JPH1022098A - Plasma device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the active species density uniform, when a processing of a large area substrate is carried out, by forming slots at a specific condition, in a plasma device which leads in a microwave propagated through a microwave waveguide, from the slots to an airtight container through a microwave leading-in window, so as to excite a medium gas. SOLUTION: Plural slots 21 and 22 are formed almost parallel each other to the surface H vertical to the electric field direction of the microwave advancing in a microwave waveguide 9a, and when the wave length of the microwave propagating through a free space is made λ0 , the dielectric constant of a dielectric to form a microwave leading-in window is made ε, and the wave length of the microwave propagating in the microwave waveguide 9a is made λg , the slots 21 and 22 are formed at the slot width d to satisfy the formula: <=λ0 /5, at the slot-to-slot distance D to satisfy the formula 1, and at the slot length L to satisfy the formula 2 (where n is an integral number).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for exciting a medium gas by, for example, introducing a microwave from a slot into an airtight container to generate a plasma, and processing a workpiece by active species generated by the plasma. The present invention relates to a plasma device for use.

[0002]

2. Description of the Related Art In recent years, in the field of plasma processing, an etching apparatus and an ashing apparatus using a microwave have become mainstream. FIG. 18 is a configuration diagram of such a process plasma apparatus.

An airtight container (cavity) 1 is composed of a process chamber 2 and a plasma chamber 3, of which a substrate 4 to be processed (hereinafter referred to as a substrate) such as a liquid crystal substrate is mounted inside the process chamber 2. A processing stage 5 is provided. At the bottom of the process chamber 2,
A gas exhaust duct 6 is provided.

The hermetic container (cavity) 1 has a shape and a shape such that the substrate 4 can be sufficiently accommodated therein, and that the microwave radiated by the microwave waveguide 9 can be uniformly and efficiently entered into the hermetic container 1. It is designed for size and so on.

The plasma chamber 3 contains CF ₄ , O
₂ , a process gas supply device 7 for supplying a process gas (medium gas) used for etching or ashing such as Cl ₂ into the plasma chamber 3 is connected.

[0006] A punching plate 8 as shown in FIG. 19 is provided below the plasma chamber 3 for blocking microwaves and passing active species (radicals) generated by the plasma through the process chamber 2.

On the other hand, a microwave waveguide 9 for propagating microwaves from a microwave source is provided above the airtight container 1. The microwave waveguide 9 has a microwave introduction window 10 at a portion connected to the plasma chamber 3, that is, a plane perpendicular to the direction of the electric field of the microwave traveling in the microwave waveguide 9 (hereinafter, referred to as an H plane). Is connected to the plasma chamber 3 via the.

With such a configuration, a process gas such as CF ₄ , O ₂ , Cl ₂ is supplied into the plasma chamber 3, and the microwave propagating through the microwave waveguide 9 is supplied to the microwave introduction window. When introduced into the plasma chamber 3 through 10, the process gas is excited and a plasma 11 is generated.

[0009] The active species 12 and electrons and ions are generated by the plasma 11, and the active species 12 are supplied to the substrate 4 through the punching plate 8, and the substrate 4 is processed.

By the way, the microwave source used in such an apparatus is inexpensive, can transmit large power relatively easily, and has a high input density (for example, 100 kW / cm) equal to or higher than that of DC pulse discharge. ³ or more) can be obtained a stable discharge even for the reason frequency 2.45GHz widely used in microwave ovens and the like from such
Most adopt a magnetron.

At present, it is necessary to efficiently perform ashing and etching of a large-area substrate such as a liquid crystal substrate or the like. In a commonly used microwave, the wavelength in free space is 12.2 at a frequency of 2.45 GHz.
The size of the plasma 11 is 4 cm, and the generated plasma 11 becomes a strong microwave absorber. In order to prevent this, high-density plasma locally generated near the microwave introduction window 10 is intentionally attenuated by the punching plate 8 to make the active species density distribution on the substrate 4 uniform.

The aperture ratio of the punching plate 8 used for correcting non-uniformity caused by the electron density distribution of the plasma 11 generated as described above has a high active species density distribution proportional to the electron density. It is manufactured so that the aperture ratio of the portion (central portion) is low and the aperture ratio of the portion (peripheral portion) where the active species density distribution is low is high.

For example, if the microwave waveguide 9 is connected on the central axis of the plasma chamber 3 and the microwave is introduced on the central axis of the plasma chamber 3, the punching plate 8 has an aperture ratio of the central part. 3% at the periphery, 60 at the periphery
%.

However, just below the punching plate 8, the uniformity of the active species is still insufficient, so that the active species diffused from the punching plate 8 are regarded as uniform in order to realize the uniformity of the active species. A certain distance (diffusion distance) is required between the punching plate 8 and the substrate 4 until the state is reached.

For this reason, in the current process plasma apparatus, the active species density is not increased by increasing the diffusion distance on the basis of the low plasma density condition in the peripheral portion, but not the high plasma density condition in the central portion. Since the homogenization is performed, the utilization efficiency of the active species generated by the plasma is low.

