JPH09330917A - Plasma light detecting window for plasma treating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma light detecting window for a plasma treating apparatus capable of extending cleaning or replacing time. SOLUTION: One or more blind holes 100c having an opening surface 100a is provided at the side of the treating chamber 12 of a detecting window 100, and the spectrum of a plasma is transmitted from the bottom 100d of the hole 100c to the light receiving part of a finishing point detector 38. Thus, the adherence of reactive product to the bottom 100d can be reduced or suppressed for etching. The cleaning or replacing time of the window 100 is extended to be capable of improving the productivity and reducing the production cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma light detection window of a plasma processing apparatus.

[0002]

2. Description of the Related Art "In the following description, components having substantially the same functions and configurations are designated by the same reference numerals, and a duplicate description will be omitted." Conventionally, in a plasma processing apparatus, for example, a parallel plate type plasma etching apparatus 10 shown in FIG. 10, a lower electrode 16 on which an object to be processed can be placed in an airtight processing chamber 12, and a position facing the lower electrode 16. Is provided with an upper electrode 26, a predetermined processing gas is introduced into the processing chamber 12 from a processing gas supply source 34, and a predetermined reduced pressure atmosphere is maintained by the operation of the evacuation means 24. When high frequency power is applied from the high frequency power supply 18 to the processing chamber 1,
A plasma is generated in 2.

A detection window DW is provided on a part of the side wall of the processing container 14.
And a detection window D outside the processing container 14
An end point detector 38 is provided at a position facing W. The conventional example of the detection window DW will be described in detail. The conventional detection window DW (hereinafter, regarding the conventional detection window DW,
Reference number 36 will be used. ) Is shown in FIGS.
As shown in FIG. 3, the surface 36a on the processing chamber 12 side is the processing container 1
4 has a shape substantially the same as the curvature of the inner wall, and an O-ring 42 is provided on the peripheral edge of the inner wall.
For example, when tightened with bolts 46, the processing container 14
It is configured to be in close contact with the wall portion of the.

The end of plasma processing is detected by the processing chamber 12
The emission spectrum generated therein is introduced into the light receiving portion of the end point detector 38 through the detection window 36, and is detected by the change in the emission spectrum. Also,
A heater 40 is provided in a substantially annular shape inside the detection window 36, and is configured to heat the detection window 36 to reduce adhesion of reaction products generated during plasma processing to the detection window 10. .

[0005]

However, the surface 36a of the detection window 36 on the processing chamber 12 side is adhered or etched by reaction products during plasma processing,
Since the amount of transmission of the emission spectrum is reduced, it has been necessary to wash or replace the emission spectrum in a relatively short time in order to detect the desired emission spectrum. Further, the detection window 36
The plasma treatment must be interrupted at the time of cleaning or replacement, and it is difficult to improve productivity.

The present invention has been made in view of the above problems of the plasma light detection window of the conventional plasma processing apparatus, and it is possible to prevent the reaction product from adhering to the detection window or being etched. It is an object of the present invention to provide a new and improved end point detector for a plasma processing apparatus, which can extend the cleaning or replacement time of the detection window by suppressing and improve the productivity.

[0007]

In order to solve the above-mentioned problems, according to claim 1, the plasma light of the plasma processing apparatus which transmits the emission spectrum of the plasma generated in the processing chamber to the light receiving portion of the end point detector. The detection window provided in the wall portion of the processing chamber includes one or more blind holes having an opening on the processing chamber side, and at least the bottom of the blind hole is made of a transparent member. It is characterized by being. Therefore, the surface area of the processing chamber side of the detection window is substantially increased, and the emission spectrum is transmitted from the bottom of the blind hole, so that the amount of reaction products or etchant ions entering the blind hole is increased. Can be reduced, and the distance between the bottom and the surface of the detection window on the end point detector side can be substantially shortened. Therefore, the reaction product is prevented from being attached or etched to the bottom, and the amount of transmitted light in the emission spectrum is increased, so that the cleaning or replacement time of the detection window can be extended. In the present specification, a blind hole means a hole that does not penetrate, and a bottom part means a part of the detection window that does not penetrate in the same direction as the blind hole.

