JPH11283926A - Plasma processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processor, capable of generating high density plasma provided with a uniform plasma density over a large area by the combination of a static coupling mechanism and the confinement effect of electrons by a cusp magnetic field. SOLUTION: This plasma processor is constituted of a reactor 10 which is provided with a plasma source and a substrate holder 15. The reactor 10 is constituted of a top plate 11 of a non-magnetic metal, a bottom plate 13 of a metal and a cylindrical type side wall 12 provided with a ceramic part at least on a part. The substrate holder 15 is provided on the bottom plate 13 and a plurality of magnets 21 are arranged separately on the top plate 11. The polarity of the magnets to the inside of the reactor is alternately changed and the magnets generate the cusp magnetic field near the inner surface of the top plate. This constitution is applied to one or two power supply systems.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus and, more particularly, to ions, electrons, neutral radicals, and ultraviolet rays useful for processing chemical vapor deposition or etching of micron-scale elements on integrated circuits in the semiconductor industry. And a plasma processing apparatus having an improved plasma source capable of supplying visible light.

[0002]

BACKGROUND OF THE INVENTION With the development of 300 mm Si (silicon) wafers (substrates) into the semiconductor industry, there is a great demand for high density plasmas having a uniform plasma density over the entire surface of the substrate to be processed. For example, 200
Even though increasing the size of existing plasma devices designed to process mm wafers is one approach to satisfying the above requirements, the hardware difficulties of existing plasma devices do not. Hinder you from doing so. This is illustrated by using two conventional plasma sources according to FIGS. 15 and 16, and these two plasma sources are mainly used in a conventional plasma processing apparatus for a 200 mm wafer.

[0005] One example of the conventional plasma source shown in FIG. 15 includes a reaction vessel 50 made of metal, and this reaction vessel is formed by a top plate 51, a bottom plate 52 and a cylindrical side wall 53. In the reaction vessel 50,
The substrate holder 54 on which the wafer or substrate 61 is placed is located at a lower position near the bottom plate 52, and the substrate holder is parallel to both the top plate 51 and the bottom plate 52. The substrate holder 54 is electrically insulated from the reaction container 50 by an insulator 57, and a high-frequency current is supplied by a high-frequency power supply 55 through a matching circuit 56 and a capacitor 60. The reaction vessel 50 is a wire 5
8 is electrically grounded. According to the configuration of the reaction vessel 50, plasma is generated in the space 59 between the top plate 51 and the substrate holder 54 based on the electrostatic coupling of high-frequency power. The plasma source shown in FIG. 15 is a single RF power supply system.

FIG. 16 shows another example of a conventional plasma source. In this example, the configuration of the reaction vessel 70 is the same as that of the reaction vessel 50 shown in FIG.
And almost the same. The reaction vessel 70 also includes a top plate 51, a bottom plate 52, and a cylindrical side wall 5.
3 and made of metal. Further, the reaction container 70 is provided with a substrate holder 54 on which a substrate 61 is placed, a high-frequency power supply 55, a matching circuit 56, a capacitor 60, an insulator 57, and wires 58. The high-frequency electrode 71 is disposed slightly below the top plate 50 parallel to the substrate holder 54. The upper high-frequency electrode 71 is electrically insulated from the reaction container 70, and receives a high-frequency current from a high-frequency power supply 72 through a matching circuit 73. The frequency of the high-frequency current supplied to the high-frequency electrode 71 is usually
Is the same as, or higher than, the frequency supplied to The plasma is applied to the high-frequency electrode 71 and the substrate holder 54.
Generated by electrostatic coupling of high frequency power.
The plasma source shown in FIG. 16 is a two-frequency power supply system.

[0005]

One of the main problems of the conventional plasma sources shown in FIGS. 15 and 16 is that the efficiency of power transmission from the high frequency power supply (55, 72) to the plasma is low. This is due to a significant portion of the high frequency power used being wasted in unwanted ion acceleration. This is a unique attribute of the capacitively coupled plasma. This results in a low plasma density. Further, since processing 300 mm wafers is tied to 0.25 micron technology, it is taken into account that chemical processing must be performed at low pressures, eg, about 10 mTorr. However, the plasma density of the electrostatically coupled plasma decreases further with decreasing pressure. Thus, it is not possible to achieve the higher processing speeds required for an economically viable device.

