JPH06267905A - Power impressing electrode defect detecting device and dry etching device - Google Patents

Abstract

PURPOSE:To provide a power impressing electrode defect detecting device, which is capable of detecting a defect in a power impressing electrode, and a dry etching device. CONSTITUTION:A power impressing electrode defect detecting device is provided with a power impressing electrode 1, which opposes to an earth electrode 4 and has its surface coated with an insulator 2, and a potential difference measuring device 12 for measuring a potential difference between a potential in this electrode 1 and a potential in the electrode 4. Thereby, in the case where high- frequency power is impressed between the electrodes 1 and 4, the electrode 1 shows OV if the insulator 2 on the electrode 1 is in a normal state and if a pinhole is formed by a dielectric breakdown, the electrode 1 shows an inter- electrode voltage. As a result, detection of a defect in the electrode 1 becomes possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a defect of a power application electrode and a dry etching device.

[0002]

2. Description of the Related Art In recent years, in order to realize highly accurate anisotropic etching, a low temperature technique for cooling a wafer temperature to 0 ° C. or less has been attracting attention. In this low-temperature etching technique, in order to cool the wafer efficiently, a method of contacting the surface of the power application electrode whose temperature is controlled with the wafer placed on this surface is important. This contact method includes a method of mechanically applying a load to the wafer and a method of using static electricity.

An example of a dry etching apparatus of a method of cooling a wafer by static electricity using a power applying electrode whose surface is coated with an insulator will be described below with reference to FIG. FIG. 5 is a cross-sectional view showing the structure of a dry etching apparatus having a power applying electrode whose surface is coated with an insulating material. In FIG. 5, 1 is a power application electrode, 2 is an insulator, 3 is a wafer, 4 is a ground electrode, 5 is a chamber wall, 6 is a gas outlet, 7 is an exhaust port, 8 is a matching unit, and 9 is a blocking capacitor. 10 is a coil, 11
Is a high frequency power supply.

A power application electrode 1 and a ground electrode 4 connected to a high frequency power source 11 are installed inside the chamber wall 5 so as to face each other. Further, the chamber wall 5 has a gas outlet 6 for introducing a reactive gas, and an exhaust port 7 for keeping the pressure in the chamber wall 5 constant. Wafer to be etched 3
Is disposed on the power application electrode 1 to which high frequency power is applied by the high frequency power supply 11.

The operation of this dry etching apparatus will be described. That is, the high frequency power supply 11 causes a discharge between the power applying electrode 1 and the ground electrode 4. In this case, a potential difference is generated between the power application electrode 1 and the ground electrode 4 due to the difference in mobility between electrons and positive ions. The wafer 3 is charged with positive or negative charges by injecting electrons or positive ions. However, since the surface of the power applying electrode 1 is coated with the insulator 2, no charge is injected.

Therefore, a potential difference is generated between the wafer 3 and the power application electrode 1, and the wafer 3 is electrostatically adsorbed to the power application electrode 1 via the insulator 2. By electrostatically adsorbing the wafer 3 on the power applying electrode 1, the contact area between the cooling power applying electrode 1 and the wafer 3 increases, and the thermal conductivity increases. Therefore, the cooling effect of the wafer 3 is enhanced.

[0007]

However, in the above configuration, when the dielectric breakdown of the insulator 2 on the surface of the power application electrode 1 occurs for some reason, the electrostatic attraction force is weakened and the wafer 3 and The contact area with the power application electrode 1 is reduced. As a result, the wafer temperature rises due to plasma irradiation due to a defect in the power application electrode 1, and variations in basic characteristics such as resist burning as a mask material during etching, an etching rate, and an etching rate selection ratio with an underlying layer occur. Had.

Therefore, in view of the above problems, an object of the present invention is to provide a defect detecting device for a power applying electrode and a dry etching device capable of detecting a defect in the power applying electrode.

[0009]

According to another aspect of the present invention, there is provided a power detecting electrode defect detecting device, wherein a surface of the power applying electrode facing the ground electrode is coated with an insulating material, and a potential difference between the power applying electrode and the ground electrode. And a potential difference measuring device for measuring. A dry etching apparatus according to a second aspect includes the defect detecting apparatus for a power application electrode according to the first aspect.

