JPH11297802A - Electrostatic adsorption device and vacuum device mounted therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic adsorption device of a structure; wherein a body to be treated is adsorbed and held on a stage by an electrostatic force and, at the same time, the device has a cooling function for cooling the body to be treated and an electrostatic adsorbability between the body to be treated and the stage can be constantly maintained, or even in the case where the adsorption device is arranged within a vacuum device, the temperature of the body to be treated can be accurately measured, and wherein the temperature of the body to be treated can be maintained at the expected value with good accuracy by mounting the adsorption device on the vacuum device. SOLUTION: A cooling gas pressure, which is obtained between a semiconductor wafer 3 and a stage 2 by a prescribed flow rate of cooling gas which is introduced between the wafer 3 and the stage 2, is measured. There, data on the pressure obtained by a pressure detecting part 9 is inputted in a control part 12 to give an instruction to the output of a DC high-voltage power supply 11, so that the cooling gas pressure between the wafer 3 and the stage 2 is set at a pressure of a prescribed value, and an electrostatic adsorbability between the wafer 3 and the stage 2 is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck and a vacuum processing apparatus having the electrostatic chuck.

[0002]

2. Description of the Related Art FIG. 3 is a schematic view showing the structure of a dry etching apparatus equipped with a conventional electrostatic chuck. In the figure, reference numeral 1 denotes a chamber held in a vacuum state, 2 denotes a stage disposed in the chamber 1 and an insulating film is formed on the surface, 3 denotes a semiconductor wafer as an object to be processed held on the stage 2, 4 Is an exhaust passage provided in the chamber 1,
A vacuum pump (not shown) is connected to evacuate the chamber 1 to a vacuum. 5 is provided on the upper surface of the chamber 1, and is an etching gas introduction path for introducing an etching gas into the chamber 1, 6 is a microwave generator, 7 is a cooling gas introduction for introducing a cooling gas between the semiconductor wafer 3 and the stage 2. A path 8 is a cooling gas flow controller provided in the middle of the cooling gas introduction path 7, and a pressure 9 of the cooling gas introduced between the semiconductor wafer 3 and the stage 2 is measured through a measurement hole provided in the stage 2. A pressure detecting unit 10 for measuring the temperature of the semiconductor wafer 3 held on the stage 2; a DC high-voltage power supply 11 for applying a DC high voltage to the stage 2; A control unit that gives an instruction to the cooling gas flow control unit 8 based on the obtained data.

Next, an etching process using a conventional dry etching apparatus will be described. First, after the semiconductor wafer 3 as the object to be processed is placed on the stage 2 in the chamber 1, a vacuum pump (not shown) is connected to the exhaust path 4 to evacuate the chamber 1 to a vacuum state. Next, a predetermined flow rate of the etching gas is supplied through the gas introduction path 5 to the chamber 1.
The inside of the chamber 1 is set to a predetermined gas pressure, and a microwave generated by the microwave generator 6 is introduced into the chamber 1 to generate plasma, and the semiconductor wafer 3 is subjected to an etching process. In order to hold the semiconductor wafer 3 on the stage 2, a high DC voltage is applied to the stage 2, and the semiconductor wafer 3 is electrostatically attracted to the stage 2 by the generated electrostatic force. Further, in order to cool the semiconductor wafer 3 heated by the plasma processing,
A stage cooling mechanism (not shown) for circulating a refrigerant inside the stage 2 is provided as a temperature control mechanism for the stage 2. Further, in order to improve the cooling efficiency of the semiconductor wafer 3, a predetermined flow rate of the cooling gas is introduced between the semiconductor wafer 3 and the stage 2 via the cooling gas introduction path 7.

Here, the pressure of the cooling gas introduced between the semiconductor wafer 3 and the stage 2 is measured, and the data obtained by the pressure detecting unit 9 is input to the control unit 15 so that the semiconductor wafer 3 and the stage 2 An instruction is given to the cooling gas flow controller 8 so that the pressure of the cooling gas during the period becomes a predetermined value, and the flow rate of the cooling gas introduced between the semiconductor wafer 3 and the stage 2 is controlled. That is, by adjusting the flow rate of the cooling gas introduced between the semiconductor wafer 3 and the stage 2, the pressure of the cooling gas between the semiconductor wafer 3 and the stage 2 is controlled to a predetermined value, and the cooling efficiency of the semiconductor wafer 3 is reduced. Is constant.

