JP4001355B2 - Plasma generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma generator suitable for efficiently performing plasma processing such as etching, film formation, and ashing in high-precision manufacturing processes such as ICs and LCDs, and more specifically, plasma generation that efficiently generates homogeneous plasma. Relates to the device.
[0002]
[Prior art]
Conventionally, as a plasma generator used for plasma processing such as CVD, etching, ashing, etc., plasma generation is insufficient when only plasma is applied to an electric field. Therefore, a high-density plasma (HDP) is generated by sealing the plasma by applying a magnetic field. MRIE (magnetron reactive ion etcher) and the like are known. There is also known an apparatus which attempts to prevent damage by uniformizing a magnetic field using a planar coil as described in JP-A-3-79025.
[0003]
Furthermore, the plasma space is separated into a plasma processing space and a plasma generation space that communicate with each other in order to reduce damage to the object due to ions and prevent the object from being directly exposed to the high-density plasma being generated. Plasma with high-density plasma in a strong magnetic field such as ECR (Electron Cyclotron Resonance) or those in which both spaces are separated from each other, such as those described in JP-A-4-81324, ICP (Inductive Coupled Plasma), etc. It is the same in that the plasma generation space is confined to the plasma generation space adjacent to the processing space and the plasma generation space is adjacent to the plasma processing space. There are also known devices that confine high-density plasma using polarized electromagnetic waves.
[0004]
On the other hand, since it is difficult to uniformly supply plasma in a single plasma generation space as the processing target such as a liquid crystal substrate is enlarged and the plasma processing space is expanded, as described in JP-A-8-222399, In some cases, a plurality of plasma generation spaces are provided, and a control valve is provided for each of them to supply reaction gas and processing gas. In this case, the plasma generation space is divided into vertical cylindrical spaces so that the opening area does not decrease even if the number of plasma generation spaces is increased. Each side surface is surrounded by a high-frequency coil for excitation, and the magnetism for sealing the plasma is cylindrical. It is sent from the upper and lower end surfaces.
[0005]
[Problems to be solved by the invention]
By the way, in these conventional plasma generators, the plasma space is separated into the plasma generation space and the plasma processing space to reduce plasma damage and charge-up, but the distance between the plasma generation space and the plasma processing space is not so great. If they are separated from each other, ion species are suppressed more than necessary, while if both spaces are adjacent to each other, more gas flows backward from the plasma processing space to the plasma generation space. Such a backflow gas also contains components that should be discharged immediately, such as those generated by processing the object to be processed. When this gas enters the plasma generation space, it is violently decomposed and ionized by the high-density plasma, causing contamination, etc. It is inconvenient because it often changes to an undesirable one.
[0006]
This is not solved even if the plasma generation space is made plural, if the opening area from the plasma generation space to the plasma processing space remains the same. Further, it is sufficient for high-density plasma to interpose a magnet or the like between the plasma generation space and the plasma processing space in order to apply a static magnetic bias for sealing the plasma from above and below the plasma generation space. If it is going to secure magnetic force, processing and mounting of a magnetic member will become troublesome.
[0007]
On the other hand, the same applicant effectively prevents undesired gas inflow from the plasma processing space to the plasma generation space, and can easily mount the magnetic member and the like so that the magnetic member can be easily mounted. The structure of the member has been devised (Japanese Patent Application No. 9-159190, Japanese Patent Application No. 9-250111, etc.). Specifically, FIGS. 10 to 12 show longitudinal sectional views around the plasma generation space. However, the plasma generation space 22 is linearly distributed along the adjacent surface to the plasma processing space 13 and the plasma generation space 13 is dispersed. The magnetic member 25 is disposed so as to sandwich the gap.
[0008]
However, it is troublesome to process a fragile magnetic member into an arbitrary shape, and it is difficult to process even a small piece in a shape having a concave portion and not a convex polygon in particular (see the magnet in FIG. 10). 25), the cross-sectional shape is divided into a plurality of simple rectangular shapes, and these are separated and provided at a distance from the plasma processing space (upper and lower in FIGS. 11 and 12). In this case, there is an inconvenience that even though the high-density plasma 20 can be confined efficiently, the amount of plasma used for the plasma processing does not increase as expected.
Therefore, it is an issue to efficiently confine high-density plasma in the plasma generation space and efficiently supply the high-density plasma to the plasma processing space while preventing the magnetic member from being difficult to process.
[0009]
Also, if high-density plasma is sent vigorously from the dispersed plasma generation space to the plasma processing space, spots are likely to occur where the plasma is blown and where it is not, which is a factor that impairs the uniformity of the plasma processing. This is not preferable.
