JP6812237B2 - Plasma processing equipment - Google Patents

Description

The present invention relates to a plasma processing apparatus.

Conventionally, an apparatus for performing plasma treatment on the surface of a substrate such as a silicon substrate or a glass substrate has been known. For example, Patent Documents 1 and 2 disclose an apparatus for performing plasma treatment on the surface of a silicon substrate.
Generally, as shown in FIG. 12, the plasma processing apparatus 10A is provided on a tubular wall 2A having a plasma generation space 21A on which plasma is generated inside, and below the tubular wall 2A, and is an object of plasma processing. It is provided with a chamber 1A including a lower cylinder 4A provided on the inside of a mounting table 8A on which the substrate S to be mounted is placed. Further, the apparatus 10A further includes a processing gas supply means (not shown) for supplying the processing gas to the plasma generation space 21A, and a coil 5A wound along the outer surface of the tubular wall 2A. ing.
By supplying the processing gas into the plasma generation space 21A in a vacuum environment and applying high-frequency power to the coil 5A, the processing gas is turned into plasma by the induced electric field generated in the plasma generation space 21A. The plasma-generated processing gas (hereinafter, simply referred to as “plasma”) flows down into the plasma processing space 41A inside the lower cylinder 4A to reach the mounting table 8A, and the substrate S mounted on the mounting table 8A. Plasma treatment is performed on the surface of the. For example, when the etching process is executed, the surface of the substrate S is etched by plasma. The thick black arrow shown in FIG. 12 indicates the flow direction of the plasma (the same applies to FIG. 1).

Here, when the plasma processing apparatus 10A is continuously used for a long time, cracks may occur in the tubular wall 2A. When a crack occurs in the tubular wall 2A, the vacuum state in the chamber 1A cannot be maintained, and the plasma treatment cannot be normally performed thereafter.
When such a problem occurs, it is necessary to interrupt the plasma processing, wait for the entire chamber 1A to cool, and then replace the tubular wall 2A, so that the efficiency of the plasma processing is significantly reduced.

Japanese Unexamined Patent Publication No. 2006-80504 JP-A-2006-60089

An object of the present invention is to provide a plasma processing apparatus in which cracks are unlikely to occur in a tubular wall.

As a result of diligent research on the cause of cracks in the tubular wall 2A included in the conventional plasma processing apparatus 10A, the present inventor has found that the temperature difference in the vertical direction of the tubular wall 2A is large during plasma processing. I got the finding that it is one of the causes.
Specifically, the present inventor describes the conventional plasma processing apparatus 10A on the outer surface of the tubular wall 2A and the outer surface of the upper member 3A and the lower member 4A connected to the tubular wall 2A during plasma processing. As a result of examining the temperature distribution, the results shown in FIG. 13 were obtained. As shown in FIG. 13, it can be seen that the temperature of the tubular wall 2A is distributed so that the portion corresponding to the coil 5A becomes high temperature and gradually decreases as the distance from the coil 5A increases. The reason why such a temperature difference occurs is as follows.
In general, the coil 5A is wound so as to be in close contact with the outer surface of the tubular wall 2A as shown in FIGS. 12 and 13, or wound so as to be slightly separated from the outer surface of the tubular wall 2A. (Not shown). During the plasma processing, high-frequency power is applied to the coil 5A to generate high-temperature plasma in the plasma processing space 21A. The tubular wall 2A is heated by heat transfer from the inside by this high-temperature plasma, and is also heated by induction heating of the coil 5A.
A particularly large amount of plasma is generated in the region corresponding to the coil 5A of the plasma processing space 21A. Therefore, the portion of the tubular wall 2A corresponding to the coil 5A is easily heated by the high temperature plasma. In particular, the portion of the tubular wall 2A corresponding to the center position in the vertical direction of the coil 5A has the highest temperature (300 ° C. is shown in FIG. 13).

Here, the tubular wall 2A is usually formed of a material that does not hinder the generation of an induced electric field in the plasma generation space 21A, for example, a material having an insulating property such as ceramics. On the other hand, the upper member 3A connected to the upper end surface of the tubular wall 2A and the lower member 4A connected to the lower end surface of the tubular wall 2A usually have higher thermal conductivity than the tubular wall 2A. It is made of high metal. Then, as shown in FIGS. 12 and 13, the upper end surface and the upper member 3A of the tubular wall 2A and the lower end surface and the lower member 4A of the tubular wall 2A are in a state where the plasma treatment is executed. In contact with each other (usually, between the tubular wall 2A and the upper member 3A, and between the tubular wall 2A and the lower member 4A, as shown in FIG. 13, in the chamber 1A. A vacuum seal member such as an O-ring is provided to maintain the vacuum state of.)
Generally, the upper member 3A and the lower member 4A are temperature-controlled by a chamber heater (not shown) at a temperature lower than that of the tubular wall 2A. Therefore, the heat applied to the portion of the tubular wall 2A corresponding to the coil 5A is conducted from the upper end surface of the tubular wall 2A to the upper member 3A, and similarly from the lower end surface of the tubular wall 2A. Conducts to the lower member 4A. In other words, the portion of the tubular wall 2A above the coil 5A and the portion below it are cooled by the upper member 3A and the lower member 4A, respectively. Therefore, the temperature of the portion above and below the coil 5A of the tubular wall 2A is lower than that of the portion corresponding to the coil 5A.

In the examples shown in FIGS. 12 and 13, the coil 5A is wound below the center position of the tubular wall 2A in the vertical direction. Therefore, the difference (Δt ₁ ) between the uppermost temperature (250 ° C.) of the tubular wall 2A and the maximum temperature (300 ° C.) of the tubular wall 2A is 50 ° C., and the temperature of the lowermost part of the tubular wall 2A (2A) The difference (Δt ₂ ) between (260 ° C.) and the maximum temperature (300 ° C.) of the tubular wall is 40 ° C.

