JP3238933B2 - Magnetron plasma processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron plasma processing method used in, for example, a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Conventionally, as a magnetron plasma processing apparatus, for example, a dry etching apparatus and a magnetron plasma thin film forming apparatus used for manufacturing a semiconductor device are known. In this type of magnetron plasma processing apparatus, a plasma is generated in a processing chamber of the apparatus, and a desired process (such as etching or thin film formation) is performed by utilizing the action of ions, radicals, electrons, and the like in the plasma.

Hereinafter, such a magnetron plasma processing apparatus will be described with reference to the magnetron plasma etching apparatus shown in FIG.

In FIG. 1, a mounting electrode 42 for mounting a wafer 10 as an object to be processed and an upper electrode 42 are provided inside a process chamber 40 which can be evacuated and into which an etching gas can be introduced. An electrode 46 is provided. The mounting electrode 42 and the upper electrode 46 are both formed of a conductive material, and the upper electrode 46 is grounded, and outputs a high frequency power of 380 KHz or 13.56 MHz to the mounting electrode 42, for example. RF power supply 44
Is connected. With such a configuration, the upper electrode 4
Plasma can be generated facing the wafer 10 by a cathode coupling (RIE) method using the plate 6 and the mounting electrode 42 as parallel plate electrodes. The ions or radicals in the plasma react with the silicon compound forming the wafer 10 or physically act thereon, whereby the wafer 10 is etched.

Further, in this device, the two permanent magnets 38 supported by the yoke 36 are rotated about the rotation shaft 36a, thereby forming the upper electrode 4 as shown by a broken line in FIG.
The purpose is to form a uniform magnetic field having a horizontal component between the upper electrode 46 and the mounting electrode 42 between the mounting electrode 6 and the mounting electrode 42. This is because the action of the electric field generated between the upper electrode 46 and the mounting electrode 42 and the magnetic field component orthogonal to the electric field causes cycloidal motion of the electrons in the directions orthogonal to each other. This is to increase the frequency of collision with gas molecules. As a result, plasma can be generated in a low-pressure atmosphere, the amount of plasma generated can be increased, and fine etching can be performed in 16M, 32M and VLSI manufacturing processes, and therefore, the etching speed can be increased. be able to.

[0006]

In the above-described plasma etching apparatus, it is required that the amount of etching be uniform over the entire surface of the wafer 10.

However, when etching is performed using the conventional plasma etching apparatus as described above, the etching rate is generally higher near the central portion of the wafer 10 than near the peripheral portion of the wafer 10. Uniformity could not be fully satisfactory. According to the inventor's study, this is because the wafer 1
0, the magnetic field obtained by the permanent magnet 38 is substantially horizontal to the surface of the wafer 10 and therefore a component orthogonal to the electric field is large. This is considered to be because the component which is not horizontal is small in a component orthogonal to the electric field, so that the cycloidal motion of the electron hardly occurs.

[0008] Such a problem is not limited to a magnetron plasma etching apparatus, but is also common to a plasma sputtering apparatus, a plasma CVD apparatus, and the like that perform processing by plasma.

The present invention has been made in view of such problems of the prior art, and is a magnetron capable of performing processing so as to generate a uniform electron cyclotron kinetic force over the entire surface of an object to be processed. It is an object to provide a plasma processing method .

[0010]

According to the magnetron plasma processing method of the present invention, a first electrode on which an object to be processed is placed;
A second electrode having a first surface facing the first electrode, and a second surface perpendicular to the first electrode at an edge of the first surface; and comprising a magnetic field generator for forming a magnetic field between the high-frequency power supply provided as to generate an electric field, the first electrode and the second electrode between the second electrode and Magnetron plasma treatment
At device, wherein the workpiece Te method odor <br/> to plasma treatment, and該被processed perpendicular vertical component in the heart of pre Symbol workpiece at the periphery of the object to be processed It generates an electric field which have a parallel horizontal component to said processed, and該被processed parallel horizontal component at the central portion of the front Symbol workpiece, the horizontal at the periphery of the object to be processed to have a vertical component orthogonal to the component
A magnetic field is generated, and at a peripheral portion of the object, cycloid motion of electrons due to a vertical component of the electric field and a horizontal component of the magnetic field is smaller than that of the central portion of the object. increases the electron cycloidal motion by said vertical component of the horizontal component field, characterized in that to perform uniform treatment on the entire surface of the <br/> workpiece.

[0011]

By forming a surface (second surface) perpendicular to the first electrode on the second electrode, when the power is turned on, the peripheral portion of the object placed on the first electrode is turned on. Generates an electric field having a horizontal component. The horizontal component of the electric field interacts with the vertical component formed at the periphery of the object to be processed in the magnetic field generated by the magnetic field generator to cause cycloidal motion of electrons according to Fleming's left-hand rule. This increases the frequency of collisions between electrons and gas molecules in a region where the vertical component of the magnetic field is large.