[0010]

According to the defect detecting device of the power applying electrode of the first aspect, the potential difference between the electrode applying electrode and the ground electrode is zero when the insulator is not broken down, but the insulator is broken down. And a potential difference occurs between the electrode applying electrode and the ground electrode.
Therefore, it is possible to determine the dielectric breakdown of the insulator by measuring the voltage of the potentiometer.

As described above, since the potential difference between the power applying electrode and the ground electrode is measured by the potential difference measuring device, it is possible to monitor the dielectric breakdown due to the pinhole of the insulator on the surface of the power applying electrode, and to confirm the failure of the power applying electrode. It is possible to prevent the resulting trouble. According to the dry etching apparatus of the second aspect, since it has the defect detecting apparatus of the power applying electrode of the first aspect, it is possible to monitor the fluctuation of the wafer temperature due to the defect of the power applying electrode. Further, it is possible to prevent fluctuations in basic characteristics such as an etching rate selection ratio with respect to the base.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A power applying electrode defect detecting device and a dry etching device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a dry etching apparatus having a power application electrode defect detection apparatus whose surface is coated with an insulating material according to an embodiment of the present invention. In FIG. 1, 1 is a power application electrode, 2 is an insulator, 3 is a wafer, 4 is a ground electrode, 5 is a chamber wall, 6 is a gas outlet, 7 is an exhaust port, 8 is a matching box, 9 is a blocking capacitor, 10 is a coil, 11
Is a high frequency power source, and 12 is a voltmeter which is a potential difference measuring device.

In the chamber wall 5, a power applying electrode 1 connected to a high frequency power source 11 and a ground electrode 4 facing the power applying electrode 1.
Is installed. Further, the chamber wall 5 has a gas outlet 6 for introducing a reactive gas and an exhaust port 7 for keeping the pressure in the etching chamber constant. The wafer 3 to be etched is placed on the insulator 2 of the power application electrode 1 to which high frequency power is applied by the high frequency power supply 11.

The operation of the dry etching apparatus thus configured will be described. The high frequency power supply 11 is applied to the power application electrode 1 to generate plasma discharge between the opposing power application electrode 1 and the ground electrode 4 for etching. In this case, the potential difference V between the surface of the power applying electrode 1 and the ground electrode 4 (between A and B in FIG. 1) is caused by the difference in mobility of electrons and ions.
_AB occurs. However, V _AB cannot be measured because the surface of the power applying electrode 1 is coated with the insulator 2.

The defect detecting device for the power applying electrode according to the embodiment of the present invention is provided with a potential difference measuring device for measuring the potential difference between the power applying electrode 1 and the ground electrode 4. The potential difference V _CD between C and D shown in FIG. 1 is measured. This potential difference V _CD is 0 V unless a pinhole is opened in the insulator 2 on the surface of the power applying electrode 1. When processing is performed with higher power than the high frequency power supply 11, pinholes may be formed in the insulator 2 on the surface of the power application electrode 1. When the pinhole is completely formed in the insulator 2 on the surface of the power applying electrode 1, V _CD = V _AB , which can be monitored by the voltmeter 12. That is, if the voltmeter 12 shows 0 V, the wafer temperature is being controlled. However, the voltmeter 12 produces a voltage corresponding to the potential difference V _AB (generally several hundreds V).
, It can be determined that a pinhole is formed in the insulator 2.

Actually, this potential difference V _CD and the power application electrode 1
An example in which the relationship between the surface of the insulator and the pinhole of the insulator 2 was investigated will be shown below. A plurality of pinholes having different depths are forcibly formed in the Φ6 inch power application electrode 1 on the surface of which an alumina insulator having a thickness of 150 μm is formed. First, an electron beam welder was used to form the pinholes. Under the conditions of a voltage of 80 KV and a current of 5 mA, five pinholes having a diameter of 100 μm were formed in a cross shape on the insulator 2 on the surface of the power applying electrode 1. At this time, the pinhole depth was controlled by changing the beam irradiation time. Under the above conditions, the drilling speed was 10 cm / sec, and the beam irradiation time was 10 ^-4 ~.
It changed to 10 ^-6 seconds.