As described above, the tubular wall 2A provided in the conventional plasma processing apparatus 10A causes a large temperature difference in the vertical direction during plasma processing. As a result, when the plasma processing apparatus 10A is continuously driven for a long period of time, cracks may occur in the tubular wall 2A due to thermal stress in the tubular wall 2A.
Based on the above findings, the present inventor makes the temperature of the portion of the tubular wall 2A other than the portion corresponding to the coil 5A as close as possible to the maximum temperature of the tubular wall 2A (that is, the tubular wall 2A) during plasma processing. The present invention was created by finding that cracks in the tubular wall 2A can be effectively prevented by reducing the temperature difference in the vertical direction.

The plasma processing apparatus of the present invention includes a chamber and a coil to which high-frequency power is applied to perform plasma processing in the chamber, and the processing gas is supplied to the inside of the chamber to generate plasma. The tubular wall, the upper member connected to the upper end surface of the tubular wall, the lower member connected to the lower end surface of the tubular wall, the strut wall, and the first vacuum. The coil comprises a sealing member, and the coil is wound along the outer surface of the tubular wall. The strut wall is formed on the tubular wall and the outer side of the coil with the upper member and the coil. It is erected between the lower member and supports the upper member, and the first vacuum sealing member is formed on one of the upper and lower end faces of the tubular wall. Among the upper and lower members, the one end face and the connected member are not in contact with each other in a state where plasma treatment is performed in the chamber between the members connected to the one end face. It is characterized in that it is provided in such a state.

Further, in the preferred plasma processing apparatus of the present invention, the chamber is the end face of any one of the upper and lower end faces of the tubular wall and the other end face of the upper and lower members. A second vacuum seal member interposed between the member connected to the member and the other end face thereof and the connected member in a non-contact state when plasma treatment is performed in the chamber. Is further provided.

Further, in the preferred plasma processing apparatus of the present invention, the first vacuum seal member is composed of a plurality of O-rings having substantially different inner diameters arranged substantially concentrically on the same plane, and is composed of a plurality of O-rings. Among them, the wire diameter of the O-ring located on the innermost side is smaller than the wire diameter of the other O-rings, and the surface of the O-ring located on the innermost side is covered with a plasma-resistant film.

Generally, an O-ring used in a plasma processing apparatus is coated with a plasma-resistant film in order to prevent deterioration due to plasma and ensure long-term vacuum sealing property. Further, the larger the wire diameter of the O-ring, the higher the vacuum sealing property. Therefore, in general, one O-ring having a large wire diameter covered with a plasma-resistant film is used in the plasma processing apparatus. However, an O-ring having a large wire diameter having plasma resistance is very expensive because the surface area of the O-ring covering the plasma-resistant film is large.
In this respect, in this plasma processing apparatus, the first vacuum sealing member is composed of a plurality of O-rings, and the wire diameter of the innermost O-ring is smaller than the wire diameter of the other O-rings. Therefore, the O-ring located on the innermost side protects the O-ring on the outer side from the plasma. Although the innermost O-ring is covered with a plasma-resistant film, it is relatively inexpensive due to its small wire diameter. Further, since the O-ring located on the outer side has a larger wire diameter than the O-ring located on the innermost side, the vacuum sealing property of the chamber can be ensured. As described above, in this plasma processing apparatus, by using an O-ring having a plasma resistance with a small wire diameter, which is relatively inexpensive, and an O-ring having a large wire diameter in combination, the chamber can be economically and effectively used for a long period of time. It is possible to secure the vacuum state of.

Further, in the preferred plasma processing apparatus of the present invention, the first vacuum seal member and the second vacuum seal member are respectively arranged substantially concentrically on the same plane and have a plurality of O-rings having different inner diameters. The innermost O-ring has a smaller wire diameter than the other O-rings, and the innermost O-ring has a vacuum-resistant film on the surface. It is covered.

This plasma processing apparatus can more economically and effectively secure the vacuum state of the chamber for a long period of time for the same reason as described above.

As described above, according to the present invention, it is possible to provide a plasma processing apparatus in which cracks are unlikely to occur in a tubular wall.

The schematic end view which shows the plasma processing apparatus which concerns on 1st Embodiment. Partially enlarged schematic end view showing the positional relationship of the coil with respect to the tubular wall of the plasma processing apparatus. Partially enlarged schematic end view showing the most preferable positional relationship of the coil with respect to the tubular wall. FIG. 1 is an enlarged sectional view taken along line IV-IV of FIG. An enlarged view of the portion surrounded by the broken line in FIG. A partially enlarged schematic end view showing the process of vacuum sealing by the first vacuum sealing member. A partially enlarged schematic end view of the plasma processing apparatus according to the first embodiment, and a graph showing the outer surface temperature of each member in the vertical direction thereof. Partially omitted schematic end view showing the process of thermal expansion of the upper member of the plasma processing apparatus according to the first embodiment. Partially enlarged schematic end view of the plasma processing apparatus according to the second embodiment. A partially enlarged schematic end view of the plasma processing apparatus according to the second embodiment, and a graph showing the outer surface temperature of each member in the vertical direction thereof. Partially enlarged schematic end view of the plasma processing apparatus according to the third embodiment. Schematic end view showing a conventional plasma processing apparatus. A partially enlarged schematic end view of a conventional plasma processing apparatus and a graph showing the outer surface temperature of each member in the vertical direction thereof.

In the present specification, the plasma processing apparatus of the present invention will be described mainly focusing on the tubular wall, the coil, and the members located in the vicinity thereof. Therefore, in the drawings, a part of the configuration of the plasma processing apparatus (for example, the substrate transporting means (transport port), the processing gas supply means, the exhaust means in the chamber (exhaust port), etc.) is appropriately omitted and simplified. The dimensions of the components are also changed as appropriate. As for the configuration of the plasma processing apparatus not particularly mentioned in the present specification, the same configuration as that of the conventionally used plasma processing apparatus can be adopted.
Hereinafter, the plasma processing apparatus of the present invention according to the first to fourth embodiments will be described in order with reference to the accompanying drawings, but the description of the second to fourth embodiments is mainly different from the first embodiment. Focusing only on this, the description of the configuration common to the first embodiment will be omitted as appropriate.
Further, in the present specification, the numerical values connected by "-" mean a numerical range including the numerical values before and after "-" as the lower limit value and the upper limit value. When a plurality of lower limit values and a plurality of upper limit values are described separately, any lower limit value and upper limit value can be selected and connected by "~".

