JPH0831751A - Plasma processing device - Google Patents

Abstract

(57) [Summary] [Structure] The inner wall surface protection member 18 for protecting the entire inner wall surface of the reaction container 15 from the plasma atmosphere is provided with the reaction container 15
The plasma processing apparatus provided inside has a fluid passage 16d formed inside an inner wall surface protection member 18, and a fluid supply means 16 for supplying a constant temperature fluid 19 to the fluid passage 16d. [Effect] Since heat exchange between the inner wall surface protection member 18 and the constant temperature fluid 19 is directly and efficiently performed, the inner wall surface protection member 18 is kept constant by controlling the temperature and circulation amount of the constant temperature fluid 19. The temperature can be maintained, and the temperature of the inner wall surface protection member 18 can be easily made uniform. Therefore, the thermal stress caused by the difference in thermal expansion coefficient between the inner wall surface protection member 18 and the deposit can be relaxed, and the peeling of the deposit adhered to the surface of the inner wall protection member 18 can be suppressed to the minimum. be able to. Therefore, the contamination of the sample S due to particles can be reduced, the deterioration of the quality of the wafer due to the contamination can be reduced, and the operating rate of the plasma processing apparatus can be improved.

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 for subjecting a sample to plasma processing such as etching and thin film formation.

[0002]

2. Description of the Related Art A dry processing process is used in a high-definition pattern forming process required for manufacturing an LSI, and as a device for performing the dry processing, a microwave is used to perform electron cyclotron resonance (ECR). : Elec
There is a plasma processing device using tron Cycrotron Resonance).

An apparatus for generating plasma by ECR excitation can generate highly active plasma under a low gas pressure, a wide range of ion energy can be selected, and a large ion current can be obtained. Since it has advantages such as excellent directivity and uniformity of the flow, its research and development has been promoted as an essential element for manufacturing highly integrated semiconductor devices and the like.

FIG. 6 is a sectional view schematically showing a conventional plasma processing apparatus utilizing ECR excitation, and 31 in the drawing shows a plasma generating chamber. A microwave inlet 31c sealed with a quartz glass plate 31b is formed in the center of the upper wall of the plasma generating chamber 31, and the other end of the microwave inlet 31c is connected to a microwave oscillator (not shown). One end of the waveguide 32 is connected. Further, in the center of the lower wall of the plasma generation chamber 31, a plasma extraction window 31 is provided at a position facing the microwave introduction port 31c.
d is formed, and the sample chamber 33 is arranged so as to face the plasma extraction window 31d. Plasma generation chamber 31
Further, around the one end of the waveguide 32 connected thereto, an exciting coil 34 is arranged concentrically with the waveguide 32 so as to surround them.

A plasma extraction window 31 is provided in the sample chamber 33.
The mounting table 37 is disposed at a position facing d.
A sample S such as a wafer, which is carried in from a carry-in port 30 opened on the side wall of the sample chamber 33, is detachably mounted on the upper side by means such as electrostatic adsorption, and is attached to the lower side wall of the sample chamber 33. Is
An exhaust port 33a connected to an exhaust device (not shown) is formed. Further, reference numeral 33b in the drawing denotes a gas supply system communicating with the sample chamber 33.

A bell jar 38a is provided on the inner peripheral wall of the plasma generating chamber 31, and the plasma extraction window 3 is provided.
An adhesion preventing member 38b is disposed on the inner peripheral wall of the sample chamber 33 except the upper wall where 1d is opened, and the bell jar 38a and the adhesion preventing member 38b constitute the inner wall surface protecting member 38. The bell jar 38a and the deposition-inhibitory member 38b form a reaction container 35 that constitutes the plasma generation chamber 31 and the sample chamber 33.
The purpose is to prevent heavy metal contamination caused by direct irradiation of plasma to the inner peripheral wall of No. 3, and quartz glass, aluminum (hereinafter referred to as Al) or the like is used as the material of the inner wall protection member 38.

When the sample S is subjected to plasma processing such as etching and CVD using the plasma processing apparatus having the above-described structure, first, the plasma generation chamber 31 and the sample chamber 33 are set to a required degree of vacuum, and then the reaction is performed. Gas is supplied from the gas supply pipe 33b into the container 35, a direct current is passed through the exciting coil 34 to form a magnetic field, and a microwave is introduced into the plasma generation chamber 31 through the microwave introduction port 31c. Is used as a cavity resonator to resonate the gas and generate plasma. The generated plasma is generated by the divergent magnetic field formed by the exciting coil 34 and the magnetic flux density decreases toward the sample chamber 33 side.
It is projected around the inside of the sample S, and the surface of the sample S is plasma-treated by this.

