JP2003163204A - Plasma treating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize stable operation of a device by preventing discharge of the inside of a gas supply hole of a shower plate for supplying gas to a plasma treating chamber in the form of a shower. <P>SOLUTION: The gas supply hole of the shower plate is arranged in a weak electric field area being a prescribed electric field intensity or lower in accordance with an electromagnetic field distribution in a shower plate face of an electromagnetic field introduced into the plasma treating chamber. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus, and more particularly to a plasma processing apparatus suitable for processing a substrate having a diameter of 300 mm or more.

[0002]

2. Description of the Related Art As a conventional plasma processing apparatus, for example, as described in JP-A-11-260594, microwaves, UHF or VHF electromagnetic waves are transmitted to a processing chamber using a coaxial line to generate plasma. In the plasma processing device, the upper part of the processing chamber is partitioned by a quartz window, and a disk-shaped antenna connected to the end of the inner conductor of the coaxial line is installed on the side opposite to the processing window of the quartz window. It is smaller than the inner diameter, and electromagnetic waves can be introduced into the processing chamber from the outer circumference of the disk antenna through the quartz window.Furthermore, a slot antenna is provided on the disk antenna, and electromagnetic waves are introduced into the processing chamber from inside the disk antenna. There is known a plasma processing apparatus in which the plasma distribution is controlled by controlling the plasma distribution and performing uniform plasma processing.

[0003]

In the above prior art, no consideration is given to the introduction position of the processing gas, and a shower plate, which is a gas supply plate, is provided in the quartz window portion forming the processing chamber to form a shower shape in the processing chamber. When the gas is supplied, the shower plate may deteriorate due to repeated plasma treatment for a long period of time, and discharge may occur in the gas supply hole provided in the shower plate. When an electric discharge occurs in the gas supply hole of the shower plate, there is a problem that the characteristics of plasma change and the plasma processing characteristics deteriorate.

An object of the present invention is to provide a plasma processing apparatus capable of preventing discharge in the gas supply holes of the gas supply plate and performing stable plasma processing.

[0005]

The above object is to provide a processing chamber whose inside is decompressed and evacuated, a substrate electrode in which a substrate to be processed is placed in the processing chamber, and a substrate electrode which faces the substrate electrode in the processing chamber. In a plasma processing apparatus having a gas supply plate having a plurality of gas supply holes in a plane, plasma is generated by introducing an electromagnetic wave into the processing chamber, and the substrate to be processed is processed using the plasma. According to the electric field intensity distribution in the gas supply plate surface of the introduced electromagnetic wave, it is achieved by providing a gas supply hole non-formed region in the gas supply plate surface in a region where the electric field intensity is equal to or higher than a predetermined electric field intensity.

[0006] Further, the above-mentioned objects are as follows: a processing chamber whose inside is evacuated to a reduced pressure; a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is placed; A gas supply plate having a gas supply hole and an electromagnetic wave radiating unit arranged to face the gas supply plate, the electromagnetic wave radiating unit introduces an electromagnetic wave into a processing chamber to generate plasma, and the plasma is used. In a plasma processing apparatus for processing a substrate to be processed with a gas supply hole of a gas supply plate in a region where the electric field strength is equal to or lower than a predetermined electric field strength according to the electric field strength distribution in the surface of the gas supply plate of the electromagnetic wave introduced into the processing chamber. It is achieved by arranging.

Further, the predetermined electric field strength is 1/2 of the maximum value.
Is.

Further, the predetermined electric field strength is 50 kV / m.

Further, the above-mentioned objects are: a processing chamber whose inside is evacuated to a reduced pressure; a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is placed; A gas supply plate having a gas supply hole and an electromagnetic wave radiating unit arranged to face the gas supply plate, the electromagnetic wave radiating unit introduces an electromagnetic wave into a processing chamber to generate plasma, and the plasma is used. In a plasma processing apparatus for processing a substrate to be processed, the electric field intensity distribution of the electromagnetic wave introduced into the processing chamber on the surface of the gas supply plate has a plurality of maximum values, and the absolute value of the electric field is higher than the first maximum value. This is achieved by arranging the gas supply holes of the gas supply plate in a region below the second minimum value which is small.

