JP2003045856A - Plasma light observation window, plasma light observation system using the same, and plasma utilization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma light observation window that can obtain high production efficiency in an inexpensive configuration, a plasma light observation system using the plasma light observation window, and a plasma utilization apparatus. SOLUTION: The plasma light observation window is equipped with transmissive and baffle plates. The transmissive plate transmits the plasma light to the outside. The baffle plate is provided at a plasma light incident side of the transmissive plate to limit adhesion of reaction products generated by the reaction between gas and a sample onto the transmissive plate, and at the same time has an opening for allowing the plasma light to pass.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma light observation window, a plasma light observation system and a plasma utilizing apparatus using the same, and more particularly to a plasma light observation window in which plasma reaction products are hard to attach and a plasma light using the same. Observation system and plasma utilization apparatus.

[0002]

2. Description of the Related Art In the manufacturing process of semiconductors and liquid crystal displays, a plasma utilizing apparatus for processing a sample using plasma, for example, a dry etching apparatus is used.

FIG. 11 is a schematic diagram showing an example of the configuration of a dry etching apparatus 500 which is a conventional plasma utilizing apparatus. The dry etching apparatus 500 includes a closed container 1, a vacuum pump 2 that exhausts the inside of the closed container 1 to a vacuum state, and a gas supply pipe 3 that supplies an etching gas into the closed container 1. There is. Inside the closed container 1, cathode electrodes 4 facing each other in parallel are formed.
And an anode electrode 5 are provided. The dry etching apparatus 500 is provided with a high frequency power supply 6 that supplies a voltage for generating a plasma discharge 7 between the cathode electrode 4 and the anode electrode 5.

The closed container 1 is provided with an observation window 8 for observing the state of the plasma discharge 7 generated therein. The observation window 8 is a translucent plate 8A having translucency.
have. The transparent plate 8A is provided outside the closed container 1.
An optical sensor 9 is provided close to.

In the dry etching apparatus having such a structure, when the high frequency power supply 6 supplies a voltage to the cathode electrode 4, a plasma discharge 7 is generated between the cathode electrode 4 and the anode electrode 5. The etching gas activated by the plasma discharge 7 reacts with the sample placed on the cathode electrode 4 and the etching proceeds. The plasma light emitted by the plasma discharge 7 passes through the translucent plate 8A.
The optical sensor 9 detects the plasma light transmitted through the transparent plate 8A. The end of dry etching can be detected by observing the change in the intensity of the plasma light having the specific wavelength detected by the optical sensor 9. This method is often used in the production process of semiconductors and liquid crystal displays.

FIG. 12 is a schematic configuration diagram showing another example of the conventional dry etching apparatus. An optical fiber 10 for receiving plasma light emitted by the plasma discharge 7 is provided on the outer side of the hermetically sealed container 1 and a translucent plate 8A. Is provided close to. The optical fiber 10 is the optical fiber 10.
Spectrometer 1 for analyzing plasma light received by
1 is connected.

Even in such a dry etching apparatus, the plasma light emitted by the plasma discharge 7 is transmitted through the transparent plate 8.
Permeate A. The optical fiber 10 receives the plasma light transmitted through the transparent plate 8A. The spectrophotometer 11 analyzes a change in intensity of plasma light having a specific wavelength guided by the optical fiber 10.

As a method of observing the plasma light, the transparent plate 8 is used.
A method of visually observing through A, a method of detecting and observing a change in the intensity of plasma light by an optical sensor 9 arranged in the vicinity of the translucent plate 8A as shown in FIG.
As shown in FIG. 12 and FIG. 12, there is a method of guiding the plasma light to the outside of the closed container 1 by the optical fiber 10 arranged in the vicinity of the transparent plate 8A and observing it by the spectroscopic measurement device 11.