Therefore, it is also an issue to prevent the uniformity of plasma processing from being impaired even if plasma is supplied from the dispersed plasma generation space to the plasma processing space with high efficiency.
[0010]
The present invention has been made to solve such a problem, and an object of the present invention is to realize a plasma generator that efficiently supplies high-quality plasma to a plasma processing space.
Another object of the present invention is to realize a plasma generating apparatus in which high-quality plasma processing is uniformly performed.
[0011]
[Means for Solving the Problems]
About the 1st thru | or 2nd solution means invented in order to solve such a subject, the structure and effect are demonstrated below.
[0012]
[First Solution]
The plasma generator of the first solution (as described in claim 1 at the beginning of the application) includes a first mechanism in which a plasma processing space is formed, and is attached to or integrally with the first mechanism. And a second mechanism in which a plasma generation space is formed, wherein the plasma generation space is adjacent to and communicates with the plasma processing space, wherein the plasma generation space is adjacent to the plasma processing space. A magnetic member that extends linearly along the surface and runs alongside the plasma generation space is inclined.
[0013]
Here, the above-mentioned “magnetic member” corresponds to a permanent magnet and a DC excitation coil.
In addition, as the “tilt”, one or both of the shape and the magnetization direction is assumed.
Furthermore, the criteria for whether or not it is inclined include the target axis and the central axis in the cross section of the plasma generation space, the side wall surface of the plasma generation space, the adjacent surface between the plasma generation space and the plasma processing space, or the orthogonal to it. Examples include planes and orthogonal axes. In the case of a horizontal parallel plate shape, the horizontal plane and the vertical line coincide with the reference.
[0014]
In such a plasma generator of the first solution, by maintaining the conditions of separation of the plasma space and adjacent communication, plasma damage and charge-up are reduced, and the radical species component and ion species in the plasma are reduced. We are responding to the basic request of optimizing the ratio with other ingredients. Moreover, since the magnetic member that runs alongside the plasma generation space is necessarily provided along the adjacent surface of the plasma processing space on the same second mechanism side as the plasma generation space, the magnetic force can be strengthened. The cross-sectional area of the plasma generating space itself along the surface adjacent to the plasma processing space and the surface thereof is inevitably smaller than that of the plasma processing space by at least the portion occupied by the magnetic member. If there is a difference between the areas of the two spaces in this way, the ratio of the area of the communication adjacent surface and the cross-sectional area of the plasma processing space along this is the first ratio, and the area of the communication adjacent surface and the plasma generation space along this area. The first ratio is less than 1 and smaller than the second ratio, where the ratio of the cross-sectional area is the second ratio.
[0015]
When the first ratio is less than 1, the amount of gas flowing from the plasma processing space into the plasma generation space decreases. On the other hand, when the second ratio is 1, the amount of gas flowing out from the plasma generation space to the plasma processing space does not decrease. Further, even when the second ratio is less than 1 and the amount of outflow gas decreases, if the second ratio is greater than the first ratio, the degree of decrease may be small. In any case, the ratio of the gas flowing out from the plasma generation space into the plasma processing space is relatively higher than the ratio of the gas flowing into the plasma generation space from the plasma processing space. This not only suppresses the flow of undesired gas into the plasma generation space, but even when the gas enters the plasma generation space, the gas is quickly discharged into the plasma processing space together with the plasma flow. , Gas alteration due to high-density plasma can be prevented and suppressed.
[0016]
In addition, the high-quality plasma generated in this way is confined in the plasma generation space for a long time by the magnetic force of the magnetic member that runs alongside the plasma generation space, and the density increases. Etc. are flowed well toward the weaker magnetic field due to the magnetic flux density and magnetic field lines. Therefore, the amount of high-density plasma flowing from the plasma generation space to the plasma processing space can be reduced simply by installing the magnetic member so that the direction of the magnetic member is directed from the plasma generation space to the plasma processing space in advance. Can be increased.
[0017]
Furthermore, since it is sufficient to arrange small pieces of magnetic members along the linear plasma generation space, it is sufficient to make a rod-like object that is relatively easy to manufacture in advance and cut it into small pieces. As a result, the manufacture of a magnetic member or the like is facilitated. In addition, since the magnetic member only needs to be inclined in shape and magnetization direction, it can be produced in a convex polygonal shape with no recess in the cross-sectional shape, and therefore, the manufacture thereof is much easier. In addition, since the magnetic member is provided on the same side as the plasma generation space on the second mechanism side, it is not necessary to interpose between the plasma generation space and the plasma processing space, so that layout design, mounting work, and subsequent components are eliminated. Maintenance work such as replacement is also easier.
[0018]
Therefore, according to the present invention, it is possible to realize a plasma generator that efficiently supplies high-quality plasma to the plasma processing space.
