JPS594025A - Treating method with plasma - Google Patents

Abstract

PURPOSE:To activate a chemical reaction on the surface of a material to be treated while removing extraneous attached matter, and to obtain uniform etching by giving the material to be treated such as a substrate being in contact with plasma ultrasonic vibration and bringing the material to be treated into contact with plasma while mechanically vibrating the material minutely. CONSTITUTION:An electrode 1 grounded at the outside and an electrode 2 opposite to the electrode 1 are disposed into a vacuum tank 8 with a gas supply port 1-1 and a gas exhaust port 1-2 at a regular interval. A plurality of samples 6 are placed on the electrode 2, high-frequency power from a power supply 3 is applied to the electrode 2 through a matching box 4, and plasma 5 is generated between the electrodes 1 and 2. An ultrasonic vibrator 7 connected to a power supply 9 is set up to the electrode 2 in addition to the constitution, and the vibrator 7 is vibrated in frequency of 5kHz or more. Accordingly, the samples 6 are given mechanical fine vibrations in the same frequency as the vibrator 7, and an etching rate is increased while chemically active particles adhering on the surfaces are supplied with energy and scattered.

Description

[Detailed description of the invention] The present invention relates to a processing method using plasma.

As is well known, etching and CV using plasma
D (Chemical Vapor Deposition) There are various methods, but they all have one thing in common: they utilize chemical reactions between plasma and the substrate to be processed. Conventionally, these reactions involve the use of activated particles in the plasma. Although it is faster than a thermal process, it has the disadvantage that the number and energy of particles incident on the substrate are insufficient, so that deposition and etching compete with each other, resulting in poor etching speed and poor film properties.

The present invention applies ultrasonic vibrations to a workpiece such as a substrate in contact with plasma to bring it into contact with plasma while mechanically vibrating minutely, thereby activating a chemical reaction on the surface of the workpiece and attaching the workpiece. The present invention provides an etching method or CVD method that removes the kimono and has high selectivity, high etching rate, and uniformity of etching and deposition.

The present invention will be explained in detail below.

In so-called plasma processes such as dry etching and plasma CVD, reactions occur due to physicochemical interactions between plasma and the substrate surface. Therefore, if the reaction can be promoted from the outside by some means, the above-mentioned drawbacks of the conventional methods should be improved. The present invention was made based on this idea, and focuses on ultrasonic waves as energy not present in plasma, and uses this as an energy source to promote reactions.

FIG. 1 is a schematic diagram showing an embodiment of the present invention and the configuration of a dry etching device that uses ultrasonic vibration.
An example in which a parallel plate high-frequency discharge type plasma etching apparatus is used as the dry etching apparatus is shown. 1st
In the figure, the symbol 1°2 indicates an electrode, and input from a power source 3 is supplied to the electrode 2 through a matching box 4 to generate plasma 5 and etch the sample 6.

The above is the configuration of a normal etching apparatus, but in the present invention, an ultrasonic vibrator 7 is further attached and used. When this ultrasonic vibrator 7 is vibrated at a frequency of 5KH2 or more, the vibration is supplied to the sample 6 through the electrode 2 that is in close contact with the ultrasonic vibrator 7. Therefore, the sample 6 undergoes minute mechanical vibrations at the same frequency as the frequency of the imager 7. On the other hand, since mechanical vibrations generated by ultrasonic waves hardly propagate inside the plasma, the relative position between the plasma 5 and the sample 7 changes depending on the frequency of the vibrator 7. This action is an important factor that promotes the entire etching reaction. For example, when etching Si with CF4 gas plasma, the pressure is 0.1 Torr.

When ultrasonic vibration of 20KH2 is supplied to the sample under the condition of 200W input, an artificial ching rate of 1000 people/- is obtained, which is approximately 1.5 times lower than the value of 700 people/- when no ultrasonic vibration is supplied.
It has doubled.