According to a second aspect of the present invention, there is provided a plasma light detection window of a plasma processing apparatus for transmitting an emission spectrum of plasma generated in the processing chamber to a light receiving portion of an end point detector, the wall of the processing chamber. The detection window provided in the section is provided with one or more blind holes having an opening on the processing chamber side,
At least the bottom of the blind hole is composed of a transparent member, which is a light-transmissive first member forming a part of the outer wall of the processing chamber, and at least the surface of the first member exposed to the processing chamber. The second member can be attached airtightly, and at least the portion of the second member corresponding to the bottom of the blind hole of the first member is transparent. Therefore, when the transmission amount of the emission spectrum decreases, the second
Only the member needs to be washed or replaced, and when a heater for reducing the adhesion of reaction products is provided in the detection window, the heater is provided in the first member so that the heater is provided in the second member. No wiring is required, and cleaning or replacement is easy.

Further, according to a third aspect of the present invention, there is provided a plasma light detection window of a plasma processing apparatus for transmitting an emission spectrum of plasma generated in the processing chamber to a light receiving portion of an end point detector, the wall of the processing chamber. The detection window provided in the section includes a light-transmissive first member that forms a part of the outer wall of the processing chamber, and
Or a second member having two or more through holes, wherein the first member has a transparent member at least at the bottom of the through hole, and the second member has an open end on the processing chamber side. And the other end is attached to the first member such that the other end is hermetically sealed by the first member. Therefore, since the first member is configured on the end point detector side, the cleaning or replacement work can be easily performed. Further, as the material forming the second member, it is possible to use a material having gas resistance and plasma resistance higher than that of quartz, for example, ceramic, and it is possible to extend the replacement time of the second member. .

According to a fourth aspect of the present invention, there is provided a plasma light detection window of a plasma processing apparatus for transmitting an emission spectrum of plasma generated in the processing chamber to a light receiving portion of an end point detector, which is the processing window of the processing chamber. A wall is provided with one or more through holes, and a transparent member, at least a portion corresponding to the bottom of the through hole is transparent, is airtightly attached to the outer wall of the processing chamber on the light receiving portion side of the through hole. It is characterized by that. Therefore, the structure of the detection window is simplified and the number of members is reduced, so that the detection window can be easily cleaned, replaced or processed.

According to a fifth aspect of the present invention, the light transmitting portion of the detection window can collect the light in the processing chamber and guide it to the light receiving portion of the end point detector. Therefore, it becomes possible to introduce the emission spectrum into the light receiving part of the end point detector more efficiently, and improve the detection sensitivity of the end point of the plasma treatment. further,
Since it is not necessary to provide the light collecting means in the light receiving portion, the end point detector can be provided even in a narrow space.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment in which the plasma light detection window of the plasma processing apparatus according to the present invention is applied to a parallel plate type plasma etching apparatus will be described in detail.

A plasma etching apparatus 10 shown in FIG.
The processing chamber 12 is formed in the processing container 14. A lower electrode 16 on which an object to be processed, for example, a semiconductor wafer W can be placed is formed at the bottom of the processing container 14, and high frequency power oscillated from a high frequency power supply 18 is passed through the matching unit 20 to the lower electrode 16. Are configured to be applied.

An exhaust pipe 22 is provided below the side wall of the processing container 14, and a vacuum evacuation means P24 is connected to the exhaust pipe 22. Can be maintained in a predetermined reduced pressure atmosphere.

An upper electrode 26 is provided on the upper portion of the processing container 14 at a position facing the lower electrode 16. Upper electrode 2
6, a gas introduction pipe 28 is connected, and the gas introduction pipe 28 is provided with a valve 30 and a mass flow controller MF.
It is connected to the processing gas supply source 34 via C32. Therefore, a predetermined processing gas is introduced from the processing gas supply source 34 into the processing chamber 12 via the mass flow controller MFC 32, the valve 30, the gas introduction pipe 28 and the upper electrode 26.