[0019]
[Second Solution]
The plasma generating apparatus of the second solution means (as described in claim 2 at the beginning of the application) is a first mechanism in which a plasma processing space is formed, and is attached to or integrally with the first mechanism. And a second mechanism in which a plasma generation space is formed, wherein the plasma generation space is adjacent to and communicates with the plasma processing space. It extends linearly along the adjacent surface and widens toward the plasma processing space.
[0020]
Here, the “magnetic member” includes a permanent magnet and a DC excitation coil.
In addition, the basic operation and effect of supplying high-quality plasma by effectively preventing undesired gas inflow from the plasma processing space to the plasma generation space is the same as described above.
[0021]
Furthermore, in such a plasma generator of the second solution, the plasma generation space extending linearly along the adjacent surface to the plasma processing space is widened toward the plasma processing space. Therefore, when the plasma generated in the plasma generation space flows out toward the plasma processing space, it does not become a constricted jet state but expands in a fan shape or a trumpet shape.
[0022]
As a result, even if plasma is supplied from the plasma generation space to the plasma processing space with high efficiency, the high-density plasma immediately diffuses in the plasma processing space and becomes homogeneous quickly. It is kept uniform.
Therefore, according to the present invention, it is possible to realize a plasma generating apparatus in which high-quality plasma processing is uniformly performed.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The plasma generator of the present invention achieved by such a solution is generally used by being mounted in an appropriate vacuum chamber. For this purpose, each mechanism such as the first mechanism in which the plasma processing space is formed and the second mechanism in which the plasma generation space is formed has a balance between the ease of incorporation into the vacuum chamber and the necessity of the degree of vacuum. In many cases, it is attached separately after being formed from the standpoint of, for example, but it is often closely attached and fixed, but part or all of the same or a single member such as a clad material is used. It may be integrally formed by processing or the like.
[0024]
Hereinafter, specific embodiments for implementing such a plasma generator will be described with reference to the first to sixth embodiments. However, the first to fifth embodiments embody the first solving means. In the sixth embodiment, the second solving means is embodied in addition to the first solving means.
[0025]
[First embodiment]
A specific configuration of the plasma generator according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a longitudinal sectional perspective view around the plasma generation space, and FIG. 1 is an enlarged view of one of the plasma generation spaces. FIG. 3 is a longitudinal sectional view including a plasma processing space.
[0026]
This plasma generator generally includes a first mechanism for securing a plasma processing space, a second mechanism for securing a plasma generation space, and an additional portion thereof, and an application for applying an electric field or a magnetic field to each plasma. And a circuit part.
In both the first mechanism and the second mechanism, when a rectangular object such as a liquid crystal substrate is processed, a main part is formed in a substantially rectangular shape, but here, a round object such as an IC silicon wafer is formed. A case where the main part is formed in a substantially round shape, a cylindrical shape, or an annular shape in order to process a processed object will be described (see FIG. 2).
[0027]
In the first mechanism, a metal anode portion 11 is disposed on the upper side, and a metal cathode portion 12 that is insulated on the upper surface is disposed on the lower side for mounting the workpiece 1 such as a wafer. A plasma processing space 13 for the low temperature plasma 10 is formed at the sandwiched position (see FIG. 3). In addition, the anode portion 11 is previously formed with a plurality of communication ports 14 penetrating therethrough and a processing gas supply port 15 opening toward the plasma processing space 13 is also formed (FIGS. 1 to 1). (See FIG. 3). In this example, the ratio of the cross-sectional area of the communication port 14 to the effective cross-sectional area of the plasma processing space 13, that is, the first ratio is 0.05. The processing gas B supplied to the plasma processing space 13 through the processing gas supply port 15 is supplied by mixing a suitable amount of diluent gas with a reactive gas such as CF gas or silane gas. It is also.
[0028]
The second mechanism mainly includes a plasma generation chamber 21 made of an insulating material such as ceramic. The plasma generation chamber 21 includes a plurality of plasma generation spaces 22 (two in FIG. 2 and four in FIG. 3). Are formed by concentric engraving. Thereby, the plasma generation space 22 is dispersed in a linear shape. The plasma generation chamber 21 is fixed in a state where the opening side (the lower surface in the longitudinal sectional view) of the plasma generation space 22 is in close contact with the upper surface of the anode portion 11. At that time, alignment is performed so that the opening of the plasma generation space 22 overlaps the communication port 14 of the anode portion 11. As a result, the plasma generation space 22 and the plasma processing space 13 are adjacent to and communicated with each other, and the plasma generation space 22 extends linearly along the adjacent surface to the plasma processing space 13. In this example, the ratio between the cross-sectional area of the communication port 14 and the cross-sectional area of the plasma generation space 22, that is, the second ratio is 0.5. Note that these ratio values can be freely changed as long as the magnitude relationship is not reversed.
