WO2012058785A1

WO2012058785A1 - Variable eccentricity type magnetron

Info

Publication number: WO2012058785A1
Application number: PCT/CN2010/001752
Authority: WO
Inventors: 王人成; 胡伟; 阎绍泽; 季林红; 程嘉
Original assignee: 清华大学
Priority date: 2010-11-02
Filing date: 2010-11-02
Publication date: 2012-05-10

Abstract

A variable eccentricity type magnetron comprises a rotation drive module (100), a variable eccentricity module (200) and a magnetron module (300). The magnetron adopts a rotating motor and a linear motor. The rotating motor controls the magnetron to rotate around the axis of a sputtering target. The linear motor regulates the distance between the magnetron and the center of rotation. The magnetron improves the coverage rate and the uniformity of the surface field of the sputtering target, and the etching efficiency.

Description

Variable eccentric magnetron

Technical field

The invention relates to the technical field of magneto-electric tube motion trajectory control, in particular to a variable eccentricity magnetron for improving the uniformity of magnetic field distribution on a surface of a sputtering target and then improving the utilization ratio of the sputtering target.

Background technique

Sputtering is a PVD technology that has been gradually developed and applied since the beginning of the 20th century. Sputtering is a coating technique because it has better step coverage than the evaporation coating method, and has fewer radiation defects than the electron-binding evaporation method, and is often used in manufacturing processes such as integrated circuits of integrated circuits.

During the sputtering process, the sputtering chamber is first evacuated to a high vacuum by a vacuum pump, and then an inert gas such as argon gas is charged, and a negative bias voltage of several hundred volts is applied to the sputtering target to cause the inert gas to collide with the electrons. The ionization causes the glow discharge to form a plasma, and the positive ions strike the surface of the sputtering target under the action of the electric field, and the incident positive ions collide with the atoms in the sputtering target, so that the atoms on the surface of the sputtering target obtain kinetic energy from the lattice constraint; Splash deposition onto the surface of the sputtered material forms a film. In sputtering, a magnetic field is usually used to form a magnetic field on the surface of the sputtering target to accelerate the movement of electrons and increase the probability that they collide with inert gas atoms to generate positive ions. This process is called magnetron sputtering.

In an ideal magnetron sputtering system, the magnetic field component formed parallel to the surface of the sputtering target should be uniformly covered on the surface of the sputtering target because only the horizontal component can improve the sputtering efficiency. Due to structural size, weight, manufacturing process and cost, power consumption, maintenance and other factors, the uniformity and coverage of the magnetic field on the surface of the sputtering target in the actual magnetron sputtering system are difficult to achieve the above ideal state. From the sputtering target utilization index, the difference between the surface magnetic field of the sputtering target and the above ideal state can be reflected. At present, the sputtering target utilization rate of the conventional magnetron sputtering system is about 30%, and some optimized magnetron sputtering The sputtering target utilization rate of the firing system may reach 60-70%. It should be noted that the uniformity and coverage of the magnetic field component parallel to the surface of the sputtering target are increased, It is only possible to increase the utilization rate of the sputtering target, and it plays an important role in improving the uniformity of the thickness of the film deposited on the surface of the material to be sputtered, the coverage of the film, and the like.

The uniformity and coverage of the magnetic field component parallel to the surface of the sputter target are generally optimized by optimizing the structure of the magnetron and controlling the variation of the magnetic field over time. The former improves the magnetic field coverage and uniformity of the surface of the sputtering target by changing the spatial geometry and arrangement of the magnetron; the latter places the electromagnetic coil around the sputtering target or mechanical means to make the magnetron behind the sputtering target Performing the motion such as rotation to improve the magnetic field coverage and uniformity of the surface of the sputtering target.

There are many patents related to the use of mechanical devices to rotate the magnetron behind the sputtering target to improve the magnetic field coverage and uniformity of the sputtering target surface.

