JPH07161488A - High density plasma generating device - Google Patents

Abstract

PURPOSE:To obtain a useful plasma source by providing a high frequency coil antenna outside of a dielectric wall for partitioning a vacuum chamber, and providing a permanent magnet along the antenna to form a magnetic field in the direction crossing the high frequency current flowing in the antenna. CONSTITUTION:A permanent magnet 5 is provided in the direction crossing the high frequency current flowing in a high frequency antenna 2 to obtain a large magnetic field slope. Plasma at a high density is thereby generated near a plasma generating area of the vacuum chamber by the work of the induction electric field (E=sigmaB/sigmat, B means a magnetic filed formed by a high frequency antenna). A high frequency magnetic field near the center of the plasma generating area of the vacuum chamber is therefor quickly attenuated, and the diffusing speed of the plasma in the peripheral direction of the plasma generating area of the vacuum chamber can be reduced. As a result, high density plasma, of which distribution density in the peripheral direction is even can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching apparatus which requires a low pressure, particularly an atmospheric pressure of about 0.1 Pa,
The present invention relates to a high-density plasma generation device capable of processing a large area at high speed with high uniformity in a P-CVD device, a sputtering device, or the like.

[0002]

2. Description of the Related Art Conventionally, as a device for generating high-density plasma, there has been known a device for generating high-density induction plasma by using a coil magnet and diffusing the induction plasma by a divergent magnetic field. It can be used for pre-cleaning, etc. by enabling vapor deposition and etching over a large area by expanding the magnetic field (Japanese Patent Laid-Open No. 3-68773).
(See Japanese Patent Laid-Open No. 4-290428). FIG. 11 of the accompanying drawings shows an example of a well-known conventional high-frequency induction plasma generator. In the illustrated apparatus, an RF coil antenna B is provided on the outer circumference of a quartz tube A, and this RF coil antenna B is provided with a matching circuit C. It is configured to be connected to a high frequency power source D via. In this case, an electric field induced by the RF coil antenna B is formed in the quartz tube A, and in this electric field,
A plasma P is generated in the quartz tube A by introducing an inert gas such as Ar so as to have an atmospheric pressure of about 1 Pa. FIG. 12 shows another example of the conventional plasma generation apparatus. In this case, in addition to the configuration shown in FIG. 11, a solenoid coil E is provided on the outer circumference of the quartz tube A, and a static magnetic field as indicated by arrow F is applied. I am trying to do it. Solenoid coil E
By applying a static magnetic field due to the above, it is possible to generate a higher density plasma P than in the device of FIG. A planar loop antenna is known as a plasma source that does not use a magnetic field (see Japanese Patent Laid-Open No. 3-79025). In this example, as shown in FIG. 13, a quartz plate H is provided above the vacuum chamber G, and an RF loop antenna, that is, a planar coil I is provided outside the quartz plate H. The planar coil I is a matching circuit J.
It is connected to the high frequency power supply K via.

[0003]

In such a conventional plasma generator, for example, the plasma source having the structure shown in FIGS. 11 and 12 has a poor distribution as a plasma source for large area processing. That is, in the configuration of FIG.
As shown in (b) of 11, there is a problem that the density distribution of the generated plasma changes greatly in the radial direction, and the density cannot be as high as about 10 ⁸ -10 ¹⁰ cm ^-3 . Fig. 12
In the example using a solenoid coil as shown in Fig. 12, a high density plasma can be obtained by applying a static magnetic field generated by the solenoid coil, but the density distribution of the obtained plasma is shown in Fig. 12 (b). As shown in the figure, it is worse than when no static magnetic field is applied (Fig. 11), and there is a problem that it cannot be used in various processes as it is. On the other hand, when the planar loop antenna is used, the plasma uniformity is good at a high pressure of 10 Pa or more, but there is a problem that the density is not sufficient at a low pressure and the distribution is not as good as when the pressure is high.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems and to provide a high density plasma generator capable of generating high density and high uniformity plasma in a wide pressure range. Another object of the present invention is to provide various process devices using this high-density plasma generation device.