FIG. 13 is a sectional view of the observation window 8 provided in the dry etching apparatus 500 shown in FIG. 12. In FIG. 13, the observation window 8 is generated by the reaction between the etching gas and the sample inside the closed container 1. An adhesion model in which the reaction product adheres to the inner surface of the transparent plate 8A is also shown. Wall 1
The light-transmitting plate 8A provided on A has a light-transmitting plate 8A fitted in the through hole 1B of the wall surface 1A.
An optical fiber 10 for receiving the plasma light of the plasma discharge 7 is provided on the outer surface of the optical fiber 10 in the vicinity of the transparent plate 8A.
The light-transmissive plate 8A has an outer peripheral edge portion fitted over the entire circumference on the outer side of the through hole 1B provided in the wall surface 1A. Therefore, the light-transmissive plate 8A has an outer peripheral edge portion over the entire circumference. It faces the inside of the closed container 1 except.

In this case, the reaction product of the etching gas and the sample flies and adheres to the inner surface of the transparent plate 8A facing the inside of the closed container 1. On the inner surface of the light-transmissive plate 8A, the reaction product flying from the flying direction within the range of the angle α shown in FIG. 13, that is, ((π
Reaction products flying from the flying direction having an angle of -α) / 2) or more are attached.

The optical fiber 10 receives the plasma light emitted by the plasma discharge 7. The optical fiber 10 receives the plasma light incident from a direction within its own light receiving angle, that is, the light receiving angle γ shown in FIG.

[0012]

However, in the translucent plate 8A having such a structure, the reaction product generated by the reaction between the etching gas and the sample inside the closed container 1 adheres to the inner surface of the translucent plate 8A. As a result, the transmissivity of the translucent plate 8A that transmits the plasma light decreases, and there is a problem in that it does not fulfill its function.

In particular, when a metal film is etched by a dry etching apparatus, this transmittance decreases in a short time. Therefore, it is necessary to open the dry etching device each time to clean the stains on the inner surface of the transparent plate 8A, and as a result, there is a serious problem that the production efficiency is extremely deteriorated.

In order to solve this problem, Japanese Patent Laid-Open No. 63-154940 discloses a method of opening a device without opening it.
A technique for cleaning dirt on the inner surface of the transparent plate that constitutes the observation window is disclosed. In this technique, a reaction product attached to the transparent plate is removed by irradiating the transparent plate with laser light. However, such a method has a problem that a large investment is required for the device.

An object of the present invention is to provide a plasma light observation window capable of obtaining high production efficiency with an inexpensive structure, a plasma light observation system and a plasma utilizing apparatus using the same.

Another object of the present invention is to provide a plasma light observation window which can be used for a long period of time without opening the device, a plasma light observation system using the same, and a plasma utilization device by an inexpensive structure. is there.

Still another object of the present invention is to provide a plasma light observation window having a low cost structure in which reaction products generated in the plasma use device are less likely to adhere, a plasma light observation system using the same, and a plasma use device. To do.

Still another object of the present invention is to provide a plasma light observation window having a structure capable of easily recovering the transmittance of the observation window even when the reaction products generated in the plasma utilizing apparatus are attached. It is to provide a plasma light observation system and a plasma utilizing apparatus using the same.

[0019]

A plasma light observation window according to the present invention is provided in a plasma utilizing apparatus using a gas activated by plasma to detect the plasma light of the plasma from the outside. It ’s an observation window,
A light-transmitting plate that transmits the plasma light to the outside, and a light-transmitting plate that is provided on the plasma light incident side of the light-transmitting plate to restrict the products generated by the plasma from adhering to the light-transmitting plate. And a baffle plate having an opening through which plasma light passes, thereby achieving the above object.

A moving means for moving the opening with respect to the transparent plate may be further provided.

The plasma light observation system according to the present invention comprises:
A plasma light observation window according to the present invention, an optical fiber arranged to face the opening of the baffle plate, for receiving the plasma light, and an analyzer for analyzing the plasma light guided by the optical fiber, The above object is achieved thereby.

The opening of the baffle plate may have a shape that does not block the plasma light incident on the optical fiber.