[First Embodiment]
As shown in FIG. 1, the plasma processing apparatus 10 of the present invention according to the first embodiment includes a chamber 1 and a coil 5. The chamber 1 includes a tubular wall 2, an upper member 3 connected to the upper end surface of the tubular wall 2, a lower member 4 connected to the lower end surface of the tubular wall 2, and a first unit. The vacuum seal member 6 of the above is provided.
Hereinafter, the coil 5 and the first vacuum seal member 6 will be described in detail after each member (excluding the first vacuum seal member 6) constituting the chamber 1 is explained in detail.

<Cylindrical wall>
The tubular wall 2 is a tubular member having a plasma generation space 21 in which plasma is generated by supplying a processing gas. The shape of the tubular wall 2 is not particularly limited, provided that the plasma generation space 21 is provided inside. In the present embodiment, the tubular wall 2 has a cylindrical body 22 formed in a straight body (the outer diameter is constant in the vertical direction) and a tubular body 22 at the lower end portion of the tubular body 22. It has a flange portion 23 that protrudes in the outer diameter direction. The flange portion 23 is a portion to which the clamp 25 described later is attached.
Plasma is generated by converting the processing gas introduced inside the tubular wall 2 into plasma by an induced electric field generated by the coil 5 described later. Therefore, the tubular wall 2 is formed of an insulating material that does not prevent an induced electric field from being generated inside the tubular wall 2. Examples of such a material include a material containing ceramics as a main component.

In the present specification, the material containing ceramics as a main component means the material having the highest ratio (mass%) of ceramics among all the components constituting the material. Therefore, the material containing ceramics as a main component includes not only materials containing substantially only ceramics but also ceramics and materials containing components other than ceramics (for example, metal). The "material containing substantially only ceramics" means a material containing 98% by mass or more of ceramics.
Ceramics is a general term for sintered bodies obtained by baking and hardening inorganic substances, and is not specified by a specific chemical formula. Examples of the ceramics include alumina (aluminum oxide), quartz (silicon dioxide), aluminum nitride, yttrium (ittrium oxide), titania (titanium dioxide), zirconia (zirconium dioxide), and mixtures thereof. In the present invention, ceramics containing at least one of alumina and quartz as a main component are preferably used, and more preferably, ceramics containing at least one of alumina and quartz substantially are used.

The thickness of the tubular wall 2 is not particularly limited. However, if the thickness of the tubular wall 2 is too thin, it becomes difficult to provide the first vacuum sealing member 6 described later, and there is a risk that the vacuum state in the chamber cannot be sufficiently maintained. On the other hand, if the tubular wall 2 is too thick, there is a risk that a temperature difference will occur not only in the vertical direction of the tubular wall 2 but also in the thickness direction (horizontal direction on the paper surface of FIG. 1), and cracks are likely to occur in the tubular wall 2. Not only is there a risk that plasma will be less likely to be generated in the chamber.
Considering these, the lower limit of the thickness of the tubular wall 2 is usually 5 mm, preferably 7 mm, and more preferably 10 mm. The upper limit of the thickness of the tubular wall 2 is usually 20 mm, preferably 15 mm, and more preferably 13 mm.

In the present embodiment, the tubular body 22 is a straight cylinder, but the shape of the tubular body 22 can be any other shape. For example, although not particularly shown, the tubular body 22 may be a square cylinder or a side-view conical trapezoidal cylinder. Further, when the tubular wall 2 and the lower member 4 are not in contact with each other, the flange portion 23 can be omitted.

<Upper member and lower member>
The upper member 3 is a member provided on the upper side of the tubular wall 2, and the lower member 4 is a member provided on the lower side of the tubular wall 2. The upper member 3 is connected to the upper end surface of the tubular wall 2, and the lower member 4 is connected to the lower end surface of the tubular wall 2.
The upper member 3 and the lower member 4 are formed of, for example, a metal, and examples of such a metal include an aluminum alloy.

The shape of the upper member 3 is not particularly limited as long as the upper end opening of the tubular wall 2 can be closed and can be connected to the upper end surface of the tubular wall 2. In the present embodiment, the plate-shaped top plate member 3 that closes the upper end opening of the tubular wall 2 is adopted as the upper member 3. A recess 31 recessed downward is formed in a substantially central portion of the top plate member 3. Although not particularly shown, a processing gas supply port is usually provided on the upper surface of the top plate member 3 except for the recess 31, and the processing gas supply means processes the plasma generation space 21 through the processing gas supply port. Gas is supplied.
Since the recess is formed in the substantially central portion of the top plate member 3, the plasma generation space 21 is a space having a substantially U-shaped cross section as shown in FIG. By adopting such a plasma generation space 21 having a substantially U-shaped cross section, it is possible to generate high-density plasma with relatively small electric power.

The shape of the lower member 4 is not particularly limited as long as it has a plasma processing space 41 connected to the plasma generation space 21 inside and can be connected to the lower end surface of the tubular wall 2. In the present embodiment, the lower tubular body 4 which is a cylinder having an outer diameter larger than that of the tubular wall 2 is adopted as the lower member 4.
The lower tubular body 4 includes a body portion 42 which is a straight cylinder having an outer diameter larger than that of the tubular wall 2, and a bottom plate portion 43 which closes the lower end opening of the body portion 42 and supports the entire chamber 1. It has an annular support portion 44 extending from the upper end edge of the body portion 42 in the axial direction of the body portion 42. In the present embodiment, the tubular wall 2 is connected to the support portion 44 of the lower tubular body 4.
In the plasma processing space 41 inside the lower cylinder 4, a mounting table 8 on which the substrate S to be plasma-processed is placed is provided. The height of the mounting table 8 can be adjusted to an arbitrary height by an elevating means such as an elevating cylinder.
Further, high frequency power is applied to the mounting table 8 by the first high frequency power supply 47 connected via the first impedance matching box 46.

The shape of the top plate member 3 and the shape of the lower cylinder 4 can be changed as appropriate. For example, although not particularly shown, the top plate member 3 may have a flat plate shape having no recess 31. Further, the body portion 42 of the lower cylinder 4 may be a straight cylinder having an outer diameter substantially the same as the outer diameter of the tubular wall 22, and in this case, a cylinder is formed at the upper end of the body portion 42. Since the shaped wall 2 can be connected, the support portion 44 can be omitted.