[0005]

In order to achieve the above object, the high-density plasma generator according to the present invention is provided with at least one high-frequency antenna capable of flowing a high-frequency current around a plasma generation region of a vacuum chamber. It is characterized in that at least one permanent magnet that generates a magnetic field in a direction intersecting with a high-frequency current flowing through the high-frequency antenna is provided along the high-frequency antenna. In the high-density plasma generation device according to the present invention, the dielectric member that defines the plasma generation region of the vacuum chamber has a cylindrical shape, and the coil-shaped high frequency antenna may be arranged on the outer periphery thereof. The dielectric member defining the plasma generation region of the vacuum chamber may be plate-shaped instead of cylindrical. In either case, the permanent magnet may be positioned between the dielectric member and the high frequency antenna or outside the high frequency antenna. When the dielectric member that defines the plasma generation region of the vacuum chamber has a plate shape, the high frequency antenna preferably provided on the outer surface thereof may be arranged in a loop shape. The magnetic field generated by each permanent magnet may have a direction within ± 30 ° with respect to the direction orthogonal to the high frequency current flowing through the high frequency antenna. The pressure in the vacuum chamber is 100 Pa to 0.
Can be 01Pa. Furthermore, in the high-density plasma generator according to the present invention, a plurality of high frequency antennas are provided, and each high frequency antenna can be connected to an independent high frequency power source. Preferably, the pitch of the arrangement of the permanent magnets, the distance between the permanent magnets and the high frequency antenna, or the strength of the permanent magnets can be set so that a uniform plasma distribution can be obtained.

[0006]

In the high-density plasma generating apparatus according to the present invention having the above-described structure, the permanent magnet for generating the magnetic field in the direction intersecting with the high-frequency current flowing through the high-frequency antenna is provided, so that the magnetic field can be largely oriented. become able to. As a result, the induction electric field (E = ∂B / ∂t, where B
Due to the magnetic field generated by the high frequency antenna, high density plasma is generated near the periphery of the plasma generation region of the vacuum chamber. Therefore, the high-frequency magnetic field near the center of the plasma generation region of the vacuum chamber is rapidly attenuated, and since the magnetic field near the periphery of the plasma generation region of the vacuum chamber is strong, the diffusion rate toward the periphery of the plasma generation region is increased. It will be possible to make it smaller.
As a result, it becomes possible to obtain a high-density plasma having a uniform distribution density in the circumferential direction.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 (a) schematically shows a high-density plasma generating apparatus according to an embodiment of the present invention, in which a high frequency for plasma generation is formed on the outer circumference of a quartz tube 1 which is a dielectric defining a plasma generating region of a vacuum chamber. The coil antenna 2 is arranged. One end of the high frequency coil antenna 2 is connected to the high frequency power source 4 via the matching circuit 3, and the other end is grounded. The high frequency coil antenna 2 is provided between the outer surface of the quartz tube 1 and the high frequency coil antenna 2.
A cylindrical permanent magnet 5 is arranged along the
Are configured to form a magnetic field substantially orthogonal to the direction of the high frequency current flowing from the high frequency power supply 4 to the high frequency coil antenna 2. In the operation of the illustrated apparatus thus configured, the permanent magnet 5 forms a magnetic flux line as shown by reference numeral 6 inside the quartz tube 1 and a large magnetic field distribution can be taken.
Due to the action of the induction electric field, a plasma 7 having a high density and a uniform distribution density from near the inner wall of the quartz tube 1 to the central portion thereof can be generated as shown in FIG. 1 (b). The magnetic field generated by the permanent magnet 5 does not have to be in a direction perpendicular to the high-frequency current flowing in the high-frequency coil antenna 2 exactly, and may be within ± 30 ° with respect to the orthogonal direction.