That is, in the present invention, the first electrode and the second electrode
Of the magnetic field formed between the first electrode and the first electrode, the horizontal magnetic field component in the central region of the object to be processed is determined by the first surface of the second electrode (the surface facing the first electrode) and the first electrode And an electric field component perpendicular to the object to be processed, which causes electrons in the plasma to perform cycloidal motion, and a vertical magnetic field component in a peripheral region of the object to be processed is generated by the second electrode of the second electrode. The object to be formed formed by the second surface (a surface perpendicular to the first electrode) and the first electrode and a horizontal electric field component act on the object,
Causes electrons in the plasma to perform cycloidal motion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, as a first embodiment of the present invention, a case where the present invention is applied to a magnetron plasma etching apparatus will be described as an example.

FIG. 1 is a sectional view schematically showing the configuration of a magnetron plasma etching apparatus according to this embodiment. The wafer 10 to be processed is the first susceptor 1
2 is mounted and fixed on the upper surface. As a method for mounting and fixing, for example, an electrostatic chuck (not shown) method can be used. This is because the wafer 10
Is fixed by suction. The first susceptor 12 is detachably fixed to an upper surface of the second susceptor 14. As described above, the susceptor is divided into two parts because the first susceptor becomes upper when the susceptor is contaminated.
Only the susceptor 12 needs to be replaced, in order to facilitate its maintenance.

The side and bottom surfaces of the first and second susceptors 12 and 14 are covered with an insulating ceramic 16. On the lower surface of the insulating ceramic 16, a liquid nitrogen storage unit 20 as a cooling unit is provided. The bottom surface of the inner wall of the liquid nitrogen accommodating portion 20 is formed, for example, in a porous manner so that each boiling can be caused, and the liquid nitrogen inside thereof can be maintained at -196 ° C.

A chamber for forming a reaction chamber is formed of an upper chamber 30 and a lower chamber 32. The lower chamber 32 contains the first susceptor 12.
Has a bottomed cylindrical portion that exposes only the wafer mounting surface of the above into the chamber chamber and covers other portions. That is, the first and second susceptors 12, 14, the insulating ceramic 1
6, a side wall 32a that covers a side surface of the liquid nitrogen storage unit 20,
And a support wall 32b. On the other hand, the upper chamber 30 is formed in a cylindrical shape so as to cover the periphery of the side wall 32 a of the lower chamber 32, and the lower end thereof is connected and fixed to the lower chamber 32. The upper chamber 30 has a first surface 30 a facing the upper surface of the first susceptor 12, and a second surface 30 b perpendicular to the upper surface of the first susceptor 12. Note that the etching gas is introduced through a hole (not shown) in the first surface 30a.

A reaction chamber constituted by the upper chamber 30 and the lower chamber 32 can be evacuated by a pipe 34.

As shown in FIG. 1, the first susceptor 12, the second susceptor 14, the insulating ceramic 1
6. A through hole is provided in each of the liquid nitrogen accommodating portions 20, and a pipe 36 is disposed in the through hole. The joint surface between the wafer 10 and the first susceptor 12 has voids due to minute irregularities on the back surface of the wafer 10, which causes uneven temperature in the wafer 10. By filling the gap with H ₂ gas at a predetermined pressure through the gap 36, such uneven temperature can be prevented.

In the magnetron etching apparatus of the present embodiment, the upper chamber 30 is grounded, and RF power is supplied to the first and second susceptors 12 and 14, thereby forming two electrodes. That is, the upper chamber 30
First the surface 30a and the second surface 30b to act as it then anode <br/> over cathode electrode, by applying a surface of the first susceptor 12 as cathodes when cathode electrode, RIE method magnetron plasma It constitutes an etching apparatus. Then, an etching gas is introduced while the inside of the chamber is evacuated, and plasma is generated between the opposed electrodes by the etching gas. Thus, in this embodiment,
Since the upper chamber 30 is used as a cathode electrode, the configuration of the apparatus can be simplified, and a permanent magnet 38 described later can be arranged at the top outside the upper chamber 30. Also, by disposing the permanent magnet 38 outside the upper chamber 30 in this manner,
Since the volume of the reaction chamber can be reduced, the piping 34
The load on a vacuum pump (not shown) connected to the apparatus can be reduced, or the time required for evacuation can be reduced.