Further, the above object is to provide a processing chamber whose inside is evacuated under reduced pressure, a substrate electrode in which the substrate to be processed is placed in the processing chamber, and a plurality of electrodes provided in the processing chamber so as to face the substrate electrode. A gas supply plate having a gas supply hole and an electromagnetic wave radiating means arranged so as to face the gas supply plate. The electromagnetic wave radiating means introduces an electromagnetic wave into the processing chamber and forms a magnetic field in the processing chamber. In a plasma processing apparatus for generating a plasma by the action and processing a substrate to be processed by using the plasma, an area where a gas supply hole is not formed is provided in an area of a central portion of a gas supply plate that is 30% or less of a diameter of a processing chamber. Is achieved by

Further, the above-mentioned objects are: a processing chamber whose inside is evacuated to a reduced pressure; a substrate electrode in which a substrate to be processed is placed in the processing chamber; and a plurality of electrodes provided in the processing chamber so as to face the substrate electrode. A dielectric gas supply plate having a gas supply hole of
And a flat plate-shaped antenna arranged through a dielectric window facing the gas supply plate to form a processing chamber, the flat plate-shaped antenna introduces electromagnetic waves into the processing chamber to generate plasma, and the plasma is used. In a plasma processing apparatus for processing a substrate to be processed, a gas supply hole of the gas supply plate is arranged in a region where the electric field strength is equal to or lower than a predetermined electric field strength according to the electric field strength distribution of the electromagnetic wave introduced into the processing chamber in the gas supply plate. It is achieved by

Further, the above object is to provide a processing chamber whose inside is evacuated to a reduced pressure, a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is placed, and a flat plate which is provided in the processing chamber and faces the substrate electrode. -Shaped antenna and a conductive gas supply plate that is attached to the side surface of the plate electrode of the plate-shaped antenna and has a plurality of gas supply holes in the plane, and the plate-shaped antenna introduces electromagnetic waves into the processing chamber to generate plasma Then, in the plasma processing apparatus for processing the substrate to be processed using the plasma, the gas is applied to a region where the electric field strength is equal to or lower than a predetermined electric field strength according to the electric field strength distribution in the gas supply plate surface of the electromagnetic wave introduced into the processing chamber. This is achieved by arranging the gas feed holes in the feed plate.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the case where a shower plate, which is a gas supply plate located below an antenna for supplying electromagnetic waves, which is an electromagnetic wave radiating means, is provided in the processing chamber so as to face a substrate electrode, and is made of a dielectric The electromagnetic waves supplied into the processing chamber for generating plasma inside the shower plate are distributed in a certain pattern determined by the surrounding boundary conditions, the power of the input electromagnetic waves, and the like. When the shower plate, which is a gas supply plate located below the antenna for supplying electromagnetic waves, is made of a conductive material and attached to the lower surface of the antenna, it is formed at the interface between the shower plate and the plasma generated in the processing chamber. The electromagnetic field of the input electromagnetic wave is distributed in the sheath region.

On the other hand, it is considered that the threshold value of the electric field intensity of the discharge generated in the gas supply hole is determined by the pressure of the processing chamber, the gas species, the shape of the gas supply hole in the shower plate, and the like. If a region having an electric field strength exceeding the threshold exists in the shower plate or in a sheath region in contact with the shower plate, and if there is a gas supply hole in that region, discharge will occur in the gas supply hole. Therefore, depending on the electric field distribution in the shower plate, by disposing the gas supply hole while avoiding the region where the electric field is strong, it is possible to prevent discharge in the gas supply hole of the shower plate.

