JPH0634242U - Microwave plasma processing equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To homogenize the distribution of the reactive gas concentration in the radial and circumferential directions on the sample surface. A plurality of jetting components each having a jetting direction component in the radial direction and the circumferential direction toward the surface side of the sample S in the etching chamber 3 and jetting the reactive gas in a vortex shape around the center of the sample S An annular gas supply pipe 7 having a nozzle hole 7c is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a microwave plasma processing apparatus that uses microwaves to generate plasma and uses the plasma to perform film formation, etching, and sputtering processing on a sample surface.

[0002]

[Prior art]

 FIG. 6 is a schematic sectional view showing a conventional microwave plasma processing apparatus disclosed in Japanese Patent Laid-Open No. 1-235326, and 11 in the drawing shows a plasma processing chamber. A hollow spindle-shaped space 12 is formed in the center of the upper wall of the plasma processing chamber 11, and one end of a taper type waveguide 13 is connected to the space 12. A gas supply device 14 is arranged on the peripheral wall of the space 12, and an exciting coil 15 is arranged on the upper part of the plasma processing chamber 11 and the peripheral wall of the waveguide 13 connected thereto.

A sample stage 16 is installed in the center of the inside of the plasma processing chamber 11, and a sample S is placed on the sample stage 16. The gas supply device 14 comprises a plurality of gas supply pipes 14a, 14b, 14c, 14d, of which the gas supply pipe 14a is connected to an annular gas passage 12a formed in the peripheral wall of the space 12. The annular gas passage 12a is provided with a plurality of nozzles, which open obliquely upward and are formed on the inner surface of the peripheral wall of the space 12, and the plasma seed gas supplied to the annular gas passage 12a through the gas supply pipe 14a is discharged from the nozzles into the space 12. It is designed to be ejected inward.

The gas supply pipe 14b is also connected to the annular gas passage 12b formed in the peripheral wall of the space 12. The annular gas passage 12b is provided with a plurality of nozzles that are opened substantially horizontally toward the center side of the space 12 on the inner surface of the peripheral wall of the space 12, and the reactivity supplied to the annular gas passage 12b through the gas supply pipe 4b. The gas is ejected horizontally from the nozzle into the space 12. The gas supply pipe 14c is also connected to an annular gas passage 12c formed in the peripheral wall of the space 12.

The annular gas passage 12c is provided with a plurality of nozzles which are open to the inner surface of the peripheral wall of the space 12 at a downward direction of 30 ° toward the center side of the space 12, and the annular gas passage 12c is provided through the gas supply pipe 14c. The reactive gas supplied to the nozzle is jetted downward from the nozzle by 30 ° into the space 12.

Further, the gas supply pipe 14d is connected to an annular gas passage 12d formed in the peripheral wall of the space 12. In the annular gas passage 12d, there is an opening on the inner surface of the peripheral wall of the space 12 at a downward angle of 60 ° toward the center of the space 12. It is equipped with a plurality of nozzles, and the reactive gas supplied to the annular gas passage 12d through the gas supply pipe is jetted downward from the nozzles into the space 12 by 60 °.

In such a conventional microwave plasma processing apparatus, an electric field by microwaves is formed in the plasma processing chamber 11 through the waveguide 13 and a magnetic field is formed by the exciting coil 15, and the gas is supplied through the gas supply tubes 14a to 14d. A seed gas for plasma and a reactive gas are introduced into the plasma processing chamber 11 and the space 12. As a result, the seed gas for plasma is ionized by electron cyclotron resonance excitation to generate plasma, and the generated plasma is guided toward the sample S side by the divergent magnetic field formed by the exciting coil 15. As a result, the reactive gas is excited or ionized by plasma, activated, moves to the surface of the sample S, and a film is formed on the surface of the sample S.

[0008]

[Problems to be solved by the device]

 By the way, in such a conventional apparatus, when viewed from the sample S side, the reactive gas ejected from each nozzle goes upward and downward of the sample S, so that the gas concentration in the upward and downward directions on the sample S is made uniform. However, there is a problem that the gas concentration in the upper center of the sample S becomes higher than the gas concentration in the peripheral portion, which causes a difference in the film forming rate in the radial direction of the sample S.

The present invention has been made in view of the above circumstances, and its purpose is to make uniform the gas concentration distribution in the upper, lower, and radial directions of the sample surface to form a uniform film or etch rate. It is to provide a microwave plasma processing apparatus capable of achieving the above.