As a versatile and practical solution, two slots (openings) are formed in the H plane of the microwave waveguide 9 on the upper surface of the microwave introduction window 10 so that microwaves leaking from these slots are superposed. A uniform plasma is obtained by the combination (slot antenna method).

However, the conventional slot antenna system has been put to practical use for a small-scale plasma source for a semiconductor wafer. However, when this technique is used to generate a large-area plasma used for a liquid crystal substrate or the like, However, a sufficiently high plasma density could not be obtained, and the uniformity was low, so that it was not practical.

In view of the above, there is a need for a technique for improving the uniformity of the active species 12 generated by the plasma 11 and processing a large-area substrate at a high speed. In addition, the slot antenna method has a problem that when used for a long time or when a large amount of power is applied, the shape of the slot formed in the microwave waveguide 9 is thermally deformed due to radiant heat from the plasma 11 or the like.

When the slot is thermally deformed as described above,
The operation becomes unstable due to a change in the transmission mode of the microwave waveguide 9 or an increase in microwave reflection.

[0020]

As described above, first, when the plasma generated by directly radiating the microwave propagating in the microwave waveguide 9 is used, the plasma at the peripheral portion on the substrate 4 is used. The density of the active species is adjusted by adjusting the aperture ratio distribution of the punching plate 8 on the basis of the condition that the density of the active species is low, and by making the diffusion distance longer, the active species density is made uniform. Cannot be made uniform.

On the other hand, in the slot antenna system, when the shape of the slot portion formed in the microwave waveguide 9 is thermally deformed due to radiant heat from the plasma 11, the transmission mode of the microwave waveguide 9 changes, or The operation becomes unstable due to an increase in wave reflection and the like.

Accordingly, an object of the present invention is to provide a plasma apparatus capable of making the active species density uniform when processing a large-area substrate. Also, the present invention
Performs stable operation even when receiving radiant heat from plasma,
Further, it is an object of the present invention to provide a plasma apparatus capable of making active species density uniform when performing processing on a large-area substrate.

[0023]

According to the first aspect of the present invention, the microwave propagating through the microwave waveguide is introduced from the slot into the airtight container through the microwave introduction window, and the medium gas in the airtight container is excited. In the plasma device, a plurality of slots are formed substantially parallel to each other on a plane (H plane) perpendicular to the direction of the electric field of the microwave propagating in the microwave waveguide, and the slots define the wavelength of the microwave propagating in free space. Assuming that λ _o , this is a plasma device formed with a slot width d satisfying d ≦ λ _o / 5.

With such a plasma apparatus, for example, uniform plasma can be obtained by superimposing microwave power radiated from two adjacent slots parallel to the microwave traveling direction, for example. The uniformity of the active species in the slot direction is maintained according to the slot length in the traveling direction. Accordingly, a sufficient amount of active species can be supplied to the substrate having a large area so that the etching / ashing process can be efficiently performed in a short time.

According to the second aspect of the present invention, the microwave propagating through the microwave waveguide is introduced from the slot into the hermetic container through the microwave introduction window and the medium gas in the hermetic container is excited. substantially parallel to form together a plurality perpendicular plane (H plane) in the direction of the electric field of the microwaves traveling in the microwave tube, and slots, the wavelength of the microwave propagating in the free space lambda _o, the microwave introduction Assuming that the dielectric constant of the dielectric forming the window is ε,

[0026]

(Equation 3) This is a plasma device formed with a distance D between slots that satisfies the following.

According to the third aspect, in the plasma apparatus for introducing the microwave propagating through the microwave waveguide from the slot into the airtight container through the microwave introduction window and exciting the medium gas in the airtight container, A plurality of slots are formed substantially parallel to each other on a plane (H plane) perpendicular to the direction of the electric field of the microwave propagating in the microwave waveguide, and the slot is defined assuming that the wavelength of the microwave propagating in the microwave waveguide is λ _g , (2n / 3) · λ _g / 2 ≦ L ≦ (4n / 3) · λ _g / 2
(N: an integer).

According to the fourth aspect, the microwave propagating through the microwave waveguide is introduced from the slot into the hermetic container through the microwave introduction window, and the medium in the hermetic container is excited. A plurality of microwaves are formed on a plane (H plane) perpendicular to the direction of the electric field of the microwave propagating in the microwave waveguide, almost in parallel with each other, and the wavelength of the microwave propagating in free space is λ _o , and a microwave introduction window is formed. Assuming that the dielectric constant of the dielectric material to be formed is ε and the wavelength of the microwave propagating in the microwave waveguide is λ _g , a slot width d satisfying d ≦ λ _o / 5 is formed.

[0029]

(Equation 4) And a slot length L that satisfies (2n / 3) · λ _g / 2 ≦ L ≦ (4n / 3) · λ _g / 2.

According to the fifth aspect, the microwave propagating through the microwave waveguide is introduced into the hermetic container from the slot through the microwave introduction window, and the plasma device for exciting the medium gas in the hermetic container is provided with the slot. A plurality of slots are formed substantially parallel to each other on a plane (H plane) perpendicular to the direction of the electric field of the microwave traveling in the microwave waveguide, and the slots have openings formed with a predetermined slot width and a predetermined distance between slots. A first metal plate in which at least a band at the center of the slot formed by these openings is slidably fitted, and each of the openings at both ends of the first metal plate is fitted; A second metal plate that forms each of the openings with a predetermined slot length.

