The electrode 13 is neutralized.

Note that a frame-like member 22 may be provided above the end of the LCD substrate S so as to be able to move up and down. The ring frame member 22 has a function of concentrating plasma, and is also used as an auxiliary clamp for holding the periphery of the LCD substrate S as in the related art.

A plurality of small through holes 14 are formed in the suction member 11. These small through holes 14 are H
It is connected to the e gas supply system 18. He gas for heat transfer is sent out between the LCD substrate S and the support table 2 through the flow pipe 17 and the small through hole 14.

A shower head 4 is provided near the top wall of the chamber 1 so as to face the support table 2. The shower head 4 is provided with a large number of gas discharge holes 5 on its lower surface, and has a gas inlet 6 on its upper part. And the gas introduction part 6 is an annular insulating member 7.
And is attached to the top wall of the chamber 1 via. The insulating member 7 allows the chamber 1 and the shower head 4
Are electrically insulated. The chamber 1 is grounded.

A gas supply pipe 8 is connected to the gas introduction section 6, and the other end of the gas supply pipe 8 is connected to a processing gas supply system 9 for supplying a processing gas consisting of a reactive gas for etching and a diluting gas. Is connected. As a reaction gas, a halogen-containing gas such as CHF ₃ or CF ₄ is used, and as a diluting gas, an inert gas such as Ar gas is used.

An exhaust port 15 is formed on the bottom wall of the chamber 1, and an exhaust system 16 is connected to the exhaust port 15. By operating the vacuum pump of the exhaust system 16, the inside of the chamber 1 is exhausted through the exhaust port 15, and the inside of the chamber 1 can be depressurized to a predetermined degree of vacuum.

A high frequency power supply 23 is connected to the shower head 4 via a matching circuit (not shown). When high-frequency power is supplied from the high-frequency power supply 23 to the shower head 4, a high-frequency electric field is formed in a space between the shower head 4 and the support table 2, whereby plasma of a processing gas is formed in the space. , LCD
A film formed on the substrate S, for example, an oxide film is etched.

In the etching apparatus configured as described above, first, the LCD substrate S is carried into the chamber 1 by a transfer arm (not shown), and the LCD substrate S is placed on the suction member 11. In this case, the delivery of the LCD substrate S is performed by a lifter pin (not shown) which is inserted into the inside of the support table 2 and is provided so as to be able to move up and down.

Next, while the inside of the chamber 1 is kept airtight, the inside of the chamber 1 is brought into a high vacuum state of the order of 10 ⁻⁶ Torr by operating a vacuum pump provided in the exhaust system 16. An etching gas is supplied from the gas supply system 9 into the chamber 1 through the gas discharge holes 5 of the shower head 4. At this time, the pressure inside the chamber 1 is adjusted to a predetermined pressure by the flow rate of the supplied gas.

Next, a predetermined DC voltage (for example, 0 to 5 Kv) is applied to the electrode 13 from the DC power supply 21 through the cable 19.
Is applied. In the illustrated example, the voltage is applied by setting the switch 20 to the terminal a side.

In this state, a high frequency (RF) power of a predetermined frequency (for example, 13.56 MHz) is supplied from the high frequency power supply 23 to the shower head 4, and a high frequency electric field is applied to a space between the shower head 4 and the support table 2. Form. This high-frequency electric field forms a plasma of the processing gas in the space.

As described above, when DC power is applied to the electrode 13 as described above in a state where plasma is present in the chamber 1, opposite charges are generated on the LCD substrate S and the electrode 13. Therefore, Coulomb force is generated between the two. That is, when a DC voltage is applied to the electrode 13, charges are accumulated on the LCD substrate S from the plasma, and the charges and the electrode 13 to which the voltage is applied act as a capacitor, forming a closed circuit via the plasma. Therefore, the LCD substrate S is electrostatically attracted to the attracting member 11.

At this time, the peripheral edge of the substrate S may be held by the frame member 22 for the purpose of assisting the electrostatic attraction force. However, the frame-shaped member 22 mainly has a function of concentrating the plasma, and is used only for auxiliary holding of the LCD substrate S.

In the state where the substrate is electrostatically adsorbed on the adsorption member 11 as described above, the conditions of the flow rate of the processing gas and the high-frequency power are set to predetermined values, and the plasma of the processing gas formed forms the LCD substrate S. Is subjected to an etching process. At the time of this etching, in order to cool the substrate S to a constant temperature, a cooling medium is caused to flow through a cooling medium flow path 3 formed in the supporting table 2 to cool the supporting table 2.
In this case, since the inside of the chamber 1 is maintained at a low pressure of about several mTorr, the heat transfer efficiency is poor.
Cannot be effectively cooled, a He gas for heat transfer is supplied from the He gas supply system 18 between the LCD substrate S and the support table 2 through the flow pipe 17 and the small through hole 14, and the substrate S Is uniformly cooled to realize a uniform etching process.

