JP2002033307A - Plasma generator and plasma processing apparatus provided with the same - Google Patents

Abstract

(57) [Problem] To provide a plasma generating apparatus for generating plasma capable of improving in-plane uniformity of processing of an object to be processed, and a plasma processing apparatus including the same. SOLUTION: It has a cylindrical vacuum wall 4 which forms a plasma generation region 6 inside. A cylindrical dielectric 2 is provided along the inner peripheral surface of the cylindrical vacuum wall 4. The microwave waveguide 1 is connected to the outer peripheral surface of the cylindrical vacuum wall 4. In order to radiate the microwave guided by the microwave waveguide 1 to the annular plasma generation region 6 via the cylindrical dielectric 2, the inner space of the microwave waveguide 1 and the outer peripheral surface of the cylindrical dielectric 2 And an opening 3 is formed between the two.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma generator and a plasma processing apparatus provided with the same.
The present invention relates to a plasma generating apparatus for processing an object to be processed using plasma generated by irradiating a process gas with microwaves, and a plasma processing apparatus including the same.

[0002]

2. Description of the Related Art As an apparatus for processing an object to be processed such as a silicon wafer for manufacturing a semiconductor or a glass substrate for a liquid crystal display, a plasma for performing a dry etching process, an ashing process, or the like on the object using microwave plasma. There is a processing unit. Surface treatment such as fine processing and thin film formation by plasma technology using this plasma processing apparatus is an indispensable technique for, for example, high integration of semiconductors.

There are several types of plasma processing apparatuses. For example, high-frequency power is supplied to an antenna and applied to a process gas in a vacuum vessel to generate plasma.
There is a type in which an object to be processed is subjected to a dry etching process or the like using this plasma. More specifically, the microwave guided by the microwave waveguide is radiated from an opening (slot antenna) formed in the microwave waveguide, and introduced into the vacuum vessel through the microwave transmission window member. In some cases, a plasma is generated by irradiating a process gas in a vacuum container with microwaves, and the plasma is used to perform a surface treatment such as microfabrication or thin film formation on an object to be processed.

This type of plasma processing apparatus includes a plasma processing apparatus in which plasma generated inside a vacuum vessel is brought into contact with the surface of an object to be processed, and a surface treatment such as dry etching or ashing is performed using active species or the like in the plasma. There is a method in which a generation region and a processing chamber are separated from each other, and a downflow from plasma is guided to a surface of a processing object to perform a surface treatment such as dry etching or ashing.

[0005]

When a plasma is generated by microwaves and the object is processed using the plasma, it is desirable that the processing speed be uniform over the entire surface of the object to be processed. It is. However, if the density distribution of the plasma formed in the vacuum chamber is not uniform, the processing speed on the surface to be processed also becomes uneven.
For example, in the case of an apparatus configuration in which the object to be processed is arranged in the center of the vacuum container and the plasma generation unit is located directly above the object to be processed, the density of the plasma formed inside the vacuum container is The processing speed tends to be higher at the central portion and lower at the peripheral portion. As a result, the processing speed at the central portion of the object to be processed becomes faster than that at the peripheral portion.

Accordingly, in order to uniformly treat the entire surface of the object to be treated, the supply amount of particles such as active species and ions supplied from the plasma to the surface of the object to be treated, such as active species and ions. However, it is important that it is uniform over the entire surface to be processed.

The present invention has been made in view of the above-mentioned circumstances, and has a plasma generating apparatus for generating plasma capable of improving in-plane uniformity of processing of an object to be processed, and the apparatus. It is an object to provide a plasma processing apparatus.

[0008]

In order to solve the above-mentioned problems, a plasma generating apparatus according to the present invention comprises a cylindrical vacuum wall forming a plasma generating region inside, and a peripheral wall along the inner peripheral surface of the cylindrical vacuum wall. A cylindrical dielectric, a microwave waveguide connected to an outer peripheral surface of the cylindrical vacuum wall, and a microwave guided by the microwave waveguide, generating the plasma through the cylindrical dielectric. An opening formed between the internal space of the microwave waveguide and the outer peripheral surface of the cylindrical dielectric is provided for radiating light to a region.

Preferably, an inner cylindrical wall having a diameter smaller than that of the cylindrical vacuum wall is arranged concentrically with the cylindrical vacuum wall to form the plasma generating region in an annular shape.

Preferably, the opening has a slot antenna structure having directivity so that a microwave electric field is radiated in a circumferential direction of the cylindrical dielectric.

[0011] Preferably, a plurality of openings are provided, and microwaves are radiated to the plasma generation region from a plurality of directions.

[0012] Preferably, a plurality of the microwave waveguides are provided.

Preferably, the plurality of microwave waveguides are arranged at equal angular intervals along the circumferential direction of the cylindrical vacuum wall.