In such a plasma apparatus, when radiant heat from the plasma is received, the central band of the first metal plate thermally expands, but the extension in the longitudinal direction is particularly large compared to the width direction. Since the band can extend in the longitudinal direction, the shape of the slot is maintained at a predetermined slot width, a predetermined inter-slot distance, and a predetermined slot length.
Accordingly, stable operation can be performed even when receiving radiation heat from plasma, and the density of active species can be made uniform when processing a large-area substrate.

According to a sixth aspect of the present invention, in the plasma device according to the fifth aspect, the first metal plate is formed so that a central band body is slidable, and the second metal plate is provided for each slot. It is formed in a shape that fits into the opening.

According to the seventh aspect, in the plasma device according to the fifth aspect, the first and second metal plates are electrically connected to the end of the microwave waveguide via a plunger having a leaf spring. A strip at least at the center of the first metal plate is slidably provided on the plunger.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The same parts as those in FIG. 18 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a configuration diagram of a process plasma apparatus.

As shown in FIG. 2, three microwave waveguides 9 are provided for the plasma chamber 3 of the airtight container 1. These microwave waveguides 9 (9a, 9b, 9
c) is formed in a rectangular shape, and each end thereof is connected to each of the microwave oscillators 20a, 20b, and 20c.

These microwave waveguides 9a, 9b, 9c
A microwave, for example, TE ₁₀ mode rectangular wave waveguide has become what is transmitted. Note that each of the microwave oscillators 20a, 20b, and 20c has a frequency of 2.45 here.
It has a function of oscillating a microwave of GHz.

The upper surface 9f of the microwave introduction window 10 in each of the microwave waveguides 9a, 9b, 9c, that is, the H plane perpendicular to the direction of the electric field of the microwave propagating into the microwave waveguides 9a, 9b, 9c is As shown in FIG. 3, two slots 21 and 22 are formed in parallel with each other.

The slots 21 and 22 are formed in parallel with the microwave traveling direction, and have a predetermined slot width d, a predetermined slot distance D and a predetermined slot distance D as shown in FIG.
It is formed in a shape satisfying a predetermined slot length L.

That is, assuming that the wavelength of the microwave propagating in the free space is λ _o , the slot width d is d ≦ λ _o / 5 (1)
Is formed so as to satisfy the following. Assuming that the wavelength D of the microwave propagating in free space as described above is λ _o and the dielectric constant of the dielectric material forming the microwave introduction window 10 is ε,

[0040]

(Equation 5) Is formed so as to satisfy the following.

The slot length L is determined by the wavelength of the microwave propagating in the microwave waveguides 9a, 9b and 9c.
_g, when the n is an integer, are formed so as to satisfy the _{(2n / 3) · λ g} / 2 ≦ L ≦ (4n / 3) · λ g / 2 ... (3).

Next, the operation of the device configured as described above will be described. A process gas such as CF ₄ , O ₂ , Cl ₂ or the like used for ashing or etching is supplied into the plasma chamber 3 from the process gas supply device 7.

At the same time, three microwave oscillators 20
a, 20b, the microwave having a frequency of 2.45GHz as hereinbefore described to each destination from 20c is oscillated, these microwave rectangular waveguide TE ₁₀ mode in each microwave waveguide 9a, 9b, 9c Are transmitted from each other, are radiated from two slots 21 and 22 parallel to each other, pass through the microwave introduction window 10, and are introduced into the plasma chamber 3.

When the microwave is introduced into the plasma chamber 3 as described above, the process gas is excited, and the plasma 11 is generated. Here, the microwave absorptivity at the portion where the plasma is formed is high.

In the microwave, the superposition of the microwave modes propagating through the dielectric material in the free space is substantially reflected in the plasma generation pattern. In the above formulas (1) and (2), the antennas in which the microwaves propagating in the dielectric material reinforce each other without being canceled out by the interference and the slots 21 and 22 efficiently radiate the microwave by the formula (3) It has an effect.

When the plasma 11 is generated in this way, active species 12 are generated by the generation of the plasma 11, and the active species 12 are supplied to the substrate 4 through the punching plate 8 and processed on the substrate 4. (Etching or ashing) is performed.

Next, the experimental results in the two slots 21 and 22 will be described. FIG. 5 shows the results of examining the slot width d and discharge stability. It can be seen that the wider the slot width d, the lower the discharge stability. this is,
This is because unnecessary mode components of the microwave are radiated into the microwave introduction window 10 made of a dielectric material, and the microwave power is offset by the interference effect between the modes.

FIG. 6 shows the result of examining the distance D between slots and the discharge stability under the condition that the slot width d is kept within the specified value of the above equation (1). The distance D between the slots is calculated by the above equation (2).
In both cases where the width was wider than the specified value and the width where the width was narrowed, the discharge stability decreased. This is for each slot 2
This is because the microwaves radiated from the first and the second 22 interfere in the microwave introduction window 10 made of a dielectric, and the microwave power is canceled.

