JPH1126188A - Plasma device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity of an electronic device by quickly and easily performing plasma ignition. SOLUTION: A plasma device 1 guides a microwave which is generated by a microwave oscillator 10 and is propagated by a waveguide 11, to the vicinity of an opening window part 2a of a reaction vessel 2 in which a plasma chamber 3 is arranged, and is provided with a dielectric plate 12 to make a surface wave generated by its microwave incident on the plasma chamber 3. The plasma device 1 is provided with a plasma ignition means 14 which can freely contact with and separate from the surface of the dielectric plate 12 and introduce the microwave guiding the dielectric plate 12 into the plasma chamber 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a plasma apparatus used in a manufacturing process of an electronic device or the like. More specifically, the present invention relates to a plasma apparatus for performing an etching process or a CVD process on a semiconductor element substrate or the like.

[0002]

2. Description of the Related Art A conventional plasma apparatus will be described with reference to FIG. FIG. 11 is an overall configuration diagram showing a conventional plasma device.

As shown in FIG. 11, in a conventional plasma apparatus 101, a lower electrode 105 connected to a high-frequency power supply 104 and a semiconductor substrate mounted on the lower electrode 105 are placed in a plasma chamber 103 of a reaction vessel 102. 106 are accommodated. The fenestration 102a of the reaction vessel 102 is sealed by a vacuum window 107 formed of a material that transmits surface waves, which will be described later. The reaction chamber 102 is further filled with a process gas such as an etching gas or a CVD gas.
Gas supply means 108 for supplying to the plasma chamber 103 and the plasma chamber 103
A vacuum pump 109 for evacuating the inside is provided.

A dielectric plate 112 on which microwaves generated by the microwave oscillator 110 and propagated through the waveguide 111 are incident is provided above the window 102 a of the reaction vessel 102. Further, a microwave dispersion plate 113 for dispersing microwaves leaked from the dielectric plate 112 is provided between the dielectric plate 112 and the vacuum window 107.

[0005] The plasma apparatus 10 configured as described above
In 1, when microwaves enter the dielectric plate 112,
The microwave is guided while being totally reflected in the dielectric plate 112, and a surface wave is generated at an interface between the inside and the outside of the dielectric plate 112. On the other hand, after the inside of the plasma chamber 103 of the reaction vessel 102 is evacuated by the vacuum pump 109, the process gas is supplied from the gas supply unit 108.

Here, when a surface wave generated at the interface of the dielectric plate 112 is incident on the plasma chamber 103, energy is transmitted to the process gas in a resonant manner, and plasma is generated in the plasma chamber 103. Generated. Then, active species such as radicals and ions are generated in the plasma chamber 103, and the active species reacts with a material to be etched (not shown) on the semiconductor substrate 106, so that the semiconductor substrate 106 is subjected to etching or CVD. Processing and the like are performed.

According to the conventional plasma apparatus 101 configured as described above, high-density plasma can be generated under low pressure. However, on the other hand, there is a problem that the plasma ignitability of the process gas is insufficient.

Since the surface wave is an evanescent wave, the electric field density is highest at the interface of the dielectric plate 112, and the electric field density of the surface wave decreases exponentially as the distance from the dielectric plate 112 increases. Therefore, if electrons generated by spontaneous ionization do not exist in a very limited space in the vicinity of the dielectric plate 112 in the space inside the plasma chamber 103, energy is transmitted to the process gas in a resonant manner by the electric field of the surface wave. Can not do. As a result, plasma ignition is not performed,
No plasma is generated.

Therefore, in the conventional plasma apparatus 101, after setting various conditions such as the composition of the process gas and the gas pressure in the plasma chamber 103 to conditions different from the conditions for the etching process, the CVD process, and the like, Ignition was taking place.

[0010]

However, after performing the plasma ignition as described above, while maintaining the plasma state, various conditions of the process gas in the plasma chamber set for the plasma ignition are changed by the etching process or the like. CV
Changing to the conditions for D processing or the like requires a lot of trouble and time, and is a factor that hinders improvement in productivity of electronic devices.

Furthermore, if the conditions of the process gas for the etching process, the CVD process, etc. after the change are not accurate, the etching process, the CVD process, etc. will not be performed normally, and an electronic device having a defect will be produced. It will be produced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a plasma apparatus capable of performing plasma ignition quickly and easily and improving the productivity of electronic devices.

