JPH06196421A - Plasma device - Google Patents

Abstract

PURPOSE:To inhibit the generation of particles from a bell-jar and to relax a temperature change to contrive to inhibit the generation of particles from the bell-jar and an adhesion preventive plate. CONSTITUTION:A bell-jar 4, which is subjected to frost treatment and is subjected to surface-roughening processing, is provided in a plasma producing chamber 1, which is provided with a microwave introducing window 1a and a plasma lead-out window 1b, a gas intro-ducing tube 9 and an exhaust tube 11 are connected to a sample chamber 3, which is connected to the chamber 1 and is arranged with a placement stage 8 for placing a sample S, and an adhesion preventive plate 5 is provided on the inner surface of the chamber 3, on the stage 8 and extending over one end part of the tube 11. An upper warming wall 6 and a lower warming wall 7 are respectively provided on the sidewall of the chamber 1 and on the sidewall and bottom wall of the chamber 3 and the outer surfaces of the end parts of the tube 11. An exciting coil 12 is provided on the periphery of the wall 6 and extending over one end part of a waveguide 2 connected to the chamber 1. A warm liquid is circulated in the walls 6 and 7 and the sample S is subjected to plasma treatment while the bell-jar 4 and the plate 5 are warmed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma device for processing semiconductor elements or electronic materials using plasma.

[0002]

2. Description of the Related Art A plasma apparatus utilizing electron cyclotron resonance (hereinafter referred to as "ECR") can generate a plasma having a high ionization degree at a low gas pressure, can select a wide range of ion energy, and can direct and uniform the ions. Since it has advantages such as excellent properties, research and development have been carried out as essential for processes such as thin film formation or etching in the manufacture of highly integrated semiconductor devices.

FIG. 6 is a schematic cross-sectional view showing a conventional ECR plasma device, in which 1 is a plasma generating chamber for generating plasma. A sample chamber 3 is provided below the plasma generation chamber 1.
, A quartz glass microwave introduction window 1a for sealing the plasma generation chamber 1 at the center of the upper wall, and the microwave introduction window at the center of the lower wall for partitioning the sample chamber 3. Circular plasma extraction windows 1b are provided at positions facing 1a, respectively. A bell jar 14, which is a transparent quartz glass container, is arranged in the plasma generation chamber 1 from the upper wall to the side wall in order to prevent heavy metal contamination.

One end of a waveguide 2 whose other end is connected to a high-frequency oscillator (not shown) is connected to the microwave introduction window 1a, and the periphery of the plasma generation chamber 1 and the waveguide 2 connected to it are connected. Exciting coils 12 are arranged concentrically with these so as to surround them over one end.

On the other hand, a gas supply pipe 9 for supplying a reaction gas and an exhaust pipe 11 for discharging the gas are connected to the side wall of the sample chamber 3. A mounting table 8 is disposed inside the sample chamber 3 so as to face the plasma extraction window 1b, and a loading port for loading a sample S such as a wafer opened on the side wall of the sample chamber 3 into the mounting table 8 The sample S carried in from 10 is detachably mounted by means such as electrostatic adsorption. And the plasma extraction window
The inner surface of the sample chamber 3 excluding the upper wall of the sample chamber 3 in which 1b is opened, the surface of the mounting table 8 and the inner surface of the exhaust pipe 11 are roughened by frosting with high-pressure, high-speed sand. A quartz deposition preventive plate 5 is provided.

In order to process the surface of the sample S with such an apparatus, the reaction gas is supplied from the gas supply pipe 9 to the plasma generation chamber 1 and the sample chamber 3 which are set to the required vacuum degree by the exhaust pipe 11. A microwave is introduced into the plasma generation chamber 1 while forming a magnetic field by the exciting coil 12 to generate plasma, and the generated plasma is diverged by the divergent magnetic field formed by the exciting coil 12 to place the table 8 in the sample chamber 3. The sample S is guided to the periphery of the sample S and the surface of the sample S is subjected to processing such as film formation or etching.