For example, Zhejiang University Wang Demiao and Ren Gaochao's Chinese patent ZL87106947 proposed a "separated magnet type planar magnetron sputtering source". Wang Demiao and Ren Gaochao designed a rotating magnetron, and its magnetron has three structural forms:

1) consisting of a V-shaped outer magnet (N pole), a sector-shaped eccentric inner magnet (S pole), and a 0-shaped outer magnetic ring (N pole) whose center is at the center of rotation;

2) It consists of a radial outer magnet (N pole), a sector-shaped eccentric inner magnet (S pole) corresponding to the number of outer magnets, and an O-shaped outer magnetic ring (N pole) whose center is at the center of rotation, such as a radial outer magnet. When it is X-shaped, there are 4 fan-shaped eccentric inner magnets;

3) It consists of two ω outer magnets (dip poles), a magnet with a center at the center of rotation and a shape matching the shape of the outer magnet (S pole), and a dome-shaped outer magnetic ring (dip pole) whose center is at the center of rotation. The most important feature of the rotating magnetron designed by Wang Demiao and Ren Gaochao is that the pole of the magnetron is separated, consisting of two parts: the outer magnet and the outer magnetic ring. The outer magnetic ring is fixed, the outer magnet and The inner magnet makes a rotary motion.

For example, Chinese patent ZL03816946.0 of Applied Materials Co., Ltd., Ian Richard H., et al. proposed an "asteroid magnetron": the first rotating arm is directly driven by the motor, and the sputtering target axis The heart turns, In addition to directly driving the first rotating arm, the motor further drives the second rotating arm to rotate by mechanical transmission; the rotating center of the second rotating arm is located on the first rotating arm, and a cylindrical inner magnet and a circle are mounted on the second rotating arm. A magnetron composed of a ring-shaped outer magnet. The ratio of the rotational speed of the first rotating arm to the second rotating arm is less than 1, and is not an integer, which gives a specific speed ratio of 1.03 to 6 in one embodiment. The main feature of the asteroid-type magnetron designed by Yi Yang Richard Hong et al is that it can realize the magnetic field coverage and uniformity of the surface of the high sputtering target by using a simple-shaped magnetron, which is beneficial to reduce the magnetoelectricity. The cost of manufacturing and maintenance.

Similar to the invention of the patent ZL87106947, only a rotating magnetron is eccentrically rotated, and the magnetic field does not cover the central region of the surface of the sputtering target, or excessive etching occurs in the central region of the surface of the sputtering target, that is, this method cannot simultaneously It has a high coverage and a high uniformity in the central region of the surface of the sputtering target. The planetary magnetron invented by the patent ZL03816946.0, although a suitable magnetic field parameter and a rotational speed ratio are selected, a magnetic field with a high coverage and a high uniformity can be obtained, but the etching efficiency is relatively low. Summary of the invention

In view of the insufficiency of the coverage and uniformity of the magnetic field formed by the magnetron on the surface of the sputtering target in the existing magnetron sputtering apparatus, or the etching efficiency is not high, the present invention proposes a variable eccentric magnetron .

The invention adopts a rotating electric machine and a linear motor. The rotating electric machine controls the magnetron to rotate around the axis of the sputtering target, and the linear motor is responsible for adjusting the distance between the magnetron and the center of rotation (ie, the eccentricity), so that the magnetic field of the sputtering target surface has Higher coverage and higher uniformity, combined with higher etching efficiency.

The specific technical solution is as follows: The variable eccentric magnetron comprises a rotary drive component, a variable eccentric component and a magnetron component.

The rotary drive assembly is mounted on the upper cover of the PVD device to support the variable eccentricity assembly and the magnetron assembly and to rotate the magnetron assembly about the sputtering target axis; the variable eccentric component is mounted on An output end of the rotational movement of the rotary drive assembly functions to support the magnetron and adjust the distance between the magnetron and the center of rotation; the magnetron assembly is mounted on the variable eccentric component on the surface of the sputtering target Forming a magnetic field, To improve the utilization of the sputtering target and the quality of the deposited film on the surface of the sputtered material.