[0020] In the present embodiment, as described above, anode <br/> chromatography cathode electrode (upper chamber 30), the electrode unit that faces the cathodes when cathode electrode (first susceptor 12) (first Face 30
a) a cathode over cathode electrode and the vertical electrode section (second surface 30b)
As shown by the solid line in FIG. 1, the electric field formed by the cathode electrode and the anode electrode is substantially vertical near the center of the wafer 10 and becomes more horizontal as it approaches the periphery. The components increase.

In the magnetron etching apparatus of this embodiment, the upper chamber 30 and the first chamber are rotated by rotating the permanent magnet 38 at a position facing the wafer 10 and outside and above the upper chamber 30. A magnetic field can be formed between the susceptor 12 and the susceptor 12. Thus, forming the magnetic field between the upper chamber 30 and the first susceptor 12 by the permanent magnet 38 is as follows.
And the electric field generated between the upper chamber 30 first susceptor 12, by the action of the magnetic field component perpendicular to the electric field, according to Fleming's left-hand rule, perform electronic cycloidal motion in the direction orthogonal to each This is to increase the frequency of collision between electrons and gas molecules.

The magnetic field formed by the permanent magnet 38 is
As shown by the broken line in FIG. 1, the wafer 10 is substantially horizontal above the center of the wafer 10, and the closer to the periphery, the greater the inclination of the arc (ie, the greater the vertical component).
In contrast, in the present embodiment, as described above, the anode over cathode electrode (upper chamber 30), cathodes when cathode electrode (first
The electric field formed by the upper chamber 30 and the first susceptor 12 is almost vertical near the center of the wafer 10 because the electrode section 30a and the electrode section 30b perpendicular to the susceptor 12) are provided. Therefore, the horizontal component increases as the position approaches the periphery. Therefore, in the plasma near the center of the wafer 10, the cycloid motion of the electrons is such that the force mainly caused by the action of the vertical component of the electric field and the horizontal component of the magnetic field is made uniform around the center. The closer to the periphery of the wafer 10, the smaller the vertical component of the electric field and the horizontal component of the magnetic field. At the same time, however, the horizontal component of the electric field on the wafer surface increases and the vertical component of the magnetic field increases. Therefore, the wafer 1
0, the cycloidal motion of the electrons caused by the action of the vertical component of the electric field and the horizontal component of the magnetic field on the wafer surface decreases, while the horizontal component of the electric field and the vertical component of the magnetic field decrease. The cycloidal motion of the electrons caused by the action increases. Thus, in the present embodiment, the difference between the amount of plasma generated at the peripheral portion of the wafer 10 and the amount of plasma generated at the central portion is eliminated. Thereby, the etching rate of the wafer 10 can be made uniform, and the amount of etching can be made uniform.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

[0024]

Further, the present invention is not necessarily applied to a magnetron plasma etching apparatus, but can be similarly applied to other magnetron plasma apparatuses such as a sputtering apparatus, a plasma CVD apparatus, an ion source and an X-ray source.

[0026]

As described above in detail, according to the magnetron plasma processing method of the present invention, uniform processing can be performed on the entire surface of the object to be processed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a magnetron plasma etching apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a conventional magnetron plasma etching apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Wafer 12,14 Susceptor 20 Cooling part (liquid nitrogen storage part) 30 Upper chamber 30a First surface of upper chamber 30b Second surface of upper chamber 32 Lower chamber 34, 36 Piping
TE032401

Continuation of the front page (72) Inventor Toshihisa Nozawa 2-3-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo Inside Tokyo Electron Limited (56) References JP-A-1-211625 (JP, A) JP-A-63- 13158 (JP, A) JP-A-62-2325 (JP, A) JP-A-2-94522 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3065 C23C 14 / 34

Claims (1)

(57) [Claims] A first electrode on which an object to be processed is placed; a first surface facing the first electrode; and an edge of the first surface perpendicular to the first electrode. A second electrode having a second surface; a high-frequency power supply provided to generate an electric field between the first electrode and the second electrode; Magnetron plasma comprising a magnetic field generator for generating a magnetic field between the electrodes
In the processing apparatus, the Oite <br/> the object to be processed to a method for plasma treatment, prior SL and該被processed at the center portion of the specimen perpendicular to the vertical component, the peripheral portion of the specimen and該被processed parallel horizontal component in generating an electric field have a parallel horizontal component to said processed, the center of the pre-Symbol target object at said at peripheral portion of the specimen wherein generating a magnetic field that have a vertical component which is perpendicular to the horizontal component, the center of the object in the processed peripheral portion of the electronic cycloidal movement the object to be processed with the vertical component due to the horizontal component of the magnetic field of the field while smaller than parts, it increases the electronic cycloidal motion by said vertical component of the magnetic field and the horizontal component of the electric field, and characterized in that to perform uniform treatment on the entire surface of the object to be processed Magnetron plasma processing method .