FIG. 7 shows the relationship between the slot length L and the discharge under the condition that the slot width d is within the specified value of the above equation (1) and the distance D between the slots is within the specified value of the above equation (2). The results of examining the stability are shown.

In both cases where the slot length L was made longer or shorter than the specified value of the above equation (3), the discharge stability decreased. This is because the microwave is slot 21,
Since no antenna function can be performed in the microwave oscillator 22, each of the slots 21 and 22 has a microwave oscillator 20 a, 20 b, 20
This is because many higher-order mode microwaves existed in the microwave introduction window 10 made of a dielectric material and acted as a leakage source rather than the function of c, and interfered with each other, thereby canceling out microwave power.

As a result of the above experiment, the microwave waveguide 9 having the slots 21 and 22 satisfying the above equations (1) to (3) is obtained.
When a, 9b, and 9c are used, uniform plasma 11 can be obtained in the plasma chamber 3 of the hermetic container 1.

For example, 1 kW is applied to three rectangular microwave waveguides 9a, 9b, 9c having a cross-sectional area of 96 mm × 27 mm.
(Frequency 2.45 GHz, λ _o = 122.
4 mm) in the TE ₁₀ mode, and the above equation (1)
(3), for example, d = 10 mm, D = 50 mm, L = 480 mm, and radiate into the plasma chamber 3 through the quartz microwave introduction window 10. I let it.

FIG. 8 is a view showing the relative value of the density distribution of active species (radicals) reaching the substrate 4 when microwaves are radiated into the plasma chamber 3 through the slots 21 and 22. The size of the substrate 4 used this time is 1000 mm × 1000 mm.

As can be seen from the active species density distribution, the uniformity of the active species density distribution with respect to the large-sized substrate 4 having a meter size, for example, is ± 10% as compared with the related art. As described above, in the first embodiment, two parallel surfaces each having a shape satisfying the slot width d, the inter-slot distance D, and the slot length L are provided on the H plane in the microwave waveguides 9a, 9b, 9c. Since the slots 21 and 22 are formed, the plasma 11 having a uniform electron density distribution can be generated, and the active species density on the large-area substrate 4 can be uniformed.

Further, it is not necessary to correct the loss due to the punching plate 8 in order to obtain a uniform active species density, and the punching plate 8 can be manufactured with a high aperture ratio based on a portion where the electron density is high. For example, it is possible to increase the average aperture ratio of the punching plate 8 to about twice, and to increase the process speed to about twice, thereby contributing to productivity.

Further, the same experiment was performed on a substrate 4 of 2000 mm × 2000 mm size, and a larger substrate 4 was formed. Plasma generation was performed using six microwave oscillators and six microwave waveguides. As a result, 1000
When the substrate 4 having the size of mm × 1000 mm was processed, the same etching rate could be obtained.

Further, the effect of the scaling was remarkable, and it was confirmed that there was no problem in practical use. Note that the first embodiment may be modified as follows. In the first embodiment, the rectangular microwave waveguide 9 has the slot 21,
Although the formation of the groove 22 has been described, in actuality, the slots 21 and 22 may be formed at the coupling position with the microwave waveguide and the hermetic container 1, and furthermore, a micro-shaped member having an arbitrary shape depending on the application. Wave waveguides, airtight containers 11, and slots 21 and 22 may be formed. Further, it may be other types, such as TEM ₁₁ also transmission mode of the microwaves. Further, the oscillation frequency is not limited to 2.45 GHz, and a similar system may be constructed using a high-frequency power supply between 10 GHz and 100 GHz.

Further, three microwave oscillators 20a, 20
Instead of using b and 20c, two or less and four or more microwave oscillators may be used. For example, when one microwave oscillator 23 is used, as shown in FIG. 9, the microwave waveguide 24 is bent several times and passes through the microwave introduction window 10 of the airtight container 1 three times, for example. To place.

The slots 21 and 22 are formed in three portions of the microwave waveguide 24 which are in contact with the surface of the microwave introduction window 10. As shown in FIG. 10, the microwave waveguide 25 is branched into two, and these two branched microwave waveguides 25 are arranged on the surface of the microwave introduction window 10 of the airtight container 1.

The slots 21 and 22 are formed in each of the portions of each of the branched microwave waveguides 25 that come into contact with the surface of the microwave introduction window 10. As described above, even if one microwave oscillator 23 is used and the microwave waveguide 24 is folded or the microwave waveguide 25 is branched, the same effect as that of the first embodiment can be obtained.

As shown in FIG. 11, a plurality of sets of slots, for example, slots 27 and 28, are formed in the H plane of the microwave waveguide in parallel with the microwave traveling direction of the microwave waveguide 26. , 29 and 30, 31 and 3
2 may be formed.

With this configuration, it is possible to obtain a large-area plasma corresponding to the net slots 27 and 28, 29 and 30, and 31 and 32. (2) Next, a second embodiment of the present invention will be described.

FIG. 12 is a configuration diagram of a process plasma apparatus. A processing stage 41 on which the substrate 4 such as a liquid crystal substrate is mounted is provided inside the airtight container 40, and a gas exhaust duct 42 is provided at the bottom thereof.