[0006] If the diameter of the substrate to be processed is small, for example 200 mm, higher RF power can be applied to increase the plasma density. However, if the diameter of the substrate to be processed is 300 mm, the applied radio frequency power must be increased by at least 2.25 times to maintain the same power density. This is because the surface area of a 300 mm wafer is 2.25 times larger than the surface area of a 200 mm wafer. Therefore, the requirement for high frequency power to maintain the desired power density will be limited to some applications.

In addition, a 200 mm wafer processing apparatus is
When increasing its scale for use as a 00 mm wafer processing apparatus, the pumping speed in the processing chamber must be increased as well to maintain the same reaction rate.

[0008] Due to the difficulty in the above hardware,
The conventional plasma source for a 200 mm wafer shown in FIGS. 15 and 16 cannot simply be scaled up for a 300 mm wafer plasma source. In order to avoid these problems, it is important to design a plasma source that produces a higher plasma density over a 300 mm diameter area. There must also be higher plasma uniformity over the entire surface of the 300 mm wafer. Because, some semiconductor processing methods, such as the plasma-assisted anisotropic etching method, require better than 95% plasma uniformity across the surface of the substrate to be processed.

It is an object of the present invention to create a magnetically enhanced and electrostatically coupled planar plasma for use in the chemical vapor deposition and etching of large area substrates used in the semiconductor industry. It is an object of the present invention to provide a plasma processing apparatus capable of generating high-density plasma having a uniform plasma density over a large area by a combination of the above and a cusp magnetic field for confining electrons.

It is still another object of the present invention to realize a low aspect ratio plasma source.

[0011]

In order to achieve the above object, a plasma processing apparatus according to the present invention includes a plasma source and a substrate holder, and includes a top plate made of a non-magnetic metal and a bottom plate made of a metal. A substrate and a reaction vessel arranged above the bottom plate, and a reaction vessel arranged above the bottom plate and arranged separately outside the top plate. A plurality of magnets, wherein the polarity of the magnet toward the inside of the reaction vessel is alternately changed, and the magnets include a plurality of magnets that generate a cusp magnetic field with a magnetic flux closed at a location near the inner surface of the top plate. Be prepared.

According to the invention described above, the arrangement of the magnets on the top plate creates the desired cusp field below the top plate. In the cusp magnetic field, the magnetic flux lines are generated in a space near the inner surface of the top plate, and all the magnetic flux lines are closed to form a loop.
The cusp field controls the electrons and enhances the plasma density of the capacitively coupled planar plasma which produces a plasma having a uniform plasma density over a large area.

In the above configuration, the top plate has a flat circular shape, and the magnet is directly fixed to the outer surface of the flat top plate.

In the above configuration, the top plate has a dome shape. The dome top plate can be used with cusp fields of different dimensions.

In the above configuration, the magnets are arranged on the inner surface of the dome-shaped cover existing so as to cover the dome-shaped top plate. The cusp field created in the reaction vessel by the arrangement of magnets can be of a desired size.

In the above arrangement, the top plate is electrically insulated from other parts of the reaction vessel by being placed on the part made of a dielectric material.

In the above-described configuration, high frequency power is preferably supplied to the top plate. Further, it is also preferable to adopt a structure in which high-frequency power is supplied to the substrate holder while high-frequency power is not supplied to the top plate. In this configuration, the top plate is in an electrically insulated state or is in an electrically grounded state.

In the above arrangement using a flat top plate, the magnets are preferably located in the peripheral area of the top plate, leaving a magnetic field-free area in the center of the top plate.