Furthermore, the etching speed of the etching material and the etching speed of the mask material (for example, photoresist) can be changed by setting the vibration amplitude and frequency of the vibrator. This phenomenon is due to the effect of ultrasonic vibrations imparting energy to chemically active particles adsorbed on the material to be etched, and resonantly promoting a reaction with the material to be etched. For example, Si
In order to etch O and O at the same frequency and at the same speed, more than 10 times the oscillator energy required for etching Si is required, and these are photoresists.

It varies depending on the material such as 8iN. frequency 110
If the temperature is 0 KH2 or higher, vibration damping within the stainless steel occurs, but chemical reactions tend to become active.

Etching using the present invention also has excellent uniformity of etching depth. This is due to periodic minute changes in the position of the etching material relative to the plasma. Ueno 1
The error in etching depth within - is less than ±5%, which is superior to ±10% in the conventional method.

The present invention is effective not only in the parallel plate type etching apparatus shown in FIG. 1, but also in a microwave plasma etching apparatus. FIG. 2 is a configuration diagram when an ultrasonic sensor is attached to a well-known microwave etching apparatus. Sample 11
An ultrasonic vibrator 13 was attached to the sample stage 12 on which the sample 11 was placed, and the ultrasonic vibrations applied to the sample 11 promoted the separation between the sample 11 and the plasma 14.

In FIG. 2, the symbol 15 represents a vacuum chamber, 16 a magnetron, 17 and 18 a magnet, 19 a gas supply hole, and 20 an exhaust port.

In the present invention, as shown in FIG.
The table 22 on which the device is placed may be composed of an ultrasonic vibrator 23 and an exterior material 24 such as a quartz plate. In this case, the sample is directly imaged and the reaction promoting effect of the ultrasonic waves is enhanced, making the etching speed about 30% faster than in the case shown in FIG.

FIG. 4 shows another embodiment of the present invention, and shows an example in which the present invention is applied to plasma CVD. If an ultrasonic vibrator 33 is attached to the sample stage 32 on which the deposition substrate 31 is placed and the sample 31 is vibrated when depositing a film using the plasma 38, the denseness of the deposited film obtained is significantly improved, and the film is The optical properties and electrical properties of this method are close to those of thermal CVD. The above effects in plasma CVD are caused by effects similar to those in etching.

In addition, in FIG. 4, symbol 34 is a vacuum chamber, 35 is a power supply,
36 represents a matching box, and 37 represents a power source, respectively.

The present invention is also effective as a countermeasure against contamination in processes using dry etching and plasma CVD equipment. In FIGS. 1, 2, and 4, ultrasonic vibrations are attached to the walls of the vacuum chambers 8, 15, and 34 during etching and deposition.
Alternatively, if vibration is applied before and after etching and before and after deposition during cleaning, the amount of contaminants from the vacuum inner wall and electrodes will be about 172 compared to when vibration is not applied. The frequency of the vibrator is 20
~60KH2 is the most effective, but effects can also be seen at higher frequencies.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and the final diagram are schematic diagrams showing different embodiments of the present invention, respectively. FIG. 3 is a diagram showing a cross-sectional structure of a part of the sample stage used in the present invention. 1...electrode, 2...electrode, 3...power supply, 4...
Matching box, 5... Plasma, 6... Sample, 7... Ultrasonic vibrator, 8... Vacuum chamber, 9... Power supply, 1-1... Gas supply port, 1- 2...Exhaust, 11
... Sample, 12... Sample stage, 13... Ultrasonic transducer, 14... Plasma, 15... Vacuum chamber, 16...
・Magnetron, 17...Magnet, 18...Magnet, 19...Gas supply port, 20...Exhaust, 2
DESCRIPTION OF SYMBOLS 1... Sample, 22... Sample stage, 23... Ultrasonic vibrator, 24... Exterior material, 31... Deposition substrate, 32
...Sample stage, 33...Ultrasonic sensor, 34...Vacuum chamber, 35...Power source, 36...Matching box, 37...%1 Figure 3 Figure 4

Claims (1)

[Claims] 1. A plasma processing method, characterized in that the surface of the workpiece placed in a reaction vessel is treated by applying ultrasonic vibration to the workpiece and bringing the workpiece into contact with plasma.