An embodiment of the plasma processing apparatus of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 shows an etching apparatus which is an embodiment of the plasma processing apparatus of the present invention. A dielectric window 5 is airtightly attached to the upper portion of the processing chamber 7, and the inside of the processing chamber 7 can be depressurized by a vacuum exhaust device (not shown). On the upper surface of the dielectric window 5, a disk-shaped flat plate antenna 1 serving as an electromagnetic wave radiating means is provided, and in this case, a frequency of 450 M is generated through the coaxial line 2 and the matching box 3.
It is connected to a high frequency power source 4 of Hz. A lower surface of the dielectric window 5, in other words, a shower plate 6 which is a gas supply plate is provided between the dielectric window 5 and the processing chamber 7, and the processing gas is supplied by the gas supply device 8 so that it can be introduced into the processing chamber. Has become. The shower plate 6 is made of a dielectric material, and as shown in FIG.
Have. The gas supply hole 9 is provided with a plurality of holes each having a diameter of 0.5 mm. A substrate electrode 11 on which the substrate 10 to be processed can be mounted is attached to the lower portion of the processing chamber 7 so as to face the dielectric window 5, and a bias power supply 13 is connected to the substrate electrode 11 via a matching unit 12. . An electromagnet 1 is provided around the processing chamber 7.
4 is provided so that a static magnetic field can be formed inside the processing chamber 7.

In this case, the processing chamber 7 has an inner diameter of about 50 so that a 12-inch wafer can be processed.
It has a cylindrical shape of 0 mm. Although quartz is used as the material of the dielectric window 5 and the shower plate 6, other materials such as alumina ceramics may be used as long as they do not adversely affect the plasma processing and the loss of electromagnetic waves is not large. The shower plate 6 and the dielectric window 5 do not necessarily have to be made of the same material. For example, one may be quartz and the other may be alumina ceramic. The diameter of the gas supply hole 9 is set to 0.5 mm, but a smaller diameter is desirable from the standpoint of preventing discharge in the gas supply hole.

In the apparatus configured as described above, the processing gas is introduced into the processing chamber 7 by the gas supply apparatus 8 from the gas flow path provided between the shower plate 6 and the dielectric window 5 into the gas supply hole 9. Supplied. On the other hand, the electromagnetic wave from the high frequency power source 4 is radiated to the processing chamber 7 through the dielectric window 5 provided directly below the flat antenna 1, and a magnetic field is formed by the electromagnet 14 to utilize the action of the electric field and the magnetic field. Plasma is generated in the processing chamber 7. Further, it is possible to control the plasma diffusion by the static magnetic field and adjust the plasma distribution. Furthermore, by generating a static magnetic field (0.016 Tesla) that matches the frequency of the cyclotron motion of the electrons in the plasma with the frequency of the input electromagnetic waves (450 MHz), the energy of the electromagnetic waves is efficiently supplied to the electrons.
A CR (Electron Cyclotron Resonance) phenomenon can also occur. Thereby, the plasma can be stably generated, and the plasma density can be improved. Bias power can be supplied to the target substrate 10 from the bias power source 13 via the matching unit 12. By applying the bias power, the ions in the plasma can be drawn into the substrate to be processed, and the etching process can be made more efficient and the etching shape can be controlled.

The present inventors changed the radius of the region where there is no gas supply hole in the central portion of the shower plate and simulated whether or not discharge occurs in the gas supply hole. This will be described below.

FIG. 3 shows the electric field intensity distribution of an electromagnetic wave of 450 MHz supplied for generating plasma in the shower plate 6. The conditions at this time are: electric power: 1200 W, plasma density: 9 × 10 ¹⁶ / m ³ , the radius of the shower plate 6 is about 500 mm, which is the same as the inner diameter of the processing chamber, and the materials of the dielectric window 5 and the shower plate 6 are The simulation results are for the case where uniform plasma exists in the processing chamber for each case of quartz. The simulation was performed by solving Maxwell's equation by the finite element method.