[0008]

In the above-described plasma processing apparatus, as the number of wafers subjected to plasma processing is increased, the substances generated during the plasma processing adhere to the inner wall surface protection member 38, and if the adhered matter becomes thicker. The particles are separated and become particles, and fall on the sample S to cause etching defects during plasma etching and film formation defects during plasma CVD. In order to avoid this, the plasma processing apparatus is stopped before the peeling amount increases, and the inner wall surface protecting member 38 is cleaned or replaced. However, when manufacturing an LSI, this operation reduces the operation rate of the apparatus, It is an obstacle to improving productivity. Therefore, it is required to extend the continuous operation time of the apparatus (increase the number of continuously processed sheets).

As one of the countermeasures against this, the inner wall surface protection member 3
A method is adopted in which a heater or the like is provided outside the device 8 and the inner wall surface protection member 38 is kept at a constant temperature by controlling power or the like.

In FIG. 7, heating means 39 is provided on the inner wall surface protection member 38.
FIG. 3 is a schematic cross-sectional view of a plasma processing apparatus provided with.
An electric resistor 39a is arranged outside the inner wall surface protection member 38, and is connected to the electric resistor 39a from the power introduction terminal 39b.
When electric power is supplied to, Joule heat is generated. The inner wall surface protection member 38 is heated by this Joule heat. Such a plasma processing apparatus reduces the thermal stress caused by the difference in thermal expansion coefficient between the inner wall surface protection member 38 and the deposit, thereby causing a crack in the deposit film, which becomes a particle. It is intended to prevent

[0011]

However, the plasma generation chamber 31 and the sample chamber 33 are generated due to the heat generated by the plasma.
The internal temperature is likely to be non-uniform, and there is a problem that it is difficult to make the temperature of the inner wall surface protection member 38 uniform even if the power control is performed by measuring the temperature at many points. Also,
Even if the power is turned off, the temperature of the inner wall surface protection member 38 may rise due to the plasma irradiation, and the temperature of the inner wall surface protection member 38 should decrease during plasma non-treatment to keep the temperature of the inner wall surface protection member 38 constant. There was a problem that was difficult.

The present invention has been made in view of the above problems, and the temperature at all points of the inner wall surface protection member can be easily made uniform and constant, and the deposits generated by the plasma treatment are the inner wall surfaces. An object of the present invention is to provide a plasma processing apparatus capable of preventing peeling from a protective member, preventing deterioration of wafer quality due to generation of particles, and improving the operating rate of the apparatus.

[0013]

In order to achieve the above object, in the plasma processing apparatus according to the present invention, an inner wall surface protection member for protecting the whole or a part of the inner wall surface of the reaction vessel from the plasma atmosphere is provided in the reaction vessel. In the plasma processing apparatus arranged in, a fluid path is formed at least inside the inner wall surface protection member present on the plasma generation part side, and a fluid supply means for supplying a constant temperature fluid to the fluid path is provided. It has a feature.

[0014]

According to the plasma processing apparatus of the present invention, a fluid path is formed inside at least the inner wall surface protection member existing on the plasma generating portion side, and a fluid supply means for supplying a constant temperature fluid to the fluid path is provided. Therefore, heat exchange between the inner wall surface protection member and the constant temperature fluid is directly and efficiently performed, and the inner wall surface protection member is controlled by controlling the temperature and circulation amount of the constant temperature fluid. The temperature of the inner wall surface protecting member is maintained at a constant temperature, and the temperature of the inner wall surface protecting member is easily equalized.
Therefore, the thermal stress caused by the difference in thermal expansion coefficient between the inner wall surface protection member and the adhered matter is relaxed, and the exfoliation of the adhered matter adhered to the surface of the inner wall surface protection member is suppressed. Therefore, the contamination of the wafer due to particles is reduced, and the deterioration of the wafer quality due to the contamination is reduced.
Further, the operating rate of the plasma processing apparatus can be improved.

