JPH07321096A - Microwave plasma treating device - Google Patents

Abstract

PURPOSE:To prevent microwave from leaked outside of a plasma treating device by assigning the second cylindrical microwave leakage preventing means consisting of at least a microwave absorbing body at the outside periphery of a plasma transport tube an the opposite side of a rectangular wave guide tube, coaxially with the first microwave leakage preventing means. CONSTITUTION:As the second microwave leakage preventing means 22a and 22b, fluid microwave absorbing body F is used. Then, the space far accommodating the fluid is assigned on the end face side opposite to a wave guide tube 2g of the first microwave leakage preventing means 11a and 11b. Further, a cylindrical fluid housing member formed at the outside periphery of a plasma transportation tube 3 is assigned outside of the plasma transportation tube, coaxially with the first microwave leakage preventing means 11a and 11b. The fluid housing member forms the common space for the space which houses the microwave absorbing body F and that which houses the cooling media of the microwave leakage preventing means 11a and 11b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave plasma processing apparatus in which a microwave leakage prevention means having a microwave choke structure is provided with another microwave leakage prevention means.

[0002]

2. Description of the Related Art CVD, which is one of the devices for forming a thin film
2. Description of the Related Art Some apparatuses and plasma processing apparatuses such as etching apparatuses for semiconductor manufacturing use plasma generated by microwaves. FIG. 4 is a schematic configuration diagram of a conventional microwave plasma processing apparatus, and FIG. 5 is a schematic configuration diagram showing a main part thereof. As illustrated, the microwave generated by the microwave oscillator 1 is supplied to the plasma generation space 4 in the quartz plasma transport tube 3 via the waveguide circuit 2. The waveguide circuit 2 is composed of a plurality of rectangular waveguides 2a to 2g. In the middle of the waveguide circuit 2, an isolator 2b for protecting the oscillator 1 from reflected waves, a power monitor 5 for measuring incident waves and reflected waves, and impedance matching for effectively transmitting power to a load. And an impedance matching device 6 for

The plasma transport tube 3 is provided so as to penetrate through the waveguide 2g at the end of the waveguide circuit, and at the end of the waveguide 2g, the maximum electric field position in the waveguide is transported by plasma. A termination mechanism 7 is provided with a movable short circuit plate for adjusting to match the position of the tube 3. A gas supply port 3a is provided at one end of the plasma transport tube 3, a processing chamber 8 is provided at the other end, a substrate holder 9 is arranged therein, and a substrate 10 is held on the holder. . The plasma transport tube 3 and the processing chamber 8 are evacuated by an exhaust device (not shown).

When performing plasma processing with such an apparatus, the processing gas is supplied from the gas supply port 3a while exhausting the inside of the plasma transport pipe 3 so that the inside of the processing chamber 8 has a predetermined gas pressure. Adjust. After that, the microwave (2.45 GHz) generated by the microwave oscillator 1 is supplied to the plasma generation space 4 in the plasma transport tube 3, plasma P is generated in this plasma generation space 4, and the inside of the plasma transport tube 3 is gradually increased. The plasma is diffused all over the substrate, and the substrate 10 is subjected to a predetermined plasma treatment by the plasma diffused to the processing chamber 8.

Therefore, as shown in FIG.
Since the plasma P behaves in a conductive manner at the joint between g and the plasma transport tube 3, the through hole 2g1 of the waveguide,
In order to prevent the leakage of microwaves propagating in the TEM mode through the gap between 2g2 and the plasma P generated in the plasma generation space 4, known microwave leakage prevention means 11a and 11b having a microwave choke structure are provided. The leakage preventing means 11a and 11b are attached to the waveguide 2g on the gas supply port 3a side and the processing chamber 8 side so as to surround the plasma transport tube 3, respectively. And inner cylinder members 11a2 and 11b2. In order to cool these microwave leakage prevention means, cylindrical fluid storage members 12a, 12b forming a space for storing the cooling medium W on the outer circumference are concentrically provided outside the microwave leakage prevention means 11a, 11b, respectively. The water is circulated as a cooling medium by a cooling water circulating device (not shown).