In this embodiment, the electromagnetic wave is supplied from the center by the coaxial line, the electromagnetic field distribution is axisymmetric and uniform in the azimuth direction, and the electric field strength distribution is determined by the distance from the center. It has a maximum value at the center, and the electric field strength tends to fall as a whole as it moves away from the center. When quartz is used as the dielectric window, there is a first peak having a first maximum value at the center and a second peak having a second maximum value (hereinafter referred to as a second peak) at a position of a radius of about 160 mm. . When a material having a high relative dielectric constant is used for the shower plate 6 and the dielectric window 5, the wavelength in the material is shortened, so that the number of peaks in the shower plate 6 increases. For example, when alumina ceramic (relative permittivity 9.8) is used as the dielectric window 5, the electric field peak in the shower plate 6 is 3 regardless of whether the shower plate 6 is quartz (relative permittivity 3.8) or alumina ceramic. Increase.

If the gas supply hole 9 is arranged at a place where the electric field strength is high, the possibility of electric discharge in the gas supply hole 9 increases.
FIG. 4 shows a case where a region where the gas supply holes 9 do not exist is provided in a circular shape near the center of the shower plate 6 and a region where the gas supply holes 9 uniformly exist is provided outside the shower plate 6 without the gas supply holes 9. The relationship between the radius of the region and the maximum electric field in the region where the gas supply holes 9 are present is shown. According to this, the gas supply hole 9
When the region without the gas is expanded from the central portion in the circumferential direction, the maximum value in the region where the gas supply hole 9 exists gradually decreases. However, when the area without the gas supply hole 9 is expanded to a radius of about 90 mm, the second peak near the radius of 160 mm becomes the maximum value of the electric field after that, so that even if the area without the gas supply hole 9 is expanded. The maximum value of the electric field does not decrease. Further, when the region without the gas supply hole 9 is expanded and the radius exceeds about 160 mm, the maximum value of the second peak is not included and the electric field strength starts to decrease again. On the other hand, from the standpoint of controlling the gas flow in the processing chamber, it is desirable that the gas supply hole 9 can be freely arranged in the shower plate 6. Therefore, when it is desired to reduce the electric field strength in the region where the gas supply hole 9 exists, it is desirable to set a region without a gas supply hole in a region having a radius of about 90 mm or less from the center.

From the above results, in the case of the present embodiment, by setting the region having no gas supply hole in the region of the radius of about 75 mm, the discharge in the gas supply hole 9 is prevented under the process condition of UHF power up to 1200 W. can do. FIG. 5 shows the results of simulating the UHF input power dependence of the electric field strength at a radius of 75 mm from the center of the shower plate 6 at various plasma densities. The plasma density directly below the shower plate 6 in this apparatus is 9 × 10.
It has been measured to be around ¹⁶ / m ³ . Therefore, from FIG. 5, the present inventors presume that the threshold value of the electric field strength that causes discharge in the gas supply hole 9 is about 50 kV / m. Here, the size of the region having no gas supply hole largely depends on the electric field distribution in the shower plate, and is also defined by the diameter of the processing chamber 7 or the shower plate 6. When the diameter of the processing chamber 7 or the shower plate 6 is reduced or expanded, the diameter of the region having no gas supply hole may be determined by the ratio with the diameter of the processing chamber 7 or the shower plate 6. In the case of this embodiment, the diameter of the processing chamber 7 or the shower plate 6 is 500 mm.
On the other hand, the area without gas supply holes has a diameter of 150 mm (radius 7
5 mm) and the ratio is 30%. Further, the UHF electric field at the position of 150 mm in diameter in the region without the gas supply hole has an electric field intensity which is about half of the central position where it takes the maximum value from FIG.

As described above, according to the present embodiment, there is an effect that the discharge in the gas supply hole of the shower plate can be prevented and stable plasma processing can be performed.

