JPH05234697A - Microwave plasma treating device - Google Patents

Abstract

PURPOSE:To provide a microwave plasma treating system for treating an object with high rate and high accuracy by forming microwave-produced plasma into high-density and high-uniform plasma. CONSTITUTION:A plasma controlling mechanism is provided with a means comprising an ground electrode 100, an insulating material 101, displacement converting members 102, and pulse motors 103 and for varying a ground electrode area and a means comprising the ground electrode 100, a coil 200, a capacitor 201, and a variable resistor 202, and for varying impedance between plasma and ground through the ground electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus, and more particularly to a microwave plasma processing apparatus suitable for generating high density and uniform plasma using microwaves.

[0002]

2. Description of the Related Art A conventional device suppresses the ion focusing action at the cathode edge by using a combination of an auxiliary electrode and a protective ring with a variable height as described in JP-A-46-3105. It has been shown that uniform sputtering can be performed. However, no consideration has been given to the stability of plasma using a microwave and a high frequency power source for controlling the energy of ions in the plasma. Also, no consideration was given to continuous treatment of multiple layers.

[0003]

The prior art is effective in making the ions incident on the sample uniform under a single processing condition.

On the other hand, recent semiconductor devices have been miniaturized with higher density than ever before, and more precise plasma treatment by highly uniform plasma is required, and high-speed treatment is also required for improving productivity. Has been done. For this reason, microwave is used as a part of high-density plasma generation means,
An etching apparatus using a high frequency power source is used for controlling ion energy in plasma. In the etching process using this device, when non-uniform plasma with different plasma density is locally generated due to the change of plasma impedance and the change of the plasma generation condition or the state change of the object to be processed during the plasma process. was there.

An object of the present invention is to provide a microwave plasma processing apparatus capable of processing an object to be processed at high speed and with high accuracy by making the plasma generated by microwaves into high density and highly uniform plasma. is there.

[0006]

In order to achieve the above-mentioned object, a plasma control mechanism comprising means for varying the area of the ground electrode and means for varying the impedance between the plasma and the ground via the ground electrode. Is used to generate high-density and high-uniformity plasma.

[0007]

With the plasma control mechanism including the means for varying the area of the ground electrode and the means for varying the impedance between the plasma and the ground via the ground electrode, the plasma generated in the microwave plasma processing apparatus can be controlled. By adjusting the impedance between the grounds, stable high density plasma can be generated even when the plasma operating factors such as magnetron current, processing pressure, gas flow rate, and high frequency power are changed. Thereby, the object to be processed can be plasma-processed at high speed and with high accuracy.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a configuration diagram of a microwave plasma processing apparatus to which the present invention is applied.

In FIG. 1, a discharge gas 2 is placed in a vacuum chamber 1.
Is introduced, the microwaves generated by the magnetron 3 and made incident on the bell jar 17 through the waveguide 16 and the magnetic field generated by the solenoid coil 4 act on the discharge gas 2 in the bell jar 17 to generate the plasma 5. Generated and plasma 5
The surface of the object 6 to be processed is etched by utilizing the radicals and ions therein. A high-frequency power source 8 is placed on the electrode 7 for placing the object to be processed.
Are connected to generate a negative bias voltage on the workpiece mounting electrode 7. Therefore, the etching shape of the object 6 can be controlled by the action of ion energy. In addition,
The gas pressure in the vacuum chamber 1 is adjusted by the vacuum exhaust device 9 to the exhaust port 1
The gas is exhausted from 0 and maintained at a predetermined value. The vacuum container 20 and the bell jar 17 are airtightly assembled by an O-ring 18. The vacuum container 20 and the workpiece mounting electrode 7 are hermetically assembled by a vacuum sealing material 19.

The plasma control mechanism comprises means for varying the area of the ground electrode and means for varying the impedance between the plasma and the ground via the ground electrode. This means is configured by being attached to a cover 21 provided at the bottom of the vacuum container 20. The means for varying the area of the ground electrode is composed of the ground electrode 100, the insulating material 101, the displacement conversion member 102 and the pulse motor 103. The ground electrode area is the height of the ground electrode 100 to be inserted in the plasma 5 This can be changed by controlling the displacement conversion member 102 using 103. On the other hand, the means for varying the impedance between the plasma 5 and the ground via the ground electrode 100 are the ground electrode 100, the coil 200, and the capacitor 20.
1 and variable resistor 202.

FIG. 2 shows a signal control system during the etching process. The light emission detector 1 for detecting the end point of the object 6 to be processed.
4, a control computer 15 for controlling the entire etching apparatus and a ground electrode 100 for controlling the plasma state
The pulse motor 103 controls the height of the
In addition, the impedance between the ground electrode 100 and the ground can be changed by controlling the resistance value of the variable resistor 202 by the control computer 15.

Uniform plasma processing is achieved by using the etching apparatus having the configuration shown in FIGS.

Hereinafter, the etching process when the Al oxide film is the main constituent and the Si oxide film is formed on the underlayer will be described. At the time of etching the Al film, the height of the ground electrode and the resistance value are controlled to preset values so that the plasma state is optimum for etching the Al film, and the Al film is etched. The emission of Al is monitored by the emission detector 14 during the etching of the Al film. The etching end point detection signal of the Al film is sent from the light emission detector 14 to the control computer 15 which controls the entire etching apparatus. The control computer 15 controls the height and impedance of the ground electrode to be a plasma state that is optimal for etching the Si oxide film that is the base film of the Al film.

Therefore, even under various plasma generation conditions, it is possible to stably generate high density plasma in a wide range by controlling the ground electrode area and impedance suitable for the generated plasma.

According to the present invention, continuous processing can be performed in a stable and high-density plasma state optimal for each etching layer even under a plurality of etching conditions due to the above-described structure and operation, so that processing can be performed at high speed and with high accuracy, and the processed object can be processed. There is an effect that the productivity of the product can be improved.

In the above embodiment, the etching process mainly using the Al film was described, but the etching layer is not limited to this, and the optimum etching conditions for each etching layer are set in advance in the control computer. By doing so, it is possible to carry out continuous etching treatment in a stable plasma state even with etching treatment of a plurality of types and a plurality of layers.

[0017]

According to the present invention, since a plurality of etching layers can be continuously and stably treated with high density plasma, processing can be performed at high speed and with high accuracy, and the productivity of the object to be processed can be improved. There is.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a microwave plasma processing apparatus to which the present invention has been applied.

FIG. 2 is a diagram showing a configuration of a signal control system during an etching process.

[Explanation of symbols]

6 ... Object to be processed, 7 ... Object to be processed mounting electrode, 14 ... Emission detector, 15 ... Control computer, 16 ... Waveguide, 17 ...
Bell jar, 18 ... O-ring, 19 ... Vacuum sealing material,
20 ... Vacuum container, 21 ... Cover, 100 ... Ground electrode, 1
01 ... Insulating material, 102 ... Displacement conversion member, 103 ... Pulse motor, 200 ... Coil, 201 ... Capacitor, 202
… Variable resistance.

Claims (1)

[Claims] 1. A discharge gas is introduced into a vacuum chamber, and a microwave generated by a magnetron and a magnetic field generated by a solenoid coil act on the discharge gas to generate plasma.
Moreover, in an apparatus for etching the surface of a sample while controlling the energy of ions in plasma by supplying electric power from a high frequency power source, the means for varying the area of the ground electrode and the impedance between the plasma and the ground via the ground electrode are set. A microwave plasma processing apparatus, characterized in that it is provided with a variable means.