[0005]

In order to process a sample with high accuracy and uniformity using a vacuum processing apparatus, it is necessary to maintain a sample (semiconductor wafer) being processed at an appropriate temperature. Further, the temperature during processing of the semiconductor wafer 3 held by the electrostatic chuck cannot be controlled only by keeping the pressure of the cooling gas introduced between the semiconductor wafer 3 and the stage 2 constant. It is known that it depends on the electrostatic attraction force between the stages 2 (microscopically, the distance between the semiconductor wafer 3 and the stage 2). The vacuum processing apparatus equipped with the conventional electrostatic suction device is configured as described above. If the pressure of the cooling gas introduced between the semiconductor wafer 3 and the stage 2 is kept constant, the semiconductor wafer being processed is not processed. 3 cannot be maintained at the desired value, and
Since the electrostatic chucking force between the semiconductor wafer 3 and the stage 2 changes due to a change in the plasma state and manufacturing variations of the electrostatic chuck, it is difficult to maintain the temperature of the semiconductor wafer 3 as expected. And so on. Further, in the electrostatic chucking device mounted on the dry etching device, the temperature of the semiconductor wafer 3 electrostatically sucked is low in temperature detection accuracy, so that there is a problem that the temperature of the semiconductor wafer 3 during processing cannot be accurately measured.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can maintain a constant electrostatic attraction force in an electrostatic attraction device for attracting and holding an object to be processed to a stage by electrostatic force. Alternatively, it is an object of the present invention to obtain an electrostatic attraction device capable of measuring the temperature of an object to be processed with high accuracy even when the device is disposed in a vacuum processing apparatus for performing plasma processing or the like. In addition, in a vacuum processing apparatus equipped with an electrostatic suction device having a function of cooling the object to be processed while electrostatically attracting the object to be processed to the stage by electrostatic force, the electrostatic attraction force is kept constant, or An object of the present invention is to provide a vacuum processing apparatus that has a function of measuring the temperature of a body with high accuracy and can maintain the temperature of an object to be processed during processing at a desired value with high accuracy.

[0007]

An electrostatic chuck according to the present invention includes a stage having an insulating film formed on a surface thereof, and a DC high voltage stage mounted on the stage for electrostatically attracting an object to be processed on the insulating film of the stage. DC high-voltage power supply for applying voltage, temperature control mechanism for adjusting the temperature of the stage, and cooling for supplying a cooling gas introduced between the workpiece and the stage electrostatically adsorbed on the insulating film of the stage A gas supply unit, a pressure detection unit that measures the pressure of the cooling gas introduced between the processing target and the stage, and a pressure detection unit that is introduced between the processing target and the stage based on data obtained by the pressure detection unit. A control unit is provided for controlling the output of the DC high voltage power supply so that the pressure of the cooling gas becomes a predetermined value. Also, a stage having an insulating film formed on its surface, a DC high-voltage power supply for applying a DC high voltage to the stage for electrostatically adhering the object to be processed on the insulating film of the stage, and a control for adjusting the temperature of the stage. A temperature mechanism, a cooling gas supply unit that supplies a cooling gas introduced between the stage and the stage electrostatically adsorbed on the insulating film of the stage, and a temperature detection unit that measures the temperature of the stage. And a control unit that controls the output of the DC high-voltage power supply based on the data obtained by the temperature detection unit so that the temperature of the object to be processed becomes a predetermined value. Further, the temperature detecting section for measuring the temperature of the object to be processed has an infrared temperature sensor.