<Strut wall>
The support column wall 24 is a member that supports the upper member 3 (the top plate member 3 in this embodiment). In the present embodiment, the support column wall 24 is vertically erected from the upper surface of the support portion 44 of the lower cylinder 4 to the lower surface of the top plate member 3.
As will be described later, since the first vacuum seal member 6 is interposed between the tubular wall 2 and the upper member 3, the upper end surface of the support column wall 24 is larger than the upper end surface of the tubular wall 2. Located on the upper side. The height difference between the upper end surface of the support column wall 24 and the upper end surface of the tubular wall 2 corresponds to the gap G described later.

<Coil>
The coil 5 is a linear member spirally wound along the outer surface of the tubular wall 2. As shown in FIGS. 1 to 3, the coil may be wound while being in contact with the outer surface of the tubular wall 2, and although not particularly shown, the coil is wound so as to be slightly separated from the outer surface of the tubular wall 2. (In this case, a member that supports the coil 5 is used). However, when the coil 5 is in contact with the outer surface of the tubular wall 2, the temperature of the tubular wall 2 tends to rise, so that the coil 5 is wound so as to be slightly separated from the outer surface of the tubular wall 2. Is preferable.

FIG. 2 is a partially enlarged cross-sectional view of the plasma processing apparatus 10 illustrating the positional relationship of the coil 5 with respect to the tubular wall 2, and FIG. 3 shows the present embodiment in which the coil 5 is wound in the most preferable position. It is a partially enlarged sectional view of the plasma processing apparatus 10. Hereinafter, a preferable positional relationship between the coil 5 and the tubular wall 2 will be described with reference to FIGS. 2 and 3.
Since the positional relationship of the coil 5 is an index that defines the positional relationship with the first vacuum seal member 6 described later, for convenience, in FIGS. 2 and 3, the coil 5, the upper member 3, and the tubular wall 2 are shown. , And only the lower member 4. Further, in FIGS. 2 and 3, for convenience, the tubular wall 2, the upper member 3 and the lower member 4 are shown in contact with each other.
Further, in FIGS. 2 and 3, "C" represents a central position (hereinafter, referred to as "center position C") in the vertical direction of one end and the other end of the coil 5 which is a spiral linear shape, and "W" is used. , Represents the center position of the tubular wall 2 in the vertical direction (hereinafter, referred to as "center position W").
In the present invention, the position of the tubular wall 2 around which the coil 5 is wound can be changed as appropriate, but it is preferable to set the position in consideration of both the plasma generation position and the temperature difference of the tubular wall 2. ..

Specifically, in the plasma generation space 21, a particularly large amount of plasma is generated in the region corresponding to the position where the coil 5 is wound. Then, it is possible to execute the plasma processing more accurately by generating the plasma as close to the substrate S as possible. Therefore, considering the accuracy of plasma processing, the winding position of the coil 5 is preferably on the lower side as much as possible.
Considering this, as shown in FIG. 2A, in the coil 5, the entire coil 5 is located below the center position W, and the lower end of the coil 5 is the lower end of the tubular body 22 of the tubular wall 2. It is preferable that the coil is wound so as to be located above the center position, and as shown in FIG. 2B, the entire coil 5 is located below the center position W, and the lower end of the coil 5 and the tubular wall 2 are located. It is more preferable that the lower end of the tubular body 22 (the upper end of the flange portion 23) is wound so as to be substantially aligned with each other.
On the other hand, as described above, if the upper end surface of the tubular wall 2 is too far from the coil 5, the temperature difference between the portion where the coil 5 of the tubular wall 2 is wound and the upper end surface of the tubular wall 2 becomes very large. There is a risk that the tubular wall 2 will be easily cracked. Therefore, in consideration of preventing cracks in the tubular wall 2, the coil 5 is preferably wound so that the heights of the center position C and the center position W match, as shown in FIG. 2C. ..

Considering these points comprehensively, it is most preferable to wind the coil 5 below the center position W as much as possible while preventing the temperature difference in the vertical direction of the tubular wall 2 from becoming too large. Therefore, as shown in FIG. 3, it is most preferable to wind the coil 5 so that the center position C is lower than the center position W and the upper end of the coil 5 is located above the center position W.

As shown in FIG. 1, a second high-frequency power supply 52 is connected to the coil 5 via a second impedance matching box 51, and high-frequency power is applied to the coil 5 from the second high-frequency power supply 52. To. By supplying the processing gas into the plasma generation space 21 in a vacuum environment and applying high-frequency power to the coil 5, the processing gas is turned into plasma by the induced electric field generated in the plasma generation space 21, and as a result, the substrate S is turned into plasma. Plasma treatment can be applied.
The frequency and power of the high frequency power applied to the coil 5 are not particularly limited, but for example, the frequency is set in the range of 10 MHz to 100 MHz, and the power is set in the range of 100 W to 10000 W.

<First vacuum seal member>
The plasma processing apparatus 10 includes at least the first vacuum sealing member 6.
The first vacuum seal member 6 is a member that mainly maintains a vacuum state in the chamber 1 during plasma processing, and in the present invention, is also a member provided to reduce the temperature difference in the vertical direction of the tubular wall 2. (The same applies to the second vacuum seal member 7 described later).
The first vacuum seal member 6 is the end face of the upper and lower end faces of the tubular wall 2, which is farther from the center position C, and the far side of the upper member 3 and the lower member 4. Between the members connected to the end faces of the above, the far end face and the connected members are interposed in a state where the plasma treatment is executed in the chamber 1 in a non-contact state.

Hereinafter, the first vacuum seal member will be specifically described with reference to FIGS. 4 to 7. Note that FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 1, but for convenience, a portion of the tubular wall in which the first vacuum seal member 6 is provided is surrounded by a broken line. There is. Further, with respect to FIGS. 5 to 7, for convenience, the hatching showing the cross section of the first vacuum seal member is omitted (the same applies to FIGS. 8 to 11 described later).