In the above-described configuration using the dome-shaped top plate, the dome-shaped cover having the magnet fixed to the inner surface is rotated.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments will be described below with reference to the accompanying drawings. Details of the present invention will be made clear through the description of this embodiment.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an overall configuration of a plasma source used in the plasma processing apparatus according to the first embodiment. In particular, FIG. 1 shows the structure on the upper wall (outside) of the plasma source and the structure on the inside. Reaction vessel 1 for forming plasma source
The zero geometry is first described. The reaction vessel 10 includes a top plate 11, a cylindrical side wall 12, and a bottom plate 13. Lower portion 12b of cylindrical side wall 12
The bottom plate 13 is made of metal, for example, stainless steel or Al (aluminum).
The upper part 12a of the cylindrical side wall 12 is made of ceramic (dielectric substance). The top plate 11 has a flat circular shape, and the top plate 11 made of a non-magnetic metal, for example, Al, is placed on the upper portion 12a of the cylindrical side wall 12, so that the other portions of the reaction vessel 10 Electrically insulated from parts. The top plate 11 functions as an electrode when generating plasma. Upper part 12a and lower part 12b of cylindrical side wall 12
Have the same diameter. The value of the diameter is not critical and can vary between 40 cm and 60 cm. The height of the ceramic part (12a) of the cylindrical side wall 12 is likewise not critical and lies in the range 1 cm to 5 cm. The lower portion 12b of the cylindrical side wall 12 and the bottom plate 13 are electrically grounded through a ground wire 14. The diameter of the top plate 11 corresponds to the diameter of the cylindrical side wall 12.

A substrate holder 15 attached to the bottom plate 13 exists in the internal space of the reaction vessel 10. The substrate holder 15 is coupled to a well-known high-frequency power supply 8 through, for example, a matching circuit 9. The high frequency power supply 8 is arranged outside the reaction vessel 10. The wafer or substrate 17 to be processed is arranged on a substrate holder 15. Reference numeral 18 indicates a gas exhaust port used as an exhaust port. The gas exhaust port 18 is connected to a well-known exhaust device (not shown). The top plate 11 is connected to the high frequency power supply 1 through a matching circuit 20.
9. The top plate 11 is supplied with necessary high frequency power from a high frequency power supply 19.

The substrate holder 15 arranged below the reaction vessel 10 is parallel to the bottom plate 13. The substrate holder 15 is electrically insulated from the reaction vessel 10 by an insulator 16. FIG. 1 shows a substrate holder 1 through a matching circuit 9.
Although the high-frequency power supply 8 connected to 5 is shown, the substrate holder 15 may or may not be connected to a high-frequency power supply depending on the purpose of application. If high frequency power is applied to the substrate holder 15, the frequency of the high frequency power is usually lower than the frequency of the high frequency power supplied to the top plate 11 by the high frequency power supply 19. However, for some applications, the two high frequencies of the high frequency power supplies 8, 19 may be the same. Otherwise, the substrate holder 15 is grounded.

As shown in FIGS. 1, 3 and 4, a plurality of magnets 21 are arranged on the top plate 21 and are fixed to the outer surface of the top plate 11. Since the magnets 21 are arranged in a symmetrical positional relationship, only a quarter area of the top plate 11 is shown in a plan view in FIG. The magnet 21 is arranged on the outer surface of the top plate 11 so as to generate a cusp magnetic field inside the top plate 11. In this case, strictly speaking, the cusp magnetic field 23 is called a point-cusp magnetic field determined by the four magnets 21. The only requirement for creating a point cusp field is that each adjacent magnet must have the opposite polarity at the pole towards the top plate 11. This means that the polarity of the magnet toward the inside of the reaction vessel changes alternately. For example, as shown in FIG.
1 are arranged at respective corners (corners) of a rectangle 22 drawn by a dotted line. 3 and 4, N and S mean the magnetic polarity of the magnet 21. The spacing (distance) between any two adjacent magnets is not critical and can vary from 2 cm to 10 cm depending on the strength of the magnet and the diameter of the top plate 11. The arrangement of the magnets 21 creates a point cusp magnetic field 23 with a cusp 23a created between two adjacent such magnetic fields 23 below the top plate 11, as shown in FIG. Reference numeral 23b indicates a magnetic flux line. The magnetic flux line 23b emerging from the pole bends directly to the nearest opposite pole. Thus, a point cusp magnetic field 23 is formed. The point cusp magnetic field 23 generated in the space near the inner surface of the top plate 11 has a magnetic flux line 23b closed in a loop.
To form Many magnetic flux loops are formed near the inner surface of the top plate 11, and as a result, a cusp 23a of the magnetic field is formed. The uniformity of the plasma below the top plate 11 changes depending on the arrangement structure formed by the magnets 21 on the top plate 11.