The plasma utilizing apparatus according to the present invention includes a hermetically sealed container, a pair of electrodes provided in the container for generating plasma light, and provided in the container for observing the plasma light of the plasma. And a plasma light observation window, wherein the plasma light observation window is a transparent plate for transmitting the plasma light to the outside, and a product generated by the plasma is attached to the transparent plate. The baffle plate which is provided on the plasma light incident side of the translucent plate for limiting the plasma light and has an opening through which the plasma light passes, and the baffle plate is arranged so as to face the opening of the baffle plate. It is characterized by comprising an optical fiber for receiving light and an analyzer for analyzing the plasma light guided by the optical fiber, whereby the above object is achieved.

According to one aspect of the present invention, the baffle plate limits the adhesion of the reaction product generated by the reaction of the gas and the sample to the transparent plate, so that the reaction product flying to the transparent plate is prevented. The amount attached to the transparent plate is reduced. As a result, the plasma utilizing apparatus can be used for a longer period of time without cleaning the dirt of the reaction product attached to the transparent plate.

According to another aspect of the present invention, the moving means moves the opening with respect to the transparent plate, so that the reaction product is not attached to the transparent plate because it is covered with the baffle plate. The opening can be moved to the area. For this reason,
A region where the reaction product is not yet attached can be newly used as an observation window. As a result, even if the reaction products adhere to the light-transmitting plate and the function of the light-transmitting plate is no longer fulfilled, the plasma is generated for a longer period of time without cleaning the dirt of the reaction product adhering to the light-transmitting plate. Utilization equipment can be used.

According to still another aspect of the present invention, since the opening of the baffle plate is formed in a shape that does not block the plasma light incident on the optical fiber, even if the baffle plate is attached, the optical fiber receives light. The amount of plasma light received by the surface does not decrease. As a result, it is possible to significantly extend the cumulative plasma generation time until the light is attenuated to a predetermined intensity.

The reaction products generated inside the plasma utilizing apparatus adhere to the inner surface of the transparent plate uniformly with almost no so-called directivity. By providing a baffle plate on the inner surface of the light-transmitting plate, which restricts a part of the direction in which the reaction products come in, it is possible to improve the stain caused by the products adhering to the light-transmitting plate.

Further, when the amount of the product adhering still progresses and the function of the light-transmitting plate is no longer fulfilled, the region of the light-transmitting plate corresponding to the position of the opening of the baffle plate is moved to the baffle plate. Since the area covered and to which the product is not attached can be newly used as a transparent plate, it can be used for a longer period of time.

Further, in a system in which an optical fiber is attached to the outside of the transparent plate and the plasma light inside is guided and observed, the optical fiber only receives plasma light within a predetermined light receiving angle. Even if a baffle plate that blocks plasma light outside this acceptance angle is attached, the amount of plasma light received by the optical fiber is not impaired, and reaction products that fly in from directions other than the flight direction limited by the baffle plate are obstructive. Since it is blocked by the plate, it is possible to improve the stain caused by the product adhering to the transparent plate.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

(First Embodiment) FIG. 1 is a schematic configuration diagram of a dry etching 100 which is a plasma utilizing apparatus according to the first embodiment. This dry etching apparatus 100
Is used in the production process of semiconductors and liquid crystal displays.

The dry etching apparatus 100 includes a closed container 1, a vacuum pump 2 for exhausting the inside of the closed container 1 to a vacuum state, and a gas supply pipe 3 for supplying an etching gas to the inside of the closed container 1. Is equipped with. Inside the closed container 1, a cathode electrode 4 and an anode electrode 5 facing each other in parallel are provided. The dry etching apparatus 100 is provided with a high frequency power supply 6 that supplies a voltage for generating a plasma discharge 7 between the cathode electrode 4 and the anode electrode 5.

The closed container 1 is provided with a transparent observation window 31 for observing the state of the plasma discharge 7 generated therein. An optical sensor 9 is provided on the outer side of the closed container 1 close to the observation window 31.

FIG. 2 is a sectional view of the observation window 31.
Referring to FIGS. 1 and 2, the observation window 31 includes a light-transmitting light-transmitting plate 8A and a baffle plate 14 attached to the inner surface side of the light-transmitting plate 8A.