[0010]

[Means for Solving the Problems]

 A microwave plasma processing apparatus according to the present invention converts a gas into a plasma by an electric field generated by a microwave and a magnetic field generated by an excitation coil, and guides the generated plasma to a sample side in a plasma processing chamber to perform plasma processing on the sample. In the processing apparatus, an annular gas supply pipe having a plurality of gas ejection ports for ejecting gas in a vortex shape around the center of the sample is provided in the plasma processing chamber.

[0011]

[Action]

 In the present invention, this makes the gas on the upper surface of the sample vortex-like and makes the gas concentration uniform not only in the upward and downward directions but also in the surface direction of the sample.

[0012]

【Example】

 An embodiment in which the present invention is applied to a plasma etching apparatus will be specifically described below with reference to the drawings. FIG. 1 is a schematic vertical sectional view of a microwave plasma processing apparatus according to the present invention, in which 1 is a plasma generation chamber, 2 is a waveguide, 3 is an etching chamber as a plasma processing chamber, and 4 is an exciting coil. Shows.

The plasma generation chamber 1 is made of stainless steel and is formed in a hollow cylinder shape. The microwave introduction port 1a sealed with a quartz glass plate is provided in the center of the upper side wall, and the lower wall opposite to this is provided. A plasma outlet 1b is opened in the center. One end of a waveguide 2 is connected to the microwave introduction port 1a, and an etching chamber 3 is provided so as to face the plasma extraction port 1b, and the plasma generation chamber 1 and the waveguide connected thereto. An exciting coil 4 is provided around the end portion of 2.

The other end of the waveguide 2 is connected to a magnetron 5, and the microwave generated by this magnetron 5 is introduced into the plasma generation chamber 1 through the waveguide 2. The exciting coil 4 is connected to a constant current power source (not shown) and forms a magnetic field so that plasma is generated by the introduction of microwave into the plasma generation chamber 1 by the flow of current. .

On the other hand, in the etching chamber 3, an exhaust port (not shown) connected to an exhaust system is provided on the lower side wall facing the plasma outlet 1b, and a mounting table is provided in the center facing the plasma outlet 1b. 6 is installed so that the sample S can be detachably fixed to the surface of the mounting table 6 by electrostatic attraction. An annular gas supply pipe 7 is arranged immediately below the upper wall in the etching chamber 3 concentrically with the plasma outlet 1b, in other words, concentrically with the sample S.

FIG. 2 is a plan view of the annular gas supply pipe, and FIG. 3 is an enlarged cross-sectional view taken along the line III-III of FIG. 2, which realizes the uniformization in the vertical direction in the configuration of the present invention. The annular gas supply pipe 7 is formed in an annular shape concentric with the plasma outlet 1b, has a rectangular cross section as shown in FIG. 3, and has a gas passage 7a having a circular cross section in the center. A connection hole 7b for connecting a gas supply pipe is provided at one position in the circumferential direction, and a plurality of (12 in the embodiment) nozzle holes 7c are formed in the inner peripheral wall at intervals of approximately 30 ° in the circumferential direction. As is clear from FIGS. 2 and 3, each nozzle hole 7c is horizontal and is opened at an angle of 45 ° with respect to the radial direction in the inner peripheral wall surface of the annular gas supply pipe 7. The angle of inclination with respect to the radial direction is not particularly limited to 45 ° and may be in the range of 20 ° to 60 °.

As shown in FIG. 4, the reaction gas is blown from the annular gas supply pipe 7 toward the inside of the annular gas supply pipe 7 so as to form a vortex flow. 5 (a) and 5 (b) are sectional views similar to FIG. 3 showing another example of the annular gas supply pipe 7. In the example shown in FIG. 5 (a), the nozzle hole 7d is inclined downward by approximately 30 ° with respect to the horizontal plane, and is inclined 45 ° with respect to the radial direction. The other structure is substantially the same as the structure shown in FIGS.

In the example shown in FIG. 5 (b), the nozzle hole 7c shown in FIG. 3 and the nozzle hole 7d shown in FIG. 5 (a) are combined into a pair to form an inner wall surface of the annular gas supply pipe 7. It has been opened. In the example shown in FIG. 5 (b), the opening positions of the nozzle holes 7c, 7d may be opened on the inner peripheral wall surface of the annular gas supply pipe 7 so as to face upward and downward, but they may be displaced in the circumferential direction. It may be opened. The other structure is substantially the same as that of the annular gas supply pipe 7 shown in FIGS. 2, 3 and 5 (a).