[0029]
In the plasma generation chamber 21, a plasma gas supply path 23 is also formed in an annular shape and a linear shape by a gas distribution member 21 a attached deeper in the plasma generation sky 22 (upward in the longitudinal sectional view). Are connected by a large number of small holes, and the plasma generation space 22 is supplied with the plasma generating gas A from the bottom (upward in the longitudinal sectional view) to generate the high-density plasma 20 and the plasma processing space 14 through the communication port 14. It will be sent to 13. As the plasma generating gas A, an inert gas that does not chemically react, such as argon, is used.
[0030]
Further, the back surface (upper surface in the longitudinal sectional view) of the plasma generation chamber 22 is cut away so that the side wall and the bottom portion surrounding the plasma generation space 22 are left in the plasma generation chamber 21. Then, one permanent magnet 25b (lower side in the longitudinal sectional view of FIG. 1 and the like), the coil 24 and the other permanent magnet 25a (upper side in the longitudinal sectional view of FIG. 1 and the like) are stacked and packed in order. These magnetic members 25, that is, the pair of permanent magnets 25a and 25b, are packed between the concentric annular plasma generation spaces 22 to form an annular shape, but are divided into small pieces in order to cut off the undesired induced current in the annular shape. ing. A large number of permanent magnet pieces 25 are arranged along the side wall of the plasma generation space 22, thereby forming an annular magnetic circuit corresponding to the plasma generation space 22. Thereby, the magnetic member 25 is provided on the second mechanism side and attached to the plasma generation space 22 and extends linearly along the plasma generation space 22 and the adjacent surface of the plasma generation space 22 and the plasma processing space 13. It runs alongside the plasma generation space.
[0031]
The permanent magnet 25 has a height obtained by adding the coil 24 to the pair 25a, 25b substantially equal to that of the plasma generation space 22, and the magnetic poles are directed in the direction of the horizontal plasma generation space 22 (see FIG. 1). . The lower magnet 25b has a simple shape with a rectangular cross section, and is placed horizontally so as to be parallel to the top surface of the anode section 11 and the plasma generation chamber 21 which are cut out. The magnetization direction is also the same horizontal direction as the vertical symmetry axis in the cross section. The lower magnet 25b is made smaller.
[0032]
The upper magnet 25a is larger than that. This is also made of the same simple rectangular shape that is magnetized in the horizontal direction, but its both side surfaces are cut off diagonally to form a trapezoid whose section is inverted. And while the lower side is short, the upper side is made longer than the width of the lower magnet 25b. Thus, the magnetic member 25a has a side surface directed toward the plasma generation space 22 that is not parallel to the side wall surface of the plasma generation space and is not orthogonal to the adjacent surface of the plasma generation space and the plasma processing space. The shape is slanted. Although the magnetization direction is not inclined, the magnetic flux lines 26 from the vicinity of the upper side protrude strongly and widely based on the inclined shape, whereas the magnetic flux lines 26 from the vicinity of the lower side and the magnetic flux lines from the lower magnet 25b. 26 is relatively weak and narrow.
[0033]
The magnetic force state will be described in detail. Since the magnetic flux lines 26 that protrude from the lower half of the upper magnet 25a to the side in the figure pass near the coil 24 and return to the opposite side in the figure, the permanent line at the upper side in the figure. A magnetic peak is formed with the lower end of the magnet 25a at the top. A substantially similar magnetic peak is also formed at the upper end of the lower magnet 25b. Since the permanent magnet 25 is attached to both sides of the plasma generation space 22, four magnetic peaks are formed around the plasma generation space 22. Therefore, in the plasma generation space 22, a so-called magnetic basin (minimum point of magnetic field strength) surrounded by magnetic mountains is formed. Then, electrons are captured here. Although described as a potential field wind, it is actually a vector field, so it will be complicated to describe accurately. However, in general, electrons are sealed in a ring shape in the columnar / beam-like plasma generation space 22 as a whole. is there.
[0034]
Then, the magnetic flux lines 26 appearing from the upper half of the upper magnet 25a to the side in the figure are located on the opposite side while becoming dense in the plasma generation space 22 (upward in the figure) and in the plasma gas supply path 23. Returning, further, a part of the magnetic flux of the upper magnet 25a extends downward and wraps around the lower magnet 25b, so that the state of the overall magnetic force distribution in the longitudinal section is similar to an image in which the virtue is reversed. And tightly tightened in the back of the plasma generation space 22 and loosened and swelled in the middle of the plasma generation space 22 and squeezed slightly at the adjacent surface between the plasma generation space 22 and the plasma processing space 13, and finally the plasma It is in a state of being released at the processing space 13.