The shape of the magnet 21 is preferably a cube or a column having a square or circular cross section, respectively. As shown in FIG. 2, each of the magnets 21 has a hole 11 a formed on the outer surface of the top plate 11.
Is placed inside. For example, the thickness of the top plate 11 is approximately 20 mm, and the depth of the hole 11a is approximately 17 mm.
mm. Therefore, the bottom surface of the magnet 21 approaches the internal space of the reaction vessel 10.

The sectional shape of the magnet 21 is circular or square. If the cross section of the magnet 21 is circular, its diameter is in the range of 10 mm to 40 mm. The value of the diameter is not important. If the cross-sectional shape of the magnet 21 is square, dimensions corresponding to those of a magnet having a circular cross-sectional shape are selected.
The height of the magnet 21 is also not critical,
m to 10 mm. The magnetic strength of the magnet 21 is approximately 50 gauss below the top plate 11.
(Gauss) to a magnetic field strength of 500 Gauss.

In addition, a circular gas passage 24 is formed inside the top plate 11 as shown in FIG. The circular gas passage 24 is connected to a gas supply source (not shown) through a gas supply pipe 25 and
Has a plurality of gas introduction holes 6 on the inner surface thereof. The process gas supplied by the gas supply source is a circular gas passage 2
4 and the gas introduction hole 26 are introduced into the internal space of the reaction vessel 10. The process gas is first supplied to the circular gas passage 24 and then introduced into the internal space of the reaction vessel 10 through several gas introduction holes 26.

The internal pressure of the reaction vessel 10 is controlled by adjusting the gas flow rate and adjusting a well-known variable orifice (not shown) located at the gas exhaust port 18. The internal pressure of the reaction vessel 10 is changed, for example, in the range of 1 mTorr to 100 mTorr. The appropriate pressure is determined by the type of application.

The frequency of the high frequency power supply 19 is about 1 MHz
To 100 MHz, typically 13.56M
It operates at a frequency of Hz. The high frequency power supply 19 typically has a low impedance, typically around 50 ohms, and can produce a current of around 10 to 50 amps. The output of the high-frequency power supply 19 is supplied to the center of the top plate 11 through the matching circuit 20.

If high frequency power is supplied to the substrate holder 15 by the high frequency power supply 8, the frequency of the high frequency power is in the range of 100 kHz to 15 MHz. This high frequency power supply 8 also has a low impedance, typically about 50 ohms, and can produce a current of about 1 to 50 amps. The high frequency power is applied to the substrate holder 15 through the matching circuit 9.

Next, the mechanism of plasma generation in the reaction vessel 10 having the above-described plasma source will be described. When the high-frequency current 19a is supplied from the high-frequency power supply 19 to the top plate 11, plasma is generated by a mechanism of electrostatic coupling of the high-frequency power. The electrons in the plasma then undergo cyclotron rotation due to the presence of a point cusp magnetic field 23 created by a magnet 21 located on top plate 11. This increases the length of the passage of the electrons, thereby resulting in a higher ionization rate of the process gas. In addition, the collision of the top plate 11 with electrons and ions is caused by the point cusp magnetic field 23.
Is partially suppressed by Therefore, the presence of the magnetic field 23 results in an increase in the plasma density.

Generally, in the absence of a magnetic field, the plasma created by the mechanism of electrostatic coupling between the two parallel plates has a higher radial uniformity. In the presence of a magnetic field, this plasma uniformity changes. The magnet 21 disposed on the top plate 11 in the first embodiment forms a point cusp magnetic field 23 below the top plate 11. The plasma density is maximum where the intensity of the magnetic field 23 existing parallel to the top plate 11 is maximum. Similarly, where the intensity of the magnetic field 23 existing parallel to the top plate is minimum, the plasma density is low. Therefore, the plasma density becomes maximum and minimum near the top plate 11. However, as these maxima and minima of the plasma density are close to each other, diffusion at a shorter distance from the top plate 11 on the downstream side creates plasma uniformity. Further, since the magnets 21 are alternately arranged to have opposite polarities, the magnetic flux lines 23 b of the point cusp magnetic field 23 bend at a short distance from the inner surface of the top plate 11. Therefore, an environment without a magnetic field at a distance closer to the top plate 11 is obtained.