The transparent plate 8A is made of quartz glass. The thickness of this quartz glass is about 2 mm, for example.
And the hermetically sealed container 1 excluding the outer peripheral edge portion as the translucent plate 8A.
The region facing the inside of the has a circular shape with a diameter of about 50 mm, for example.

FIG. 3 is a schematic view of the baffle plate 14 according to the embodiment. As shown in FIG. 3, the baffle plate 14 has a disk shape with a circular opening 21 formed concentrically in the central portion. The opening 21 provided in the baffle plate 14 is a translucent plate 8A of the reaction product generated by the reaction between the gas and the sample.
Restrict the direction of flight to. The thickness d of the baffle plate 14 is, for example, about 20 mm, and the opening dimension L of the opening 21 is, for example, about 10 mm.
Is.

An optical sensor 9 for detecting plasma light is attached to the outer surface of the transparent plate 8A. The optical sensor 9 has a circular light receiving area having a diameter of about 8 mm. As shown in FIG. 2, the optical sensor 9 is attached so that its center is concentric with the center of the opening 21 formed in the baffle plate 14.

In the dry etching apparatus having such a structure, when the high frequency power supply 6 supplies a voltage to the cathode electrode 4, the plasma discharge 7 is generated between the cathode electrode 4 and the anode electrode 5. The etching gas activated by the plasma discharge 7 reacts with the sample placed on the cathode electrode 4 and the etching proceeds. The plasma light emitted by the plasma discharge 7 passes through the opening 21 formed in the baffle plate 14. The plasma light that has passed through this opening 21 passes through the translucent plate 8A. The optical sensor 9 detects the plasma light transmitted through the transparent plate 8A. The end of dry etching can be detected by observing the change in the intensity of the plasma light having the specific wavelength detected by the optical sensor 9.

As described above, the etching gas activated by the plasma discharge 7 reacts with the sample placed on the cathode electrode 4. The reaction product generated by this reaction passes through the opening 21 of the baffle plate 12 and adheres to the inner surface of the transparent plate 8A.

Since the reaction product attached to the inner surface of the light-transmitting plate 8A has passed through the opening 21 of the baffle plate 14, the reaction product flying from the flying direction within the range of the angle β shown in FIG. An object, that is, ((π−
Reaction products flying from the flying direction having an angle of β) / 2) or more are attached. This angle β is smaller than the angle α shown in FIG. 13 because the baffle plate 14 is provided. That is, the flying direction of the reaction product attached to the translucent plate 8A is limited. Therefore, the amount of reaction products attached to the transparent plate 8A is reduced as compared with the prior art.

In this way, the baffle plate 14 restricts the flight direction of the reaction product adhering to the light transmitting plate 8A, so that the amount of the reaction product adhering to the light transmitting plate 8A is reduced. As a result, for a longer period of time, it is not necessary to clean the dirt of the reaction product attached to the transparent plate 8A, and the use efficiency of the dry etching apparatus is improved.

FIG. 4 is a graph showing the relationship between the cumulative plasma generation time of the dry etching apparatus according to the first embodiment and the received light intensity of the optical sensor. The broken line 41 is the case of a conventional dry etching apparatus without a baffle, and the solid line 42
Shows the case of the dry etching apparatus of the first embodiment to which the baffle plate 14 is attached.

When the light receiving intensity received by the optical sensor 9 when the light transmitting plate 8A is in a clean state is 100, if the light receiving intensity falls to 20 or less, the end point of dry etching cannot be detected.

As shown in FIG. 4, in the conventional device shown by the broken line 41, the received light intensity becomes 20 or less when the cumulative plasma generation time exceeds 20 hours. On the other hand, solid line 4
In the dry etching apparatus shown in 2 in which the baffle plate 14 according to the first embodiment is attached, the received light intensity of the plasma light is about 70 at the beginning because the baffle plate 14 reduces the amount of received plasma light as compared with the conventional example. However, the baffle plate 14 is a transparent plate 8A.
As a result of limiting the flying direction of the reaction product attached to the transparent plate 8A, the amount of the reaction product attached to the translucent plate 8A is reduced, and the decrease in the received light intensity with the cumulative plasma generation time is slower than that of the conventional device. It is possible to achieve plasma discharge for 60 hours or more until the intensity becomes 20 or less.

