JPH07258844A - Film forming device utilizing discharge plasma of magnetic neutral line - Google Patents

Abstract

PURPOSE:To prevent adhesion of a film forming material to electric field coils and to always stably maintain a high-purity plasma state by providing a film forming device with a shielding material for capturing unnecessary materials along the inner side of the electric field generating coils thereof. CONSTITUTION:This film forming device is provided with the three electromagnetic coils 4, 5, 6 as magnetic field generating means on the outer side of a cylindrical metallic partition wall delineating a cylindrical plasma generating chamber 2. The high-frequency discharge plasma of high purity is formed within a magnetic neutral line 7 formed in the plasma generating chamber 2 by an antenna 8 and a target 13 is sputtered over the entire surface thereof. Of the sputtered particles, the particles advancing toward the side wall of the vacuum chamber 1 are captured by a cylindrical deposition preventive body 10 disposed on the inner side of the antenna 8, by which the adhesion of sputtering materials to the side wall is prevented. The antenna 8 is enclosed by a dielectric enclosing member 9 for preventing sputtering. A rectangular strip-like deposition preventive plate may be used well in place of the cylindrical deposition preventive body 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus for forming a substance on a substrate such as a semiconductor or an electronic component by sputtering, etching, CVD or the like using magnetic neutral line discharge plasma.

[0002]

2. Description of the Related Art The applicant of the present invention has previously proposed a discharge plasma processing apparatus utilizing magnetic neutral line discharge plasma in the application of Japanese Patent Application No. 5-183899. This discharge plasma processing apparatus is basically a magnetic field generating means for forming a magnetic neutral line which is a position of a magnetic field zero continuously existing in the vacuum chamber, and the magnetic field generating means forms the magnetic neutral line in the vacuum chamber. And an electric field generating means for generating an electric discharge plasma in the magnetic neutral wire by applying an electric field along the magnetic neutral wire. Various film forming apparatuses have been studied and developed by applying or developing the basic concept of the magnetic neutral line discharge plasma. As an example thereof, the present applicant has provided a magnetic field generating means for forming a magnetic neutral line which is a position of a magnetic field zero continuously existing in the vacuum chamber in the application of Japanese Patent Application No. 6-. ,
An electric field generating coil for applying an electric field along the magnetic neutral wire formed in the vacuum chamber by the magnetic field generating means to generate discharge plasma in the magnetic neutral wire is provided in the vacuum chamber, and in an ultrahigh vacuum atmosphere. We proposed a discharge plasma processing system that enables film formation, and therefore the entire vacuum chamber can be constructed with a metal container, making it easy to maintain and maintain ultra-high vacuum.

[0003]

In the film forming apparatus of the same application, an electric field is applied along the magnetic neutral wire formed in the vacuum chamber by the magnetic field generating means to generate discharge plasma in the magnetic neutral wire. By providing the electric field generating coil in the vacuum chamber, the entire vacuum chamber can be configured with a metal container, and it is possible to operate in an ultra-high vacuum, but on the other hand, plasma is generated in the vacuum chamber. The deposited film substance adheres to the electric field generation coil and becomes a pollution source, and especially when the generated film formation substance is a metal, if it adheres to the electric field generation coil, the electric field is blocked and the magnetic neutral line is A new problem arises, such as the inability to apply an electric field along with the generation of plasma. Therefore, an object of the present invention is to provide a film forming apparatus capable of operating in an ultra-high vacuum and solving such a problem to prevent adhesion of a film forming substance to an electric field generating coil. I am trying.

[0004]

In order to achieve the above-mentioned object, according to the first aspect of the present invention, a magnetic neutral line which is a position of a magnetic field zero continuously existing in a vacuum chamber is formed. The magnetic field generating means and the electric field generating means are provided in the vacuum chamber, and an electric field is applied along the magnetic neutral line formed in the vacuum chamber by the magnetic field generating means to discharge plasma to the magnetic neutral line. And an electric field generating coil for generating an electric field are generated along with the inner surface of the electric field generating coil in a film forming apparatus for forming a film on a substrate using magnetic neutral line discharge plasma in a vacuum chamber. It is characterized in that a shielding means for preventing unnecessary substances including a film-forming substance toward the coil is provided. The shielding means may preferably consist of a thin-walled cylindrical shielding body provided along the inner surface of the side wall of the vacuum chamber. Further, the film forming apparatus according to the first aspect of the present invention can be provided with a means for expelling the unnecessary substance adhering to the shielding means, and the means for expelling the unnecessary substance generates a high frequency induction electric field for high frequency cleaning. It can consist of means or heating means.