For the purpose of obtaining a uniform plasma density, another arrangement of the magnets 21 different from the above-described configuration can be found. For example, the interval between two adjacent magnets near the center of the top plate 11 can be made larger than the interval between two adjacent magnets near the peripheral portion, or, as shown in FIG. The magnet in the center can be removed. Here, the magnet 21 is arranged in a band shape (as a band) only at a position close to the peripheral portion of the top plate 11. Radius r ₁ is the radius of the top plate 11, the radius r ₂ is the radius of the circular area magnet is not arranged. Due to these arrangements, the number of magnets 21 near the center of the top plate 11 is smaller than the number near the peripheral edge. That is, the top plate 11
Has a lower magnetic flux density at the center and at the periphery thereof than at the portion near the periphery.

Next, experimental results of plasma processing based on the plasma processing apparatus using the above-described plasma source will be described. Experiments are performed on two different magnet arrangements (I) and (II). The arrangement of these magnets 21 and their magnetic field strengths have already been described. In the magnet arrangement (I), the magnets 21 are arranged on the top plate 11 with a uniform density as shown in FIG. In the magnet arrangement (II), the magnet 21 is connected to the top plate 11 as shown in FIG.
Are arranged only in the region between the radii r ₁ and r ₂ of the The radius of the top plate 11 indicated by r ₁ is, for example, 240 mm. The value of the radius r ₂ is, for example, 110
mm. 10mm x 10mm x in both cases
An Sm-Co magnet having a size of 12 mm was used. The magnets 21 were arranged on the top plate 11 at a distance of 40 mm from each other. Magnet 2
1 has a magnetic field intensity of 915 kA / m (B
_r = 12.1 kGauss). The pattern and intensity of the magnetic field below the top plate 11 were calculated by computer simulation, and the data was obtained as shown in FIGS.
Indicated by 0.

FIGS. 6 and 7 show the structure of the magnet array used in the computer simulation and the pattern of the generated magnetic flux. A rectangular area 31 drawn by a thick line in FIG. 6 is used for computer simulation. As shown in FIG. 7, many arrows 32 in the enlarged rectangular area 31 indicate the strength and direction of the magnetic field in the XY plane. A plane parallel to the top plate 11 is treated as an XY plane. An axis perpendicular to the XY plane is treated as a Z axis. The lower surface of the magnet 21 is regarded as Z = 0 mm. Z is measured from the lower surface of the magnet 21 toward its lower side (downstream side).

FIGS. 8, 9 and 10 show an enlarged rectangular area 3.
1, Z = 20 mm and 30 m on the XY plane
3 shows the contour 33 of the magnetic flux at m and 50 mm. As shown in FIGS. 8 to 10, the strength of the magnetic field decreases as the distance increases from the magnet 21 toward the downstream side. When Z = 50mm, the point
The strength of the cusp field will be less than 5 Gauss. Therefore, if the substrate 17 is placed in a place where Z ≧ 50 mm, the magnetic field 23 has no effect on the reaction processing occurring on the surface of the substrate 17.

Regarding the magnet arrangements (I) and (II),
The plasma operates at a frequency of 13.56 MHz.
Generated by applying 00 W RF power. The pressure inside the reaction vessel 10 was set at 2 mTorr. Argon at a flow rate of 100 sccm was used as the plasma gas. The ion current density of the plasma was observed by using a Langmueller probe at a distance of 75 mm from the top plate 11, and the observed graph is shown in FIG. The non-uniformity of the radial plasma density _{± [(I max -I min)} / (I max +
I _min )] (%) and the data are given in Table 1 shown in FIG. Where I _max and I _max
min is the maximum ion current density and the minimum ion current density.

The result of the above experiment is that if the top plate 1
It is noted that if the lower point cusp field pattern of 1 is uniform, the center of the reaction vessel 10 will exhibit a higher plasma density. When the high-density plasma generation region shifts toward the peripheral edge of the top plate 11 by removing the magnet 21 near the center, uniform plasma in the radial direction can be obtained at a closer distance from the top plate 11.

Next, a second embodiment of the present invention will be described.
This second embodiment will be described with reference to FIG. Except for the configuration of the top plate and the arrangement of the magnets, all other configurations are substantially the same as those in the first embodiment.