A detection window DW is provided on the side wall of the processing container 14, and the end point detection for detecting the end point of the plasma processing from the plasma emission spectrum is further provided at a position facing the detection window DW outside the processing container 14. A container 38 is provided.

The plasma etching apparatus 1 shown in FIG.
FIG. 11 shows a cross-sectional view taken along the line XX ′ of 0 of FIG. Surface DWa of the processing window 12 side of the detection window DW
Is substantially the same as the curvature of the inner wall of the processing container 14, and the detection window DW can be provided on the wall of the processing chamber 12 without forming an uneven portion other than a blind hole in the processing chamber 12. It becomes possible and stable plasma can be obtained.

The detection window DW according to this embodiment will be described in detail. The detection window DW (hereinafter, the reference numeral 100 is used for the detection window DW according to this embodiment) is shown in FIGS. In accordance with the number of light receiving portions of the end point detector 38, the opening surface 100a, which is the surface on the processing chamber 12 side, is substantially perpendicular to the bottom surface 100b on the end point detector 38 side. In the direction, blind holes, for example, four blind holes 100c are provided at predetermined positions. This blind hole 10
The diameter and depth of 0c are set in consideration of the intensity of the detection window 100, the transmission amount of the emission spectrum, or the fact that the larger the ratio of the depth to the diameter is, the less the amount of the reaction product is attached. , The diameter and depth are, for example, 8
mm and 20 mm.

At least the bottom 100d of the detection window 100
Is made of a gas-resistant and plasma-resistant transparent member such as quartz, and the emission spectrum is introduced into the light receiving portion of the end point detector 38 through the bottom portion 100d.

An O-ring 106 is provided on the periphery of the detection window 100.
Is provided, and is configured to come into close contact with the wall portion of the processing container 14 when tightened by, for example, a bolt 110 via the fixing plate 108. Further, a heater 112 is provided in the detection window 100 in a substantially annular shape.
By heating the bottom of the reaction product 100d
It is configured to further reduce adherence to.

The detection window 100 according to the present embodiment having substantially the same size (however, the heater 112 is not provided).
FIG. 3 shows the result of measuring the output voltage of the end point detector by detecting the end point of the plasma etching process using the conventional detection window 36. The output voltage of the detection window 100 immediately after the start of application of high-frequency power is about twice as high as the output voltage of the conventional detection window 36.
Bottom 10 transparent to the emission spectrum for a thickness of 0
This is because the thickness of 0d is reduced and the transmission efficiency is improved.

Further, comparing the output voltages of the detection window 100 and the conventional detection window 36, the same high frequency power application time,
That is, at the same plasma processing time, the detection window 1
The output voltage of 00 can always obtain a voltage that is about twice as high as that of the output voltage of the conventional detection window 36, so that the deposition rate of reaction products is low or it is difficult to etch. I can confirm. Therefore, the detection window 10
By providing the heater 112 in the zero position, it is possible to further reduce the adhesion of reaction products, and it is possible to further extend the cleaning or replacement time of the detection window 100.

As another embodiment, like the detection window 120 shown in FIG. 4, it has an opening on the side of the processing chamber 12 and has a blind hole 12.
0c, a transparent member having a hole substantially larger than the size of the blind hole 102c, for example, a transparent member having a blind hole 120c having an opening on the processing chamber 12 side in a first member 122 made of quartz, For example, the second member 124 made of quartz may be hermetically attached. According to this configuration, when the transmission amount of the emission spectrum decreases, the second
Only the member 124 need be cleaned or replaced. Also,
When the heater 112 is provided in the detection window 120, by providing the heater in the first member 122, wiring of the heater 112 is not required in the second member 124, which facilitates cleaning or replacement. In addition, the processing container 1 in the detection window 120
The mounting configuration of the No. 4 on the wall is substantially the same as that of the detection window 100.