FIG. 2 shows the relationship between the beam irradiation time and the pinhole depth. The vertical axis represents the pinhole depth, and the horizontal axis represents the beam irradiation time. Beam irradiation time 10 shown in FIG.
^-6 seconds 1 μm depth, 10 ⁻⁵ seconds 10 μm depth, 10 ⁻⁴ seconds 100 μm depth, 10 ⁻³ seconds completely pinhole (15
0 μm) was formed to expose the material of the underlying power applying electrode 1.

Next, the film was forcibly formed under the conditions shown in FIG.
Pinhole depth and plasma discharge (during etching)
Potential difference V between C and D_CDThe relationship is shown in FIG. Vertical axis is potential
Difference V _CDThe horizontal axis represents the pinhole depth. In addition,
The discharge conditions at this time are etching gas SF.₆ / CF_Four 
= 20/20 SCCM, gas pressure 175 mTorr, R
It was discharged at F power of 300 W for 10 minutes. Pinhole depth 1
V at 10 μm_CDIs 0 V and 30 at 100 μm
At V, 150 μm (complete pinhole), the potential suddenly rises
Difference V_CDRose to 250V. This voltage
V explained using _ABCan be estimated to be equivalent to.

At this time, a heat label (manufactured by Micron Co.) was attached on the wafer 3 and the temperature of the wafer was measured. The result is shown in FIG. The power application electrode 1 circulates cooling water having a water temperature of 30 ° C. by a circulator to cool it.
Wafer temperature of 50 when pinhole depth is 1 to 10 μm
The temperature is constant, and it can be said that the wafer 3 is cooled by electrostatic attraction. On the other hand, in the power applying electrode 1 in which the pinhole is completely formed, the effect of electrostatic attraction is weakened, and the contact area between the wafer 3 and the power applying electrode 1 is reduced, so that the heat conduction efficiency is lowered and the wafer temperature is reduced. It can be seen that the temperature rises sharply to 150 ° C. In this state, product wafer 3
When etching is performed, the resist burning as the mask material, the etching rate of the object to be etched, and the etching rate selection ratio with the base deteriorate, and all the product wafers 3 become defective.

By measuring the potential difference V _{CD in} this way,
The state of the insulator 2 on the surface of the power applying electrode 1, that is, the presence or absence of pinholes can be monitored, and the wafer temperature can be controlled.

[0021]

According to the defect detecting device of the power applying electrode of the first aspect, since the potential difference between the power applying electrode and the ground electrode is measured by the potential difference measuring device, it is possible to use the pinhole of the insulator on the surface of the power applying electrode. There is an effect that it is possible to monitor dielectric breakdown and the like, and to prevent problems caused by defects of the power application electrodes.

According to the dry etching apparatus of the second aspect, since it has the defect detecting apparatus of the power applying electrode according to the first aspect, it is possible to monitor the fluctuation of the wafer temperature due to the defect of the power applying electrode. It is possible to prevent variations in basic characteristics such as the etching rate and the etching rate selection ratio with respect to the base.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a dry etching apparatus having a defect detection device for a power application electrode according to an embodiment of the present invention.

FIG. 2 shows the relationship between the beam irradiation time and the pinhole depth of the insulator when the electron beam welding machine is used to forcibly form a pinhole in the insulator coating the surface of the power application electrode. It is the figure shown.

3 is a diagram showing the relationship between the pinhole depth forcibly formed under the conditions shown in FIG. 2 and the potential difference V _CD between C and D in FIG. 1 during discharge.

FIG. 4 is a diagram showing a relationship between a pinhole depth forcibly formed under the conditions shown in FIG. 2 and a wafer temperature.

FIG. 5 is a schematic diagram of a conventional dry etching apparatus without a defect detection apparatus for power application electrodes.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power application electrode 2 Insulator 4 Ground electrode 12 Voltmeter which is a potentiometer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Domae 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A defect detecting device for a power applying electrode, comprising: a power applying electrode having a surface facing the ground electrode coated with an insulating material; and a potential difference measuring device for measuring a potential difference between the power applying electrode and the ground electrode. . 2. A dry etching apparatus having the defect detection device for a power application electrode according to claim 1.