In FIG. 13, a reaction vessel 10 for forming a plasma source includes a top plate 41, a cylindrical side wall 12, and a bottom plate 13 made of a non-magnetic metal. The lower part 12b of the cylindrical side wall 12 and the bottom plate 13 are made of metal. The upper part 12a of the cylindrical side wall 12 is made of ceramic. The bottom plate 13 is electrically grounded through a ground line 14. The reaction vessel 10 includes a substrate holder 15 therein, and the substrate holder is disposed on the bottom plate 13 by an insulator 16. A substrate 17 to be processed is mounted on a substrate holder 15. Gas exhaust port 1
8 is formed below the bottom plate 13 below the substrate holder 15.

As shown in FIG. 13, the top plate 41 used in the second embodiment has a dome shape. Since the dome-shaped structure is generally stronger than the flat-plate-shaped structure, the thickness of the top plate 41 can be considerably reduced. Further, the thickness at the center of the dome-shaped top plate 41 can be selected to be thinner than the thickness at the boundary of the open peripheral edge. The inner diameter of the dome-shaped top plate 41 is not important. Usually, the height of the dome-shaped top plate 41 indicated by the symbol h in FIG.
Included in the range. This height basically depends on the radius of the cylindrical side wall. The radius of the cylindrical side wall 12 changes as described in the first embodiment. In addition, the internal structure of the dome-shaped top plate 41 is the same as that of the top plate 11.

High frequency power is supplied from the high frequency power supply 19 to the center of the dome-shaped top plate 41 through the matching circuit 20. The dome-shaped top plate 41 has the same frequency and other electrical polarities as the electrodes described in the first embodiment.

The magnet 21 is fixed to the inner surface of a dome-shaped cover 42 made of metal. Dome cover 4
2 is arranged above the dome-shaped top plate 41.
3 cm to 5 cm at the top of the dome-shaped cover 42
Is formed. This hole 42a is
It is made to connect the high-frequency power line 43 from the matching circuit 20 to the dome-shaped top plate 41 located below the dome-shaped cover 42. The arrangement of the magnets 21 is the same as that described in the first embodiment.
However, due to the dome shape of the surface, the magnets are arranged at trapezoidal corners instead of square corners. The dome-shaped cover 42 to which the magnet 21 is fixed is supported on a rotating mechanism 44 and connected to an electric motor 45 via a gear mechanism 46. The dome-shaped cover 42 is rotated by a rotation mechanism 44 so that the dome-shaped cover 42 can rotate around its axis.
Of the bearing 44a. The electric motor 45 is connected to the outer surface of the dome-shaped cover 42 via a gear mechanism 46. The electric motor 45 is usually
The dome-shaped cover 42 is rotated at a rotation frequency of 5 Hz (that is, 180 degrees per second). However, the rotation frequency may be as high as about 10 Hz. Thus, the dome-shaped cover 4 having many magnets 21
2 is rotated by the electric motor 45 at the desired angular velocity. The distance between each of the magnets 21 fixed to the inner surface of the dome-shaped cover 42 and the dome-shaped top plate 41 is maintained at about 5 mm to 10 mm.

Next, the technical advantages of the second embodiment will be described.

In addition, the thickness of the dome top plate is smaller, resulting in a higher magnetic flux density below the dome top plate 41. This causes an increase in plasma density. Further, if this configuration is used, an inexpensive magnet having a low magnetic force can be used.

The surface area of the dome-shaped top plate is the first
It is higher than the surface area of the flat top plate used in the embodiment. This results in an increase in the volume of the plasma generation region.

The radial plasma density obtained by the first embodiment with the magnet arrangement (I) shows a higher plasma density at the center of the cylindrical chamber of the reaction vessel. This tendency is avoided when using a dome top plate. When a dome top plate is used, the plasma generation region at the center of the dome top plate is farther from the substrate level than the plasma generation region near the cylindrical sidewall. Therefore, the plasma generated near the center of the dome top plate will flow a longer distance than the plasma generated near the cylindrical sidewall. This causes a greater decrease in plasma density at the center of the cylindrical chamber. However, the reduction in plasma density at the center is compensated for by the diffusion of the plasma generated near the cylindrical sidewall. This results in a radially uniform plasma at the substrate level.

In addition, the magnets 21 arranged in the second embodiment are separated from the dome-shaped top plate 41. This facilitates the heating of the dome top plate required in some substrate processing.