[0007]

By the way, in the ECR plasma apparatus, the ions in the plasma and the sample react in parallel with the processing of the sample surface, and the product is deposited on the wall surface of the sample chamber, which is separated. And become particles that are minute foreign substances and fall on the sample, causing defective processing of the sample. On the other hand, in the conventional device, the product is strongly adhered to the irregularities on the surface of the adhesion-preventing plate described above to prevent the product from peeling and suppress the generation of particles.

However, this product also deposits on Berja. FIG. 7 is a graph showing the results of measuring the surface roughness of a conventional bell jar. As is apparent from FIG. 7, the surface roughness of the conventional bell jar is as smooth as 0 to 0.6 kÅ, and very gentle unevenness exists in this range. Therefore, the product accumulated on the bell jar is easily separated from the product to generate particles.

Further, there is a problem that the product deposited on the bell jar and the product attached to the deposition preventive plate are peeled off due to temperature change at the start and end of the plasma processing to generate particles. The present invention has been made in view of such a problem, and its object is to suppress the generation of particles from the bell jar, and also to reduce the temperature change to suppress the generation of particles from the bell jar and the deposition preventive plate. The present invention is to provide a plasma device.

[0010]

In the plasma device according to the first aspect of the present invention, plasma generated in a plasma generation chamber provided with a bell jar that protects the inner surface of the plasma device is used to deposit deposits on the inner surface. In a plasma device for guiding and processing a sample in a sample chamber provided with an adhesion preventive plate, the plasma generation chamber is provided with a bell jar whose inner surface is roughened to attach the deposit. It is characterized by

In the plasma apparatus according to the second aspect of the present invention, the deposition preventive plate prevents the plasma generated in the plasma generation chamber having the bell jar for protecting the inner surface thereof from adhering deposits to the inner surface. In a plasma device for guiding a sample into a sample chamber in which the above is arranged and processing the sample, a means for heating the bell jar and the deposition preventive plate is provided.

Further, in the plasma device according to the third aspect of the present invention, the deposition preventive plate prevents plasma generated in the plasma generation chamber having a bell jar for protecting the inner surface thereof from adhering deposits to the inner surface. In a plasma device for guiding and processing a sample in a sample chamber in which the bell jar having the roughened surface is arranged, the bell jar and the deposition preventive plate are heated. It is characterized by comprising means.

[0013]

In the plasma apparatus according to the first aspect of the present invention, since the bell jar having the roughened surface for adhering the deposit to the inner surface thereof is arranged in the plasma generating chamber, the deposit adheres, and the adhered deposit adheres to the bell jar. It prevents the particles from peeling off and suppresses the generation of particles. The plasma device of the second invention is
Since the bell jar disposed in the plasma generation chamber and the means for heating the deposition preventive plate disposed in the sample chamber are provided, the bell jar and the deposition preventive plate are heated from before the plasma treatment is started to after the plasma treatment is completed. As a result, at the start and end of the plasma treatment, these temperature changes are alleviated to prevent the deposits from peeling off, and at the time of the plasma treatment, the adherence of the deposits is suppressed. Furthermore, since the plasma device of the third invention comprises the bell jar having the roughened surface according to the first invention and the means for heating the bell jar and the deposition preventive plate according to the second invention, both the above-mentioned actions are performed. Furthermore, the generation of particles is suppressed.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. FIG. 1 is a schematic cross-sectional view showing an example of an ECR plasma device according to the present invention, in which 1 is a cylindrical plasma generation chamber. A sample chamber 3 is connected below the plasma generation chamber 1, and a quartz glass microwave introduction window for sealing the sample chamber 3 is provided in the center of the upper wall of the plasma generation chamber 1.
A circular plasma extraction window 1b is provided at a position facing the microwave introduction window 1a at the center of the lower wall that separates it from the sample chamber 3. Inside the plasma generation chamber 1, there is provided a bell jar 4 which has been roughened by frosting the inner surface of the quartz glass container from the upper wall to the side wall thereof. An upper heating wall 6 for heating is provided around the wall. Upper heating wall 6
Has a double structure, and is designed to heat and discharge the warm fluid from the supply pipe 6a and the discharge pipe 6b connected to the upper end to heat the outer surface of the plasma generation chamber 1 and the bell jar 4.