However, to explain the microwave leakage preventing means 11a having the above microwave choke structure, the microwave propagated in the TEM mode through the gap at the point C is split at the point B toward the point A (F1). ) Is propagated, and is branched to the point D side (F2) and propagated. The microwave propagating to the A point side is short-circuited at the A point, so
Although it is totally reflected to the point, this reflected wave is split and propagated to the point D side (R1) and propagated to the point C side (R2) at point B. Therefore, the above demultiplexing (F2) and demultiplexing (R
In order to prevent the microwave combined with 1) from leaking out of the device from the point D, the fluid storage members 12a, 12
Microwave attenuating tubes 13a and 13b having appropriate lengths are provided so as to extend along the outer periphery of the plasma transport tube 3 on the side opposite to the waveguide 2g from the end of the plasma transport tube 3 side of b. The gap between the attenuating tube and the plasma P is attenuated by propagating in the TEM mode.

[0007]

By the way, as a general need, there is a tendency to avoid increasing the size of the device, and there is an order from the customer for downsizing specifications.
Since the microwave attenuating tubes 13a and 13b are also shortened as the plasma transport tube 3 is shortened, the leaked microwaves are not sufficiently attenuated, so that the microwaves are applied to the substrate 10. There is a problem that the device such as the substrate is damaged.

[0008]

According to a first aspect of the present invention, a rectangular waveguide for propagating microwaves is penetrated by a plasma transport tube having a processing chamber at one end, and the rectangular waveguide and plasma transport are provided. A microwave plasma processing apparatus that includes microwave leakage preventing means having a microwave choke structure disposed on the outer periphery of a plasma transport tube at a joint portion with the tube and that generates plasma by microwaves in the plasma transport tube. The second microwave leakage prevention means, which is at least a microwave absorber having a tubular shape, is connected to the conventional microwave leakage prevention means, which is the first microwave leakage prevention means, and is a rectangular waveguide. It is arranged coaxially with the first microwave leakage prevention means on the outer periphery of the plasma transport tube on the opposite side, and the length of the microwave absorber on the side of the plasma transport tube is the first microwave. Characterized in that it is set larger than the gap width between the leakage preventing means and the plasma.

According to a second aspect of the present invention, the second microwave leakage prevention means comprises a fluid microwave absorber and a fluid storage member forming a space for filling the fluid microwave absorber. To do.

Further, according to a third aspect of the present invention, the fluid storage member is made of metal having a protrusion provided on the inner surface.

Further, in a fourth aspect of the present invention, the second microwave leakage prevention means is made of a solid microwave absorber.

[0012]

According to the structure described in claim 1, the microwave leaked from the first microwave leakage prevention means having the microwave choke structure is prevented from leaking to the outside of the plasma processing apparatus, and Irradiation of the substrate to be plasma-treated is prevented.

According to the second aspect of the invention, the microwave leaked from the first microwave leakage prevention means is absorbed while the first microwave leakage prevention means is cooled, and the second microwave leakage prevention means is absorbed. The structure of the wave leakage prevention means is simplified.

Further, according to the structure described in claim 3,
In particular, the microwave leaked from the first microwave leak prevention means is efficiently absorbed by the microwave absorber.

Further, according to the structure described in claim 4, a member for accommodating the microwave absorber becomes unnecessary, and the microwave absorber can be easily attached.

[0016]

【Example】

<Embodiment 1> FIG. 1 is a schematic configuration diagram showing a main part of a first embodiment according to the present invention. In the figure, 2g is a rectangular waveguide, 3 is a plasma transport tube, 3a is a gas supply port, 8 is a processing chamber, 11a and 11b are microwave leakage preventing means having a microwave choke structure. It is exactly the same as in FIG.

In this embodiment, the microwave leakage prevention means 11a and 11b of FIG. 5 showing the conventional example are used as the first microwave leakage prevention means, and the second microwave leakage prevention means 22a and
A microwave absorber F of the fluid is used as 22b, and a space for accommodating the fluid is provided on the end face side of the first microwave leakage prevention means 11a, 11b in the direction opposite to the waveguide 2g and at the plasma transport tube 3 A cylindrical fluid storage member formed on the outer periphery of the first and second microwave leakage prevention means 11a and 11b is arranged outside the plasma transport tube coaxially therewith.