Hereinafter, in the present specification, the upper end surface of the tubular wall 2 is simply referred to as an "upper end surface", the lower end surface of the tubular wall 2 is simply referred to as a "lower end surface", and the end surface farther from the center position C. May be referred to as a "far end face", and the end face closer to the center position C may be referred to as a "near end face".
By changing the winding position of the coil 5, the upper end surface and the lower end surface of the tubular wall 2 can be a far end surface or a near end surface. As shown in FIG. 2C, when the heights of the center position C and the center position W match, one of the upper end surface and the lower end surface of the tubular wall 2 is set as the far end surface and the other is set as the far end surface for convenience. The near end surface.

In the present embodiment, as shown in FIGS. 1 and 3, the coil 5 is wound so that the center position C is located below the center position W. Therefore, the far end surface of the tubular wall 2 is the upper end surface thereof, and the near end surface of the tubular wall 2 is the lower end surface thereof. Therefore, in the present embodiment, as shown in FIG. 5, the first vacuum seal member 6 is interposed between the upper end surface of the tubular wall 2 and the member connected to the upper end surface (that is, the upper member 3). ing.
The first vacuum seal member 6 is not particularly limited, but is preferably an annular elastic member over the entire circumference of the far end surface (upper end surface in this embodiment) of the tubular wall 2 as shown in FIG. In the present embodiment, an elastic member (so-called O-ring) having a circular cross-sectional shape is used as the first vacuum seal member 6. By using the first vacuum seal member 6, the vacuum state in the chamber can be easily maintained. The reason for this will be described below with reference to FIG.

FIG. 6A shows a state before connecting the tubular wall 2 and the upper member 3. In this state, the first vacuum seal member 6 (O-ring 6) is fitted into the groove portion 9 formed on the lower end surface of the upper member 3.
When brought close to the lower surface of the upper member 3 to the upper end surface of the standoff walls 24, as shown in FIG. 6 (b), the first vacuum sealing member 6 is pressed from the upper and lower slightly elastically deformed. In this state, since there is a fine gap between the first vacuum sealing member 6, the upper member 3 and the tubular wall 2, the inside and outside of the chamber 1 are not spatially separated (non-vacuum sealing). State).
Next, from the state of FIG. 6 (b), evacuate the chamber 1 while pressing the upper member 3 so as to be in contact with the upper end surface of the standoff walls 24. Then, the first vacuum seal member 6 is greatly elastically deformed so as to be in close contact with the upper member 3 and the tubular wall 2, the fine gap disappears, and the inside and outside of the chamber 1 are spatially as shown in FIG. It is in a separated state (vacuum sealed state).
In the present embodiment, since the upper end surface of the standoff wall 24 is positioned above the upper end surface of the cylindrical wall 2, never first vacuum sealing member 6 is too crushed by the pressure of the vacuum evacuation. Therefore, the vacuum state in the chamber 1 can be maintained while the upper end surface of the tubular wall 2 and the lower surface of the upper member 3 are not in contact with each other.

As described above, in the present invention, as shown in FIG. 5, the far end surface (upper end surface of the tubular wall in FIG. 5) and the member connected to the far end surface (in FIG. 5 in FIG. 5) are connected to the far end surface (in FIG. In, the upper member 3) is not in contact with the member 3). In other words, the upper end surface of the tubular wall 2 and the upper member 3 are not in direct contact with each other, but are indirectly connected via the first vacuum seal member 6.
By executing the plasma treatment, the temperature of the tubular wall 2 rises as described above, but in the present invention, since the far end surface and the member connected to the far end surface are non-contact, from the far end surface of the tubular wall 2. No direct heat conduction to the connected members occurs. Further, since the first vacuum seal member 6 usually has a low thermal conductivity, indirect heat conduction through the first vacuum seal member 6 is unlikely to occur.

Therefore, as shown in FIG. 7, in the present invention, the far end surface (upper end surface in the present embodiment) of the tubular wall 2 is cooled by a member (upper member 3 in the present embodiment) connected thereto. Since it is difficult, the temperature difference in the vertical direction of the tubular wall 2 during the plasma treatment becomes small.
Specifically, as shown in FIG. 7, the difference (Δt ₁ ) between the uppermost temperature (280 ° C.) of the tubular wall 2 and the maximum temperature (300 ° C.) of the tubular wall 2 is 20 ° C. The temperature difference is smaller than the value of Δt ₁ (50 ° C.) of the conventional plasma device 10A shown in FIG. 13 described above.
Therefore, in the plasma processing apparatus 10 of the present invention, cracks are less likely to occur in the tubular wall 2 during the plasma processing, and the plasma processing can be stably executed for a long time.

In the present embodiment, an O-ring is interposed between the lower end surface, which is the near end surface of the tubular wall 2, and the lower member 4 connected to the lower end surface, but as shown in FIG. 7, the cylinder The flange portion 23 of the shaped wall 2 and the lower member 4 are forcibly brought into contact with each other by using the clamp 25. Therefore, the temperature distribution of the tubular wall 2 below the coil 5 is substantially the same as that of the conventional tubular wall 2A shown in FIG. 13 described above.

The outer surface temperatures of each member of the plasma processing apparatus 10 according to the present embodiment, Δt ₁ and Δt ₂ , shown in FIG. 7 are examples. These values vary depending on the electric power applied to the coil, the material of the tubular wall 2, the adjustment temperature of the upper member 3 and the lower member 4 (temperature of the chamber heater), etc., but what are these values? Even if there is, it is possible to reduce the temperature difference in the vertical direction of the tubular wall 2 by using the first vacuum sealing member 6. The same applies to the second to fourth embodiments described later.

Further, in the present invention, since the far end surface (upper end surface in the present embodiment) of the tubular wall 2 and the member connected to the far end surface (upper end surface in the present embodiment) are not in contact with each other, the plasma In the processing state, it is possible to effectively prevent the generation of particles in the plasma processing space. Hereinafter, description will be made with reference to FIG. FIG. 8A shows a state immediately after the start of the plasma treatment, and FIG. 8B shows a state just before the end of the plasma treatment. In FIGS. 8 (a) and 8 (b), the broken line represents a reference line passing through an intermediate point in the thickness direction of the tubular body 22 of the tubular wall 2.