Further, like the detection window 140 shown in FIG. 5, a transparent member of a substantially flat plate having a bottom portion 140d of the through hole 140c, for example, a first member 142 made of quartz, has a through hole 140c, for example, quartz. A gas- and plasma-resistant material, for example a second ceramic material
The member 144 may be hermetically attached. According to this configuration, when the transmission amount of the emission spectrum is reduced, only the first member 142 needs to be washed or replaced, and these operations can be performed more easily. Also,
By using, for example, ceramic for the second member 144, it is possible to extend the replacement time of the second member 144. The attachment structure of the detection window 140 to the wall portion of the processing container 14 is substantially the same as that of the detection window 100.

Further, in the detection window 160 shown in FIG. 6, the surface 160a of the second member 164 on the processing chamber 12 side has substantially the same shape as the detection window 140, and the shape of the through hole 160c is formed with respect to the processing chamber 12 side. By adopting an inversely tapered configuration, that is, by making the diameter of the through-hole 160c on the end point detector 38 side substantially larger than the diameter on the processing chamber 12 side, the through-hole 160c and the bottom portion 160d are formed. The surface area is substantially increased. Therefore, the adhesion of the reaction product is further reduced than that of the detection window 140, the cleaning or replacement time of the first member 162 is further extended, and the cleaning, replacement or processing is facilitated. The attachment structure of the detection window 160 to the wall of the processing container 14 is substantially the same as that of the detection window 100.

Further, in the detection window 180 shown in FIG. 7, a through hole 180c is provided directly in the wall portion of the processing container 14,
By adopting a configuration in which a substantially flat transparent member having a bottom portion 180d, for example, a member 182 made of quartz, is attached in an airtight manner, the configuration of the detection window 180 becomes simpler than that of the other detection windows according to the present embodiment. Since the number of members is reduced, it is easy to clean or replace the detection window 180. Further, when the peripheral portion of the through-hole 180c on the processing chamber 12 side has a curved line, when the material forming the processing container 14 is, for example, anodized aluminum, the corner portion is formed due to the concentration of the electric field. Can be prevented from being etched. The attachment structure of the detection window 180 to the wall of the processing container 14 is substantially the same as that of the detection window 100.

The detection windows 100, 120 according to this embodiment,
Bottoms 100d, 120d of 140, 160 and 180,
By making 140d, 160d, and 180d a configuration for condensing an emission spectrum, for example, a convex lens shape,
The emission spectrum can be efficiently introduced into the light receiving part of the end point detector 38, and the end point detection sensitivity can be improved. Further, since it is not necessary to provide the light collecting means in the light receiving portion, the end point detector 38 can be provided even in a narrow space. Furthermore, the detection window 12
0, 140, and 160, the light collecting structure is set to the first
By providing within members 122, 142 and 162,
The cost of the second members 124, 144 and 164 can be reduced.

The detection window for plasma light of the plasma processing apparatus according to this embodiment is constructed as described above. For example, in the parallel plate type plasma processing apparatus, the detection window 1 according to this embodiment is used.
The case where the target film on the wafer W, for example, the silicon oxide film is etched by applying No. 00 will be described below. In the plasma etching processing apparatus 10, the wafer W is first placed on the lower electrode 16 and then held.

In the processing chamber 12, a predetermined processing gas is supplied from the processing gas supply source 34 to the mass flow controller MFC3.
2, the valve 30, the gas introduction pipe 28, and the upper electrode 26. Further, in the processing chamber 12, a predetermined depressurized atmosphere is maintained by the operation of the vacuuming means P24.

When the high frequency power oscillated from the high frequency power supply 18 is applied to the lower electrode 16 through the matching device 20,
Plasma is generated between the upper electrode 26 and the wafer W, and the etching process is performed on the wafer W. The emission spectrum of this plasma is introduced into the light receiving portion of the end point detector 38 through the detection window 100, and the end point is detected.