In order to solve the above-mentioned problems, the present invention provides a plasma processing apparatus which irradiates a process gas with microwaves to generate plasma and uses the plasma to process an object to be processed. Any of a plasma generator, a vacuum vessel internally forming a vacuum chamber connected to the plasma generation region, and a stage provided inside the vacuum chamber and holding the object to be processed. It is characterized by the following.

[0015] Preferably, the apparatus further comprises means for applying high frequency power to the stage.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Hereinafter, a plasma processing apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the plasma processing apparatus according to the present embodiment has a vacuum vessel 1 in which a vacuum chamber 7 is formed.
3 and a plasma generator 14 formed above the vacuum vessel 13. A stage 11 for holding a workpiece 10 such as a semiconductor wafer is provided inside the vacuum chamber 7.
Is provided, and high frequency power can be applied to the stage 11 by the high frequency bias power supply 12 connected to the stage 11. By applying a bias to the stage 11, it is possible to control the energy when ions in the plasma enter the object 10. A gas inlet 8 for introducing a process gas into the vacuum chamber 7 is formed on a side wall of the vacuum vessel 13. An exhaust port 9 for exhausting the inside of the vacuum chamber 7 is formed in the bottom plate of the vacuum vessel 13.

As shown in FIGS. 1 and 2, the plasma generator 14 has a cylindrical vacuum wall 4 forming a plasma generation region 6 inside, and is in contact with the inner peripheral surface of the cylindrical vacuum wall 4 to form a cylindrical shape. A dielectric 2 is provided around. The upper opening of the cylindrical vacuum wall 4 is sealed by a disk-shaped top plate 15. One microwave waveguide 1 is connected to the outer peripheral surface of the cylindrical vacuum wall 4.

As shown in FIGS. 1 to 3, a pair of openings 3 is formed between the inner space of the microwave waveguide 1 and the outer peripheral surface of the cylindrical dielectric 2, The microwave guided by the tube 1 is radiated from the pair of openings 3 toward the dielectric 2. Microwaves propagated annularly along the cylindrical dielectric 2 are radiated to the plasma generation region 6, and the process gas is excited by the microwaves to generate annular plasma.

Here, the opening 3 has a slot antenna structure in order to enhance the directivity in the direction of electric field emission.
More specifically, the opening 3 has directivity such that a microwave electric field is radiated in a circumferential direction of the cylindrical dielectric 2 (a direction orthogonal to the tube axis of the microwave waveguide 1). In order to achieve this, the antenna has a slot antenna structure extending along a direction parallel to the central axis of the cylindrical dielectric 2. By radiating the microwave electric field in the circumferential direction of the cylindrical dielectric 2, an annular plasma can be efficiently generated inside the plasma generation region 6.

The length of the slot antenna formed by the opening 3 is preferably at least １ ／ of the wavelength of the microwave in the microwave waveguide 1. For example, if the microwave frequency is 2.45 GHz and the internal size of the microwave waveguide 1 is 27 × 96 mm, the microwave waveguide 1
Since the wavelength of the microwave inside the antenna is about 160 mm, it is preferable that the length of the slot antenna is 80 mm or more, and the height of the cylindrical dielectric 2 is also 80 mm or more.

As described above, according to the present embodiment, an annular plasma can be generated above the object to be processed 10, so that active species supplied from the plasma to the surface to be processed of the object to be processed 10 It is possible to make the supply amount of particles such as ions uniform over the entire surface to be processed, thereby improving the in-plane uniformity of the processing of the object 10 to be processed.

Second Embodiment Next, a plasma processing apparatus according to a second embodiment of the present invention will be described with reference to FIGS. Note that the present embodiment is obtained by adding a part of the configuration to the above-described first embodiment, and a portion different from the first embodiment will be described below.

As shown in FIGS. 4 and 5, a pair of microwave waveguides 1 are connected to the outer peripheral surface of the cylindrical vacuum wall 4, and these microwave waveguides 1 have a diameter of the cylindrical vacuum wall 4. They are arranged facing each other on the line. The pair of microwave waveguides 1 is configured by branching one microwave waveguide (not shown) from the middle, and is generated by one microwave oscillation source (not shown). After passing through one microwave waveguide, the microwave is branched into a pair of microwave waveguides 1. As a modification, three or more microwave waveguides 1 can be arranged at equal angular intervals along the circumferential direction of the cylindrical vacuum wall 4.

A plurality of openings 3 are formed between the inner space of the microwave waveguide 1 and the outer peripheral surface of the cylindrical dielectric 2, and the microwave (2) guided by the microwave waveguide 1 is formed. .45 GHz) is radiated from the plurality of openings 3 toward the dielectric 2, and is radiated to the annular plasma generation region 6 via the dielectric 2. The structure of the opening 3 is the same as that of the first embodiment.
This is the same as the embodiment.

As described above, according to the present embodiment, an annular plasma can be generated above the object to be processed 10 as in the first embodiment. It is possible to make the supply amount of particles such as active species and ions supplied to the surface uniform over the entire surface to be processed, thereby improving the in-plane uniformity of the processing of the processing object 10. it can.