[0015]

EXAMPLES AND COMPARATIVE EXAMPLES Examples of the plasma processing apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a plasma processing apparatus according to an embodiment, and 11 in the drawing shows a plasma generation chamber. A microwave inlet 11c sealed with a quartz glass plate 11b is formed in the center of the upper wall of the plasma generation chamber 11, and the other end of the microwave inlet 11c is connected to a microwave oscillator (not shown). One end of the waveguide 12 is connected. Further, in the center of the lower wall of the plasma generation chamber 11, a plasma extraction window 11d is formed at a position facing the microwave introduction port 11c, and a sample chamber 13 is arranged so as to face the plasma extraction window 11d. The plasma generation chamber 11 and the waveguide 12 connected to the plasma generation chamber 11 and the sample chamber are provided with an exciting coil 14 concentrically with the plasma generation chamber 11 and the waveguide 12 connected to the plasma generation chamber 11. 13 is composed of a reaction vessel 15.

A plasma extraction window 11 is provided in the sample chamber 13.
The mounting table 17 is disposed at a position facing d.
A sample S, such as a wafer, carried in from a carry-in port 10 opened on the side wall of the sample chamber 13 is detachably mounted on the surface of the sample chamber 7 by means of electrostatic adsorption or the like. An exhaust port 13a connected to an exhaust device (not shown) is formed in the chamber, and a gas supply pipe 13b is connected to the sample chamber 13.

A bell jar 18a made of opaque quartz glass is provided on the inner peripheral wall of the plasma generating chamber 11, and the sample chamber 13 except the upper wall of the sample chamber 13 having the plasma extraction window 11d opened. The inner peripheral wall of the protective member 18b is also made of opaque quartz glass.
And the bell jar 18a and the deposition preventing member 18b.
The inner wall surface protection member 18 is configured by the above. A fluid passage 16d for allowing the constant temperature fluid 19 to flow therethrough is formed inside the inner wall surface protection member 18, and one end of the fluid introduction pipe 16b and one end of the fluid discharge pipe 16c are detachably connected to the fluid passage 16d. There is. A constant temperature chiller 16a is connected to the other ends of the fluid introduction pipe 16b and the fluid discharge pipe 16c, and the constant temperature chiller 16a, the fluid introduction pipe 16b, and the fluid discharge pipe 16c constitute a fluid supply means 16, and the constant temperature chiller 16a. The constant temperature fluid 19 kept at a desired temperature by means of can be circulated in the fluid path 16d at a desired flow velocity.

When the sample S is subjected to plasma processing such as etching or CVD using the plasma processing apparatus thus constructed, the constant temperature fluid 19 is first circulated in the fluid passage 16d at a predetermined flow velocity to form an inner wall surface. The protection member 18 is controlled to have a constant temperature. Next, after mounting the sample S on the mounting table 17, the inside of the plasma generation chamber 11 and the sample chamber 13 is set to a required degree of vacuum, and the reaction container 1 is passed through the gas supply pipe 13b.
5 is supplied to the inside of the plasma generating chamber 11 through the microwave inlet 11c to form a magnetic field by supplying a direct current to the exciting coil 14 to form a magnetic field. Resonance excitation is performed to generate plasma. When the excitation coil 14 is energized, a divergent magnetic field whose magnetic flux density decreases along the direction of the sample chamber 13 is formed uniformly over almost the entire area of the plasma generation chamber 11, and the divergent magnetic field causes the plasma in the sample S to have a uniform density. Is projected. When the plasma treatment on the surface of the sample S is completed, the introduction of the microwave and the gas is stopped, the plasma is cut off, and the sample S is exchanged. While the above process is repeated, the temperature of the inner wall surface protection member 18 can be always kept constant.

FIG. 2 is a sectional view showing another embodiment of the plasma processing apparatus according to the present invention, in which parts having the same functions as in FIG. 1 are designated by the same reference numerals. In FIG.
A bell jar 28a made of a metal such as Al is provided on the inner peripheral wall of the plasma generation chamber 11 excluding the upper wall which is in contact with the microwave introduction port 11c, and the upper wall where the plasma extraction window 11d is opened is formed. An adhesion preventing member 28b, which is also formed of a metal such as Al, is disposed on the inner peripheral wall of the sample chamber 13 except for the bell wall 28a and the adhesion preventing member 28b, and an inner wall surface protecting member 28 is formed. A predetermined distance is secured between the inner wall surface protection member 28 and the inner peripheral wall of the reaction container 15, and this space serves as a fluid path 16d for allowing the constant temperature fluid 19 to flow therethrough. One ends of a fluid introduction pipe 16b and a fluid discharge pipe 16c are detachably connected to the fluid passage 16d. Also, a constant temperature chiller 1 is attached to the other ends of the fluid introduction pipe 16b and the fluid discharge pipe 16c.
6a is connected.