When the above-mentioned end point is detected, by using the detection window 100 according to this embodiment, it is possible to prevent the reaction product from adhering to or etching the bottom 100d during the etching process. Emission spectrum can be efficiently introduced into the light receiving part of 38,
Furthermore, since the cleaning or replacement time of the detection window 100 is extended, the productivity can be improved.

The preferred embodiment of the present invention has been described above by taking the parallel plate type plasma etching apparatus for etching the silicon oxide film on the semiconductor wafer W as an example, but the present invention is not limited to such a configuration. Not something. A person skilled in the art should be able to conceive various modifications and changes within the scope of the technical concept of the claims, and it is understood that these also naturally belong to the technical scope of the present invention.

In the above embodiment, the detection windows 100 and 120 have four blind holes, and the detection windows 140, 160 and 1
Although 80 has been described with reference to an example having two through holes, the present invention is not limited to such a configuration, and depending on the plasma processing apparatus for carrying out the present invention and the light receiving portion of the end point detector thereof,
A configuration in which one or more blind holes or through holes are provided, for example, as in the detection window 200 shown in FIG. 8, one blind hole or through hole is formed in a direction substantially perpendicular to the bottom surface 200d from the processing chamber side surface 200a. The hole 200c may be provided, and as in the detection window 220 shown in FIG. 9, the hole 7c may be formed in a direction substantially perpendicular to the bottom 220d from the surface 220a on the processing chamber side.
It is also possible to provide individual blind holes or through holes 220c. The blind hole 220c of the detection window 220 corresponds to one light receiving part, but by increasing the ratio of the depth to the diameter of the blind hole in this way, the reaction product adheres to the bottom. This can be further suppressed.

In the above embodiment, the blind holes 200c and 220c of the detection windows 200 and 220 correspond to the end point detector having one light receiving portion, but the present invention is not limited to such a constitution. The detection window may be provided with blind holes corresponding to two or more light receiving portions. Also,
In the above-described embodiment, the blind hole and the through hole are formed in a substantially circular shape, but the present invention is not limited to such a configuration, and a shape corresponding to the light receiving portion of the plasma processing apparatus and the end point detector for carrying out the present invention. Alternatively, it can be sized.

In the above embodiment, the detection window 100,
Although the heater 112 and the light condensing unit are provided in 120, 140, 160, and 180, the invention is not limited to such a configuration and is not necessarily required in the practice of the invention. The plasma light detection window of the plasma processing apparatus according to the present invention can be applied to any plasma processing apparatus, for example, a plasma etching processing apparatus, a plasma ashing processing apparatus,
It is also possible to use a glass substrate for LCD or the like as the object to be processed.

[0036]

As described above, according to the present invention,
In the plasma light detection window of the plasma processing apparatus, one or more blind holes having an opening are provided on the processing chamber side of the detection window due to the configuration of the light receiving portion of the end point detector, and the plasma light is emitted from the bottom of the blind hole. It becomes possible to suppress the adhesion of the reaction product to the bottom part or to suppress the etching by adopting the structure of transmitting the emission spectrum of
It is possible to improve the productivity and reduce the production cost by extending the cleaning or replacement time of the detection window. Further, when the detection window is composed of a plurality of members, it is possible to limit the members that need to be cleaned or replaced, and it becomes easier to clean or replace the detection window.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a detection window to which the present invention can be applied.

FIG. 2 is a front view of the detection window 100 of FIG. 1 viewed from the end point detector side.

3 shows the output voltage of the end point detector in the case of using the detection window 100 of FIG. 1 according to the present embodiment and the conventional detection window 36 of FIG. 12 in the plasma etching process.

FIG. 4 is a schematic sectional view showing an embodiment of a detection window to which the present invention can be applied.

FIG. 5 is a schematic sectional view showing an embodiment of a detection window to which the present invention can be applied.

FIG. 6 is a schematic sectional view showing an embodiment of a detection window to which the present invention can be applied.

FIG. 7 is a schematic sectional view showing an embodiment of a detection window to which the present invention can be applied.