The shape and size of the hermetic container 40 are such that the substrate 4 can be sufficiently accommodated and the microwaves radiated by the microwave waveguide 43 can be uniformly and efficiently entered into the hermetic container 40. Designed for

The airtight container 40 contains CF ₄ , O ₂ , C
nozzle 44 for supplying a l _2, etc. of the process gas (medium gas) therein is provided. On the other hand, the microwave waveguide 43 for transmitting the microwave from the microwave source 45 is provided above the airtight container 40.

The microwave waveguide 43 has an end connected to the airtight container 40 through a microwave introduction window 46 formed of a dielectric material. This microwave waveguide 4
3, two slots (slot antennas) 47 and 48 parallel to each other are provided on the portion connected to the microwave introduction window 46, that is, on the H plane perpendicular to the direction of the electric field of the microwave traveling in the microwave waveguide 43. Is formed.

As shown in FIG. 13, the slots 47 and 48 are provided with a first metal plate 49 and two second metal plates 5.
0, 51. The first and second metal plates 49, 50, and 51 are connected to the microwave waveguide 43.
Is attached to the opening of the metal channel 43a having the U-shaped cross section.

The first metal plate 49 is formed in an E shape having two slot openings 49a and 49b parallel to the longitudinal direction.
A central band 49c formed by a and 49b is slidably formed in the longitudinal direction (a).

Each of the second metal plates 50 and 51 is formed in an L shape to be fitted into each of the slot openings 49a and 49b. Thus, the first and second metal plates 4
The dimensions of the two slots formed by combining 9, 50 and 51 are determined by the equations (1) to (1) in the first embodiment.
The slot width d, the inter-slot distance D and the slot length L are respectively represented by (3).

Next, the operation of the device configured as described above will be described. CF ₄ , O ₂ , Cl ₂ in the airtight container 40
Is supplied. This microwave e.g. frequency 2.45GHz from the microwave source 45 is oscillated together with the microwaves transmitted each microwave waveguide 43 in TE ₁₀ mode of the rectangular waveguide, the two mutually parallel slots 47,48 , Is transmitted through the microwave introduction window 46, and is introduced into the airtight container 40.

When the microwave is introduced into the hermetic container 40 in this manner, the process gas is excited and plasma is generated. When the plasma is generated in this way, active species are generated by the generation of the plasma, and the active species is
The processing is performed on the substrate 4 (etching or ashing).

Here, when used for a long time or when large electric power is applied, the first and second metal plates 4 forming the two slots 47 and 48 by radiant heat from plasma or the like.
9, 50, 51 are heated.

The first and second metal plates 49, 50,
When the member 51 is heated, the central band 49c of the first metal plate 49 expands most in the longitudinal direction as shown in FIG. 13 (49d).

The band 49 c is formed by the microwave waveguide 43.
The metal channel 43a and the micro are slidably provided with respect to the introduction window 46. Therefore, even if the thermal expansion is caused by heating by the microwave, the expansion is absorbed without bending of the band 49c due to the sliding. You.

Therefore, the first and second metal plates 49, 5
Even if 0 and 51 are heated and the band 49c thermally expands,
The dimensions of the two slots 47 and 48 are determined by the above equations (1) to (3).
Is maintained at the slot width d, the inter-slot distance D, and the slot length L represented by

As described above, in the second embodiment, the two slots 47 and 48 are formed in parallel with each other in the longitudinal direction.
It is formed into an E shape having two slot openings 49a, 49b, and these slot openings 49a, 49b are formed.
A first metal plate 49 slidably formed with a band 49c at a central portion formed by
Since each of the second metal plates 50 and 51 formed into an L-shape to be fitted to 49b is formed in combination, the first and second metal plates 49 and 5 receive radiant heat from the plasma.
Even if 0 and 51 are heated, the dimensions of the two slots 47 and 48 can be maintained at the initial slot width d, the inter-slot distance D and the slot length L, and a plasma having a uniform electron density distribution can be generated. The active species density on the surface of the substrate 4 can be made uniform.

Further, as in the first embodiment, it is not necessary to correct the loss due to the punching plate 8 in order to obtain a uniform active species density, and a high aperture ratio based on a portion having a high electron density. Thus, the punching plate 8 can be manufactured. For example, it is possible to increase the average aperture ratio of the punching plate 8 to about twice, and to reduce the process speed by about 2 times.
Double the speed and contribute to productivity. (3) Next, a third embodiment of the present invention will be described.
The same parts as those in FIG. 12 are denoted by the same reference numerals, detailed description thereof will be omitted, and only parts different from the process plasma apparatus shown in FIG. 12 will be described.

FIG. 14 is a configuration diagram of a slot portion applied to a process plasma apparatus. At the end of the metal channel 43a forming a part of the microwave waveguide 43, slot openings 61a, 61b are inserted through a plunger 60.
Is attached.

The plunger 60 has a box shape and has a plurality of leaf springs 62 provided on the outer peripheral surface thereof. These leaf springs 62
Are pressed against the metal channel 43a and the metal plate 61, respectively, as shown in FIGS. The metal channel 43a and the plunger 60 are electrically connected to the metal plate 61.