As described above, according to the first embodiment, the baffle plate 14 restricts the flying direction of the reaction product adhering to the transparent plate 8A, so that the reaction product adheres to the transparent plate 8A. The amount is reduced. As a result, for a longer period of time, the transparent plate 8A
The dry etching apparatus can be used without cleaning the dirt of the reaction product attached to the.

(Second Embodiment) FIG. 5 is a sectional view of a plasma light observation window 31A according to a second embodiment. The same components as those of the plasma light observation window 31 described above with reference to FIG. 2 are designated by the same reference numerals. Detailed description of these components will be omitted.

The plasma light observation window 31A has a translucent plate 8A having translucency, a baffle plate 14A attached to the inner surface side of the translucent plate 8A, and a gear 15 engaged with the baffle plate 14A.
And a handle 16 for rotating the gear 15.

Similar to the first embodiment, this translucent plate 8A
Are made of quartz glass. The thickness of this quartz glass is about 2 mm, and the region facing the inside of the closed container 1 excluding the outer peripheral edge portion as the translucent plate 8A has a circular shape with a diameter of about 50 mm, for example.

FIG. 6 is a schematic view of the baffle plate 14A and the gear 15 as seen from the direction of the arrow 17 shown in FIG. The baffle plate 14A has a disc shape, and as shown in FIG.
The opening 22 is formed. This opening 22 is a baffle plate 1.
The diameter is smaller than the radius of 4A, and the center of the baffle plate 14A is arranged at a position separated from the center of the baffle plate 14A by the radius dimension of the opening 22 or more. The diameter L of the opening 22 is about 10 mm like the opening 21 of the first embodiment, and the thickness d of the baffle plate 14A is also the baffle plate 14 of the first embodiment.
Is about 20 mm.

As shown in FIG. 6, teeth are formed on the outer peripheral surface of the baffle plate 14A over the entire circumference and mesh with the teeth of the gears 15 arranged adjacent to each other. The gear 15 has a handle 1 that can be operated from outside the closed container 1.
6 is attached, and the gear 15 is rotated by operating the handle 16 from the outside of the closed container 1.
The handle 16 is rotatably supported on the wall surface of the closed container 1.

An optical sensor 9 is attached to the outer surface of the transparent plate 8A. The optical sensor 9 has a circular light receiving area having a diameter of about 8 mm. The optical sensor 9 is attached such that its center is concentric with the opening 22 formed in the baffle plate 14A.

In the dry etching apparatus having such a structure, when the handle 16 is rotated from the outside of the closed container 1, the gear 15 directly connected to the handle 16 rotates,
At the same time, the baffle plate 14A meshing with the gear 15 rotates. When this baffle plate 14A rotates, the baffle plate 14A
The opening 22 formed in the closed container 1 in the transparent plate 8A
Circulates in a region facing the inside of the.

When the reaction product adheres to the light-transmitting plate 8A and the transmittance of the light-transmitting plate 8A for transmitting the plasma light decreases, and the function is no longer fulfilled, the handle 1
6 is rotated so that the reaction product is not yet attached to the transparent plate 8A because it is covered with the baffle plate and the opening 22 is opened.
To move. Then, the opening 22 is made to face the area on the translucent plate 8A where the reaction product is not yet attached, and the optical sensor 9 is moved so as to face the opening 22. As a result, the reaction product attached to the transparent plate 8A can be continuously used for a long period of time without being removed.

In this case, in order to move the optical sensor 9 according to the movement of the opening 22, a moving mechanism (not shown) for moving the optical sensor 9 in synchronization with the movement of the opening 22 may be added.

In the second embodiment, the example in which the gear 15 is used has been described, but any means capable of moving the opening 22 with respect to the transparent plate 8A may be used, and the invention is not limited to the gear. For example, those skilled in the art can easily understand that a cam mechanism, a link mechanism, a belt mechanism and the like can be used.