Another advantage is that the dome-shaped top plate 41
Is that the time-averaged chemical action near the dome-shaped top plate 41 becomes uniform. Therefore, if a film is deposited on the inner surface of the dome-shaped dopping plate 41, the thickness of the film becomes uniform. Similarly, if etching occurs on the inner surface of the dome-shaped top plate 41, the etching shape (etching depth) will be the same over the entire surface. This facilitates the cleaning process of the reaction vessel 10. However, the mechanism for rotating the magnet 21 in the second embodiment can be adopted by fixing the magnet on a separated plate and disposing it slightly above the top plate.

The plasma sources described in the previous embodiments are of the dual frequency supply system type. The configuration of the plasma source according to the present invention can be modified as follows.

The third embodiment of the present invention will be described with reference to FIG. 14, which shows a sectional view of a plasma source. The difference between this embodiment and the first embodiment is that the plasma source does not have a high frequency power source for the top plate 11 and therefore the top plate 11 is not supplied with high frequency high frequency power and the substrate The high frequency power source 80 for supplying power to the holder 15 has a higher frequency band than that of the high frequency power source 8 described above. In this case, the top plate 11 is in an electrically floating state, that is, an electrically insulated state, or an electrically grounded state. Except for these differences, the configuration of the plasma source provided by the third embodiment is the same as that of the first embodiment.
Are substantially the same as those given in the embodiment.
Thus, this plasma source belongs to the type of single frequency supply system.

In the third embodiment, the substrate holder 15
Functions as both a high-frequency electrode and a substrate holder. The frequency of the high-frequency current supplied to the substrate holder is supplied from the high-frequency power source 80, is included in the range of 10 MHz to 100 MHz, and typically operates at 13.56 MHz. The high frequency power source 80 typically has a low impedance, typically around 50 ohms, and a 0.1 ohm power source.
High frequency power of 5 kW to 3 kW can be produced. The output of the high-frequency power source 80 is supplied to the substrate holder 15 through the matching circuit 9.

A method of introducing a process gas, a method of creating a vacuum,
The method of determining the pressure is the same as that described in the first embodiment. The mechanism of plasma generation is likewise and almost similar to that described above in the first embodiment. The only difference is that the plasma in this embodiment is generated by the substrate holder 15 only by the electrostatic coupling of high frequency power. However, since there is a magnetic field between the top plate 11 and the substrate holder 15,
As mentioned earlier, the plasma density increases. Furthermore, electron losses to the top plate 11 are similarly reduced due to electron confinement. This event is the top plate 1
1 reduces the sheath voltage and the sheath thickness at the inner surface. The decrease in the sheath voltage causes a decrease in the sputtering rate of the top plate 11.
1 to reduce the energy of the colliding ions.

The technical advantages of the third embodiment will be described below. This plasma source has all the advantages described in the previous embodiment. In addition, this plasma source uses only one RF power source. This means
Simplify the configuration of the plasma source and reduce manufacturing costs. Second, since the top plate does not have high-frequency electrical connection, the configuration of the top plate is simple. Therefore, the volume of the top plate is reduced, resulting in a further reduction in the aspect ratio of the plasma source.

[0055]

The plasma processing apparatus according to the present invention can produce a large-area high-density plasma having a uniform distribution over the entire surface of a substrate, and can realize a plasma source having a low aspect ratio.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment showing the internal and external structures of a plasma processing apparatus.

FIG. 2 is a partial sectional view of a top plate showing a fixing structure of the magnet.

FIG. 3 is a partial cross-sectional view of a top plate located in a plasma source, showing the internal structure and the magnetic field.

FIG. 4 is a plan view of a quarter region of the top plate showing the magnet arrangement (I).

FIG. 5 is a plan view of a quarter region of the top plate showing the magnet arrangement (II).

FIG. 6 is a diagram showing a magnet structure and a square region used in a computer simulation at Z = 0 mm on the XY plane.

FIG. 7 is a diagram showing a Z = Z in a rectangular area on the XY plane.
It is a figure which shows the intensity | strength and direction of a magnetic flux line in 0 mm.

FIG. 8 is a view showing a state in which Z =
FIG. 9 is a diagram showing an outline of a computer simulation of a magnetic flux line density at 20 mm.