FIG. 15A shows the microwave waveguide 43.
Is a cross-sectional view of the microwave waveguide 43 viewed from above, and FIG. 2B is a cross-sectional view of the microwave waveguide 43 viewed from above. That is, each leaf spring 62 presses against the metal channel 43a and the metal plate 61 by the urging force.

The metal plate 61 is formed in an E shape having two slot openings 61a and 61b in parallel with the longitudinal direction, and a central band body 61c formed by the slot openings 61a and 61b is formed. It is formed to be slidable in the longitudinal direction (b).

The front end of the central band 61c is formed to have a large width, so that each slot opening 61a,
61b is formed as two slots 63, 64 and is adapted to contact each leaf spring 62 of the plunger 60.

The two slots 6 thus formed
The dimensions of 3 and 64 are determined by the equations in the first embodiment.
The slot width d, the inter-slot distance D, and the slot length L represented by (1) to (3) are formed.

Next, the operation of the device configured as described above will be described. CF ₄ , O ₂ , Cl ₂ in the airtight container 40
Is supplied. This microwave e.g. frequency 2.45GHz from the microwave source 45 is oscillated together with the microwaves transmitted each microwave waveguide 43 in TE ₁₀ mode of the rectangular waveguide, the two mutually parallel slots 63 and 64 , Is transmitted through the microwave introduction window 46, and is introduced into the airtight container 40.

When the microwave is introduced into the hermetic container 40 in this way, the process gas is excited and plasma is generated. When the plasma is generated in this manner, active species are generated by the plasma, and the active species is supplied onto the substrate 4 and processing (etching or ashing) on the substrate 4 is performed.

Here, when used for a long time or when a large amount of electric power is applied, the metal plate 61 forming the two slots 63 and 64 is heated by radiant heat from plasma or the like.
When the metal plate 61 is heated, as shown in FIG. 14, the band 61c at the center of the metal plate 61 is moved in the longitudinal direction (b).
Inflates the most.

Since the band 61c is slidably provided via the respective leaf springs 62 of the plunger 60, even if thermal expansion occurs, its expansion is released in the longitudinal direction of the band 61 by sliding. It is.

Accordingly, even if the metal plate 61 is heated and the strip 61c is thermally expanded, it does not bend, and the dimensions of the two slots 63 and 64 are represented by the above equations (1) to (3). Slot width d, distance D between slots, and slot length L
Is held.

According to the third embodiment, as in the second embodiment, even if the metal plate 61 is heated by receiving the radiant heat from the plasma, the two slots 63 and 64 are formed. Can be maintained at the initial slot width d, the inter-slot distance D, and the slot length L, plasma having a uniform electron density distribution can be generated, and the active species density on the large-area substrate 4 can be uniformed. .

Further, similarly to the first embodiment, it is not necessary to correct the loss due to the punching plate 8 in order to obtain a uniform active species density, and a high aperture ratio based on a portion where the electron density is high. Thus, the punching plate 8 can be manufactured. For example, it is possible to increase the average aperture ratio of the punching plate 8 to about twice, and to reduce the process speed by about 2 times.
Double the speed and contribute to productivity.

Further, since the plunger 60 with the leaf spring 62 is provided, even if the metal plate 61 thermally expands, the metal channel 43a forming the microwave waveguide 43 and the metal plate 6
1 can be sufficiently secured. (4) Next, a fourth embodiment of the present invention will be described.
The same parts as those in FIG. 12 are denoted by the same reference numerals, detailed description thereof will be omitted, and only parts different from the process plasma apparatus shown in FIG. 12 will be described.

FIG. 16 is a configuration diagram of a slot portion applied to a process plasma apparatus. At the end of the metal channel 43a of the microwave waveguide 43, a waveguide bottom metal plate 7 is provided.
0 is attached.

The waveguide bottom metal plate 70 is formed in an E shape having two slot openings 70a and 70b parallel to the longitudinal direction.
A band 70c at the center formed by a and 70b is slidably formed in the longitudinal direction (C).

The end of the central band 70c is formed to have a large width, so that each slot opening 70a,
70b is formed as two slots 71 and 72. The dimensions of the two slots 71 and 72 formed in this manner are determined by the slot width d, the inter-slot distance D, and the slot length L represented by the equations (1) to (3) in the first embodiment. Is formed.

A notch 7 is formed between the wide end portion of the band 70c and each of the bands 70d and 70e on both sides.
3 is included. Each band 70 on both sides
A plurality of elliptical screw holes 74 are formed at predetermined intervals in d and 70e. These screw holes 74 are provided in each band 70.
The major radius of the ellipse is formed in the same direction as the longitudinal direction of d and 70e.

Accordingly, the waveguide bottom metal plate 70 is fastened to the metal channel 43a of the microwave waveguide 43 by the screw 75 with a spring. Next, the operation of the apparatus configured as described above will be described.

A process gas such as CF ₄ , O ₂ , Cl ₂ is supplied into the airtight container 40, and a microwave source 4
5 is transmitted through the microwave waveguide 43, is radiated from the two slots 71 and 72 parallel to each other, passes through the microwave introduction window 46, and passes through the airtight container 40.
When introduced into the process gas, the process gas is excited and a plasma is generated.