Further, according to the second aspect of the present invention, the magnetic field generating means and the electric field generating means are arranged so as to form a magnetic neutral line which is a position where the magnetic field is continuously present in the vacuum chamber. An electric field generating coil which is provided in the vacuum chamber and which applies an electric field along the magnetic neutral line formed in the vacuum chamber by the magnetic field generating means to generate discharge plasma in the magnetic neutral line, In a film forming apparatus for forming a film on a substrate by using magnetic neutral line discharge plasma in the inside of the electric field generating coil or surrounding the electric field generating coil, in the circumferential direction of the generated high frequency electric field. A Faraday shield cage is provided to prevent inhomogeneous electrostatic field components from entering the inside of the vacuum chamber.The Faraday shield cages are arranged at equal intervals along the circumferential direction and one end is electrically connected to the other. That comprises a plurality of strip-shaped metal flakes bound is characterized in.

[0006]

In the film-forming apparatus according to the present invention having the above-described structure, the film-forming material shielding means and the Faraday cage are provided to prevent the film-forming material from heading to the electric field generating coil and to prevent the film from forming on the coil. The adhesion of the film substance can be prevented. When the film-forming substance is a metal, the metal film adheres to the surface of the film-forming substance shielding means to shield the electric field from the coil. Even if the film-forming substance is a metal oxide dielectric, the substance to be attached may have electrical conductivity, and in this case also, the attached film blocks the electric field from the coil. Therefore, in the film forming apparatus according to the first aspect of the present invention, in the case of an attached substance that evaporates at a relatively low temperature, the attachment means is heated by the heating means, while when a substance having a low vapor pressure is attached, Is adapted to generate an induction electric field by means of a high frequency induction electric field to sputter the deposited material. The second invention of the present invention is applied when the adhered substance cannot be suppressed by the heating means or the high frequency induction electric field generating means. That is, the Faraday shield cage is composed of a plurality of strip-shaped metal thin pieces having narrow gaps in the direction orthogonal to the coil surface, and its end is grounded to ground in order to stabilize its own potential. By this Faraday shield cage, a non-uniform electrostatic field in the circumferential direction is blocked, but a uniform induction electric field in the circumferential direction is not blocked, and electric power can be supplied to the plasma. Further, since the gap is open, even if the metal substance adheres to the strip-shaped metal thin piece of the Faraday shield basket, this induction electric field is introduced without any influence.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment in which the present invention is implemented as a sputtering apparatus. In FIG. 1, 1 is a vacuum chamber,
The whole is composed of a metal container, and includes a cylindrical plasma generation chamber 2 and a substrate processing chamber 3. Three electromagnetic coils 4, 5 and 6 forming magnetic field generating means are provided on the outer side of the cylindrical metal partition wall defining the cylindrical plasma generation chamber 2, and two electromagnetic coils, one above the other, are provided as shown in the figure. The coils 4 and 6 are supplied with the same constant current in the same direction, and the intermediate electromagnetic coil 5 is supplied with reverse current. As a result, a continuous magnetic field zero position is formed inside the plasma generation chamber 2 at the level of the intermediate electromagnetic coil 5, and a ring-shaped magnetic neutral wire 7 is formed. The position and size of the ring-shaped magnetic neutral wire 7 are appropriately set by changing the ratio of the current flowing through the two upper and lower electromagnetic coils 4 and 6 and the current flowing through the intermediate electromagnetic coil 5. can do.
For example, when the current flowing through the upper electromagnetic coil 4 is made larger than the current flowing through the lower electromagnetic coil 6, the position where the magnetic neutral line can be formed is lowered toward the electromagnetic coil 6 side. Go up to the coil 4 side. Further, as the current flowing through the intermediate electromagnetic coil 5 is increased, the diameter of the ring of magnetic neutral wire becomes smaller and the gradient of the magnetic field at the position where the magnetic field is zero becomes gentle. At the level of the intermediate electromagnetic coil 5, there is provided a high frequency electric field generating antenna 8 concentrically forming electric field generating means along the inner surface of the cylindrical metal partition wall.
Connected to 13.56MHz high frequency power supply. This antenna 8 can be configured as a single or multiple high frequency coil.
The antenna 8 is surrounded by a dielectric enclosing member 9 for preventing spatter as shown in the figure, so that the antenna 8 itself is prevented from being sputtered. Further, inside the antenna 8, a cylindrical cylindrical protective body 10 serving as a sputtering material shielding means is provided along substantially the entire height of the cylindrical partition wall, and a dielectric surrounding member 9 surrounding the inner surface of the cylindrical partition wall and the antenna 8. The spatter material is prevented from adhering to. Here, the high-frequency electric field generating antenna 8 needs to be positioned so as to be located farther than the cylindrical partition wall of the vacuum chamber 1 and near the cylindrical cylindrical protective body 10. Antenna 8 for high frequency electric field generation
Also functions as a means for generating a high-frequency induction electric field for high-frequency cleaning and driving out unnecessary substances including sputtered substances that adhere to the inner surface of the cylindrical protective body 10. In this case, the high frequency applied to the antenna 8 is different between the discharge and the sputter cleaning, for example, 13.56 MH for discharge.
It is also possible to switch and apply a high frequency of 400 kHz for z and sputter cleaning. A cathode 11 functions as an upper lid of the vacuum chamber 1 via an insulator (not shown) on the top of the cylindrical plasma generation chamber 2, and a DC bias voltage is applied to the cathode 11 by a DC bias power supply 12. Is applied. A target 13 is mounted inside the cathode 11. Meanwhile, the vacuum chamber 1
The substrate 14 is mounted on the substrate holder 15 in the substrate processing chamber 3 facing the target 13, and the vacuum chamber 1 has the exhaust port 1a.
Therefore, the vacuum exhaust system (not shown) is used for vacuum exhaust.

