JP2928555B2 - Plasma processing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a plasma processing apparatus, and more particularly to a plasma processing apparatus suitable for processing a sample such as a semiconductor substrate using plasma.

[Conventional technology]

For example, among semiconductor manufacturing process technologies, the importance of so-called dry process technology using gas plasma such as dry etching, sputtering, and plasma CVD has been increasing with the progress of finer patterns due to higher integration of devices. It is. In particular, in submicron level devices, higher precision etching and higher quality thin film formation are required, and processes using high density plasma at a lower gas pressure than in the past have been dominant.

Conventionally, in a plasma processing apparatus using plasma in a low gas pressure region of, for example, 0.2 Pa or less, in order to easily start discharge, the gas pressure in the processing chamber is temporarily reduced by one before and after application of a high voltage. A method has been used in which plasma is generated by increasing the pressure to about several Pa, and the process is started after the gas pressure is gradually reduced to a desired process pressure while maintaining the second plasma. Related devices of this type include, for example, Japanese Utility Model Application Laid-Open No. 63-90830.

Further, as another conventional technique, there is known a technique in which a mechanism for generating an arc discharge by applying a high voltage to a processing chamber is provided, thereby generating plasma. Related devices of this type include, for example, JP-A-59-17237.
And the like.

[Problems to be solved by the invention]

While the demand for clean semiconductor manufacturing equipment is increasing due to the miniaturization of patterns accompanying the high integration of semiconductor devices in recent years, single-wafer processing apparatuses are becoming popular in order to perform strict control of process parameters.

Looking at the above prior art from this point of view, in the former, the partial pressure of impurities in the process gas is reduced by the use of low-pressure plasma, and while moving in the direction of cleanliness,
When plasma is generated, the pressure is increased by an order of magnitude, causing a contradictory phenomenon that the degree of cleanliness is reduced. In addition, there is a problem that particles in the processing chamber are often wound up.

In addition, when the process gas pressure is temporarily increased, it is necessary to wait for the start of the process until the process gas pressure reaches the actual process pressure. Points.

In the latter case, it is necessary to install an electrode for generating an arc discharge by applying a high voltage in the substrate processing chamber, which causes problems such as heavy metal contamination, generation of particles due to adhesion and separation of a film-forming substance, and the like. It was easy to happen.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a clean and high-throughput plasma processing apparatus.

[Means for solving the problem]

The above object is to provide a vacuum processing chamber having a plasma generation means, which is set to a processing pressure which is a gas pressure under conditions where plasma is hardly generated when a sample is placed, and a plasma processing chamber which is preliminarily set to a pressure at which plasma is easily generated. Is generated, and then provided between the plasma processing chamber and the plasma processing chamber in which the plasma is maintained in accordance with the processing pressure in the vacuum processing chamber, and between the vacuum processing chamber and the plasma generating chamber. A vacuum shut-off means capable of opening and shutting off the gas. When the pressure of the gas introduced into the vacuum processing chamber is stabilized at the processing pressure, the vacuum shut-off means is opened and the plasma in the plasma generation chamber is introduced into the vacuum processing chamber. In addition, plasma is generated in the vacuum processing chamber by the plasma generating means, and after the plasma is generated, the vacuum shut-off means can be shut off.

[Action]

The problem with the conventional technology is that the clean processing environment and the stable plasma generation conditions do not always match, and in order to achieve both in one processing chamber, some cost must be paid for contamination and an increase in processing time. Was in

In the present invention, a plasma generation chamber is provided in a vacuum chamber provided with a means for generating plasma for sample processing via a vacuum interception means, and stable plasma is generated in the plasma generation chamber independently of the vacuum chamber. , Can be kept. As a result, plasma can be introduced and processing can be started as soon as a clean processing environment in the vacuum chamber is prepared, and clean plasma processing can be performed without loss of time.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a schematic configuration of a dry etching apparatus used for carrying out the present invention. The apparatus comprises a load lock chamber 10 for loading and recovering a sample, an etching chamber 20 for performing an etching process on a wafer 50 as a sample, and a plasma generating chamber 30 for generating and holding plasma. They are isolated and communicated with each other via 40 and 41. In the etching chamber 20, for generating plasma together with the gas supply device 21 and the exhaust device 22,
In this case, the etching electrode 24 to which the high-frequency power source 23 is connected
And a counter electrode 25. The plasma generation chamber 30 has a gas supply device 21, an exhaust device 31, and a plasma generation device.
In this case, an electrode 32 and a high-frequency power supply 33 are provided.
In FIG. 1, an etching chamber 20 is a vacuum chamber provided with a means for generating plasma for sample processing. Also, gate valve 41
However, in this case, it corresponds to a vacuum interception means.

Next, a dry etching method using the above apparatus will be described.