When the plasma is generated as described above, active species are generated by the plasma, and the active species is supplied onto the substrate 4, and the substrate 4 is processed (etched or ashed).

Here, when used for a long time or when large power is applied, the waveguide bottom metal plate 70 having the two slots 71 and 72 is heated by radiant heat from the plasma or the like.

When the waveguide bottom metal plate 70 is heated, the central band 70c expands most in the longitudinal direction (C). Since the band 70c is provided so as to be slidable in the longitudinal direction, even if thermal expansion occurs, the elongation is released in the longitudinal direction by sliding.

Also, even if the belts 70d and 70e on both sides are thermally expanded by receiving the radiation heat of the plasma, the elliptical screw holes 74 are also formed.
And is fastened by a screw 75 with a spring,
The extension is absorbed by sliding.

Therefore, even if the waveguide bottom metal plate 70 is heated and the band 70c thermally expands, the two slots 7
The dimensions 1 and 72 hold the slot width d, the inter-slot distance D and the slot length L expressed by the above equations (1) to (3).

As described above, according to the fourth embodiment, the same effects as those of the third embodiment can be obtained. (5) Next, a fifth embodiment of the present invention will be described.
The same parts as those in FIG. 12 are denoted by the same reference numerals, detailed description thereof will be omitted, and only parts different from the process plasma apparatus shown in FIG. 12 will be described.

FIG. 17 is a configuration diagram of a slot portion applied to a process plasma apparatus. An E-shaped first metal plate 81 is attached to an end of the metal channel 43 a of the microwave waveguide 43 via a plunger 80.

The plunger 80 has a box shape and has a plurality of leaf springs 82 provided on the outer peripheral surface thereof. These leaf springs 82
Are pressed against the metal channel 43a and the first metal plate 81, respectively. The metal channel 43a and the plunger 60 are electrically connected to the first metal plate 81.

The first metal plate 81 has an E shape and has two slot openings 81a and 81b parallel to the longitudinal direction.
A band 81c at the center formed by the slot openings 81a and 81b is slidably formed in the longitudinal direction (d).

At the tip of the first metal plate 81, L-shaped second metals 83 and 84 which are fitted into the slot openings 81a and 81b are respectively attached. .

The first metal 81 and the second metal 83,
Numerals 84 are formed on the slopes of each other, and have a rubbing structure so that the band 81c of the first metal plate 81 can slide in the longitudinal direction (d).

However, two slots 85 and 86 are formed by attaching the second metals 83 and 84 to the tip of the first metal plate 81. These slots 85,
The dimensions of 86 correspond to the equations (1) to (3) in the first embodiment.
, The slot width d, the inter-slot distance D, and the slot length L.

Next, the operation of the device configured as described above will be described. CF ₄ , O ₂ , Cl ₂ in the airtight container 40
And the like, and a microwave oscillated from the microwave source 45 is supplied to the microwave waveguide 43.
From the two slots 85 and 86 parallel to each other, pass through the microwave introduction window 46, and
When introduced into zero, the process gas is excited and a plasma is generated.

When the plasma is generated in this manner, active species are generated by the plasma, and the active species is supplied onto the substrate 4, and processing (etching or ashing) on the substrate 4 is performed.

Here, when used for a long time or when large electric power is applied, the first metal plate 81 and the second metal plate 81 which form the two slots 85 and 86 by radiant heat from plasma or the like.
Are heated.

The first and second metal plates 81, 83,
When 84 is heated, the band 81c at the center of the first metal plate 81 expands most in the longitudinal direction (d). The band 81c is slidably provided in the longitudinal direction thereof while being electrically connected via the respective leaf springs 82 of the plunger 80. Therefore, even if thermal expansion occurs, the elongation of the band 81c is reduced. Escaping in the longitudinal direction.

Therefore, the first and second metal plates 81, 8
Even if the band 81c is thermally expanded due to the heating of 3, 84,
The dimensions of the two slots 85 and 86 are determined by the above equations (1) to (3).
Is maintained at the slot width d, the inter-slot distance D, and the slot length L represented by As described above, according to the fifth embodiment, the same effects as those of the third embodiment can be obtained.

[0115]

As described above in detail, according to the present invention, it is possible to provide a plasma apparatus capable of making the active species density uniform when processing a large-area substrate. Further, according to the present invention, it is possible to provide a plasma apparatus which can perform a stable operation even when receiving radiant heat from plasma and can uniform the density of active species when processing a large-area substrate.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a plasma device according to the present invention.

FIG. 2 is a diagram showing three microwave waveguides provided in an airtight container.

FIG. 3 shows two slots formed in parallel.

FIG. 4 is a diagram showing a slot width, an inter-slot distance, and a slot length of a slot.

FIG. 5 is a diagram showing a result of examining a slot width and discharge stability.

FIG. 6 is a view showing the results of examining the slot width and discharge stability under the condition that the slot width is kept within a predetermined specified value.

FIG. 7 is a diagram showing the results of examining the slot width and discharge stability under the condition that the slot width and the inter-slot distance are kept within specified values.