Even in the annular gas supply pipe 7 shown in FIGS. 5 (a) and 5 (b), the reaction gas ejected from the nozzles 7c and 7d forms a vortex flow, and the reaction gas above the mounting table 6 or the sample S is formed. In the containing etching chamber 3, it can be more uniformly distributed not only in the horizontal direction but also in the vertical direction.

Next, the operation of the device of the present invention will be described. In the device of the present invention, the sample S is mounted on the mounting table 6 in the etching chamber 3 through a load lock chamber (not shown). Reactive gas is supplied into the plasma generation chamber 1 and the etching chamber 3 through the annular gas supply pipe 7. Part of the supplied reactive gas is also supplied into the plasma generation chamber 1. Further, a current is passed through the exciting coil 4 to form a magnetic field, and a microwave is introduced through the waveguide 2 to form an electric field to generate plasma by electron cyclotron resonance excitation of gas. The generated plasma is guided to the etching chamber 3 side by utilizing the divergent magnetic field formed by the exciting coil 4.

On the other hand, the reactive gas is also supplied into the etching chamber 3 through each nozzle hole 7c of the annular gas supply pipe 7, and this reactive gas is injected from each nozzle hole 7c and above the sample S. It swirls like a vortex and has a uniform distribution in the upward and downward directions on the sample S and in the radial direction of the sample S, is activated by the plasma introduced into the etching chamber 3, and etches the sample S at a uniform speed. Will be done.

In the case of the annular gas supply pipe 7 shown in FIG. 5 (a), the reactive gas is swirl-supplied in a swirling manner through the nozzle hole 7d, and the annular gas supply pipe 7 shown in FIG. In this case, the reactive gas is likewise swirled and supplied in a swirling manner through the nozzle holes 7c and 7d. Using the device of the present invention and the conventional device, the polysilicon on the surface of the silicon wafer was etched under the condition of pressure of 1 mTorr using 20 sccm of Cl ₂ gas and ₂ sccm of O ₂ gas, and the etching speed uniformity was compared. It was confirmed that the speed difference was 7% in the device, whereas it was 4% in the device of the present invention.

In the above-described embodiment, the annular gas supply pipe 7 is provided with a plurality of nozzle holes 7c, 7d in the circumferential direction, but the number of nozzle holes is not particularly limited. Instead, set it as needed. Further, in the embodiment shown in FIG. 5 (b), the case where the downward inclination angle of the nozzle hole 7d of the annular gas supply pipe 7 is set to 30 ° has been described, but it is not particularly limited to this angle. Instead, it may be appropriately set within the range from the horizontal direction to the vertical downward direction. Further, although the above-mentioned embodiment has explained the constitution in which the present invention is applied to the etching apparatus, it is needless to say that it can be applied to the CVD apparatus and the sputtering apparatus.

[0024]

[Effect of device]

 As described above, in the device of the present invention, the opening direction of the nozzle of the gas supply device is set to incline upward, downward, and circumferentially, so that the gas in the plasma processing chamber becomes a vortex flow and becomes uniform around the sample. The present invention has excellent effects such as uniformization of processing speed such as film forming speed and etching speed, and improvement of uniformity of plasma processing on a sample.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a microwave plasma processing apparatus according to the present invention.

FIG. 2 is a front view of an annular gas supply pipe.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an explanatory diagram showing a jet direction of a reaction gas.

FIG. 5 is a cross-sectional view showing another example of the annular gas supply pipe.

FIG. 6 is a schematic vertical sectional view showing a conventional microwave plasma processing apparatus.

[Explanation of symbols]

 1 Plasma generation chamber 2 Waveguide 3 Etching chamber 4 Excitation coil 7 Annular gas supply pipe 7c, 7d Nozzle hole

Claims (1)

[Scope of utility model registration request] 1. A microwave plasma processing apparatus in which a gas is made into plasma by an electric field generated by microwaves and a magnetic field generated by an exciting coil, and the generated plasma is guided to a sample side in a plasma processing chamber to perform plasma processing on the sample. A microwave plasma processing apparatus, wherein an annular gas supply pipe having a plurality of gas ejection ports for ejecting gas in a vortex shape centered on the center of a sample is provided in a chamber.