[0013]

In order to achieve the above object, the present invention provides a plasma apparatus comprising: a reaction vessel section provided with a plasma chamber to which a process gas for generating plasma is supplied; A dielectric plate for guiding microwaves incident from the substrate and for causing surface waves generated by the guided microwaves to enter the plasma chamber. Plasma ignition means is provided for causing the microwave to be waved to enter the plasma chamber.

As a result, since the microwave is directly incident on the plasma chamber, if electrons which are the "seed" of plasma ignition exist in the plasma chamber, they do not necessarily exist in the vicinity of the dielectric plate. Also, plasma ignition is performed to generate plasma.

[0015] The plasma ignition means may further include a microwave pull-in portion into which the microwave guided through the dielectric plate portion enters, and a microwave entering the microwave pull-in portion inside the dielectric plate portion. And a reflection layer portion for allowing the light to enter the interface at an angle of incidence equal to or less than the critical angle at the interface on the plasma chamber side with the outside.

According to the plasma apparatus configured as described above, when the microwave is totally reflected and guided by the dielectric plate, the microwave pull-in portion of the plasma ignition means is connected to the dielectric plate. When brought into contact with the surface, since the refractive indices of the microwave inlet and the dielectric plate are almost the same, the microwave guided through the dielectric plate does not undergo total reflection and enters the microwave inlet. I do. The microwave that has entered the microwave inlet is reflected by the reflection layer of the plasma ignition means.
Since the microwave reflected by the reflection layer portion is incident on the interface between the inside and the outside of the dielectric plate portion at a critical angle or less at the interface on the plasma chamber side between the inside and the outside, the microwave passes through the dielectric plate portion, It is directly incident on the plasma chamber.

Thus, if electrons serving as "seed" for plasma ignition are present in the plasma chamber, plasma ignition is performed and plasma is generated even if they do not necessarily exist near the dielectric plate. You.

Further, the reflection layer portion is divided into a plurality of surfaces, and each surface of the divided reflection layer portion concentrates the microwaves having entered the microwave pull-in portion on a part of the plasma chamber. By adopting a configuration in which it is oriented so as to reflect, the microwave reflected by the reflection layer of the plasma ignition means is concentrated in a certain part in the plasma chamber, so that the The energy density is increased, and the plasma ignitability is improved.

Further, the reflection layer portion is formed to have a curved surface having a curvature such that the microwave entering the microwave inlet portion is concentrated and reflected in a part of the plasma chamber. Also in this case, since the microwave reflected by the reflection layer of the plasma ignition means is concentrated in a certain part in the plasma chamber, the energy density of the microwave at that location is increased, and the plasma ignition property is improved.

A plurality of the plasma ignition means are provided, and each of the plasma ignition means is arranged so as to be directed so that the microwave guided through the dielectric plate portion is concentrated and reflected at one point in the plasma chamber. With this configuration, the microwave reflected by the reflection layer of the plasma ignition means is concentrated at a certain point in the plasma chamber, so that the energy density of the microwave at that point is further increased, and the plasma ignition property is improved. Is further improved.

Further, even when the plasma ignition means is configured to have a curvature such that the microwave guided through the dielectric plate portion is concentrated and reflected at one point in the plasma chamber, the plasma ignition means may be used. Since the microwave reflected by the reflection layer of the means is concentrated at a certain point in the plasma chamber, the microwave energy density at that point is further increased, and the plasma ignitability is further improved.

[0022]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an overall configuration diagram of one embodiment of the plasma apparatus of the present invention, and FIG. 2 is a cross-sectional view showing the plasma ignition means and the dielectric plate shown in FIG. However, the reaction vessel 2, plasma chamber 3, high-frequency power supply 4, lower electrode 5, semiconductor substrate 6, vacuum window 7, gas supply means 8, vacuum pump 9, microwave oscillator 10, waveguide 11, dielectric shown in FIG. Body plate 1
2. Since each configuration of the microwave dispersion plate 13 is the same as the configuration of the conventional plasma apparatus 101 shown in FIG. 11, detailed description thereof will be omitted, and only the configuration different from the conventional one will be described below.

As shown in FIG. 1, the plasma device 1 of the present embodiment is provided with a plasma ignition means 14.
Further, as shown in FIG. 2, the plasma ignition means 14 includes a microwave inlet 15 provided on a surface of the dielectric plate 12 opposite to the plasma chamber 3, and a dielectric plate 12 of the microwave inlet 15. And a reflective layer 16 that covers a part or all of the surface that is not in contact. Thereby, the microwave pull-in portion 15 has a reflective layer surface 14 a covered with the reflective layer 16 and a microwave pull-in surface 14 b in contact with the dielectric plate 12.