[0035]
Depending on how the magnetic fluxes from the upper and lower magnets 25a and 25b overlap, a plurality of locally small magnetic basins may be generated in addition to the above magnetic basin, which may undesirably contain electrons or plasma or plasma Although it causes a collision with the inner wall of the generation space 22, they are also located outside the plasma generation space 22. Then, the magnetic circuit surrounding the large magnetic basin at the center of the plasma generation space 22 is inclined such that the upper magnetic field is stronger and the lower magnetic field is weaker. The high-density plasma 20 composed of components that are not ionized or have a large mass even if ionized is likely to flow out from the plasma generation space 22 to the plasma processing space 13.
[0036]
The application circuit unit is divided into a first application circuit centered on the RF power source 31 and a second application circuit centered on the RF power source 32.
The RF power supply 31 has a variable output power, and applies an alternating electric field to the grounded anode part and generates a bias voltage, so that its output is sent to the cathode part 12 via a blocking capacitor. (See FIG. 3). For this, a frequency of 500 KHz to 2 MHz is often used. As a result, the first application circuit applies an electric field that contributes to the enhancement of the low temperature plasma 10 to the plasma processing space 13 to some extent.
[0037]
The RF power source 32 also has variable output power, and drives both coils 24 sandwiching the plasma generation space 22 to apply an alternating magnetic field to the plasma generation space 22 (see FIG. 2). The maximum output power is large, and the frequency is often set to 13 MHz to 100 MHz. Thus, the second application circuit applies a magnetic field that contributes to generation and strengthening of the high-density plasma 20 to the plasma generation space 22.
[0038]
The use mode and operation of the plasma generator of the first embodiment will be described with reference to the drawings. FIG. 4 is a longitudinal sectional view showing a state where the vacuum chamber is mounted.
[0039]
Prior to use, the cathode 12 of the plasma generator is installed at the center of the box-shaped vacuum chamber body 2 with the top opened and supported by support legs 12a. The vacuum chamber main body 2 has a vacuum chamber lid 3 attached to the top so that it can be opened and closed, and a vacuum pump 5 such as a turbo pump is connected to the bottom or side through a variable valve 4 for vacuum pressure control. ing. The vacuum chamber main body 2 is attached with the plasma generation chamber 21 and the anode 11 and can be cooled with water. When the vacuum chamber main body 2 is closed, the inside of the vacuum chamber main body 2 as well as the plasma processing space 13 and the plasma generation space 22 are Sealed. Then, when the vacuum pump 5 is operated and the supply of the plasma gas A through the plasma gas supply path 23 and the supply of the processing gas B through the processing gas supply port 15 are appropriately started, the cathode 12 Preparation for plasma processing is performed on the workpiece 1 mounted on the substrate.
[0040]
Next, when the RF power source 32 is operated, an RF electromagnetic field is applied to the plasma generation space 22 via the coil 24, and the electrons of the plasma gas A are vigorously moved. At this time, the electrons stay for a long time in the plasma generation space 22 by the action of the magnetic circuit by the permanent magnet piece 25, and fly around in the annular space while spirally exciting the plasma gas A. In this way, the high-density plasma 20 is generated, but since the electrons sealed in the plasma generation space 22 contain a large amount of high energy of 10 to 15 eV or more that greatly contributes to ionic species generation, the high-density plasma 20 Has a high ratio of ionic species components.
[0041]
In the high-density plasma 20 expanded in the plasma generation space 22, the radical species and ionic species components in particular try to jump out of the plasma generation space 22 due to the expansion pressure. When it is pushed back to the center and the expansion pressure increases, it flows out from the communication port 14 having a relatively weak magnetic force. When the expansion pressure is further increased, it quickly flows out from the communication port 14 to the plasma processing space 13. At that time, since the collision is suppressed by being pushed back against the inner surface and the bottom surface of the side wall of the plasma generation space 22 having a relatively strong magnetic force, energy loss due to the collision with the wall surface is reduced, and plasma generation efficiency is increased. Most of it flows out through the communication port 14. Thus, the high-density plasma 20 generated in the plasma generation space 22 is efficiently carried to the plasma processing space 13 based on the expansion pressure and the gradient of the magnetic force distribution.
[0042]
When the RF power source 31 is operated, an RF electric field is also applied to the plasma processing space 13 via the anode part 11 and the cathode part 12. Since there is no magnetic circuit or the like for containing electrons, high-density plasma cannot be produced even when the processing gas B or the like is excited. When only the power from the RF power source 31 is used, the low temperature plasma 10 has a small number of electrons having energy of 10 to 15 eV or more, and therefore the ratio of the radical species component becomes high. However, in the case of the low-temperature plasma 10 in this apparatus, since the above-described high-density plasma 20 is mixed, the ratio of the actual radical species component to the ionic species component is any ratio between the two.