Further, according to a vacuum processing apparatus of the present invention, in the vacuum processing apparatus in which an object to be processed is placed in a chamber maintained in a vacuum state, the stage of the above-mentioned electrostatic suction device is provided in the chamber. The object to be processed is held on the insulating film of the stage by electrostatic attraction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a vacuum processing apparatus equipped with an electrostatic suction device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows Embodiment 1 of the present invention.
1 is a schematic diagram showing a configuration of a vacuum processing apparatus (a dry etching apparatus in the present embodiment) according to the present invention. In the figure, reference numeral 1 denotes a chamber held in a vacuum state, 2 denotes a stage which is disposed in the chamber 1 and has an insulating film formed on the surface, 3 denotes a semiconductor wafer which is an object to be processed held on the stage 2, 4 Is an exhaust path provided in the chamber 1 and connected to a vacuum pump (not shown) to evacuate the chamber 1 to a vacuum state. 5 is provided on the upper surface of the chamber 1, and is an etching gas introduction path for introducing an etching gas into the chamber 1, 6 is a microwave generator, 7 is a cooling gas introduction for introducing a cooling gas between the semiconductor wafer 3 and the stage 2. Road,
Reference numeral 8 denotes a cooling gas flow control unit provided in the middle of the cooling gas introduction path 7, and 9 measures the pressure of the cooling gas introduced between the semiconductor wafer 3 and the stage 2 through a measurement hole provided in the stage 2. A pressure detector 10 for measuring the temperature of the semiconductor wafer 3 held on the stage 2;
Is a DC high voltage power supply for applying a DC high voltage to the stage 2,
Reference numeral 12 denotes a control unit including a microcomputer or the like for controlling the output of the DC high-voltage power supply 11 based on data obtained by the pressure detection unit 9.

Next, an etching process using a dry etching apparatus equipped with the electrostatic suction device according to the present embodiment will be described. First, the semiconductor wafer 3 to be processed is
Is mounted on the stage 2 in the chamber 1 and a vacuum pump (not shown) is connected to the exhaust path 4 to evacuate the chamber 1 to a vacuum state. Next, a predetermined flow rate of the etching gas is introduced into the chamber 1 through the gas introduction path 5 to bring the inside of the chamber 1 to a predetermined gas pressure, and the microwave generated by the microwave generator 6 is introduced into the chamber 1. The plasma is introduced to generate plasma, and the semiconductor wafer 3 is subjected to an etching process. In order to hold the semiconductor wafer 3 on the stage 2, a high DC voltage is applied to the stage 2, and the semiconductor wafer 3 is moved by the generated electrostatic force.
Is electrostatically attracted. In order to cool the semiconductor wafer 3 heated by the plasma processing, a stage cooling mechanism (not shown) for circulating a refrigerant inside the stage 2 is provided as a temperature adjusting mechanism for the stage 2. Further, in order to improve the cooling efficiency of the semiconductor wafer 3, a predetermined flow rate of the cooling gas is introduced between the semiconductor wafer 3 and the stage 2 through the cooling gas introduction path 7.

Here, the pressure of the cooling gas between the semiconductor wafer 3 and the stage 2 obtained by a predetermined flow rate of the cooling gas introduced between the semiconductor wafer 3 and the stage 2 is measured. The output of the DC high voltage power supply 11 is controlled such that the pressure of the cooling gas between the semiconductor wafer 3 and the stage 2 becomes a predetermined value. That is, the output of the DC high-voltage power supply 11 is controlled so that the pressure of the cooling gas between the semiconductor wafer 3 and the stage 2 by the cooling gas at a predetermined flow rate introduced between the semiconductor wafer 3 and the stage 2 becomes a predetermined value. Thereby, the electrostatic attraction force between the semiconductor wafer 3 and the stage 2 (microscopically, the distance between the semiconductor wafer 3 and the stage 2) is adjusted to a constant value.

According to the present invention, the DC high voltage is applied so that the pressure of the cooling gas between the semiconductor wafer 3 and the stage 2 by the predetermined amount of the cooling gas introduced between the semiconductor wafer 3 and the stage 2 becomes a predetermined value. By controlling the output of the power supply 11, the pressure of the cooling gas between the semiconductor wafer 3 and the stage 2 and the electrostatic attraction force between the semiconductor wafer 3 and the stage 2 can be adjusted to constant values. The temperature of the semiconductor wafer 3 to be heated can be accurately maintained at a desired value.

Embodiment 2 FIG. FIG. 2 is a schematic diagram showing a configuration of a vacuum processing apparatus equipped with an electrostatic suction device according to Embodiment 2 of the present invention. In the figure, reference numeral 13 denotes a temperature detecting unit having an infrared temperature sensor 13a, and 14 denotes a temperature detecting unit 13a.
Is a control unit that controls the output of the DC high-voltage power supply based on the data obtained in (1). The other configuration is the same as that of the first embodiment, and the description is omitted. In the present embodiment, the temperature of the semiconductor wafer 3 held on the stage 2 of the electrostatic chuck is measured using the infrared temperature sensor 13a,
The data obtained by the temperature detection unit 13 is input to the control unit 14 to instruct the output of the DC high-voltage power supply 11 so that the temperature of the semiconductor wafer 3 becomes a predetermined value. The temperature of the semiconductor wafer 3 is adjusted by controlling the electrostatic attraction force.