The microwave pull-in portion 15 is desirably formed of the same material as the dielectric plate 12, but is also made of a material having a high microwave permeability and a high refractive index similar to that of the dielectric plate 12. What is necessary is just to be formed. The reflection layer 16 is desirably formed of a metal, but may be formed of a material that can reflect microwaves with high reflectance.

The angle of inclination of the reflecting layer surface 14a with respect to the microwave entrance surface 14b is determined by the dielectric plate 12 as described later.
The microwave entering the microwave inlet 15 from the substrate and reflected by the reflection layer 16 forms a critical angle at the interface between the inside and the outside of the dielectric plate 12 on the plasma chamber 3 side (“interface A” shown in FIG. 2). It is set so as to be incident on the interface at the following angles. Further, the plasma ignition means 14 is movable by a driving means (not shown), and the microwave entrance surface 14b can be freely brought into and out of contact with the surface of the dielectric plate 12.

In the plasma apparatus 1 configured as described above, when microwaves are incident on the dielectric plate 12, the microwaves are guided while being totally reflected inside the dielectric plate 12. Here, the driving means is operated to bring the microwave drawing surface 14b of the plasma ignition means 14 into contact with the surface of the dielectric plate 12, as shown in FIGS. Then, the dielectric plate 1
As shown in FIG. 2, the microwave guided while being totally reflected in the dielectric plate 12 is the microwave of the plasma ignition It enters into the draw-in section 15. The microwave that has entered the microwave inlet 15 is subjected to the plasma ignition means 14.
Is reflected by the reflective layer 16 and enters the dielectric plate 12 again. At this time, the microwave reflected by the reflection layer 16 is
Since the light is incident on the interface A at an incidence angle equal to or smaller than the critical angle at the interface between the inside and the outside of the dielectric plate 12 on the plasma chamber side (“interface A” shown in FIG. 2), the light passes through the dielectric plate 12, It is directly incident on the plasma chamber 3 (see FIG. 1).

FIG. 3 is a transparent top view showing the plasma apparatus 1 shown in FIG. 1 and the like. As shown in FIG. 3, since the reflection layer 16 of the plasma ignition means 14 is formed on one plane, the microwave reflected by the reflection layer 16 is incident on the plasma chamber 3 as a parallel wave.

The microwave directly incident on the plasma chamber 3 has no exponential decay of the electric field density like the surface wave described above. Therefore, if electrons serving as “seed” for plasma ignition are present in the plasma chamber 3, the dielectric plate 1 is not necessarily required.
Even if it does not exist in the vicinity of 2, since plasma ignition is performed and plasma is generated, good plasma ignition properties can be obtained.

Thereafter, as shown in FIG. 4, when the plasma ignition means 14 is separated from the dielectric plate 12,
The plasma state is maintained by the surface wave (not shown) generated at the “interface A”. At this time, active species such as radicals and ions are generated in the plasma chamber 3 shown in FIG. 1, and the active species reacts with a material to be etched (not shown) on the semiconductor substrate 6, so that the semiconductor substrate 6 An etching process, a CVD process, or the like is performed.

As described above, in the plasma apparatus 1 of the present embodiment, since the plasma ignition means 14 is provided, the process gas in the plasma chamber 3 can be quickly and easily ignited by the plasma. Furthermore, in the plasma device 1 of the present embodiment, for plasma ignition,
It is not necessary to set various conditions of the process gas in the plasma chamber 3 to conditions different from those for the etching process, the CVD process, and the like. Therefore, it is not necessary to change the condition of the process gas while maintaining the plasma state as in the case of the conventional plasma apparatus, so that the productivity of the electronic device can be improved.

Next, a modified example of the plasma ignition means in the plasma apparatus shown in FIGS. 1 to 4 will be described. FIG. 5 is a sectional view showing a modification of the plasma ignition means described in FIGS. 1 to 4, and FIG. 6 is a sectional view showing the plasma ignition means shown in FIG. 5 in contact with a dielectric plate.

In the plasma ignition means 21 shown in FIG. 5, a reflecting layer 22 for reflecting the microwave incident from the dielectric plate 12 (see FIG. 6) is divided into a plurality of surfaces. Each surface of the divided reflective layer 22 is formed so as to be oriented so that the reflected microwave is concentrated on a part of the plasma chamber 3 (see FIG. 1). In addition, the microwave pull-in unit 23
Are formed similarly to the plasma ignition means 14 shown in FIG.