[0043]
When the output of the RF power source 32 is increased, electrons of 10 to 15 eV or more in the plasma generation space 22 increase. And the production amount of the high-density plasma 20 increases. As a result of the mixing, the ratio of the ion species component is raised in the low temperature plasma 10. On the other hand, when the output of the RF power source 32 is lowered, electrons of 10 to 15 eV or more in the plasma generation space 22 are reduced. And the production amount of the high-density plasma 20 decreases. As a result of the mixing, the ratio of the ion species component in the low temperature plasma 10 is lowered.
[0044]
Furthermore, when the output of the RF power supply 32 is slightly lowered while the output of the RF power supply 31 is increased, the following is obtained. First, as the output of the RF power source 31 is increased, the electron density in the plasma processing space 13 shifts to a higher density and higher energy side, and low-temperature plasma in the plasma processing space 13 increases. This increases the radical concentration there, but at the same time increases the ion ratio slightly. Next, as the output of the RF power source 32 is reduced, the electron density in the plasma generation space 22 is shifted to a low density and low energy side, and the high density plasma in the plasma generation space 22 is slightly reduced. As a result, the radical concentration and the ion ratio are lowered. However, since the high energy component is originally large, the ion ratio is greatly lowered even if the output is slightly reduced. When such a high-density plasma 20 is mixed with the low-temperature plasma 10 in the plasma processing space 13, the increase or decrease in the ion ratio is almost offset, while the radical concentration increases. That is, the plasma concentration of the low temperature plasma 10 is increased without much changing the ratio of the radical species component and the ion species component. Similarly, when the outputs of the RF power sources 31 and 32 are increased or decreased in the opposite direction, the plasma concentration of the low temperature plasma 10 is lowered.
[0045]
Thus, in the low temperature plasma 10, the ratio between the radical species component and the ion species component is easily variably controlled over a wide range. In this apparatus, since the cross-sectional area of the plasma generation space 22 is much smaller than the cross-sectional area of the plasma processing space 13 and the first ratio is much smaller than the second ratio, the high-density plasma 20 In addition to being quickly sent out from the plasma generation space 22 to the plasma processing space 13, the amount of gas that flows back into the plasma generation space 22 from the plasma processing space 13 is small so that the processing gas B is directly excited by the high-density plasma 20. It is almost never decomposed or ionized until it is undesired.
Furthermore, since the upper magnet 25a having a trapezoidal cross section and the lower magnet 25b having a rectangular cross section have a simple convex polygon, they can be easily formed by processing.
[0046]
[Second embodiment]
A second embodiment of the plasma generator of the present invention will be described. FIG. 5 is a longitudinal sectional view of the main part, and corresponds to FIG. 1 described above.
The plasma generator differs from that of the first embodiment in that a pair of upper magnets 25c and 25d are provided instead of the upper magnet 25a. The lower magnet 25b and the coil 24 are the same as described above.
[0047]
The upper magnet 25c is a vertically long, simple rectangular shape, and is magnetized so that the magnetization direction is horizontal in a straight state. The same applies to the upper magnet 25d, but they are arranged side by side when installed between the concentric annular plasma generation spaces 22, and are opposite to each other so that the lower part is narrow and the upper part is wide in a V shape. Set diagonally. As a result, these magnetic members 25c and 25d have their side surfaces directed toward the plasma generation space 22 not parallel to the side wall surface of the plasma generation space, but orthogonal to the adjacent surfaces of the plasma generation space and the plasma processing space. Further, the magnetization direction is not horizontal, and both the shape and the magnetization direction are inclined.
[0048]
In this case, the upper magnets 25c and 25d sandwiching the plasma generation space 22 from both sides and viewed from both sides are narrow in the shape of a letter C and wide in the lower part. While the lines are strong and dense, the magnetic flux lines are relatively weak and rough below the anode portion 11 side. Such a magnetic force inclination state is further emphasized by the fact that the magnetic flux lines come out obliquely from the upper magnets 25c and 25d.
[0049]
Thus, also in this case, the high-density plasma generated in the plasma generation space 22 is efficiently conveyed to the plasma processing space 13 based on the expansion pressure and the gradient of the magnetic force distribution.
In addition, since not only the lower magnet 25b but also the upper magnets 25c and 25d have a simple shape with a rectangular cross section, they can be easily manufactured.
[0050]
[Third embodiment]
A third embodiment of the plasma generator of the present invention will be described. FIG. 6 is a longitudinal sectional view of the main part, and corresponds to FIG. 5 described above.
