JPS59231817A - Microwave plasma processing apparatus - Google Patents

Abstract

PURPOSE:To realize a high processing rate without damaging a specimen by a method wherein the maximum amplitude of an electric field of a standing wave is positioned between a gas inlet and a plazma nozzle. CONSTITUTION:A gas inlet 29 and a plazma nozzle 26 are provided having the position of the maximum amplitude E' of an electric field of a standing wave B generated in a plasma generating chamber 24. With a microwave plasma processing apparatus, a prescribed mixed gas is introduced through the inlet 29 into the generating chamber 24 and a specimen processing chamber. Then a plasma is generated by the action of a microwave (a) generated by a microwave generator 31 against the mixed gas in the generating chamber and the plasma etching gas is introduced into the processing chamber 21. Because the mixed gas flows through the position of the maximum amplitude of the electric field of the standing wave B, the maximum plasma generating efficiency is obtained and an etching rate of a specimen 27 is increased. Moreover, as the specimen 27 is completely shielded from the plasma, deterioration of characteristics caused by damage of a semiconductor element is not produced.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to improvements in microwave plasma processing equipment.

(b) Conventional technology and problems When performing conventional plasma processing, for example, a plasma generation chamber and sample processing as shown in Fig. 1 are required to prevent damage to samples such as silicon substrates and to ensure uniformity of sample processing. A microwave plasma processing apparatus is used in which a chamber is separated by a shielding plate having a predetermined plasma ejection hole (shield hole). That is, in the same figure, sample processing chamber l
is evacuated to a vacuum via an exhaust port 2, and a plasma generation chamber 4, which is a part of a waveguide 3, is provided above the sample processing chamber 1.

A shielding plate 5 (a part of the waveguide) interposed between the plasma generation chamber 4 and the sample processing chamber l serves as a partition wall for separating the compartments, and the shielding plate 5 has a predetermined plasma ejection hole. 6(
A plurality of seal holes are provided to communicate with the compartments. A sample stage 8 on which a sample 7 is placed is provided within the sample processing chamber 1 .

Further, the plasma generation chamber 4, which is a part of the waveguide 3, is provided with a gas inlet 9 in a part thereof, and has a microwave transmission window io.
A waveguide 8 having a dimension of 318 and a microwave oscillator 11 are connected as shown in the figure.

When plasma processing the sample 7 using the microwave plasma processing apparatus configured as described above, the sample 7 is placed on the sample stage 8, evacuated from the exhaust port 2, and then evacuated from the gas inlet 9. A desired processing gas is introduced to adjust the inside of the plasma generation chamber 4 and sample processing chamber 1 to a predetermined degree of vacuum. Next, the microwave oscillator 11 is activated, and a 2.415 GHz microwave is applied to the processing gas in the plasma generation chamber 4 through the waveguide 3 to generate plasma, and a plasma etching gas consisting mainly of radicals is generated. The sample 7 is introduced into the sample processing chamber 1 through the plasma ejection hole 6 and subjected to etching treatment.

In this case, a standing wave A is generated in the plasma generation chamber, which is a part of the waveguide, as shown in the figure, but in the conventional device, special attention must be paid to the arrangement relationship between the gas inlet 9 and the plasma ejection hole 6. is not carried out, and the introduced processing gas exceeds the maximum amplitude (t) of the electric field of the standing wave in the plasma generation chamber 4.
As shown in the diagram, the plasma generation efficiency of the processing gas may not reach its maximum and the etching rate of the sample 7 may not increase, resulting in poor efficiency. There was a problem.

(0) Object of the Invention The object of the present invention was made in view of the above problems, and is to provide a microwave plasma processing apparatus that can obtain a high efficiency processing rate without damaging the sample.

(d) Structure of the Invention In order to achieve the object, the present invention comprises a microwave generator, a waveguide extending from the microwave generator, and a gas An apparatus comprising: a plasma generation chamber provided with an introduction hole; and a sample processing chamber that is in contact with the plasma generation chamber and communicates with the plasma injection hole via the plasma injection hole, the apparatus comprising: a plasma generation chamber provided with an introduction hole; It is characterized in that there is at least one position where the amplitude of the electric field of the standing wave is maximum.

") Examples of the invention Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram of a microwave plasma processing apparatus according to an embodiment of the present invention. In the figure, 21 is a sample processing chamber, 22 is an exhaust port, 23 is a waveguide having dimensions of J Engineering S standard, 24 is a plasma generation chamber which is a part of the waveguide, 2
5 is a shielding plate, 26 is a plasma ejection hole (shield hole), 2
7 is a sample, 28 is a sample mounting table, 29 is a gas inlet, 30
3 shows a microwave transmission window, and 31 shows a microwave generator.

The difference between the microwave plasma processing apparatus according to the embodiment of the present invention and the conventional one is that, as shown in the figure, the gas inlet 29 and the plasma The point is that an ejection hole 26 is provided.

In this example, the height of the plasma generation chamber 24, which is a part of the waveguide 23, that is, the internal dimension in the direction of the electric field, is reduced to, for example, about 0.8 m to increase the microwave density of 2.45 GHz and increase the plasma generation efficiency. Improving.

The length of the plasma generation chamber 24 is set to 74, which is about half the wavelength of the microwave in the tube.

Using a microwave plasma processing apparatus having such a structure, a predetermined mixed gas of carbon tetrafluoride (CF4) and oxygen (02) is introduced into the plasma generation chamber 24 and the sample processing chamber 2 through the gas inlet 29.
1 and evacuated from the exhaust port 22 so that the degree of vacuum becomes o, s'rorr. Next, microwave generator 3
1 to generate a 2.45 GHz microwave, which acts on the mixed GAN in the plasma generation chamber 24 through the waveguide 23 and the microwave transmission window 30 to generate plasma, which mainly consists of radicals. Plasma etching gas is introduced into the sample processing chamber 21 through the plasma jet hole 26, and the sample 27 on the sample mounting table 28, such as a silicon substrate, is etched. In such a case, the mixed gas passes through the position of the maximum amplitude of the electric field of the standing eB generated in the plasma generation chamber, so that the plasma generation efficiency is maximized, and the etching v-) of the silicon substrate of sample 27 is lower than that of the conventional etching process. The value is about twice as high. Furthermore, since the sample 27 is completely shielded from the plasma by the shielding plate 25 and the plasma ejection hole (shield hole), no characteristic deterioration due to damage to the semiconductor element formed on the silicon substrate surface occurs.

(2) As described in detail, the microwave plasma processing apparatus according to the present invention enables high efficiency processing rates without damaging the sample, and is effective for increasing efficiency in the manufacturing process of semiconductor devices. It is.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a conventional device, and FIG. 2 is a schematic diagram of an embodiment of the present invention. In the figure, 21 is a sample processing chamber, 23 is a waveguide, 24 is a plasma generation chamber, 26 is a plasma ejection hole, 27 is a sample,
29 is a gas inlet, 31 is a microwave generator, B is a standing wave, and E' is the maximum amplitude of the microwave electric field.

Claims (1)

[Claims] A microwave generator, a waveguide extending from the microwave generator, a plasma generation chamber forming a part of the waveguide and provided with a gas inlet, and in contact with the plasma generation chamber. An apparatus comprising a sample processing chamber communicating with the plasma nozzle through the plasma nozzle, wherein a position where the amplitude of the electric field of the standing wave is maximum is located between the gas introduction port and the plasma nozzle. This microwave plasma processing equipment is characterized by having at least one location.