According to the plasma ignition means 21 of the present modified example configured as described above, as shown in FIG. 6, the microwave reflected by the reflection layer 22 of the plasma ignition means 21
Since it is concentrated on a certain part in the plasma chamber 3 (see FIG. 1), the energy density of the microwave at that part is increased. This makes it possible to improve the plasma ignitability of the process gas as compared with the case where the reflected microwaves are parallel waves, such as the plasma ignition means 14 shown in FIG. 2 and the like.

Next, a further modification of the plasma ignition means in the plasma apparatus described in FIGS. 1 to 4 will be described.
FIG. 7 is a sectional view showing a further modification of the plasma ignition means described in FIGS. 1 to 4, and FIG. 8 is a sectional view showing the plasma ignition means shown in FIG. 7 in contact with a dielectric plate. .

In the plasma ignition means 24 shown in FIG. 7, a reflecting layer 25 for reflecting microwaves incident from the dielectric plate 12 (see FIG. 8) has a curved surface. The curved surface of the reflection layer 25 allows the microwave totally reflected to pass through the plasma chamber 3 (see FIG. 1).
It is formed with a curvature that concentrates on a part of the inside. In addition, the microwave inlet 26 is formed in the same manner as the plasma ignition means 14 shown in FIG.

As a result, as shown in FIG. 8, the microwaves entering from the dielectric plate 12 and being reflected by the reflection layer 25 of the plasma ignition means 24 have a certain portion in the plasma chamber 3 (see FIG. 1). , The energy density of the microwave at that location is increased. As a result, FIG.
As compared with the case where the reflected microwaves are parallel waves, such as the plasma ignition means 14 shown in FIG. 1, the plasma ignitability of the process gas can be improved.

Next, another modification of the plasma ignition means in the plasma apparatus shown in FIGS. 1 to 4 will be described.
FIG. 9 is a transparent top view showing another modified example of the plasma device shown in FIGS.

As shown in FIG. 9, the plasma device of this modification is provided with a plurality of plasma ignition means 27.
Each plasma ignition means 27 is arranged so as to be oriented so as to concentrate the reflected microwave at one point in the plasma chamber 3. The configuration of the reflection layer 28 and the like of each plasma ignition means 27 is the same as that of the plasma ignition means 14 shown in FIG.
It is configured similarly to.

As a result, the microwaves entering from the dielectric plate 12 and reflected by the reflection layer 28 of each plasma ignition means 27 are concentrated at one point in the plasma chamber 3. Therefore, the energy density of the microwave at that location is further increased as compared with the case where the reflected microwave is concentrated in a certain portion as in the plasma ignition means 21 and 24 shown in FIGS. Therefore, the plasma ignitability of the process gas is further improved.

Next, a further modified example of the plasma ignition means in the plasma apparatus shown in FIGS. 1 to 4 will be described. FIG. 10 is a transparent top view showing another modification of the plasma device shown in FIGS. 1 to 4.

As shown in FIG. 10, the plasma ignition means 29 in the plasma device of this modification is formed with a curvature such that the reflected microwave is concentrated at a certain point in the plasma chamber 3. The plasma ignition means 2
The configuration of the reflection layer 30 and the like 9 is the same as that of the plasma ignition means 14 shown in FIG.

As a result, as shown in FIG. 10, the reflection layer 30 of the plasma ignition means 29 which is incident from the dielectric plate 12
The microwave reflected at the point is concentrated at a certain point in the plasma chamber 3, and the energy density of the microwave at that point is increased, so that the plasma ignitability of the process gas is improved.

In the plasma ignition means 27 and 29 shown in FIGS. 9 and 10, the plasma ignition means 1 shown in FIG.
4, the plasma ignition means 27 and 29 are different from the plasma ignition means 2 shown in FIG.
As shown in FIG. 1, the reflective layer surface may be divided into a plurality of surfaces, or the reflective layer surface may be formed as a curved surface like the plasma ignition means 24 shown in FIG. Good.

[0045]

As described above, the plasma apparatus of the present invention is provided with the plasma ignition means for causing the microwave guided through the dielectric plate to enter the plasma chamber. Because it is directly incident,
Good plasma ignitability. Therefore, plasma ignition can be performed quickly and easily, and the productivity of electronic devices can be improved.

Further, the plasma ignition means is provided with a microwave pull-in section into which the microwave guided through the dielectric plate enters.
It is also possible to adopt a configuration having a reflective layer for allowing the entered microwave to enter the interface between the inside and the outside of the dielectric plate at a critical angle or less at the interface between the inside and the outside on the plasma chamber side.