In the operation of the illustrated apparatus configured as above, a high-purity high-frequency discharge plasma is generated in the magnetic neutral wire 7 formed in the plasma generation chamber 2 by the antenna 8 and is formed on the surface of the target 13. . As a result, the target 13 is sputtered over the entire surface. In this way, of the particles sputtered from the target 13, the particles advancing toward the side wall of the vacuum chamber 1 are trapped by the cylindrical adherend 10, and the adherence of the sputtered material to the side wall can be effectively prevented. At this time, the diameter of the ring-shaped magnetic neutral wire 7 and the distance to the target 13 are changed by controlling the currents flowing through the upper and lower two electromagnetic coils 4 and 6 and the current flowing through the intermediate electromagnetic coil 5, respectively. As a result, highly uniform erosion can be achieved.

FIG. 2 shows a strip-shaped deposition plate which can be used in place of the insulating cylindrical deposition body 10 shown in FIG.
Shows 16. This adhesion-preventing plate 16 has supports 17 and 18 at both upper and lower ends,
It is composed of a plurality of strip-shaped thin metal pieces 19 extending between both supports and arranged at equal intervals, one support 17 is composed of a conductor, and the other support 18 is an insulating material such as glass or ceramic. Faraday cages are formed by electrically connecting one ends of a plurality of strip-shaped thin plate metal pieces 19 made of a material and arranged at equal intervals along the circumference with a support 17 made of a conductor. In this Faraday cage, an electrostatic field component, which is not uniform in the circumferential direction, of the high frequency electric field generated along with the prevention of the adhesion of the sputtered material from the target to the inner wall of the vacuum chamber and the dielectric surrounding member 9 enters the inside of the vacuum chamber 1. To prevent

Next, an example of an experiment conducted by using the apparatus having the configuration shown in FIG. 1 will be described. In the apparatus shown in FIG. 1, a target 13 is made of aluminum, a direct current of 13 kW (430 V, 30 A) is applied as a target bias, and the pressure of argon gas in the vacuum chamber 1 is set to 5 × 10 ^-2 Pa.
When the distance between the target 13 and the substrate 14 was set to 300 mm and the process was performed with the position and radius of the magnetic neutral line kept constant during the process, a film deposition rate of 2500 Å / min was obtained. . At this time, the erosion speed of the aluminum target was about 1.2 μm / min, and the erosion uniformity was ± 7%. Comparing the results of this experiment with the conventional DC magnetron sputtering, the film formation rate was 1.2 times, and the uniformity was about 7%, which is a very good value compared with the conventional 10 to 20%. The sputtering film formation was performed after the back pressure of 1.2 × 10 ⁻⁷ Pa was obtained by the turbo molecular pump. In the case of an aluminum target, the best anti-adhesion property was obtained when a Faraday shield member was used as the anti-adhesion means. Further, when the quartz cylindrical protective body 10 as shown in the figure is used, the effect of preventing the adhesion by the re-sputtering by the high frequency induction electric field generating means was recognized.