Second microwave leakage prevention means 22a, 2
In order to form a common space between the space for accommodating the microwave absorber F and the space for accommodating the cooling medium of the first microwave leakage prevention means 11a and 11b, the fluid accommodating member constituting 2b is 1 fluid storage member 22a1, 22
It is composed of b1 and second fluid storage members 22a2 and 22b2. The first fluid storage members 22a1 and 22b1 extend the fluid storage members 12a and 12b of FIG. 5 showing the conventional example in the opposite direction to the waveguide 2g, and the fluid storage members 22a1 and 22b1 and the choke structure. Inner cylinder member 1 forming a
In order to seal 1a2 and 11b2 respectively, second fluid storage members 22a2 and 22b2 are provided on the outer periphery of the plasma transport tube 3, and these fluid storage members 22a2 and 22b2 are made of a material that transmits or absorbs microwaves. Need to be

The dimensions of the microwave absorber F may be appropriately determined according to the microwave absorption rate of the microwave absorber. In particular, the length L1 on the side of the plasma transport tube 3 is preferably shortened for the reason of miniaturization as described above, and when the gap width between the inner cylinder members 11a2, 11b2 forming the choke structure and the plasma P is L2. , L1> L2. In this case, the inner cylinder members 11a2, 1
The microwave after propagating in the TEM mode in the gap between 1b2 and the plasma P is absorbed while propagating in the microwave absorber. On the other hand, if L1 <L2, the microwave propagating through the gap is partially reflected at point D shown in the figure, but most of it is not absorbed by the microwave absorber and the length of the microwave absorber is reduced. It will pass through the gap of L1 as it is.

In this embodiment, the microwave absorber F of the fluid is used as the first microwave leakage prevention means 11a and 11b.
Since it is also used as the cooling medium, the second microwave leakage prevention means 22a and 22b can be simplified. In this case, examples of the microwave absorber include water and alcohol. Also, the first microwave leakage prevention means 11a, 1
Since the microwave leaking from 1b can be absorbed by the microwave absorber, the microwave attenuating tubes 13a and 13b shown in the conventional example are not required and the plasma transport tube 3 can be shortened.

<Embodiment 2> FIG. 2 is a schematic configuration diagram showing a main part of a second embodiment according to the present invention. In the figure, 2g
4 is a rectangular waveguide, 3 is a plasma transport tube, 3a is a gas supply port, 8 is a processing chamber, and 21a and 21b are microwave leakage preventing means having a microwave choke structure.
And exactly the same as in FIG.

In this embodiment, as in the first embodiment, the fluid containing members constituting the second microwave leakage preventing means 32a and 32b are the first fluid containing members 32a1 and 32b1 and the second fluid containing member 32a2. , 32b2, the first fluid medium forming members 32a1 and 32b1 need to be conductors, and a large number of conical projections 32c are provided on the inner surface thereof as shown in the figure. There is. Also, the second
The fluid storage members 32a2, 32b2 need to be made of a material that transmits or absorbs microwaves.

The protrusions 32c provided on the inner surfaces of the first fluid storage members 32a1 and 32b1 are provided with the fluid storage members 32a1 and 32a.
Since the microwave circuit formed in the space of b1 has a discontinuity point of impedance, the microwave leaked at this portion is reflected.

The microwave absorber F has a length L1 on the plasma transport tube 3 side of the microwave absorber, as in the first embodiment.
And the gap width L2 between the inner cylindrical members 11a2, 11b2 forming the choke structure and the plasma P is preferably L1> L2, and the microwave after propagating in the TEM mode propagates in the microwave absorber. While being absorbed, it is reflected by the projection 32c and absorbed again.

In this embodiment, the microwave absorber F that absorbs microwaves and the projection 3 that reflects microwaves are used.
Since it is also used with 2c, microwave absorption becomes efficient. The protrusion is not limited to the conical shape, and may have another shape or a band shape.

<Embodiment 3> FIG. 3 is a schematic configuration diagram showing a main part of a third embodiment according to the present invention. In the figure, 2g
Is a rectangular waveguide, 3 is a plasma transport tube, 3a is a gas supply port, 8 is a processing chamber, 11a and 11b are microwave leakage preventing means having a microwave choke structure, and 12a and 12a.
b is a fluid storage member and W is a cooling medium, which is exactly the same as in FIGS.