According to the present embodiment, the case where the electric field distribution in the shower plate 6 is axisymmetric has been described as an example. However, regarding other distributions, the gas supply holes are not provided in the same manner as described below. The area can be determined. (1) In the case of a dielectric shower plate, the electric field distribution in the shower plate is obtained. This can be carried out by providing a thermal paper at the electric field measuring portion or by using a measuring device provided with a probe inside the processing chamber. (2) Determine the electric field strength that does not cause discharge in the gas supply hole. (3) A contour map of the electric field strength is obtained from the data in (1) above, and no gas supply hole is provided in a region where the electric field is equal to or higher than the electric field strength determined in (2) above.

Further, in the case of an apparatus in which the shower plate is made of a conductive material and is directly attached to the flat plate antenna as shown in FIG. 6, as the step (1), the shower plate and the plasma interface are separated. The electric field distribution in the sheath region of is calculated. In the apparatus shown in FIG. 6, the same reference numerals as those in the apparatus shown in FIG. A supply path for the processing gas is formed in the flat plate antenna 1a, a shower plate 6a is attached to the lower portion of the flat plate antenna 1a, and the shower plate 6a also functions as an antenna.

In this embodiment, the frequency is 450 MHz.
The description has been made by taking the etching apparatus for generating plasma by electromagnetic waves in the UHF band as described above as an example. However, the structure having a locally strong electric field strength in the electric field strength distribution of the shower plate section is not limited to this embodiment, and the frequency is different. The same can be applied to other plasma processing apparatuses such as a plasma CVD apparatus and a sputtering apparatus.

[0027]

In the plasma processing apparatus having the gas supply plate for supplying the shower-like gas into the processing chamber,
There is an effect that it is possible to prevent discharge from occurring in the plurality of gas supply holes provided in the gas supply plate, and to perform stable plasma processing.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a plasma processing apparatus of the present invention.

FIG. 2 is a plan view showing details of a shower plate of the apparatus shown in FIG.

FIG. 3 is a diagram showing an electric field intensity distribution in a shower plate.

FIG. 4 is a diagram showing a relationship between a radius of a region of the shower plate where no gas supply hole is present and a maximum electric field intensity of the gas supply hole region.

FIG. 5 is a diagram showing a relationship between UHF input power and electric field strength.

FIG. 6 is a vertical sectional view showing another embodiment of the plasma processing apparatus of the present invention.

[Explanation of symbols]

1, 1a ... Flat antenna, 2 ... Coaxial line, 3 ... Matching device, 4 ... High frequency power supply, 5, 5a ... Dielectric window, 6, 6a ...
Shower plate, 7 ... Processing chamber, 8 ... Processing gas supply device, 9 ... Gas supply hole, 10 ... Substrate to be processed, 11 ... Substrate electrode, 12 ... Matching device, 13 ... Bias power supply.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Go Miya             5-20-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Stock             Ceremony Company within Hitachi Semiconductor Group (72) Inventor Kotaro Fujimoto             Yamaguchi Prefecture Kudamatsu City Oita Toyoi 794 Stock Association             Company Hitachi Industries Kasado Works (72) Inventor Akitaka Makino             Yamaguchi Prefecture Kudamatsu City Oita Toyoi 794 Stock Association             Hitachi High-Technologies Kasado Works F-term (reference) 4G075 AA24 AA30 BC02 BC04 BC06                       CA24 DA02 DA18 EB42 EC21                       EE12 FA02 FC15                 4K030 EA05 FA04 JA14 KA30 KA32                 5F004 AA01 BA03 BA04 BA05 BA14                       BB28 BC03

Claims (8)