In the embodiment shown in FIG. 1, when the target 13 is conductive, a DC bias from a DC power source is applied as shown, but when an insulating target is used, an RF bias from a high frequency power source is applied. Can be adapted to use. Also, the antenna 8 for introducing the high frequency electric field has 1
A high frequency of 3.56 MHz is applied, but the frequency is not limited to this. Further, in the present invention, as a means for excluding unnecessary substances including sputtered substances adhering to the cylindrical protective body of the dielectric, in addition to the illustrated embodiment, in the case of an adhering substance that evaporates at a relatively low temperature, It can be carried out as a heating means for heating the cylindrical body-insulating body, and when a substance having a low vapor pressure is attached, the body-shaped cylindrical coil is wound in close contact with the cylindrical body-insulating body, A high-frequency current may be applied to this coil to generate an induction electric field and sputter the deposited material. Although the illustrated embodiment has exemplified the case where the present invention is implemented as a sputtering apparatus, the present invention can naturally be similarly implemented as another film forming apparatus such as etching and CVD. By the way, in the illustrated embodiment, a magnetic neutral wire is formed inside the vacuum chamber by three magnetic field generating coils, and an alternating electric field is introduced along the magnetic neutral wire,
Although it is configured as a plasma generation type sputtering device, it will be a normal inductive coupling type discharge system if no current is passed through the magnetic field generating coil, so the inductive coupling type sputtering system with the antenna coil placed in an ultra-high vacuum is used. It can also be used as a device.

[0015]

As described above, according to the present invention, the shielding means for preventing the adhesion of the unnecessary substance including the film-forming substance to the coil for generating an electric field provided in the vacuum chamber is provided. In addition, it is possible to always stably maintain a high-purity plasma state, and thus it is possible to maintain an ultrahigh vacuum and perform film formation at a high film formation rate.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional view showing an example in which the present invention is implemented as a sputtering apparatus.

FIG. 2 is a schematic perspective view showing an example of a sputtering substance shielding means that can be used in the sputtering apparatus of FIG.

[Explanation of symbols]

 1: Vacuum chamber 2: Plasma generation chamber 3: Substrate processing chamber 4, 5, 6: Electromagnetic coil 7: Plasma ring generated on a circular magnetic neutral wire 8: High frequency electric field generation antenna 9: Dielectric enclosing member 10 : Cylindrical cylindrical protective body 11: Cathode 12: DC bias power supply 13: Target 14: Substrate 15: Substrate holder

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H05H 1/46 L 9014-2G (72) Inventor Toshio Hayashi 2500 Hagien, Chigasaki City, Kanagawa Japan Vacuum Technology Co., Ltd. (72) Inventor Taijiro Uchida 2500 Hagien, Chigasaki City, Kanagawa Japan Vacuum Technology Co., Ltd.

Claims (6)

[Claims] 1. A magnetic field generating means for forming a magnetic neutral line which is a position of a magnetic field zero continuously existing in the vacuum chamber, and an electric field generating means provided in the vacuum chamber, the magnetic field generating means It has an electric field generating coil that applies an electric field along a magnetic neutral wire formed in the vacuum chamber to generate discharge plasma in the magnetic neutral wire, and uses the magnetic neutral wire discharge plasma in the vacuum chamber. A film forming apparatus configured to form a film on a substrate by providing a shielding means along the inner surface of the electric field generating coil for blocking unnecessary substances including a film forming substance toward the electric field generating coil. Membrane device. 2. The film forming apparatus according to claim 1, wherein the shielding means comprises a thin cylindrical shield provided along the inner surface of the side wall of the vacuum chamber. 3. The film forming apparatus according to claim 1, further comprising means for expelling unnecessary substances adhering to the shielding means. 4. The film forming apparatus according to claim 3, wherein the means for driving off unnecessary substances comprises means for generating a high frequency induction electric field for high frequency cleaning. 5. The film forming apparatus according to claim 3, wherein the means for driving off the unnecessary substance comprises a heating means. 6. A magnetic field generating means for forming a magnetic neutral line which is a position where a magnetic field is continuously present in the vacuum chamber, and an electric field generating means which is provided in the vacuum chamber and is provided by the magnetic field generating means. It has an electric field generating coil that applies an electric field along a magnetic neutral wire formed in the vacuum chamber to generate discharge plasma in the magnetic neutral wire, and uses the magnetic neutral wire discharge plasma in the vacuum chamber. In a film forming apparatus configured to form a film on a substrate by using an electric field generating coil inside or surrounding the electric field generating coil, an electrostatic field component of the generated high frequency electric field that is not uniform in the circumferential direction is introduced into the vacuum chamber. A Faraday shield cage is installed to prevent the entry of the Faraday shield cage. A film forming apparatus characterized in that