In this embodiment, the microwave leakage prevention means 11a and 11b of FIG. 5 showing the conventional example are used as the first microwave leakage prevention means, and the second microwave leakage prevention means 42a and
42b is a solid microwave absorber S formed in a cylindrical shape having an inner diameter substantially the same as the outer diameter of the plasma transport tube 3.
The waveguides 2g of the fluid storage members 12a and 12b, respectively.
It is brought into contact with the end face on the opposite side to and is disposed coaxially with the first microwave leakage prevention means 11a and 11b on the outer periphery of the plasma transport tube.

The microwave absorber S has a length L1 on the plasma transport tube 3 side of the microwave absorber, as in the first embodiment.
And the gap width L2 between the inner cylindrical members 11a2, 11b2 forming the choke structure and the plasma P is preferably L1> L2, and the microwave after propagating in the TEM mode propagates in the microwave absorber. While being absorbed.

In the present embodiment, the microwave absorber S
Examples of the cement include cement containing polyiron, ferrite, and graphite. Further, if the microwave absorber is divided into halves in advance, the attachment will be easy, and after attachment, it may be tightened from the surroundings.

[0030]

As described above, according to the invention described in claim 1, the microwave leaked from the first microwave leakage prevention means having the microwave choke structure leaks to the outside of the plasma processing apparatus. This can be prevented, and irradiation of the substrate to be plasma-treated can be prevented. Further, since the microwave attenuating tube shown in the conventional example is not necessary and the plasma transport tube is shortened, the plasma processing apparatus can be downsized.

According to the second aspect of the present invention, the leaked microwave can be absorbed while cooling the first microwave leakage prevention means, and the second microwave leakage prevention means is simplified. it can.

Further, according to the invention described in claim 3,
The microwave leaked from the first microwave leakage prevention means can be efficiently absorbed by the microwave absorber.

According to the invention described in claim 4, a member for accommodating the microwave absorber is not required, and the microwave absorber can be easily attached.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a microwave plasma processing apparatus according to the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of the microwave plasma processing apparatus according to the present invention.

FIG. 3 is a schematic configuration diagram showing a third embodiment of the microwave plasma processing apparatus according to the present invention.

FIG. 4 is a schematic configuration diagram showing a conventional microwave plasma processing apparatus.

5 is a schematic configuration diagram showing a main part of FIG.

[Explanation of symbols]

2g Square wave guide 3 Plasma transport tube 8 Processing chamber 11a, 11b First microwave leakage prevention means 22a, 22b, 32a, 32b, 42a, 42b Second microwave leakage prevention means 22a1, 22b1, 22a2, 22b2, 32a1, 32b1, 3
2a2, 32b2 Fluid storage member for storing microwave absorber 32c Protrusion F Fluid microwave absorber S Solid microwave absorber

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H05H 1/46 B 9216-2G H01L 21/31 C

Claims (4)

[Claims] 1. A rectangular waveguide for propagating microwaves,
Microwave leakage prevention means having a microwave choke structure, which penetrates a plasma transport tube provided with a processing chamber at one end and is arranged on the outer periphery of the plasma transport tube at the joint between the rectangular waveguide and the plasma transport tube. In the microwave plasma processing apparatus for generating plasma by microwaves in the plasma transport tube, at least a tubular shape is provided continuously with the microwave leakage prevention unit serving as the first microwave leakage prevention unit. A second microwave leakage preventing means composed of a microwave absorber is provided on the outer circumference of the plasma transport tube on the side opposite to the rectangular waveguide.
The microwave absorber is arranged coaxially with the microwave absorber, and the length of the microwave absorber on the side of the plasma transport tube is set to be larger than the gap width between the first microwave leak preventer and the plasma. Microwave plasma processing equipment. 2. The second microwave leakage prevention means,
The microwave plasma processing apparatus according to claim 1, comprising a microwave absorber for fluid and a fluid storage member for storing the microwave absorber for fluid. 3. The microwave plasma processing apparatus according to claim 2, wherein the fluid filling forming member is made of metal having a protrusion provided on an inner surface thereof. 4. The second microwave leakage prevention means,
The microwave plasma processing apparatus according to claim 1, comprising a solid microwave absorber.