In the above structure, the inner wall surface protecting member 28
Since the hole 11e is formed in the portion in contact with the microwave introduction port 11c, the microwave transmission is not hindered even when the inner wall surface protection member 28 is made of a metal such as Al, and as a result, as shown in FIG. It is possible to obtain the same effect as the plasma processing apparatus shown in FIG.

FIG. 3 is a graph showing the relationship between the plasma irradiation time and the temperature change of the inner wall surface protecting member 18 when the sample S is etched by using the plasma processing apparatus according to the first embodiment and the comparative example. . An experiment was conducted using the plasma processing apparatus shown in FIG. 7 as the plasma processing apparatus according to the comparative example. The temperatures of the inner wall surface protecting members 18 and 38 are the same as those shown in FIGS. 1 and 7 by arrow A (plasma generation chamber) and arrow B, respectively.
It is a value measured at a site (in the reaction chamber). Solid lines (1A, 1B) show the graphs in the examples, and dotted lines (2A, 2B) show the graphs in the comparative example.

A mixed gas of Cl ₂ gas and O ₂ gas is used for etching, and the flow rate of the mixed gas is Cl ₂ gas / O.
₂ gas is 50/8 sccm, mixed gas pressure is 1.
It was set to 5 mTorr. The microwave power was 1.5 kW, the RF power was 50 W, a wafer with a polysilicon film and a diameter of 6 inches was used as the sample S, and silicon oil was used as the constant temperature fluid 19. In addition, both experiments of the example and the comparative example were performed after setting the inner wall surface protection members 18, 38 to 80 ° C. in advance. In the example, the temperature of the constant temperature fluid 19 was set to 85 ° C. Adjustment was performed by the heating means 39 so that the wall surface protection member 38 was set at 80 ° C.

As is apparent from FIG. 3, the curve 1A has a lower rate of temperature rise than the curve 2A, and the curve 1B has a lower rate of temperature rise than the curve 2B. In particular, the curve 1A has a significantly lower temperature rise than the curve 2A. You can see that Also, curve 1
In A and curve 1B, the temperature is almost constant after the plasma irradiation time of 40 minutes. This allows
With the plasma processing apparatus according to the first embodiment, it is possible to suppress the temperature change of the inner wall surface protection member 18 in the plasma generation chamber 11 and the reaction chamber 13, and particularly, the plasma generation chamber 11
It was found that the effect was remarkable inside.

FIG. 4 is a graph showing the relationship between the number of processed wafers and the increased number of particles when the sample S is subjected to the etching process using the plasma processing apparatus according to the embodiment (FIG. 1). FIG. 8 is a graph showing the relationship between the number of wafers processed and the number of increased particles when the sample S is etched using the plasma processing apparatus according to the comparative example (FIG. 7). The horizontal axis shows the number of processed wafers,
The vertical axis represents the increased number of particles having a diameter of 0.3 μm or more. A mixed gas of Cl ₂ gas and O ₂ gas was used for etching. The flow rate of the mixed gas was Cl ₂ gas / O ₂ gas of 50/8 sccm, and the mixed gas pressure was 1.5 m.
Torr. The microwave power is 1.5 kW,
The RF power was 50 W, a wafer with a polysilicon film and a diameter of 6 inches was used as the sample S, and silicon oil was used as the constant temperature fluid 19. The measurement of the number of increased particles is performed by placing the wafer whose number of particles has been measured in advance in each of the sample chambers 13 and 33 for each treatment of 10 wafers, holding it for 2 minutes, and then taking it out of the sample chamber 13 and measuring it. I did.

As can be seen from FIGS. 4 and 5, in the plasma processing apparatus according to the embodiment (FIG. 1), the maximum number of increased particles is about 30 even after the processing of 600 wafers, and the average is about 15 particles. Therefore, no extreme change in the number of increased particles due to the increase in the number of processed wafers was observed. On the other hand, according to the plasma processing apparatus according to the comparative example (FIG. 7),
The maximum number of particles increased is about 50, and the average is about 3
Since the number of processed wafers is zero, the peak of the increased number of particles is reached every time about 100 wafers are processed. Such a change with time is due to the on-of of plasma.
The reaction product attached to the inner wall protection member 38 is easily peeled off due to the stress caused by the temperature change of the inner wall protection member 38 that occurs together with f, and when the film thickness of the reaction product exceeds a certain amount, the reaction product is abundant due to its own weight. It is considered that this occurs because the particles peel off and the number of particles suddenly increases.