The plasma generator differs from that of the second embodiment in that a magnetic body 25e is interposed between the upper magnets 25c and 25d.
The magnetic body 25e is preferably a magnet from the viewpoint of strengthening the magnetic force, but from the viewpoint of workability and cost reduction, a material having a high magnetic susceptibility such as soft iron is used, and the upper magnets 25c and 25d opened in a V shape are used. It is formed in a wedge shape so as to be filled with no gap.
[0051]
In this case, since the magnetic resistance between the upper magnets 25c and 25d is weakened by the magnetic body 25e and the loss of the magnetic force there is suppressed, the magnetic force enhancement can be achieved without impairing the manufacturability of the magnetic member. .
[0052]
[Fourth embodiment]
A fourth embodiment of the plasma generator of the present invention will be described. FIG. 7A is a longitudinal sectional view of the main part, and corresponds to FIG. 5 described above.
The plasma generator differs from that of the second embodiment in that the upper magnets 25c and 25d having a rectangular cross section are replaced by the upper magnets 25f and 25g having a triangular cross section.
[0053]
The pair of upper magnets 25f and 25g are made of a magnet having a rectangular cross section (see FIG. 7B), but the magnet having a rectangular cross section is divided along a diagonal line and then turned over (see FIG. 7C). , By appropriately rotating each segment so that the right angle is diagonally upward (see FIG. 7 (d)), and finally bringing the hypotenuses to face each other and vertically (see FIG. 7 (e)), Easy to manufacture. In addition, since the acute angle part of the divided | segmented magnet piece is easy to chip, it is good to give appropriate chamfering.
[0054]
In this case, only by installing the upper magnets 25f and 25g between the plasma generation spaces 22 while maintaining the posture, the side surfaces are inclined from the vertical by an angle corresponding to the diagonal inclination angle, and the magnetization direction is also inclined from the horizontal. To do. In this way, a magnetic member whose shape and magnetization direction are both tilted is realized without impairing both the magnetic force and manufacturability of the magnetic member. Moreover, the magnetization work is easy because it can be done without tilting with respect to the rectangular magnet before division.
[0055]
[Fifth embodiment]
A fifth embodiment of the plasma generator of the present invention will be described. FIG. 8 is a longitudinal sectional view of the main part, and corresponds to FIG. 5 described above.
The plasma generator differs from that of the second embodiment in that the side wall 21b in the back of the plasma generation space 22, that is, the upper side in the figure is formed obliquely, and the plasma generation space 22 becomes narrower from the middle to the back. It is a point.
[0056]
In this case, if the upper magnets 25c and 25d arranged in parallel are viewed from the center, the upper magnets 25c and 25d are opened by the inclined outer surface 21b of the plasma generation space 22 so that the upper magnets 25c and 25d are wider apart from each other. Since the inclination of 25d can be increased, the efficiency of plasma supply from the plasma generation space 22 to the plasma processing space 13 due to the inclination of the magnetic member can be improved.
[0057]
[Sixth embodiment]
A sixth embodiment of the plasma generator of the present invention will be described. FIG. 9 is a longitudinal sectional view of the main part, and corresponds to FIG. 8 described above.
The plasma generator differs from that of the fifth embodiment in that the inclined outer surface 21b is enlarged to the entire side surface of the plasma generation space 22 and the inner side wall of the plasma generation space 22 correspondingly. The other is that the entire surface is an inclined inner side surface 21c, and that the communication port 14 is greatly expanded, and the inclined inner side surface 11b is an extended surface of the inclined inner side surface 21c. Thereby, the plasma generation space is expanded toward the plasma processing space including the adjacent portion and the communication portion.
[0058]
In this case, the inclination of the upper magnets 25c, 25d is further increased, and the plasma supply efficiency from the plasma generation space 22 to the plasma processing space 13 due to the inclination of the magnetic member is further enhanced. When flowing out into the plasma processing space 13, the air is spread from the beginning along the expansion of the inclined inner side surface 21 c and the inclined inner side surface 11 b without being throttled by the communication port 14 (see the two-dot difference line in FIG. 9).
[0059]
Thus, since the high-density plasma flows obliquely into the portion immediately below the processing gas supply port 15 having a low plasma density and is quickly mixed and diffused, the low-temperature plasma 10 in the plasma processing space 13 is uneven even in the vicinity of the anode portion 11. There is little, and it becomes a more uniform state in the vicinity of the cathode part 12 where the workpiece 1 is placed.
As a result, even if a good quality plasma is efficiently supplied, the distribution state of the plasma is kept uniform, so that a good quality plasma treatment is efficiently performed.