2 to 4 show modified examples of the high-density plasma generator according to the present invention. In the structure shown in FIG. 2, the cylindrical permanent magnet 5 is provided on the outer circumference of the quartz tube 1 for plasma generation. It is provided outside the high frequency coil antenna 2. In the modification shown in FIG. 3, a plurality of rod-shaped permanent magnets 8 are provided outside the high-frequency coil antenna 2 for plasma generation provided on the outer circumference of the quartz tube 1. In the modification of FIG. 4, a U-shaped permanent magnet 9 is arranged so as to surround the high frequency coil antenna 2 instead of the rod-shaped permanent magnet shown in FIG. Although one cylindrical permanent magnet is used in the embodiment shown in FIG. 1, a plurality of rod-shaped permanent magnets as shown in FIG. 3 may be used instead.

Next, an example in which the present invention is applied to a pre-cleaning processing apparatus before metal wiring is described with reference to FIGS. 5 and 6. In FIGS. 5 and 6, 10 is a vacuum chamber defining an etching process chamber,
A quartz plate 11 is hermetically attached to the upper opening of the vacuum chamber 10. The quartz plate 11 is placed outside the quartz plate 11.
High-frequency loop antenna 12 forming a one-turn loop parallel to
The high frequency loop antenna 12 is connected to the high frequency power source 4 via the matching circuit 3. As shown in FIG. 6, a large number of plate-shaped permanent magnets 13 are arranged below the high frequency loop antenna 12 in a loop shape orthogonal to the current flowing through the high frequency loop antenna 12 and parallel to the quartz plate 11. Form the magnetic flux lines as shown. Also a vacuum chamber
A substrate holder 15 that supports the Si wafer S is arranged in the substrate 10. The substrate holder 15 is a substrate bias matching circuit.
It is connected to the high frequency power supply 17 for substrate bias via 16 so that the high frequency bias is applied to the substrate holder 15,
The wafer S is pre-cleaned. Further, a ground shield 18 is provided around the substrate holder 15,
Further, in FIG. 5, reference numeral 19 represents an earth shield. FIG. 7 shows the density of generated plasma in the etching apparatus configured as described above in comparison with the conventional apparatus. As shown in FIG. 7, in comparison with the case of a loop antenna of 5 turns without using a permanent magnet as in the present invention (a) and the case of a loop antenna of 1 turn (b), FIGS. In the case of the device according to the present invention shown in the case (c), it is recognized that plasma which is uniform in the radial direction and has a high density can be obtained. Explaining the case where it is applied to etching in a wafer process as an actual experimental example, the gas pressure in the vacuum chamber 10 is
Keep the flow rate of 0.1Pa and (CHF ₃ + CO) at 100SCCM,
The etching rate of SiO ₂ is 800 nm when 700 W is applied to the high frequency loop antenna 12 and 200 W is applied to the substrate S.
/ Min was obtained. In this case, the distribution on an 8-inch wafer is ±
It was 4%. The etching rate of the sputtered Al film is 500 nm when the gas species is changed to (BCl ₃ + Cl ₂ ) and the pressure is set to 0.08 Pa and the flow rate is set to 80 SCCM and 500 W is applied to the high frequency loop antenna 12 and 300 W to the substrate S. / Min was obtained. In this case, the distribution on an 8-inch wafer is ± 3.2
%Met.

FIG. 8 shows an example implemented as a large-area P-CVD or etching apparatus, 20 is a vacuum chamber defining a processing chamber, and the upper opening of this vacuum chamber 20 is made of quartz. A plate 21 is hermetically attached.
Outside the quartz plate 21, three high-frequency loop antennas 22 each consisting of one loop are arranged concentrically in the same plane, and each high-frequency loop antenna 22 passes through a separate matching circuit 3 and separate high-frequency waves. It is connected to the power supply 4. Below each high frequency loop antenna 22 is shown in FIG.
A large number of permanent magnets 23 are arranged so as to form three loops in the same manner as the structure shown in FIG. A substrate holder 25 that supports the substrate S is arranged in the vacuum chamber 20, and the substrate holder 25 is connected to a substrate bias high frequency power supply 27 via a substrate bias matching circuit 26. When the a-Si film was formed by P-CVD on the substrate S of 500 mm □ using the apparatus configured as described above,
Apply 1.5kW, 500W, 200W power, vacuum chamber 20
The internal pressure is (SiH ₄ + H ₂ + He) 10Pa, and the flow rate is
When set to 500SCCM, the deposition rate is 0.3μm / min ±
A distribution of 7% was obtained.