The microwave introduction window 1a is connected to one end of a waveguide 2 whose other end is connected to a high-frequency oscillator (not shown), and is connected to the periphery of the upper heating wall 6 and the plasma generation chamber 1. An exciting coil 12 is arranged concentrically with one end of the wave tube 2 so as to surround them.

A gas supply pipe 9 for supplying a reaction gas and an exhaust pipe 11 for exhausting the gas are connected to the side wall of the sample chamber 3. In addition, the plasma extraction window 1b is provided in the sample chamber 3.
A mounting table 8 is disposed so as to oppose to each other, and the sample S carried in from a carry-in port 10 for carrying in the sample S such as a wafer opened on the side wall of the sample chamber 3 is electrostatically attracted onto the mounting table 8. It is mounted detachably by means such as.

The inner surface of the sample chamber 3 except the upper wall of the sample chamber 3 where the plasma extraction window 1b is opened, the surface of the mounting table 8 and the inner surface of the end of the exhaust pipe 11 are made of frosted quartz. The anti-adhesion plate 5 is provided, and the lower heating wall 7 having a double structure is provided on the side wall and the bottom wall of the sample chamber 3 and the outer surface of the end of the exhaust pipe 11. The warm fluid is supplied and discharged from the supply pipe 7a and the discharge pipe 7b connected to the lower heating wall 7 to heat them.

When processing the surface of the sample S with such an apparatus, a warm fluid is circulated through the supply pipes 6a, 7a and the discharge pipes 6b, 7b into the upper heating wall 6 and the lower heating wall 7, After heating the bell jar 4 and the deposition preventive plate 5 to a predetermined temperature, the reaction gas is supplied from the gas supply pipe 9 to the plasma generation chamber 1 and the sample chamber 3 which are set to a required vacuum degree by suction from the exhaust pipe 11. , A microwave is introduced into the plasma generation chamber 1 while forming a magnetic field by the exciting coil 12 to generate plasma, and the generated plasma is diverged by the divergent magnetic field formed by the exciting coil 12 to place the table in the sample chamber 3. 8 is guided to the periphery of the sample S, and the surface of the sample S is subjected to processing such as film formation and etching.

FIG. 2 is a graph showing the results of measuring the roughness of the surface of the bell jar according to the present invention, which is measured by a step gauge. As apparent from FIG. 2, the surface roughness of the frost-treated bell jar according to the present invention is 0 to 0.6 kÅ in the case of the conventional untreated bell jar described above.
Compared with (see Fig. 7), it is significantly roughened to ± 80kÅ, and large irregularities and fine irregularities between them are densely present. Therefore, frosted bell jar 4
Since the product generated in the plasma generation chamber 1 can be strongly adhered to the unevenness of the surface, the adhered product is prevented from peeling and the generation of particles is suppressed.

The upper heating wall and the lower heating wall heat the bell jar and the deposition preventive plate to a predetermined temperature exceeding the boiling point of the reaction product. The reaction product varies depending on the sample and reaction gas used, but for example, when a sample of a silicon wafer is treated with Cl ₂ gas plasma, SiCl ₄ is generated as a reaction product, and the boiling point of this SiCl ₄ is 57.6 ° C. The temperature of the fluid flowing through the upper heating wall and the lower heating wall is set so that the temperatures of the bell jar and the deposition preventive plate exceed this temperature. By doing this, in the bell jar and the deposition preventive plate, the temperature change at the start and end of plasma processing is mitigated to suppress the peeling of the product due to the temperature change and reduce the amount of the product adhered during the processing. Can be made.