The structure of the rotary drive assembly is: the internal teeth of the steel wheel mesh with the external teeth of the flexible wheel, and the wave wheel is equipped with a wave generator; wherein the steel wheel is fixed on the reducer housing by screws, and the flexible wheel is fixed by the flexible wheel positioning pin On the middle inner sleeve; the reducer housing constitutes the rotary pair via two bearings and the inner inner sleeve, ie the reducer housing, the wave generator, the steel wheel, the flexible wheel, the bearing, the intermediate inner sleeve, the flexible wheel positioning pin and the bearing ^ 3⁄4 The cover constitutes a harmonic reducer; the lower end of the output shaft of the DC servo motor and the inner hole of the wave generator of the harmonic reducer are fixed by the top wire as an input of the rotary drive; the intermediate inner sleeve is the movement of the rotary drive assembly Output terminal; an encoder for detecting the position of the motor is installed at the upper end of the output shaft of the DC servo motor for feedback control of the DC servo motor.

The structure of the variable eccentricity component is: the linear stepping motor drives the magnetron base to slide on the guide rail by an external driving nut, the magnetron base is suspended on the guide rail by a slider, and the guide rail is fixed on the rotating arm , that is, the linear stepping motor, the external drive nut, the magnetron base, the slider, the guide rail and the screw constitute a linear motion platform, and the forward and reverse rotation of the linear stepping motor increases or shortens the magnetron assembly and the rotation center' the distance.

The structure of the magnetron assembly is: the inner magnetic pole and the outer magnetic pole are fixed on the magnetic body, and the magnetic yoke is fixed on the magnetron base of the variable eccentricity assembly, so that the magnetron assembly rotates around the sputtering target shaft with the rotary driving component While the heart is rotating, it can reciprocally move linearly with the eccentricity component.

The inner magnetic pole and the outer magnetic pole are extremely similar in shape to a horseshoe-shaped annular magnet.

When the magnetron assembly moves inward, the first central point of the inner magnetic pole and the outer magnetic pole exceeds the center of the sputtering target, and when the magnetron assembly moves outward, the second central point of the inner and outer magnetic poles reaches By sputtering the edge of the target, full coverage of the surface of the sputtering target by the magnetic field can be achieved.

The beneficial effects of the present invention are as follows: The device controls the magnetron to rotate around the axis of the sputtering target by a rotating motor, and the distance between the magnetron and the center of rotation is adjusted by the linear motor, when the magnetron assembly has a preferred speed of motion When reciprocating, the surface magnetic field of the sputtering target can have higher coverage, higher uniformity and higher etching efficiency.

DRAWINGS

1 is a schematic cross-sectional view showing a variable eccentric magnetron mounted on a PVD device;

2 is a three-dimensional assembly diagram of a variable eccentric magnetron mounted on a PVD device;

Figure 3 is a schematic cross-sectional view showing the structure of the rotary drive assembly;

Figure 4 is a three-dimensional assembly schematic view of the rotary drive assembly;

Figure 5 is a schematic cross-sectional view showing the structure of the variable eccentricity assembly;

Figure 6 is a three-dimensional assembly diagram of the variable eccentricity component;

Figure 7 (a) is a top plan view of the structure of the magnetron assembly;

Figure 7 (b) is a cross-sectional view taken along line A-A of Figure 7 (a);

Figure 8 is a three-dimensional assembly diagram of a magnetron assembly; '

1-support frame; 2-sputter target; 3-seal ring; 4-sputter cavity; 5-shield; 6-wafer clip; 7-wafer; 8-wafer support; 10-RF source; 11-vacuum pump; 12-rotary screw set; 13-transfer screw set; 14-magnet tube screw set; 100-rotary drive assembly; 101-encoder;

102-DC servo motor; 103-motor bushing; 104-wave generator; 105-steel wheel; 106-reducer housing; 107-bearing; 108-bearing end cap; 109-flexible wheel; 111-Intermediate inner sleeve; 112-top wire; 113-motor screw set; 114-steel wheel screw set; 115-bearing end cap screw set; 116-positioning pin screw set; 200-variable eccentricity component; 201-rotation Arm; 202-rail; 203-slider; 204-external drive nut; 205-linear stepper motor; 206-magnet tube base; 207-rail screw set; 208-external drive nut screw set; 209-straight step Into the motor screw set; 210-slider screw set; 300-magnet tube assembly; 301-magnetic yoke; 302-external magnetic pole; 303-inner magnetic pole; 304-external magnetic pole screw set; 305-inner magnetic pole screw set. detailed description

The present invention provides a variable eccentric magnetron, and the present invention will be described in detail below with reference to the drawings and specific embodiments.