[Claims] 1. A processing chamber, the interior of which is evacuated to a reduced pressure, a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is disposed, and a plurality of substrates which are provided in the processing chamber so as to face the substrate electrode and are arranged in a plane. In a plasma processing apparatus having a gas supply plate having gas supply holes, introducing electromagnetic waves into the processing chamber to generate plasma, and processing the substrate to be processed using the plasma, the plasma processing apparatus being introduced into the processing chamber. According to the electric field intensity distribution in the gas supply plate surface of the electromagnetic wave, the non-formed area of the gas supply hole is provided in the gas supply plate surface in the area where the electric field strength is equal to or higher than a predetermined electric field strength. Plasma processing apparatus. 2. A processing chamber whose inside is evacuated to a reduced pressure, a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is disposed, and a plurality of substrates which are provided in the processing chamber so as to face the substrate electrode. A gas supply plate having a gas supply hole; and an electromagnetic wave emission means arranged to face the gas supply plate, the electromagnetic wave emission means introduces an electromagnetic wave into the processing chamber to generate plasma, and the plasma In the plasma processing apparatus for processing the substrate to be processed using, according to the electric field strength distribution in the gas supply plate surface of the electromagnetic wave introduced into the processing chamber, the electric field strength in a region below a predetermined electric field strength A plasma processing apparatus, wherein the gas supply holes of the gas supply plate are arranged. 3. The plasma processing apparatus according to claim 1 or 2, wherein the predetermined electric field strength is 1/2 of a maximum value. 4. The plasma processing apparatus according to claim 1 or 2, wherein the predetermined electric field strength is 50 kV / m. 5. A processing chamber whose inside is evacuated to a reduced pressure, a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is disposed, and a plurality of substrates which are provided in the processing chamber so as to face the substrate electrode. A gas supply plate having a gas supply hole; and an electromagnetic wave emission means arranged to face the gas supply plate, the electromagnetic wave emission means introduces an electromagnetic wave into the processing chamber to generate plasma, and the plasma In the plasma processing apparatus for processing the substrate to be processed using, the electric field intensity distribution of the electromagnetic wave introduced into the processing chamber within the gas supply plate surface has a plurality of local maximum values, and the electric field strength distribution is higher than the first local maximum value. A plasma processing apparatus, wherein the gas supply hole of the gas supply plate is arranged in a region where the absolute value of the electric field is smaller than the second maximum value. 6. A processing chamber whose inside is evacuated to a reduced pressure, a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is disposed, and a plurality of electrodes which are provided in the processing chamber so as to face the substrate electrode and are in a plane. A gas supply plate having a gas supply hole and an electromagnetic wave emission unit arranged to face the gas supply plate, and the electromagnetic wave emission unit introduces an electromagnetic wave into the processing chamber and forms a magnetic field in the processing chamber. In the plasma processing apparatus, which generates plasma by mutual action and processes the substrate to be processed using the plasma, the gas supply hole is provided in a region of the central portion of the gas supply plate that is 30% or less of the inner diameter of the processing chamber. A plasma processing apparatus having an unformed region. 7. A processing chamber whose inside is evacuated to a reduced pressure, a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is disposed, and a plurality of substrates which are provided in the processing chamber so as to face the substrate electrode and are in a plane. A dielectric gas supply plate having a gas supply hole, and a flat plate-shaped antenna arranged through a dielectric window facing the gas supply plate and forming the processing chamber. In a plasma processing apparatus that introduces electromagnetic waves into a chamber to generate plasma, and processes the substrate to be processed using the plasma, according to an electric field intensity distribution in the gas supply plate of the electromagnetic waves introduced into the processing chamber, A plasma processing apparatus, wherein the gas supply hole of the gas supply plate is arranged in a region where the electric field strength is equal to or lower than a predetermined electric field strength. 8. A processing chamber whose inside is evacuated to a reduced pressure, a substrate electrode which is provided in the processing chamber and on which a substrate to be processed is placed, and a flat plate which is provided in the processing chamber and faces the substrate electrode. An antenna and a conductive gas supply plate attached to the substrate electrode side surface of the flat antenna and having a plurality of gas supply holes in the surface are provided, and electromagnetic waves are introduced into the processing chamber by the flat antenna. Generate plasma,
In a plasma processing apparatus for processing the substrate to be processed using the plasma, a region in which the electric field strength is equal to or lower than a predetermined electric field strength according to an electric field strength distribution in the gas supply plate surface of an electromagnetic wave introduced into the processing chamber. The plasma processing apparatus, wherein the gas supply hole of the gas supply plate is arranged in the.