As is clear from these results, in the plasma processing apparatus according to the present embodiment, the inner wall surface protection member 18 for protecting the inner wall surface of the reaction container 15 from the plasma atmosphere is provided in the reaction container 15. In the plasma processing apparatus described above, the fluid path 16 is provided inside the inner wall surface protection member 18.
Since d is formed and the fluid supply means 16 for supplying the constant temperature fluid 19 to the fluid passage 16d is connected to the fluid passage 16d, the heat exchange between the inner wall surface protection member 18 and the constant temperature fluid 19 is directly efficient. Since it is often performed, the inner wall surface protection member 1 is controlled by controlling the temperature and circulation amount of the constant temperature fluid 19.
8 can be maintained at a constant temperature, and the temperature of the inner wall surface protection member 18 can be easily made uniform. Therefore, the thermal stress caused by the difference in thermal expansion coefficient between the inner wall surface protection member 18 and the deposit can be relaxed, and the peeling of the deposit adhered to the surface of the inner wall protection member 18 can be suppressed to the minimum. be able to. Therefore, the contamination of the sample S due to particles can be reduced, the deterioration of the quality of the wafer due to the contamination can be reduced, and the operating rate of the plasma processing apparatus can be improved.

Further, since the temperature of the inner wall surface protecting member 18 is kept constant irrespective of the on-off of the plasma, separation of the reaction product due to the temperature change of the inner wall surface protecting member 18 is prevented and particles are generated. Can be reliably prevented.

Although silicon oil is used as the constant temperature fluid 19 in the above embodiment, water may be used as the constant temperature fluid 19 in another embodiment when the heating temperature is approximately 90 ° C. or lower.

In the above embodiment, the case of the plasma etching apparatus is shown, but in another embodiment, plasma CVD is used.
Also in the apparatus and the like, by setting the constant temperature fluid at a desired temperature, it is possible to obtain the same effect as in the above-mentioned embodiment.

[0030]

As described in detail above, in the plasma processing apparatus according to the present invention, a fluid passage is formed inside at least the inner wall surface protection member present on the plasma generating portion side, and a constant temperature is maintained in the fluid passage. Since the fluid supply means for supplying the fluid is provided, the heat exchange between the inner wall surface protection member and the constant temperature fluid is directly and efficiently performed, and the temperature and circulation amount of the constant temperature fluid are controlled. As a result, the deposition preventing member can be maintained at a constant temperature, and the temperature of the inner wall surface protecting member can be easily made uniform. Therefore, the thermal stress caused by the difference in thermal expansion coefficient between the inner wall surface protecting member and the deposit can be relaxed, and the peeling of the deposit adhering to the surface of the inner wall protecting member can be minimized. be able to. Therefore, the sample S by particles
The contamination of the wafer can be reduced, the deterioration of the quality of the wafer due to the contamination can be reduced, and the operating rate of the plasma processing apparatus can be improved.

[Brief description of drawings]

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

FIG. 2 is a schematic cross-sectional view showing another embodiment of the plasma processing apparatus according to the present invention.

FIG. 3 is a graph showing the relationship between the plasma irradiation time and the temperature change of the inner wall surface protecting member when the sample S is subjected to plasma processing using the plasma processing apparatus according to the example and the comparative example.

FIG. 4 shows the relationship between the number of processed wafers and the number of increased particles when the plasma processing apparatus according to the embodiment is used and the temperature of the inner wall surface protecting member is set to 80 ° C. and the sample S is etched. It is the graph shown.

FIG. 5 shows the relationship between the number of processed wafers and the number of increased particles when the plasma processing apparatus according to the comparative example is used and the temperature of the inner wall surface protecting member is set to 80 ° C. and the sample S is etched. It is the graph shown.

FIG. 6 is a schematic cross-sectional view showing a conventional plasma processing apparatus.

FIG. 7 is a schematic cross-sectional view showing another conventional example of the plasma processing apparatus.

[Explanation of symbols]

 11 Plasma Generation Chamber 13 Sample Chamber 15 Reaction Vessel 16 Fluid Supply Means 18 Inner Wall Protection Member 19 Constant Temperature Fluid

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication H01L 21/3065 21/31 C H05H 1/46 C 9216-2G // G01R 33/64 G01N 24 / 14 B

Claims (1)

[Claims] 1. In a plasma processing apparatus in which an inner wall surface protecting member for protecting the whole or a part of the inner wall surface of the reaction container from the plasma atmosphere is arranged in the reaction container, at least the inner wall surface protecting member is present inside the plasma generating unit. A plasma processing apparatus, wherein a fluid path is formed inside the wall surface protection member, and a fluid supply means for supplying a constant temperature fluid to the fluid path is provided.