FIG. 9 shows an embodiment in which the present invention is applied to a sputtering apparatus. In the drawing, 30 is a vacuum chamber, which is hermetically mounted between a top wall member 30a and a bottom wall member 30b having openings and these wall members. And a quartz tube 31 forming a side wall. A high frequency loop antenna 32 consisting of one loop is arranged on the outer circumference of the quartz tube 31.
Reference numeral 32 is connected to the high frequency power source 4 via the matching circuit 3. Between the outer surface of the quartz tube 31 and the high-frequency loop antenna 32, a cylindrical permanent magnet or a large number of rod-shaped permanent magnets 33 are arranged in a loop shape as shown in the figure, and a magnetic flux as shown in the figure is provided in the vicinity of the quartz tube 31. It is adapted to form line 34. A substrate holder for supporting the substrate S in the vacuum chamber 30.
35 is arranged, and the substrate holder 35 is connected to a substrate bias high frequency power supply 37 via a substrate bias matching circuit 36. Further, the upper wall member 30 is opposed to the substrate holder 35.
A cathode 38 to which the target T is attached is hermetically attached to the opening of a through an insulator 39. Cathode 38 is high frequency power supply 40b for target via matching circuit 40a
It is connected to the.

Further, FIG. 10 shows an example in which the present invention is applied to an ion source. In the apparatus shown in FIG. 10, a high frequency loop antenna 42 is arranged around the quartz tube 41, and the high frequency loop antenna 42 is connected to the high frequency power supply 4 via the matching circuit 3. Between the outer surface of the quartz tube 41 and the high frequency loop antenna 42, a cylindrical permanent magnet or a large number of rod-shaped permanent magnets 43 are arranged in a loop shape as shown in the figure, and as shown in the figure near the quartz tube 41. The magnetic flux lines 44 are formed. One end of quartz tube 41 (upper end in the drawing)
Is hermetically sealed, and at the other end, a first multi-aperture electrode 45, an insulator 46, a second multi-aperture electrode 47, an insulator 48 and a flange 49 are hermetically mounted in that order.
The first multi-aperture electrode 45 and the second multi-aperture electrode 47 are connected to separate DC power supplies 50 and 51, respectively. In the ion source configured in this way, the ion flow
Withdrawn as shown at 52.

[0013]

As described above, in the high-density plasma generator according to the present invention, since the permanent magnet for generating the magnetic field in the direction substantially orthogonal to the high frequency current flowing in the high frequency antenna is provided, the magnetic field distribution It is possible to generate a high density plasma near the periphery of the plasma generation region of the vacuum chamber by the action of the induction electric field, and as a result, the distribution density in the circumferential direction is uniform. High-density plasma can be obtained. Therefore, it becomes possible to provide an extremely useful apparatus as a plasma source for a process apparatus that requires processing a large area at high speed and with high uniformity.

[Brief description of drawings]

FIG. 1A is a schematic partial line longitudinal cross-sectional view showing a main part of a high-density plasma generator according to an embodiment of the present invention. (b) is
The graph which shows the plasma density distribution obtained by the apparatus shown in (a).

FIG. 2 (a) is a schematic partial line longitudinal cross-sectional view of a main part showing a modified embodiment of the high-density plasma generation device shown in FIG. (b) is
FIG. 3 is a schematic partial end view of a main part of the device shown in FIG.

FIG. 3 is a schematic partial end view of a main portion showing another modified embodiment of the present invention.