As shown in FIGS. 1 through 6, the variable eccentric magnetron of the present invention is composed of a rotary drive assembly 100, a variable eccentricity assembly 200, and a magnetron assembly 300. The rotary drive assembly 100 is fixed to the support frame 1 by the rotary member screw set 12 through the reducer housing 106, and the variable eccentric magnetron is mounted directly above the sputtering target 3, and the DC servo motor in the rotary drive assembly 100 is driven. The rotating shaft of 102 passes through the axis of the sputtering target 2; the rotating arm 201 in the variable eccentric assembly 200 is fixed to the intermediate inner sleeve 111 in the rotary driving assembly 100 via the translation member screw set 13, and the variable eccentricity assembly 200 is The rotary drive assembly 100 is coupled together; the magnetic yoke 301 in the magnetron assembly 300 is fixed to the magnetron base 206 in the variable eccentric assembly 200 via the magnetron screw assembly 14, and the magnetron assembly 300 is changed. The eccentric component 200 is coupled together; the sputtering target 2 is fixed on the bottom of the support frame 1 on the PVD; the sputtering target 2 is mounted on the sputtering cavity 4 via the sealing ring 3; the wafer 7 is located on the sputtering target 3 Bottom, a plasma is formed between the wafer 7 and the sputtering target 2 at the time of sputtering; the wafer 7 is mounted on the wafer holder 8, and the wafer holder 8 is mounted at the bottom of the sputtering chamber 4, and at the wafer holder 8 The lower end is connected to the RF source 10; at the upper edge of the wafer 7, there is a ring-shaped wafer a clip 6 for fixing the wafer 7; a shield cover 5 inside the sputtering chamber 4 for protecting the sputtering chamber 4, so that atoms of the sputtering target 2 cannot be deposited in the sputtering chamber 4 during sputtering The inner surface; the vacuum pump 11 is connected to the bottom of the sputtering chamber 4, and the closed chamber formed by the sputtering chamber 4, the sputtering target 2, and the seal ring 3 is evacuated by the vacuum pump 11 before the sputtering is performed (r ⁸ Torr or lower pressure; the working gas source 9 is connected to the bottom of the sputtering chamber 4, and the working gas source 9 supplies an inert gas such as argon as a working gas during sputtering, and the working gas is discharged into a plasma during the sputtering process. Body, positively charged argon ions bombard the lower surface of the sputtering target 2, deposit atoms of the sputtering target 2 onto the upper surface of the wafer 7; during sputtering, ground the sputtering chamber 4 and the shield 5 As the anode of the plasma discharge, the sputtering target 2 was connected to a -600 volt DC bias voltage as a cathode for plasma discharge. 3 and 4 are structural cross-sectional views and a three-dimensional assembly schematic view of the rotary drive assembly 100. An encoder 101 is mounted on the upper output end of the DC servo motor 102 shaft, the DC servo motor 102 provides rotational motion for the variable eccentric magnetron, and the encoder 101 is used for feedback control of the rotary motion; The lower output end is matched with the inner hole of the wave generator 104 via the motor bushing 103, and is fixed by the top wire 112, and the DC servo motor 102 drives the wave generator 104 to rotate; the outer casing of the DC servo motor 102 is fixed to the speed reducer via the motor screw set 113. On the outer casing 106, as a variable eccentric magnetron frame; the inner hole of the flexible wheel 109 cooperates with the wave generator 104, the outer teeth of the flexible wheel 109 mesh with the inner teeth of the steel wheel 105; the steel wheel 105 passes the steel wheel screw set 114 Fixed on the reducer housing 106, the flex wheel 109 is positioned by the flex wheel positioning pin 110 and secured to the intermediate inner sleeve 111 via the set of pin screw sets 116, and the bearing end cap screw set between the bearing end cap 108 and the reducer housing 106 115 is fixed; the intermediate inner sleeve 111 constitutes a rotating pair via the bearing 107 and the bearing end cap 108 and the reducer housing 106. In fact, the reducer housing 106, the wave generator 104, the steel drum 105, the flex wheel 109, the bearing 107, the intermediate inner sleeve 111, the flex wheel positioning pin 110 and the bearing end cap 108 constitute a typical harmonic reducer, wherein the wave Generator 104 is the input and flex wheel 109 is the output.