The upper member 3 has a relatively low temperature immediately after the start of the plasma treatment, but the temperature gradually rises as the plasma treatment is continued, and the temperature becomes significantly higher just before the end of the plasma treatment than immediately after the start of the plasma treatment. Therefore, the upper member 3 thermally expands in the left-right direction from the start to the end of the plasma treatment. As a result, as shown in FIGS. 8 (a) and 8 (b), the point A (one point on the upper surface of the upper member 3) located immediately above the reference line immediately after the start of the plasma treatment ends the plasma treatment. The position shifts slightly to the right of the reference line just before. Although the tubular wall 2 also expands slightly, its coefficient of thermal expansion is usually considerably smaller than that of the upper member 3, so its influence can be almost ignored.
Here, when the tubular wall 2 and the upper member 3 are in contact with each other as in the conventional plasma processing apparatus, the upper end surface and the upper side of the tubular wall 2 are in contact with each other due to the thermal expansion of the upper member 3 as described above. The lower surface of the member 3 rubs against each other, and as a result, a part of the tubular wall 2 or a part of the upper member 3 is separated into fine particles (that is, particles are generated) and diffused into the plasma processing space 41. It may adversely affect the accuracy of plasma processing. Further, since the upper member 3 thermally expands in the vertical direction, when the tubular wall 2 and the top plate member 3 are in contact with each other as in the conventional plasma processing device, the upper member 3 causes the upper member 3 to form a tubular shape. Since the upper surface of the wall 2 is pressed, cracks may easily occur in the tubular wall 2.
On the other hand, in the present embodiment, the upper end surface of the tubular wall 2 and the upper member 3 are made non-contact by the first vacuum seal member 6. Therefore, even if the positional relationship between the upper member 3 and the tubular wall 2 is displaced due to thermal expansion, the first vacuum seal member 6 is elastically deformed, so that the displacement is maintained while maintaining the vacuum state in the chamber 1. (See FIG. 8 (b)). Therefore, the upper end surface of the tubular wall 2 and the upper member 3 do not rub against each other in the process of plasma treatment. Therefore, in the present invention, not only the generation of cracks in the tubular wall 2 can be prevented, but also the particles can be effectively prevented from diffusing into the plasma processing space 41 and adhering to the substrate.

The material of the first vacuum sealing member 6 is not particularly limited, but it is preferable to use a material having a low thermal conductivity. The lower the thermal conductivity, the less likely it is that heat conduction to the upper member 3 via the first vacuum seal member 6 will occur, and the temperature difference in the vertical direction of the tubular wall 2 can be made smaller.
The thermal conductivity of the first vacuum sealing member 6 is preferably 0.8 W / (mK) or less, more preferably 0.6 W / (mK), and particularly preferably 0.5 W / (mK) or less. Is. Known elastomers and resins can be used as materials that satisfy such thermal conductivity. Specifically, nitrile rubber, silicon rubber, acrylic rubber, ethylene propylene (EP) rubber, and styrene butadiene (SB). Rubber or the like can be used.

Further, although not particularly shown, when the far end surface of the tubular wall 2 is the lower end surface, a first vacuum seal member 6 is interposed between the lower end surface of the tubular wall 2 and the lower member 4. To.
In this case, for the same reason as described above, the difference (Δt ₂ ) between the temperature at the bottom of the tubular wall 2 and the maximum temperature (300 ° C.) of the tubular wall 2 is the conventional plasma apparatus shown in FIG. It becomes smaller than the value of Δt ₂ (40 ° C.) of 10A, and the temperature difference in the vertical direction of the tubular wall 2 can be reduced. Further, in this case, the first vacuum seal member 6 is fitted into the groove portion 9 formed on the upper end surface of the lower member 4 in the same manner as the second vacuum seal member 7 described later.

During the plasma treatment, the far end surface of the tubular wall 2 and the member connected to the far end surface are not in contact with each other, and a gap G exists between the two (see FIG. 5). The width of the gap G is not particularly limited and is appropriately set. For example, the minimum value of the gap G is 0.3 mm, preferably 0.4 mm, and more preferably 0.5 mm. The maximum value of the gap G is 1.0 mm, preferably 0.9 mm, and more preferably 0.8 mm.
When the gap G is smaller than 0.3 mm, the degree of vacuum in the chamber 1 may fluctuate slightly, so that the far end surface and a member connected to the far end surface may come into contact with each other. On the other hand, if the gap G exceeds 1.0 mm, the surface area of the first vacuum sealing member 6 exposed to plasma increases, and the first vacuum sealing member 6 may be easily deteriorated by plasma.

When an O-ring is used as the first vacuum seal member 6, its wire diameter is not particularly limited and is appropriately set in consideration of the width of the target gap G.
In general, an O-ring having a small wire diameter has a larger compression set rate than an O-ring having a large wire diameter. Therefore, when an O-ring having a small wire diameter is used, it may be difficult to maintain a stable vacuum state in the chamber for a long period of time. Considering this, the minimum value of the wire diameter of the O-ring is, for example, 2.0 mm, preferably 3.0 mm, and more preferably 5.0 mm. On the other hand, if the wire diameter of the O-ring is too large, the surface area of the O-ring exposed to the plasma in the chamber becomes large, and the O-ring may be easily deteriorated. Considering this, the maximum value of the wire diameter of the O-ring is 8.0 mm, preferably 7.0 mm, and more preferably 6.0 mm. The wire diameter of the O-ring illustrated in this specification is based on the state before elastic deformation.
The hardness of the O-ring (hardness (shore A) required in accordance with JIS K6253 "vulcanized rubber and thermoplastic rubber-how to determine hardness-") is not particularly limited, but is preferably 50 to 90, for example. Is 70 to 90.

Further, the shape of the groove portion 9 into which the first vacuum seal member 6 is fitted is not particularly limited. In the figure, the groove portion 9 having a rectangular cross-sectional view is adopted, but in addition to this, a groove (groove portion 9 having a cross-sectional viewing table shape), a groove portion 9 having a triangular cross-sectional view, and the like can also be used (FIG. Not shown).
The depth of the groove portion 9 is not particularly limited, and can be appropriately set according to the shape of the first vacuum sealing member 6. For example, when an O-ring is used as the first vacuum sealing member 6, the lower limit of the depth of the groove portion 9 is preferably 0.3 times, more preferably 0.5 times, the wire diameter of the O-ring. Yes, especially preferably 0.6 times. Further, preferably, the upper limit of the depth of the groove portion 9 is 0.9 times the wire diameter of the O-ring, more preferably 0.8 times, and particularly preferably 0.7 times.