In the present embodiment, since the temperature of the semiconductor wafer 3 to be processed can be measured with high accuracy,
The adjustment can be performed while directly monitoring the temperature of the semiconductor wafer 3, and the temperature of the semiconductor wafer 3 can be maintained at a predetermined value. .

[0015]

As described above, according to the present invention, in an electrostatic attraction device for electrostatically attracting a target object to a stage by electrostatic force, a distance between the target object and the stage holding the target object is reduced. The voltage applied to the stage is controlled so that the pressure of the cooling gas between the target object and the stage by the introduced cooling gas at a predetermined flow rate becomes a predetermined value, and the electrostatic attraction force between the target object and the stage is fixed. Value can be adjusted. Further, according to the present invention, the temperature of the object held on the stage can be measured with high accuracy even when the object is placed in a vacuum processing apparatus for performing plasma processing or the like. Further, according to the present invention, in a vacuum processing apparatus equipped with the above-mentioned electrostatic suction device, the function of maintaining the electrostatic suction force constant or having a function of accurately measuring the temperature of the object to be processed is provided. The temperature of the object to be processed can be accurately maintained at a desired value.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a vacuum processing apparatus (dry etching apparatus) equipped with an electrostatic suction device according to Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a vacuum processing apparatus (dry etching apparatus) equipped with an electrostatic suction device according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing the configuration of a conventional vacuum processing apparatus (dry etching apparatus) equipped with this type of electrostatic suction apparatus.

[Explanation of symbols]

1 chamber, 2 stages, 3 semiconductor wafers, 4
Exhaust path, 5 etching gas introduction path, 6 microwave generator, 7 cooling gas introduction path, 8 cooling gas flow control section, 9 pressure detection section, 10 temperature detection section, 11 DC high voltage power supply, 12 control section, 13a infrared ray Temperature sensor, 13 Temperature detection unit, 14 Control unit.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nobuyuki Takahashi 4-1-1 Mizuhara, Itami-shi, Hyogo Ryoden Semiconductor System Engineering Co., Ltd.

Claims (4)

[Claims] A stage having an insulating film formed on a surface thereof; a DC high voltage power supply for applying a DC high voltage to the stage for electrostatically adhering an object to be processed on the insulating film of the stage; A temperature control mechanism for adjusting the temperature of the object; a gas supply unit for supplying a gas introduced between the object to be processed electrostatically adsorbed on the insulating film of the stage and the stage; A pressure detection unit that measures the pressure of the cooling gas introduced during, and based on data obtained by the pressure detection unit, the pressure of the cooling gas introduced between the object to be processed and the stage is determined by a predetermined value. An electrostatic chuck comprising a control unit for controlling the output of the DC high-voltage power supply so as to obtain a value. 2. A stage having an insulating film formed on a surface thereof, a DC high voltage power supply for applying a DC high voltage to the stage for electrostatically adhering an object to be processed on the insulating film of the stage, and the stage. A temperature control mechanism for adjusting the temperature of the object; a cooling gas supply unit for supplying a cooling gas introduced between the object to be processed electrostatically adsorbed on the insulating film of the stage and the stage; A temperature detection unit that measures the temperature of the object, and a control unit that controls the output of the DC high-voltage power supply so that the temperature of the object to be processed becomes a predetermined value based on data obtained by the temperature detection unit. An electrostatic attraction device characterized by the above-mentioned. 3. The electrostatic adsorption device according to claim 2, wherein the temperature detector for measuring the temperature of the object to be processed has an infrared temperature sensor. 4. A vacuum processing apparatus in which an object to be processed is placed in a chamber held in a vacuum state, wherein the stage of the electrostatic suction apparatus according to claim 1 is mounted on a stage. A vacuum processing apparatus provided in the chamber, wherein the object to be processed is held on the insulating film of the stage by electrostatic attraction.