FIG. 9 is a view showing a case where Z = 3 in a rectangular area on the XY plane.
It is a figure which shows the outline of the magnetic flux line density of the computer simulation in 0 mm.

FIG. 10 is a view showing a Z in a rectangular area on the XY plane;
It is a figure which shows the outline by computer simulation of the magnetic flux linear density in = 50mm.

FIG. 11 is a graph showing a change in current density along a radius line at Z = −75 mm.

FIG. 12 is a table showing data of non-uniformity in each of the magnet arrays (I) and (II).

FIG. 13 is a vertical sectional view of the second embodiment showing the internal structure of the plasma processing apparatus.

FIG. 14 is a vertical sectional view showing a third embodiment of the present invention.

FIG. 15 is a view showing a first example of a plasma processing apparatus.
FIG. 3 is a schematic diagram showing a conventional plasma source.

FIG. 16 is a second view used in the plasma processing apparatus.
FIG. 3 is a schematic diagram showing a conventional plasma source.

[Description of reference numerals]

 DESCRIPTION OF SYMBOLS 10 Reaction container 11 Top plate 12 Cylindrical side wall 13 Bottom plate 15 Substrate holder 16 Insulator 17 Wafer or substrate 21 Magnet 23 Magnetic field 41 Dome top plate 42 Dome cover

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[Procedure amendment]

[Submission date] March 26, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0050

[Correction method] Change

[Correction contents]

[0050] The plasma source described in the above embodiment is a type of two-frequency supply system. The configuration of the plasma source according to the present invention can be modified as follows.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction contents]

A method of introducing a process gas, a method of creating a vacuum,
The method for determining the pressure is the same as that described in the first embodiment. The mechanism of plasma generation is likewise and almost similar to that described above in the first embodiment. The only difference is that the plasma in this embodiment is generated by the substrate holder 15 only by the electrostatic coupling of high frequency power. However, since there is a magnetic field between the top plate 11 and the substrate holder 15,
As mentioned earlier, the plasma density increases. Furthermore, electron losses to the top plate 11 are similarly reduced due to electron confinement. This event is the top plate 1
1 reduces the sheath voltage and the sheath thickness at the inner surface. The decrease in the sheath voltage causes a decrease in the sputtering rate of the top plate 11.
1 to reduce the energy of the colliding ions.

Claims (11)

[Claims] 1. A side plate including a plasma source and a substrate holder, a top plate made of a non-magnetic metal, a bottom plate made of a metal, and a side wall having at least a portion made of a dielectric material. Wherein the substrate holder is a reaction vessel disposed on the bottom plate, and a plurality of magnets separately disposed outside the top plate, wherein the magnets are directed toward the inside of the reaction vessel. The plurality of magnets, wherein the polarity is alternately changed, and the plurality of magnets generate a cusp magnetic field accompanied by a magnetic flux that is closed at a location near the inner surface of the top plate. 2. The flat plate according to claim 1, wherein the top plate has a flat and circular shape, and the magnet is directly fixed to an outer surface of the flat top plate.
The plasma processing apparatus as described in the above. 3. The plasma processing apparatus according to claim 1, wherein the top plate has a dome shape. 4. The plasma processing apparatus according to claim 3, wherein the magnet is disposed on an inner surface of a dome cover that covers the dome-shaped top plate. 5. The reactor of claim 1, wherein the top plate is electrically insulated from other portions of the reaction vessel by being disposed on the portion made of a dielectric material. The plasma processing apparatus according to any one of claims 4 to 4. 6. The plasma processing apparatus according to claim 1, wherein high frequency power is supplied to the top plate. 7. The plasma processing apparatus according to claim 2, wherein the magnet is disposed in an end region of the top plate by leaving a region without a magnetic field in a central portion of the top plate. 8. The plasma processing apparatus according to claim 4, wherein said dome-shaped cover on which said magnet is fixed on its inner surface is rotated by an electric motor. 9. The plasma processing apparatus according to claim 1, wherein the substrate holder is supplied with high-frequency power, while the top plate is not supplied with high-frequency power. 10. The plasma processing apparatus according to claim 9, wherein the top plate is in an electrically insulated state. 11. The plasma processing apparatus according to claim 1, wherein the top plate is in an electrically grounded state.