FIG. 7 is a graph showing the relationship between the cumulative plasma generation time and the received light intensity of the optical sensor according to the second embodiment. The broken line 41 is the case of the conventional dry etching apparatus having no baffle plate, and the solid line 72 is the case of the dry etching apparatus shown in the second embodiment to which the baffle plate 14A is attached.

The plasma light observation window 31A to which the baffle plate 14A according to the second embodiment is attached has a cumulative plasma generation time until it reaches the light receiving intensity 20 of the photosensor considered to be effective as the observation window. Although it takes about 60 hours in the same manner, when the opening 22 of the baffle plate 14A is moved to a region on the translucent plate 8A where the reaction product is not yet attached because it is covered with the baffle plate 14A as described above, As shown in FIG. 7, the received light intensity can be restored to the initial state (about 70) again.

In the second embodiment, the opening 22 of the baffle plate 14A is used.
The translucent plate 8 on which the reaction product is not adhered twice
Can be moved to the area above A, and therefore the transparent plate 8
The light-transmitting plate 8 is kept until the intensity of the light received by the optical sensor decreases to 20 over 3 times due to the deposition of the reaction product on A.
It can be used continuously without removing the reaction product from A. As a result, the cumulative plasma generation time can be extended up to three times as long as in the first embodiment. However, the number of times that the opening 22 can be moved varies depending on the position of the center of the opening 22 and the distance that the opening 22 has moved, and is not limited to two times of movement.

Further, an automatic system for detecting that the received light intensity falls below a predetermined set level, automatically moving the opening 22 by a predetermined moving distance, and moving the position of the optical sensor 9 in synchronization with the automatic system. It is also possible to build.

As described above, according to the second embodiment, the opening 22 can be moved to the region on the light-transmitting plate 8A where the reaction product is not yet attached because it is covered with the baffle plate. A region where the reaction product is not yet attached can be newly used as an observation window. as a result,
Even if the reaction product adheres and the function of the observation window is no longer fulfilled, the transparent plate 8A can be used for a longer period of time.
The plasma utilizing apparatus can be used without cleaning the dirt of the reaction product attached to the.

(Third Embodiment) FIG. 8 is a sectional view of a plasma light observation window 31B according to a third embodiment. The same components as those described above with reference to FIGS. 1 and 2 are designated by the same reference numerals. Detailed description of these components will be omitted.

The plasma light observation window 31B includes a light-transmitting light-transmitting plate 8A and a baffle plate 14B attached to the inner surface of the light-transmitting plate 8A.

Similar to the first embodiment, this transparent plate 8A
Are made of quartz glass. The thickness of this quartz glass is about 2 mm, and the region facing the inside of the closed container 1 excluding the outer peripheral edge portion as the translucent plate 8A has a circular shape with a diameter of about 50 mm, for example.

Similar to the baffle plate 14 of the first embodiment, the baffle plate 14B has a disk shape in which a circular opening 21B is concentrically formed in the central portion as shown in FIG. The opening 21B provided in the baffle plate 14B limits the direction in which the reaction product generated by the reaction between the gas and the sample comes to the transparent plate 8A. The size thereof is different from that of the first embodiment, and the thickness d of the baffle plate 14 is, for example, about 10 mm and the opening 21.
The opening dimension L of is, for example, about 6.2 mm.

In the third embodiment, the optical fiber 10 for observing the plasma light inside the closed container 1 is concentric with the center of the opening 21B of the baffle plate 14B on the outer surface side of the transparent plate 8A. It is installed as follows. The optical fiber 10 receives the plasma light emitted by the plasma discharge 7.

FIG. 9 is a schematic explanatory view of the optical fiber 10. The optical fiber 10 has a light receiving surface 10A. The light receiving surface 10A is composed of 12 optical fiber strands, and the diameter of each optical fiber strand is 25.
The diameter of the light receiving surface 10A is 0 μm and the diameter is 1.05 mm. This optical fiber 10 has its own acceptance angle, that is, FIG.
The plasma light incident from the direction within the acceptance angle γ shown in is received. This acceptance angle γ is, for example, 23 °.