Next, the results of a comparative test in which the numbers of particles generated by the device of the present invention and the conventional device are measured will be described. FIG. 8 is a graph showing the increase in the number of generated particles with respect to the number of processed samples when the sample is plasma-processed by the conventional apparatus. A 6-inch wafer on which a resist was deposited was used as a sample, and a Cl ₂ / O ₂ mixed gas was used as a reaction gas. The number of particles increased is 0.3 μ in advance.
A sample of which the number of particles of m or more was measured was placed on the mounting table in the sample chamber, and the plasma treatment was performed for 2 minutes.
It was calculated from the number of particles of 3 μm or more. As is clear from FIG. 8, in the conventional apparatus, the number of particles increased was about 1,000 at maximum, and about 100 on average.

FIGS. 3, 4 and 5 are graphs showing the increase in the number of generated particles with respect to the number of processed samples when the sample is similarly plasma-treated by the apparatus of the present invention. FIG. 3 shows a bell jar without frost treatment. Fig. 4 shows the case where the upper heating wall and the lower heating wall are heated and the frosted bell jar is installed and the upper heating wall and the lower heating wall are not heated. FIG. 5 shows a case in which a bell jar subjected to frost treatment is provided and heating is performed by the upper heating wall and the lower heating wall.

As is apparent from FIG. 3, when heating is performed using the upper heating wall and the lower heating wall, the maximum number of particles increased is about 100, and the average number is about 50. Compared with the case, it is reduced to 1/10 and 1/2, respectively. Further, as is clear from FIG. 4, when the frosted bell jar is provided, the maximum number of particles increased is approximately 50, and the average number is approximately 30, which is further reduced as compared with the conventional device. Further, as is clear from FIG. 5, when both are performed together, the number of particles increased is low on average,
The number is about 30 or less, and the number of particles increased is greatly reduced as compared with the conventional device.

As described above, the apparatus of the present invention may be used only when the bell jar which has been subjected to frost treatment is used or when the upper heating wall and the lower heating wall are used, or both may be used in combination. When both are used together, the generation of particles is most suppressed.

[0025]

As described in detail above, in the plasma device of the present invention, the present invention exhibits excellent effects such as suppressing the generation of particles and improving the reliability and yield of products.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of an ECR plasma device according to the present invention.

FIG. 2 is a graph showing a result of measuring surface roughness of a bell jar according to the present invention.

FIG. 3 is a graph showing an increase in the number of particles generated with respect to the number of processed samples when a sample is plasma-processed by the apparatus of the present invention.

FIG. 4 is a graph showing an increase in the number of particles generated with respect to the number of processed samples when a sample is plasma-processed by the apparatus of the present invention.

FIG. 5 is a graph showing an increase in the number of generated particles with respect to the number of processed samples when a sample is plasma-processed by the apparatus of the present invention.

FIG. 6 is a schematic sectional view showing a conventional ECR plasma device.

FIG. 7 is a graph showing the results of measuring the surface roughness of a conventional bell jar.

FIG. 8 is a graph showing the increased number of particles generated with respect to the number of processed samples when a sample is plasma-processed by a conventional apparatus.

[Explanation of symbols]

 1 plasma generation chamber 2 waveguide 3 sample chamber 4 bell jar 5 deposition plate 6 upper heating wall 7 lower heating wall 8 mounting table 11 exhaust pipe S sample

Claims (3)

[Claims] 1. A plasma generated in a plasma generation chamber having a bell jar for protecting its inner surface is guided to a sample in a sample chamber having a deposition preventive plate for preventing deposition of deposits on the inner surface. In the plasma device for processing the above, the plasma generation chamber is provided with a bell jar whose inner surface is roughened in order to attach the deposit. 2. A plasma generated in a plasma generation chamber having a bell jar for protecting its inner surface is guided to a sample in a sample chamber having a deposition preventive plate for preventing deposition of deposits on the inner surface. In the plasma apparatus for processing the above, a plasma apparatus comprising means for heating the bell jar and the deposition preventive plate. 3. The plasma generated in a plasma generating chamber having a bell jar for protecting its inner surface is guided to a sample in a sample chamber having a deposition preventive plate for preventing adhesion of deposits to the inner surface. In the plasma apparatus for processing the above, the plasma generating chamber is provided with the roughened bell jar, and is provided with means for heating the bell jar and the deposition preventive plate.