After the completion of such an etching process,
To release the electrostatic attraction, the switch 20 is switched to the side b (GND). Thus, the application of the voltage from the DC voltage supply unit 20 is stopped and the charge of the electrode 13 is removed, so that the LCD substrate S can be moved. If necessary, if the lifter pins are lifted up and the substrate S is floated to apply the plasma, the charge can be removed more effectively.

In this way, the electrode 13 is discharged and the LCD 13
After releasing the electrostatic attraction of the substrate S, the high frequency power supply 23 is turned off.
F, the gate of the chamber 1 is opened, and the substrate S is carried out of the chamber 1.

According to the present embodiment, since the LCD substrate S is attracted to the attracting member 11 by electrostatic attraction, the entire LCD substrate S can be reliably attracted and held, and the heat transfer H
Even if the e gas flows, an adverse effect such that the central portion of the substrate swells can be avoided. Therefore, the LCD substrate S
Can be uniformly cooled. Further, the heat transfer efficiency can be increased by setting the He gas pressure higher.

As described above, even an insulating substrate can be securely brought into close contact with a substrate supporting member by electrostatic attraction, and is particularly effective for a large LCD substrate processing apparatus.

The present invention can be variously modified without being limited to the above embodiment. For example, the insulating substrate of the object to be processed is not limited to the LCD substrate, but may be another insulating substrate. Further, the plasma formation is not limited to the above embodiment, and may be performed, for example, by supplying high-frequency power to the support table 2, or may be performed by other means such as microwaves. Further, the present apparatus is not limited to an etching apparatus, and can be applied to another plasma processing apparatus such as another film forming apparatus. Further, in the above embodiment, after a voltage is applied to the electrode 13 of the suction member 11,
Although the plasma was formed, the order may be reversed.

[0038]

As described above, according to the present invention,
Since the charges in the plasma are accumulated on the substrate, even an insulating substrate can be adsorbed by electrostatic attraction, and the entire substrate can be reliably supported. Therefore, LC
Even with a large-sized insulating substrate such as a D-substrate, it is possible to avoid such a problem that the central portion of the substrate swells due to the heat transfer gas and the temperature uniformity is lost. In addition, since the temperature of the substrate can be made uniform, variations in the etching rate can be eliminated.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of adsorption of an electrostatic adsorption device according to the present invention.

FIG. 2 is a cross-sectional view showing an electrostatic suction device according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Chamber 2 ... Support table 4 ... Shower head 9 ... Processing gas supply system 10 ... Electrostatic adsorption device 11 ... Adsorption member 13 ... Electrode 21 ... DC power supply 23 ... High frequency power supply S ... substrate

Claims (6)

[Claims] Claims: 1. A plasma is provided in a space where plasma is formed,
An electrostatic attraction device for adsorbing an insulating substrate, comprising: an insulator and an electrode provided therein; an adsorbing member for adsorbing the insulating substrate; and applying a DC voltage to the electrode. DC voltage applying means, wherein a DC voltage is applied to the electrode in a state where plasma is formed, and the electrostatic force generated between the electrode and the electric charge accumulated on the substrate from the plasma, An electrostatic attraction device, wherein an insulating substrate is attracted to the attraction member. 2. A step of placing an insulating substrate on an adsorption member having an insulator and an electrode provided therein, a step of applying a DC voltage to the electrode, and applying a plasma to the surface of the insulating substrate. Forming an insulating substrate on the attraction member by electrostatic force generated between the electrode to which a voltage is applied and the electric charge accumulated on the substrate from plasma by the voltage. An electrostatic adsorption method characterized by the following. A processing chamber for performing predetermined processing on the insulating substrate; a processing gas introducing unit configured to introduce a processing gas into the processing chamber; and a plasma forming unit configured to form a plasma of the processing gas in the processing chamber. A substrate support member for supporting the insulating substrate in the processing chamber; and an electrostatic chucking device for electrostatically holding the insulating substrate, wherein a predetermined process is performed on the insulating substrate by plasma of the processing gas. A processing device, wherein the electrostatic suction device includes: an adsorption member having an insulator and an electrode provided therein for adsorbing the insulating substrate; and a DC voltage application for applying a DC voltage to the electrode. Means for applying a DC voltage to the electrode in a state in which a plasma is formed, whereby the electrostatic force generated between the electrode and the electric charge accumulated on the substrate from the plasma, A processing apparatus, wherein an insulating substrate is adsorbed by the adsorbing member. 4. The processing apparatus according to claim 3, further comprising a heat transfer gas supply means for supplying a heat transfer gas between the insulating substrate and the adsorption member. 5. A semiconductor device provided on a substrate support member in a processing chamber,
Placing an insulating substrate on an adsorption member having an insulator and electrodes provided therein; introducing a processing gas into the processing chamber; applying a DC voltage to the adsorption member; Forming a plasma of a processing gas in the processing chamber, wherein a predetermined process is performed on the insulating substrate by the plasma of the processing gas, wherein the electrode to which power is applied, A processing method, wherein the insulating substrate is adsorbed on the adsorbing member by an electrostatic force generated between plasma and electric charges accumulated on the substrate. 6. The processing method according to claim 5, further comprising a step of supplying a heat transfer gas between the insulating substrate and the suction sheet.