Incident light within the acceptance angle γ is the optical fiber 10
Light can be received by the light receiving surface 10A. As shown in FIG. 8, the opening 21B of the baffle plate 14B is formed in a shape that does not block the incident light within the light receiving angle γ. Therefore,
The optical fiber 10 even if the baffle plate 14B is attached.
The light receiving amount of the plasma light received by the light receiving surface 10A does not decrease.

Since the reaction product attached to the inner surface of the light-transmitting plate 8A has passed through the opening 21B of the baffle plate 14B, the reaction product flying from the flying direction within the range of the angle β1 shown in FIG. That is, an object, that is, a reaction product flying from a flying direction having an angle of ((π-β1) / 2) or more with respect to the inner surface of the closed container 1 is attached. This angle β1 is smaller than the angle α shown in FIG. 13 because the baffle plate 14B is provided. That is, the flying direction of the reaction product attached to the translucent plate 8A is limited. Therefore, the amount of reaction products attached to the transparent plate 8A is reduced as compared with the prior art.

Plasma light observation window 3 according to the third embodiment
Aluminum was etched by a dry etching apparatus equipped with 1B. The plasma light emitted during etching passes through the transparent plate 8A, is received by the optical fiber 10, is taken into a spectroscope (not shown), and the intensity change of only the light of 394 nm, which is the emission spectrum of aluminum, is observed, and the etching is performed. Detected the end point of.

FIG. 10 is a graph showing the relationship between the cumulative plasma generation time of the dry etching apparatus according to the third embodiment and the received light intensity of the optical fiber. The broken line 73 is the case of the conventional dry etching apparatus without the baffle plate, and the solid line 74 is the case of the dry etching apparatus of the second embodiment to which the baffle plate 14B is attached.

The optical fiber 10 receives the plasma light of 394 nm. As the etching is repeatedly performed, that is, as the cumulative plasma generation time elapses,
Since the reaction product generated during etching adheres to the inner surface side of the transparent plate 8A containing quartz glass, the transparent plate 8A
The transmittance of the light is reduced, and the intensity of light received by the optical fiber 10 is attenuated.

When the intensity of received light in a state where the quartz glass is cleaned is 100%, the end point of etching cannot be detected with the intensity of received light of 20% or less. The broken line 73 showing the conventional example without the baffle plate attenuates to 20% of the received light intensity in the cumulative plasma generation time within about 150 hours, but the embodiment shown by the solid line 74 with the baffle plate 14B interposed therebetween. In No. 3, the cumulative plasma generation time until the received light intensity is attenuated to 20% is about 500.
I was able to extend it to time.

Initial stage (plasma generation time = 0 hours)
The light receiving intensity of the baffle plate 14B does not interfere with the light receiving angle γ of the optical fiber 10, that is, the opening 2 of the baffle plate 14B.
Since 1B is formed in a shape that does not block the incident light within the acceptance angle γ, there is almost no difference from the conventional example.

The shape of the baffle plate in the third embodiment is only an example, and the opening 21B of the baffle plate 14B may be a shape that does not block the incident light within the light receiving angle γ. For example,
Even if the depth d of the baffle plate shown in FIG. 3 is further increased, the dimension of L may be defined to be larger so as not to interfere with the light receiving angle γ of the optical fiber 10. Further, if the angle β1 becomes smaller than the angle α, the flying direction of the reaction product flying to the light transmitting plate 8A is further restricted, so that the amount of the flying reaction product adhering to the light transmitting plate 8A is reduced by the conventional technique. Further, it is possible to obtain the effect that the plasma utilizing apparatus can be used for a longer period of time without cleaning the dirt of the reaction product attached to the transparent plate 8A.

Further, the opening 2 formed in the baffle plate 14A.
By combining this with Embodiment 2 in which 2 moves within the region on the transparent plate 8A, the cumulative plasma generation time can be further extended.

As described above, according to the third embodiment, since the opening 21B of the baffle plate 14B is formed so as not to block the incident light within the light receiving angle γ, the baffle plate 14B is attached. Also the light receiving surface 10A of the optical fiber 10.
The amount of received plasma light does not decrease. As a result, it is possible to significantly extend the cumulative plasma generation time until the light is attenuated to a predetermined intensity.