FIG. 4 is a schematic partial line longitudinal cross-sectional view of a main part showing still another modified embodiment of the present invention.

FIG. 5 is a schematic partial vertical cross-sectional view showing an example in which the present invention is applied to a pre-cleaning processing apparatus before performing metal wiring.

6 is a schematic plan view of a main part of the device shown in FIG.

7 is a graph showing the plasma density distribution obtained by the device shown in FIG. 5 in comparison with that obtained by the conventional device.

FIG. 8 is a schematic partial line vertical cross-sectional view showing an example in which the present invention is applied to a large-area P-CVD or etching apparatus.

FIG. 9 is a schematic partial line vertical cross-sectional view showing an example in which the present invention is applied to a sputtering apparatus.

FIG. 10 is a schematic partial line longitudinal cross-sectional view showing an example in which the present invention is applied to an ion source.

FIG. 11A is a schematic partial line vertical cross-sectional view showing an example of a conventional high-frequency induction plasma generation device. (b) is a graph showing the plasma density distribution obtained by the device shown in (a).

FIG. 12 (a) is a schematic partial line longitudinal sectional view showing another example of a conventional high-frequency induction plasma generation device. (b) is a graph showing the plasma density distribution obtained by the device shown in (a).

FIG. 13A is a schematic partial line vertical cross-sectional view showing an example of a conventional plasma generation device using a planar loop antenna. (b)
Is a graph showing the plasma density distribution obtained by the device shown in (a).

[Explanation of symbols]

 1: Quartz tube 2: High frequency coil antenna for plasma generation 3: Matching circuit 4: High frequency power supply 5: Permanent magnet 6: Magnetic flux line 7: Plasma

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01J 27/18 37/08 37/305 A 9172-5E 37/32 9172-5E H01L 21/3065

Claims (11)

[Claims] 1. At least one high-frequency antenna capable of flowing a high-frequency current is provided outside a dielectric member that defines a plasma generation region of a vacuum chamber, and a magnetic field in a direction substantially orthogonal to the high-frequency current flowing through the high-frequency antenna is provided. A high-density plasma generator characterized in that at least one permanent magnet to be generated is provided along a high-frequency antenna. 2. The high-density plasma generator according to claim 1, wherein the dielectric member that defines the plasma generation region of the vacuum chamber has a cylindrical shape, and a coil-shaped high-frequency antenna is arranged on the outer periphery thereof. 3. The high density plasma generator according to claim 2, wherein the permanent magnet is located between the cylindrical dielectric member and the high frequency antenna. 4. The permanent magnet is located outside the high frequency antenna provided on the outer periphery of the cylindrical dielectric member.
The high-density plasma generator described in. 5. The high-density plasma according to claim 1, wherein the dielectric member defining the plasma generation region of the vacuum chamber has a plate shape, and at least one loop-shaped high frequency antenna is arranged on the outer surface of the dielectric member. Generator. 6. The high-density plasma generator according to claim 5, wherein the permanent magnet is located between the plate-shaped dielectric member and the high frequency antenna. 7. The high-density plasma generator according to claim 5, wherein the permanent magnet is located outside the high-frequency antenna provided on the outer surface of the plate-shaped dielectric member. 8. The high-density plasma generator according to claim 1, wherein the magnetic field generated by each permanent magnet has a direction within ± 30 ° with respect to the direction orthogonal to the high-frequency current flowing in the high-frequency antenna. . 9. The pressure in the vacuum chamber is 100 Pa to 0.01 Pa.
The high density plasma generator according to claim 1. 10. The high-density plasma generation apparatus according to claim 1, wherein a plurality of high-frequency antennas are provided along the plasma generation region of the vacuum chamber, and each high-frequency antenna is connected to an independent high-frequency power source. 11. The high density plasma generator according to claim 1, wherein the pitch of the arrangement of the permanent magnets, the distance between the permanent magnets and the high frequency antenna, or the strength of the permanent magnets is set so as to obtain a uniform plasma distribution.