Further, by dividing the reflective layer portion into a plurality of surfaces and forming each surface of the reflective layer portion so as to be directed so as to concentrate and reflect the microwaves to a part of the plasma chamber, the microwaves are formed. Since the energy density of the microwave at the concentrated location is increased, the plasma ignitability of the process gas can be improved.

Further, even when the reflection layer is formed to have a curved surface having a curvature such that the microwaves are concentrated and reflected in a part of the plasma chamber, the microwaves at the portions where the microwaves are concentrated can be formed. Since the energy density is increased, the plasma ignitability of the process gas can be improved.

Further, a plurality of plasma ignition means are provided, and each of the plasma ignition means is oriented and arranged so that the microwave guided through the dielectric plate is concentrated and reflected at one point in the plasma chamber. Since the energy density of the microwaves at the portion where is concentrated is further increased, the plasma ignitability of the process gas can be further improved.

Further, even when the plasma ignition means is formed with a curvature such that the microwave guided through the dielectric plate is concentrated and reflected at one point in the plasma chamber, the microwave at the place where the microwave is concentrated is also obtained. Can be further improved, so that the plasma ignitability of the process gas can be further improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a plasma device of the present invention.

FIG. 2 is a sectional view showing a plasma ignition unit and a dielectric plate shown in FIG. 1;

FIG. 3 is a transparent top view showing the plasma device 1 shown in FIG. 1 and the like.

FIG. 4 is a cross-sectional view showing a state in which the plasma ignition means shown in FIG. 1 is detached from a dielectric plate.

FIG. 5 is a sectional view showing a modified example of the plasma ignition means described in FIGS.

FIG. 6 is a cross-sectional view showing a state in which the plasma ignition means shown in FIG. 5 is in contact with a dielectric plate.

FIG. 7 is a sectional view showing a further modified example of the plasma ignition means described in FIGS.

8 is a cross-sectional view showing a state in which the plasma ignition means shown in FIG. 7 is in contact with a dielectric plate.

FIG. 9 is a transparent top view showing another modified example of the plasma device shown in FIGS.

FIG. 10 is a transparent top view showing another modification of the plasma device shown in FIGS. 1 to 4;

FIG. 11 is an overall configuration diagram showing a conventional plasma device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma apparatus 2 Reaction container 2a Window part 3 Plasma chamber 4 High frequency power supply 5 Lower electrode 6 Semiconductor substrate 7 Vacuum window 8 Gas supply means 9 Vacuum pump 10 Microwave oscillator 11 Waveguide 12 Dielectric plate 13 Microwave dispersion plate 14 , 21, 24, 27, 29 Plasma ignition means 14a Reflection layer surface 14b Microwave entrance surface 15, 28 Microwave entrance portion 16, 22, 25, 28, 30 Reflection layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI // H01L 21/31 H01L 21/302 B

Claims (6)

[Claims] 1. A reaction vessel section provided with a plasma chamber to which a process gas for generating plasma is supplied, a microwave guided from a microwave oscillating section, and the guided microwave. A dielectric plate portion for causing the surface wave generated by the dielectric plate portion to enter the plasma chamber, comprising plasma ignition means for causing microwaves guided through the dielectric plate portion to enter the plasma chamber. A plasma device. 2. The plasma ignition means according to claim 1, further comprising: a microwave inlet into which a microwave guided through the dielectric plate enters; and a microwave entering the microwave inlet into an inside of the dielectric plate. 2. The plasma apparatus according to claim 1, further comprising: a reflection layer portion for causing the light to enter the interface at an angle of incidence equal to or less than a critical angle at the interface between the plasma chamber and the outside at the plasma chamber side. 3. The reflection layer portion is divided into a plurality of surfaces, and each surface of the divided reflection layer portion concentrates a microwave that has entered the microwave pull-in portion on a part of the plasma chamber. 3. The plasma device according to claim 2, wherein the plasma device is formed so as to be reflected. 4. The reflection layer portion is formed to have a curved surface having a curvature such that the microwave entering the microwave pull-in portion is concentrated and reflected in a part of the plasma chamber. The plasma device as described in the above. 5. A plurality of said plasma ignition means,
5. The plasma ignition means according to claim 1, wherein the plasma ignition means is arranged so as to be directed so as to concentrate and reflect the microwave guided through the dielectric plate portion to one point in the plasma chamber. Plasma equipment. 6. The plasma ignition means according to claim 2, wherein the plasma ignition means is formed with a curvature such that the microwave guided through the dielectric plate portion is concentrated and reflected at one point in the plasma chamber. Item 6. The plasma device according to item 1.