The plasma processing apparatus 10 according to the first embodiment is not limited to the specific embodiment described above, and is a condition that the far end surface of the tubular wall 2 and the member connected thereto are not in contact with each other during the plasma processing. It is possible to make various changes to.
For example, as the first vacuum sealing member 6, an elastic member having a quadrangular cross-sectional shape, a D-shaped cross section, an indefinite shape, or the like can be used in addition to the O-ring. The cross-sectional shape of the first vacuum seal member 6 is based on the state before the first vacuum seal member 6 is elastically deformed.
Further, the groove portion 9 may be formed on the upper end surface of the tubular wall 2, or may be formed on both the lower surface of the upper member 3 and the upper end surface of the tubular wall 2. In the latter case, it is preferable that the total value of the depths of both groove portions 9 falls within the above-mentioned numerical range.

[Second Embodiment]
In the plasma processing apparatus 10 according to the second embodiment, the chamber 1 includes a second vacuum sealing member 7 in addition to the first vacuum sealing member 6. The second vacuum seal member 7 is close to the tubular wall 2 in a state where plasma treatment is performed in the chamber 1 between the near end surface of the tubular wall 2 and the member connected to the near end surface. The end face and the member connected to the near end face are interposed in a non-contact state.
In other words, in the present embodiment, the chamber 1 is provided on both the upper end surface of the tubular wall 2 and the upper member 3 and between the lower end surface of the tubular wall 2 and the lower member 4. A vacuum sealing member (first vacuum sealing member 6) with the upper end surface of the tubular wall 2 and the upper member 3 in non-contact and the lower end surface of the tubular wall 2 and the lower member 4 in non-contact. And a second vacuum seal member 7).

For example, when the far end surface of the tubular wall 2 is the upper end surface thereof, the near end surface of the tubular wall 2 is the lower end surface thereof, and the member connected to the lower end surface is the lower member 4. Therefore, as shown in FIG. 9, a second vacuum seal member 7 (O-ring 7 in this embodiment) is interposed between the lower end surface of the tubular wall 2 and the lower member 4. Since the relationship between the upper end surface of the tubular wall 2 and the upper member 3 is the same as that of the first embodiment (FIG. 5) described above, the illustration of the portion is omitted in FIG. Further, in the present embodiment, since the lower end surface of the tubular wall 2 and the lower member 4 are not in contact with each other, the flange portion 23 is not provided with the clamp 25.
Similar to the first vacuum seal member 6 described above, the second vacuum seal member 7 is fitted into the groove portion 9 formed on the upper surface of the lower member 4. By evacuating the inside of the chamber 1 while pressing the second vacuum seal member 7 from the upper side and the lower side, the second vacuum seal member 7 is greatly elastically deformed and the tubular wall 2 and the lower member 4 are deformed. Adhere to. As a result, the inside and outside of the chamber 1 are spatially separated (vacuum sealed state).
The width of the gap G existing between the lower end surface of the tubular wall 2 and the lower member 4 is the width of the gap G existing between the upper end surface of the tubular wall 2 and the upper member 3 described above. It is preferably within the same range.

As described above, the plasma processing apparatus 10 according to the present embodiment is further provided with the second vacuum sealing member 7 in addition to the first vacuum sealing member 6, so that the plasma processing apparatus 10 is on the upper side in a state where the plasma processing is being executed. Neither the member 3 nor the lower member 4 comes into contact with the tubular wall 2. Therefore, as shown in FIG. 10, the difference (Δt ₁ ) between the uppermost temperature (280 ° C.) of the tubular wall 2 and the maximum temperature (300 ° C.) of the tubular wall 2 is 20 ° C., and FIG. 13 described above. The temperature difference is smaller than the value of Δt ₁ (50 ° C.) of the conventional plasma device 10A shown in ₁ . Similarly, in the present embodiment, the difference (Δt ₂ ) between the lowermost temperature (290 ° C.) of the tubular wall 2 and the maximum temperature (300 ° C.) of the tubular wall 2 is 10 ° C., as shown in FIG. 13 described above. The temperature difference is smaller than the value of Δt ₂ (40 ° C.) of the conventional plasma device 10A shown. Therefore, in the present embodiment, the temperature difference in the vertical direction of the tubular wall 2 can be further reduced as compared with the first embodiment.
Further, in the present embodiment, since both the upper end surface of the tubular wall 2 and the upper member 3 and the lower end surface of the tubular wall 2 and the lower member 4 are not in contact with each other. Particles can be more reliably prevented from diffusing into the chamber 1, and more accurate plasma processing can be performed.

The plasma processing apparatus 10 according to the second embodiment can be modified in various ways as in the first embodiment described above.
For example, the groove portion 9 into which the second vacuum seal member 7 is fitted may be formed not on the upper surface of the lower member 4 but on the lower end surface of the tubular wall 2. Other changes that can be assumed with respect to the second embodiment are the same as those of the first embodiment described above, and thus the description thereof will be omitted (the same applies to the third and fourth embodiments).

[Third Embodiment]
In the first embodiment, the first vacuum seal member 6 is composed of one O-ring, but in the third embodiment, the first vacuum seal member 6 is substantially concentric on substantially the same plane. It is composed of a plurality of arranged O-rings having different inner diameters, and among the plurality of O-rings, the wire diameter of the innermost O-ring is smaller than the wire diameter of the other O-rings, and is the largest. The surface of the O-ring located inside is covered with a vacuum-resistant film.
Hereinafter, the first vacuum seal member 6 composed of two O-rings will be described with reference to FIG.