[0077]

As described above, according to the present invention, it is possible to provide a plasma light observation window, a plasma light observation system using the same, and a plasma utilization apparatus that can obtain high production efficiency with an inexpensive structure. .

Further, according to the present invention, it is possible to provide a plasma light observation window which can be used for a long period of time without opening the device, a plasma light observation system using the same, and a plasma utilization device by an inexpensive structure. .

Further, according to the present invention, there is provided a plasma light observation window, a plasma light observation system using the same, and a plasma use device which have an inexpensive structure in which reaction products generated in the plasma use device do not easily adhere. You can

Further, according to the present invention, a plasma light observation window having a structure capable of easily recovering the transmittance of the observation window even when the reaction products generated in the plasma utilizing apparatus are attached, and the plasma light observation window It is possible to provide a plasma light observation system and a plasma utilizing apparatus used.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a plasma utilizing apparatus according to a first embodiment.

FIG. 2 is a sectional view of a plasma light observation window according to the first embodiment.

FIG. 3 is a schematic view of a baffle plate according to the first and third embodiments.

FIG. 4 is a graph showing changes in the intensity of light received by the optical sensor with respect to the cumulative plasma generation time according to the first embodiment.

FIG. 5 is a sectional view of a plasma light observation window according to the second embodiment.

FIG. 6 is a schematic view of a baffle plate and a gear according to the second embodiment.

FIG. 7 is a graph showing changes in received light intensity of an optical sensor with respect to cumulative plasma generation time according to the second embodiment.

FIG. 8 is a sectional view of a plasma light observation window according to the third embodiment.

FIG. 9 is a schematic explanatory diagram of an optical fiber according to a third embodiment.

FIG. 10 is a graph showing changes in received light intensity of an optical fiber with respect to plasma generation time according to the third embodiment.

FIG. 11 is a diagram showing an example of a configuration of a conventional plasma utilizing apparatus.

FIG. 12 is a diagram showing an example of a conventional plasma utilizing apparatus and a system configuration for observing plasma light.

FIG. 13 is a sectional view of a conventional plasma light observation window.

[Explanation of symbols]

8 observation windows 9 Optical sensor 10 optical fiber 11 Spectrometer 14, 14A, 14B Baffle plate 15 gears 16 handles 21, 21B, 22 openings

Continued front page    F-term (reference) 4K030 FA01 FA03 HA16 KA37 LA15                       LA18                 4K057 DA12 DB05 DB06 DD01 DJ03                       DJ07 DM03 DN01                 5F004 AA13 BA04 BC08 CA09 CB09                       CB15

Claims (5)

[Claims] 1. A plasma light observation window provided in a plasma utilizing apparatus using a gas activated by plasma to detect the plasma light of the plasma from the outside, the plasma light being transmitted to the outside. A translucent plate and a plasma light incident side of the translucent plate for limiting adhesion of a product generated by the plasma to the translucent plate, and an opening through which the plasma light passes. A plasma light observation window, characterized by comprising: 2. The plasma light observation window according to claim 1, further comprising moving means for moving the opening with respect to the transparent plate. 3. The plasma light observation window according to claim 1, an optical fiber arranged to face the opening of the baffle and receiving the plasma light, and the plasma light guided by the optical fiber. An analyzer for analyzing, and a plasma light observation system, comprising: 4. The plasma light observation system according to claim 3, wherein the opening of the baffle plate has a shape that does not block the plasma light incident on the optical fiber. 5. A hermetically sealed container, a pair of electrodes provided in the container to generate plasma, and a plasma light observation window provided in the container for observing plasma light of the plasma. The plasma light observation window is provided with a light-transmitting plate that transmits the plasma light to the outside, and the light-transmitting plate for limiting the products generated by the plasma from adhering to the light-transmitting plate. A baffle plate provided on the plasma light incident side of the plate and having an opening through which the plasma light passes; an optical fiber arranged to face the opening of the baffle plate and receiving the plasma light; An analyzer for analyzing the plasma light guided by an optical fiber, and a plasma utilizing apparatus.