FIG. 8 is a diagram showing relative values of a density distribution of active species reached on a substrate.

FIG. 9 is a configuration diagram showing a modified example when one microwave oscillator is used.

FIG. 10 is a configuration diagram showing a modification example when one microwave oscillator is used.

FIG. 11 is a diagram showing the formation of a plurality of sets of slots.

FIG. 12 is a configuration diagram showing a second embodiment of the plasma device according to the present invention.

FIG. 13 is a view showing first and second metal plates forming a slot.

FIG. 14 is a configuration diagram showing a third embodiment of a slot portion applied to a plasma device according to the present invention.

FIG. 15 is a cross-sectional view of the microwave waveguide as viewed from the side and from above.

FIG. 16 is a configuration diagram showing a fourth embodiment of a slot portion applied to a plasma device according to the present invention.

FIG. 17 is a configuration diagram showing a fifth embodiment of a slot portion applied to a plasma device according to the present invention.

FIG. 18 is a configuration diagram of a conventional process plasma apparatus.

FIG. 19 is a configuration diagram of a punching plate.

[Explanation of symbols]

1, 40 airtight container, 2 process chamber, 3 plasma chamber, 4 substrate, 7 process gas supply device, 8 punching plate, 9a, 9b, 9c, 43 microwave waveguide, 10, 46 ... Microwave introduction windows, 20a, 20b, 20c: microwave oscillators, 21, 22, ... slots, 47, 48, 63, 64, 71, 72, 85, 86 ... slots, 49, 81 ... first metal plate, 50 , 51, 83, 84 ... second metal plate, 61 ... metal plate, 70 ... waveguide bottom metal plate.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Uchida 33, Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside Toshiba Production Technology Research Institute (72) Inventor Noboru Okamoto 33, Shinisogocho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Address Co., Ltd., Toshiba Production Technology Laboratory

Claims (7)

[Claims] 1. A plasma apparatus for introducing microwaves propagating through a microwave waveguide from a slot into a hermetic container through a microwave introduction window and exciting a medium gas in the hermetic container. When substantially parallel to form together a plurality perpendicular plane (H plane) in the direction of the electric field of the microwave traveling in the tube, and wherein the slot has a wavelength of the microwave propagating through free space and lambda _o, d ≦ λ _o /
5. A plasma device formed to have a slot width d that satisfies 5. 2. A plasma apparatus for introducing microwaves propagating through a microwave waveguide from a slot into a hermetic container through a microwave introduction window and exciting a medium gas in the hermetic container. A plurality of microwaves are formed substantially parallel to each other on a plane (H plane) perpendicular to the direction of the electric field of the microwave propagating in the tube, and the slot has a wavelength of λ _o of the microwave propagating in free space, Assuming that the dielectric constant of the dielectric material forming the window is ε, Characterized in that the inter-slot distance D satisfies the following. 3. A plasma apparatus for introducing microwaves propagating through a microwave waveguide from a slot into a hermetic container through a microwave introduction window, and exciting a medium gas in the hermetic container. A plurality of slots are formed substantially parallel to each other on a plane (H plane) perpendicular to the direction of the electric field of the microwave propagating in the tube, and the slot has a wavelength of λ _g of the microwave propagating in the microwave waveguide. , (2n / 3) · λ _g / 2 ≦ L ≦ (4n / 3) · λ _g / 2
(N: an integer) formed in a slot length L satisfying the following condition: 4. A plasma apparatus for introducing microwaves propagating through a microwave waveguide from a slot into a hermetic container through a microwave introduction window and exciting a medium gas in the hermetic container. A plurality of microwaves are formed substantially parallel to each other on a plane (H plane) perpendicular to the direction of the electric field of the microwave propagating in the tube, the wavelength of the microwave propagating in free space is λ _o , and the microwave introduction window is formed. Assuming that the dielectric constant of the dielectric is ε and the wavelength of the microwave propagating in the microwave waveguide is λ _g , the slot width d satisfies d ≦ λ _o / 5. Characterized by the following formula: (2n / 3) · λ _g / 2 ≦ L ≦ (4n / 3) · λ _g / 2 apparatus. 5. A plasma apparatus for introducing microwaves propagating through a microwave waveguide from a slot into a hermetic container through a microwave introduction window and exciting a medium gas in the hermetic container. A plurality of slots are formed substantially parallel to each other on a plane (H plane) perpendicular to the direction of the electric field of the microwave propagating in the tube, and each of the slots has an opening formed with a predetermined slot width and a predetermined distance between slots. Then, a first metal plate in which at least the band at the center of the slot formed by these openings is slidably fitted, and each of the openings at both ends of the first metal plate is fitted. And a second metal plate that forms each of the openings with a predetermined slot length. 6. The first metal plate is formed such that a central band is slidable, and the second metal plate is formed into a shape that fits into each of the slot openings. The plasma device according to claim 5, wherein 7. The first and second metal plates are electrically connected to an end of the microwave waveguide via a plunger having a leaf spring, and at least a central portion of the first metal plate. 6. The plasma apparatus according to claim 5, wherein said strip plate is provided slidably with respect to said plunger.