As shown in FIG. 11, the first vacuum sealing member 6 is composed of an O-ring 61 and an O-ring 62 having different inner diameters, and the inner O-ring 61 has a smaller wire diameter than the outer O-ring. Therefore, only the O-ring 61 is exposed inside the chamber.
The two O-rings 61 and 62 are arranged concentrically on substantially the same plane. The fact that they are arranged on substantially the same plane means that the two O-rings 61 and 62 are arranged so as to be adjacent to each other along the horizontal line indicated by the broken line, as shown in FIG. Further, the concentric arrangement means that the axial center of the O-ring 61 and the vertical straight line passing through the axial center of the O-ring 62 are arranged so as to coincide with each other. The vertical line may or may not coincide with the axis of the tubular wall 2, but it is preferable that the vertical line coincides with the axis of the tubular wall 2.

The surface of the inner O-ring 61 is coated with a plasma-resistant film (hereinafter, referred to as “plasma-resistant film”). Since the O-ring 61 is covered with the plasma-resistant film, the first vacuum seal is performed without covering the O-ring 62 (O-ring 62 in FIG. 11) located outside the O-ring 61 with the plasma-resistant film. Plasma resistance can be imparted to the member 6 (plurality of O-rings).
The plasma resistant film is not particularly limited, and examples thereof include a film containing a fluororesin.
As the fluororesin, it is preferable to use a polymer of tetrafluoroethylene. Examples of the polymer of tetrafluoroethylene include ETFE (tetrafluoroethylene-ethylene copolymer), PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene-hexafluoropropylene copolymer), and PFA (tetrafluoro). (Ethylene-perfluoroalkyl vinyl ether copolymer) and the like.

In this embodiment, the inner O-ring 61 protects the outer O-ring 62 from plasma. An O-ring having plasma resistance is more expensive as the surface area covered with the plasma resistant film is larger. However, although the O-ring 61 is covered with a plasma resistant film, it is inexpensive because the wire diameter is relatively small. Further, since the outer O-ring 62 has a larger wire diameter than the O-ring 61, the vacuum sealing property of the chamber 1 can be ensured. As described above, in the plasma processing apparatus 10 according to the present embodiment, it is economical and effective to use the relatively inexpensive O-ring 61 having a small wire diameter and plasma resistance and the O-ring 62 having a large wire diameter in combination. The vacuum state of the chamber 1 can be ensured for a long period of time.

Although the case where the first vacuum sealing member 6 is composed of two O-rings has been described so far, the number of O-rings is not limited to two but may be three or more in the present embodiment. It is possible.
When there are three or more O-rings, the plurality of O-rings may be arranged in ascending order of inner diameter from the inside to the outside of the chamber 1, or may be arranged at random regardless of the size of the wire diameter. It may be (provided that the innermost O-ring has the smallest wire diameter).
When the number of O-rings is three or more, the outer O-rings (O-rings other than the innermost O-ring) may have the same wire diameter.

[Fourth Embodiment]
In the third embodiment, the first vacuum sealing member is composed of a plurality of O-rings, but in the fourth embodiment, the first vacuum sealing member and the second vacuum sealing member are substantially abbreviated. It is composed of a plurality of O-rings having different inner diameters arranged substantially concentrically on the same plane, and the wire diameter of the innermost O-ring among the plurality of O-rings is the wire diameter of the other O-rings. The surface of the smaller, innermost O-ring is covered with a vacuum resistant film.
That is, the fourth embodiment is an embodiment in which the first and second vacuum seal members included in the second embodiment described above are both composed of a plurality of O-rings as in the third embodiment described above. .. Since the specific embodiment of the second vacuum seal member in the present embodiment is the same as that in the third embodiment, the drawings and the description thereof will be omitted.

In the fourth embodiment, for the same reason as in the third embodiment, the vacuum state in the chamber can be maintained more stably, and both the first and second vacuum seal members are used by using an inexpensive O-ring. Can be imparted with plasma resistance.
Further, in the fourth embodiment, it is possible to effectively prevent particles from being mixed into the plasma processing space for the same reason as in the second embodiment.

10 ... Plasma processing device, 1 ... Chamber, 2 ... Cylindrical wall, 21 ... Plasma generation space, 22 ... Cylindrical body, 23 ... Flange part, 24 ... Support wall, 3 ... Upper member (top plate member), 31 ... recess, 4 ... lower member (lower cylinder), 41 ... plasma processing space, 42 ... body, 43 ... bottom plate, 44 ... support, 5 ... coil, 6 ... first vacuum seal member, 7 ... second vacuum seal member, 8 ... mounting table, 9 ... groove, S ... substrate

Claims (4)

It comprises a chamber and a coil to which high frequency power is applied to perform plasma processing in the chamber.
The chamber
A tubular wall where processing gas is supplied to the inside to generate plasma,
An upper member connected to the upper end face of the tubular wall,
A lower member connected to the lower end face of the tubular wall,
With the pillar wall
A first vacuum seal member and
The coil is wound along the outer surface of the tubular wall.
The strut wall is erected between the upper member and the lower member on the outer side of the tubular wall and the coil to support the upper member.
The first vacuum seal member includes an end face of either one of the upper and lower end faces of the tubular wall and a member connected to the one end face of the upper and lower members. A plasma processing apparatus, characterized in that, in a state where plasma processing is performed in the chamber, one end face thereof and the connected member are interposed in a non-contact state. The chamber is formed between an end surface of any one of the upper and lower end faces of the tubular wall and a member of the upper and lower members connected to the other end face. A second aspect of the chamber, wherein a second vacuum sealing member is further provided in a state in which the other end surface and the connected member are not in contact with each other in a state where plasma treatment is performed in the chamber. the plasma processing apparatus according to 1. The first vacuum seal member is composed of a plurality of O-rings having different inner diameters and arranged substantially concentrically on substantially the same plane.
Of the plurality of O-rings, the wire diameter of the innermost O-ring is smaller than the wire diameter of the other O-rings, and the surface of the innermost O-ring is covered with a plasma-resistant film. The plasma processing apparatus according to claim 1 or 2 , wherein the plasma processing apparatus is characterized by the above. The first vacuum seal member and the second vacuum seal member are each composed of a plurality of O-rings having substantially different inner diameters arranged substantially concentrically on the same plane.
Of the plurality of O-rings, the wire diameter of the innermost O-ring is smaller than the wire diameter of the other O-rings, and the surface of the innermost O-ring is covered with a plasma-resistant film. The plasma processing apparatus according to claim 2 , wherein the plasma processing apparatus is characterized by the above.

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