First, the wafer 50 is loaded into the load lock chamber 10, and the inside of the load lock chamber 10 is depressurized to a predetermined pressure by the exhaust device 11, then the gate valve 40 is opened to communicate with the etching chamber 20, and a transfer (not shown) The gate valve 40 is closed by placing one wafer 50 on the etching electrode 24 by means, in this case, one.

On the other hand, an etching gas is introduced into the plasma generation chamber 30 from the gas supply device 21 in advance, and a high frequency is applied to the electrode 32 from the high frequency power supply 33 to generate plasma. The plasma generation conditions at this time need not be the same as the etching processing conditions in the etching chamber 20, and conditions under which plasma is most easily generated can be selected. After the plasma is generated and stabilized, the plasma is maintained in accordance with the gas pressure in the plasma generation chamber 30 during the etching process in the etching chamber 20.

After the wafer 50 is loaded into the etching chamber 20, the etching gas is introduced from the gas supply device 21, and when the gas pressure is stabilized, the gate valve 41 is opened, and the plasma in the plasma generation chamber 30 is introduced into the etching chamber 20. At the same time as the electrode
A high frequency is applied to 24 from a high frequency power supply 23 to generate plasma. After the plasma is generated, the gate valve 41 is closed, and the etching of the wafer 50 is started.

After completion of the etching process, the supply of the etching gas is stopped, the inside of the etching chamber 20 is exhausted by the exhaust device 22, and the wafer is passed through the gate valve 40 and the load lock chamber 10.
Collect 50.

Hereinafter, the above steps are repeated to perform the processing.During this time, the plasma can be constantly maintained in the plasma generation chamber 30, or the plasma can be generated and erased each time one wafer is processed. Needless to say, there is.

According to the present embodiment, since it is not necessary to temporarily increase the gas pressure in the etching chamber for starting discharge or to use arc discharge, the wafer can be etched in a clean processing environment. At the same time, it is possible to suppress an increase in the time required for the process pressure to reach the etching processing pressure in the etching chamber, thereby shortening the wafer etching processing time and thereby improving the throughput. Also, during the processing of the wafer in the etching chamber, the plasma generation chamber is isolated from the etching chamber, so that the reaction products generated in the etching processing of the wafer in the etching chamber enter the plasma generation chamber and contaminate it. Can be prevented.

The plasma generating means in the vacuum chamber and the plasma generating means in the plasma generating chamber are not particularly limited to the one embodiment. For example, as these means, means for converting gas into plasma by microwave discharge (magnetic field, no magnetic field), means for converting gas into plasma by discharge such as magnetron discharge, means for converting gas into plasma by excitation of light energy, and the like are available. Can be adopted. Further, the etching chamber of the above embodiment is
The chamber may have a plasma generation region and a processing region in which the wafer is etched by the plasma transported from the plasma generation region. Further, in the above-described embodiment, an apparatus for performing an etching process using a plasma is described.Other devices, for example, a device for performing a film forming process using a plasma, such as a CVD device, or the like, for example, plasma ashing, The present invention can be similarly applied to a stripping apparatus and the like.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to this invention, there exists an effect which can provide the plasma processing apparatus with a clean and high throughput.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a dry etching apparatus according to one embodiment of the present invention. 20 ... Etching chamber, 21 ... Gas supply device, 22,31 ...
Exhaust device, 23, 33 RF power supply, 24 Etching electrode, 25 Counter electrode, 30 Plasma generating chamber, 32 Electrode, 41 Valve gate, 50 Wafer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI H05H 1/46 H01L 21/302 C (72) Inventor Hiroji Nishihata 794, Higashi-Toyoi, Kazamatsu, Yamaguchi Prefecture Hitachi, Ltd. Kasado Plant, Hitachi, Ltd. (72) Inventor: Atsushi Ito, 794, Higashi-Toyoi, Kazamatsu, Kamamatsu, Yamaguchi Prefecture Inside the Kasado Plant, Hitachi, Ltd. 56) References JP-A-60-43489 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C23F 4/00 H01L 21/3065, 21/205, 21/31 H05H 1 / 46

Claims (1)

(57) [Claims] A vacuum processing chamber having a plasma generating means, wherein the processing pressure is set to a processing pressure which is a gas pressure under which plasma is hardly generated when a sample is placed; Plasma is generated, and thereafter, a plasma generation chamber in which the plasma is maintained in accordance with the processing pressure in the vacuum processing chamber, provided between the vacuum processing chamber and the plasma generation chamber, and the vacuum processing chamber and the Vacuum interception means capable of opening and shutting off the plasma generation chamber, and opening the vacuum interception means when the pressure of the gas introduced into the vacuum processing chamber is stabilized at the processing pressure, Plasma in the chamber is introduced into the vacuum processing chamber, and plasma is generated in the vacuum processing chamber by the plasma generating means. Plasma processing apparatus characterized by being capable interrupting means.