[0060]
【The invention's effect】
As is apparent from the above description, in the plasma generating apparatus of the first solving means of the present invention, the shape and arrangement of the plasma generating space and the magnetic member are devised and the plasma generating space and the plasma processing space are separated. By changing the cross-sectional area ratio and directing the plasma flow based on the magnetic force of the magnetic member without impairing the workability of the magnetic member, the flow of gas from the plasma processing space to the plasma generation space is prevented. In addition, there is an advantageous effect that a plasma generator capable of supplying high-quality plasma and efficiently supplying plasma from the plasma generation space to the plasma processing space can be realized.
[0061]
Further, in the plasma generating apparatus of the second solving means of the present invention, the shape of the plasma generating space is devised to change the cross-sectional area ratio between the plasma generating space and the plasma processing space and the plasma processing from the plasma generating space. Since the plasma spreads in the form of a fan or a trumpet when it flows into the space, it is possible to realize a plasma generating apparatus that can perform high-quality plasma processing uniformly even if the plasma supply is performed with high efficiency. There is an effect.
[0062]
[Brief description of the drawings]
FIG. 1 is an enlarged vertical cross-sectional view of one plasma generation space in the first embodiment of the plasma generation apparatus of the present invention.
FIG. 2 is a longitudinal sectional perspective view around a dispersed plasma generation space.
FIG. 3 is a longitudinal sectional view including a plasma processing space.
FIG. 4 is an overall longitudinal sectional view including a vacuum chamber.
FIG. 5 is an enlarged vertical cross-sectional view of the plasma generation space of a second embodiment of the plasma generator of the present invention.
FIG. 6 is an enlarged longitudinal sectional view of a plasma generation space in a third embodiment of the plasma generator of the present invention.
FIG. 7 is an enlarged longitudinal sectional view of a plasma generation space of a fourth embodiment of the plasma generator of the present invention.
FIG. 8 is an enlarged longitudinal sectional view of a plasma generation space in a fifth embodiment of the plasma generation apparatus of the present invention.
FIG. 9 is an enlarged longitudinal sectional view of a plasma generation space in a sixth embodiment of the plasma generation apparatus of the present invention.
FIG. 10 is an example of a magnetic member having a dent in its cross-sectional shape.
FIG. 11 shows an example in which a magnetic member is divided and further separated into upper and lower parts.
FIG. 12 is another example in which a magnetic member is divided and further separated into upper and lower parts.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 To-be-processed object 2 Vacuum chamber main-body part 3 Vacuum chamber cover part 4 Variable valve 5 Vacuum pump 10 Low temperature plasma 11 Anode part (1st mechanism; 1st application circuit)
11b Inclined inner surface 12 Cathode part (first mechanism; first application circuit)
13 Plasma processing space 14 Communication port 15 Processing gas supply port 20 High-density plasma 21 Plasma generation chamber (second mechanism)
21a Gas distribution member (second mechanism)
21b Inclined outer surface 21c Inclined inner surface 22 Plasma generation space 23 Plasma gas supply path 24 Coil (second application circuit)
25 Permanent magnet (Magnetic member for magnetic circuit)
25a Upper magnet (magnetic member with side surface inclined)
25b Lower magnet 25c Upper magnet (magnetic member installed at an inclination)
25d Upper magnet (magnetic member installed at an angle)
25e Magnetic body 25f Upper magnet (magnetic member whose shape and magnetization direction are both inclined)
25g Upper magnet (magnetic member with both shape and magnetization direction tilted)
26 Magnetic flux lines (magnetic circuit)
31 RF power supply (first application circuit)
32 RF power supply (second application circuit)
A Argon gas (non-reactive gas, plasma generating gas)
B CF gas (reactive gas, processing gas)

Claims (3)

A first mechanism in which a plasma processing space is formed; and a second mechanism attached to or integrated with the first mechanism to form a plasma generation space, wherein the plasma generation space is the plasma processing space. In a plasma generator adjacent to and communicating with a space,
The plasma generation space extends linearly along a surface adjacent to the plasma processing space;
And a permanent magnet member is arranged across the plasma generation space,
The plasma generating apparatus, wherein a side surface of the permanent magnet member facing the plasma generation space is inclined so as to be away from a central axis in a cross section of the plasma generation space, as the side is closer to the plasma processing space. The permanent magnet member is composed of two permanent magnet members having a triangular or rectangular cross section, and the side facing the plasma generation space in the cross section of each permanent magnet member is in relation to the central axis in the cross section of the plasma generation space. The plasma generator according to claim 1, wherein the plasma generator is disposed in a V shape so as to be inclined with respect to the central axis as it is closer to the plasma processing space .   The plasma generation apparatus according to claim 1, wherein the plasma generation space is widened toward the plasma processing space.

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