Since microwaves are introduced into the annular plasma generation region 6 from a plurality of directions,
The uniformity of the density of the plasma generated in an annular shape can be improved.

Third Embodiment Next, a plasma processing apparatus according to a third embodiment of the present invention will be described with reference to FIGS. Note that the present embodiment is obtained by adding a part of the configuration to the above-described second embodiment, and a portion different from the second embodiment will be described below. As shown in FIGS. 6 and 7, the plasma generators 14 are arranged concentrically with each other and form a cylindrical vacuum wall 4 forming an annular plasma generating region 6 therebetween and a cylindrical vacuum wall 4 having a smaller diameter than the cylindrical vacuum wall 4. It has an inner cylindrical wall 5, and a cylindrical dielectric 2 is provided around the inner peripheral surface of the cylindrical vacuum wall 4. The space between the upper ends of the cylindrical vacuum wall 4 and the inner cylindrical wall 5 is sealed by an annular top plate 15. The density distribution of the generated plasma can be optimized by appropriately selecting the value of the diameter of each of the cylindrical vacuum wall 4 and the inner cylindrical wall 5 or the ratio of the diameters.

As described above, according to the present embodiment, an annular plasma can be generated above the workpiece 10 as in the first and second embodiments. It is possible to make the supply amount of particles such as active species and ions supplied to the surface to be processed uniform over the entire surface to be processed, thereby improving the in-plane uniformity of the processing of the object 10 to be processed. Can be done.

Since microwaves are introduced into the annular plasma generating region 6 from a plurality of directions as in the second embodiment, the uniformity of the density of the annularly generated plasma can be improved. Can be.

Furthermore, the density distribution of the generated plasma can be optimized by appropriately selecting the value of the diameter of each of the cylindrical vacuum wall 4 and the inner cylindrical wall 5 or the ratio of those diameters.

[0032]

As described above, according to the present invention, an annular plasma can be generated. By generating the annular plasma above the object to be processed, the plasma can be generated from the plasma. It is possible to make the supply amount of particles such as active species and ions supplied to the surface to be processed uniform over the entire surface of the surface to be processed, thereby improving the in-plane uniformity of the processing of the object to be processed. Can be.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a schematic configuration of a plasma processing apparatus according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line a-a ′ in FIG.

FIG. 3 is a side view of the plasma processing apparatus shown in FIG.

FIG. 4 is a longitudinal sectional view showing a schematic configuration of a plasma processing apparatus according to a second embodiment of the present invention.

FIG. 5 is a transverse sectional view taken along the line a-a ′ in FIG. 4;

FIG. 6 is a longitudinal sectional view showing a schematic configuration of a plasma processing apparatus according to a third embodiment of the present invention.

FIG. 7 is a transverse sectional view taken along the line a-a ′ in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microwave waveguide 2 Cylindrical dielectric 3 Opening 4 Cylindrical vacuum wall 5 Inner cylindrical wall 6 Plasma generation area 7 Vacuum chamber 8 Gas introduction port 9 Exhaust port 10 Workpiece 11 Stage 12 High frequency bias power supply 13 Vacuum container 14 Plasma generator

Claims (8)

[Claims] 1. A cylindrical vacuum wall forming a plasma generation region inside, a cylindrical dielectric provided along an inner peripheral surface of the cylindrical vacuum wall, and a cylindrical dielectric wall connected to an outer peripheral surface of the cylindrical vacuum wall. The microwave waveguide, and the internal space of the microwave waveguide and the cylindrical shape to radiate the microwave guided by the microwave waveguide to the plasma generation region through the cylindrical dielectric. An opening formed between the dielectric and an outer peripheral surface of the dielectric. 2. The plasma generator according to claim 1, wherein an inner cylindrical wall having a diameter smaller than that of said cylindrical vacuum wall is arranged concentrically with said cylindrical vacuum wall to form said plasma generating region in an annular shape. 3. The slot antenna structure according to claim 1, wherein the opening has a directivity such that a microwave electric field is radiated in a circumferential direction of the cylindrical dielectric. Or the plasma generator according to 2. 4. The plasma generating apparatus according to claim 1, wherein a plurality of said openings are provided, and microwaves are radiated from a plurality of directions to said plasma generating region. . 5. The plasma generating apparatus according to claim 4, comprising a plurality of said microwave waveguides. 6. The plasma generator according to claim 5, wherein said plurality of microwave waveguides are arranged at equal angular intervals along a circumferential direction of said cylindrical vacuum wall. 7. A plasma processing apparatus, wherein a plasma is generated by irradiating a microwave to a process gas, and an object to be processed is processed using the plasma. The plasma generation device described above, comprising: a vacuum container internally forming a vacuum chamber connected to the plasma generation region; and a stage provided inside the vacuum chamber and holding the object to be processed. A plasma processing apparatus characterized by the above-mentioned. 8. The plasma processing apparatus according to claim 7, further comprising means for applying high frequency power to said stage.