FIG. 8 is a schematic front view showing one embodiment of a detection window to which the present invention can be applied, as seen from the processing chamber side.

FIG. 9 is a schematic front view showing one embodiment of a detection window to which the present invention can be applied, as seen from the processing chamber side.

FIG. 10 is a schematic sectional view showing an embodiment of a parallel plate type plasma etching apparatus using a detection window to which the present invention can be applied.

11 is a schematic cross-sectional view of the parallel plate plasma etching apparatus 10 of FIG. 10 taken along a plane taken along line XX ′.

FIG. 12 is a schematic sectional view showing an example of a conventional detection window.

13 is a front view of the detection window 36 of FIG. 12 viewed from the end point detector side.

[Explanation of symbols]

 10 Plasma Etching Device 12 Processing Chamber 14 Processing Container 16 Lower Electrode 18 High Frequency Power Supply 24 Vacuum Evacuation Means 26 Upper Electrode 32 Mass Flow Controller 34 Processing Gas Supply Source 36 (DW) Detection Window 38 End Point Detector 40 Heater 42 O-ring 44 Fixed Plate 46 Bolt 100 (DW) Detection window 100a Processing chamber side surface 100b Bottom surface 100c Blind hole 100d Bottom 106 O-ring 108 Fixing plate 110 Bolt 112 Heater 120 Detection window 120c Blind hole 120d Bottom 122 First member 124 Second member 140 Detection window 140c Through hole 140d Bottom portion 142 First member 144 Second member 160 Detection window 160a Processing chamber side surface 160c Through hole 160d Bottom portion 162 First member 164 Second member 180 Detection window 180c Through hole 180d Bottom portion 182 Transparent Member DW detection window W wafer

Claims (5)

[Claims] 1. A detection window for plasma light of a plasma processing apparatus for transmitting an emission spectrum of plasma generated in the processing chamber to a light receiving portion of an end point detector, the detection window being provided on a wall portion of the processing chamber. The window is provided with one or more blind holes having an opening on the processing chamber side, and at least the bottom of the blind holes is made of a transparent member, and the plasma light detection window of the plasma processing apparatus is characterized. . 2. A detection window for plasma light of a plasma processing apparatus that transmits an emission spectrum of plasma generated in the processing chamber to a light receiving portion of an end point detector, the detection window being provided on a wall portion of the processing chamber. The window is provided with one or more blind holes having an opening on the side of the processing chamber, and at least the bottom of the blind hole is made of a transparent member, which is a light-transmissive part of the outer wall of the processing chamber. The second member can be hermetically attached to the first member and at least the surface of the first member exposed to the processing chamber, and the second member is at least at the bottom of the blind hole of the first member. A plasma light detection window of a plasma processing apparatus, characterized in that the corresponding portion is transparent. 3. A detection window of plasma light of a plasma processing apparatus for transmitting an emission spectrum of plasma generated in the processing chamber to a light receiving portion of an end point detector, the detection window being provided on a wall portion of the processing chamber. The window includes a light-transmissive first member forming a part of the outer wall of the processing chamber and a second member having one or more through holes, and the first member is at least the bottom of the through hole. Is a transparent member, and the second member is attached to the first member such that an opening end is formed on the processing chamber side and the other end is hermetically sealed by the first member. The plasma light detection window of the plasma processing apparatus, which is a feature. 4. A plasma light detection window of a plasma processing apparatus for transmitting an emission spectrum of plasma generated in the processing chamber to a light receiving portion of an end point detector, wherein one or more or more are provided on a wall portion of the processing chamber. A through hole is provided, and on the light receiving portion side of the through hole, a transparent member in which at least a portion corresponding to the bottom of the through hole is transparent, is attached to the outer wall of the processing chamber in an airtight manner, Detection window for plasma light of plasma processing equipment. 5. The light transmission part of the detection window is capable of condensing the light in the processing chamber and guiding it to the light reception part of the end point detector. A plasma light detection window of the plasma processing apparatus according to any one of 4 above.