5 and 6 are structural cross-sectional views and three-dimensional assembly diagrams of the variable eccentricity assembly 200. The outer casing of the linear stepping motor 205 is fixed to the side of the rotating arm 201 via a linear stepping motor screw set 209, and the two guiding rails 202 are fixed to the bottom surface of the rotating arm 201 via the rail screw set 207; the outer driving nut 204 is externally driven by the nut screw set. The 208 is fixed on the side of the magnetron base 206, and the output shaft of the linear stepping motor 202 rotates to push the external driving nut 204 to perform linear motion, and pushes or pulls the magnetron base 206 to linearly reciprocate along the guide rail 202; The tube base 206 is fixed to the four sliders 203 via the slider screw set 210, and the slider 203 slides on the two guide rails 202. In fact, the rotating arm 201, the linear stepping motor 205, the external driving nut 204, the slider 203, the guide rail 202 and the magnetron base 206 constitute a linear motion platform, wherein the rotating arm 201 is a frame, a linear stepping motor 205 is the power source and the magnetron base 206 is the output.

7 and 8 are structural cross-sectional views and three-dimensional assembly diagrams of the magnetron assembly 300. Magnetoelectric tube group The member 300 is a horseshoe-shaped magnet, and the outer magnetic pole 302 and the inner magnetic pole 303 are horseshoe-shaped annular magnets, and the outer magnetic pole 302 and the inner magnetic pole 303 are fixed to the magnetic yoke 301 via the outer magnetic pole screw set 304 and the inner magnetic pole screw set 305, respectively.

The above embodiments are merely illustrative of the present invention and are not to be construed as limiting the scope of the invention, and various modifications and changes can be made without departing from the spirit and scope of the invention. Equivalent technical solutions are also within the scope of the invention, and the scope of the invention is defined by the claims.

Claims

Claim

A variable-biased magnetron, which uses a rotating electrical machine and a linear motor to respectively control the rotation and translation of the magnetron, including a rotary drive assembly (100), a variable eccentric component (200), and a magnetron assembly (300), characterized in that

The rotary drive assembly (100) is mounted on the upper cover of the PVD device to support the variable eccentric assembly and the magnetron assembly and to rotate the magnetron assembly about the sputtering target axis;

The structure of the rotary drive assembly (100) is: the internal teeth of the steel wheel (105) mesh with the external teeth of the flexible wheel (109), and the wave generator (104) is installed in the flexible wheel (109); wherein the steel wheel (105) ) fixed to the reducer housing (106), the flexible wheel (109) is fixed to the intermediate inner sleeve (111) by the flex wheel positioning pin (110); the reducer housing (106) is passed through the two bearings and the intermediate inner sleeve (111) Constituting the rotating pair, that is, the reducer housing, the wave generator, the steel wheel, the flexible wheel, the bearing, the intermediate inner sleeve, the flexible wheel positioning pin and the bearing end cover constitute a harmonic reducer; the lower end of the output shaft of the DC servo motor (102) The inner bore of the wave generator (104) with the harmonic reducer is fixed by the top wire as an input of the rotary drive; the intermediate inner sleeve (111) is the motion output end of the rotary drive assembly (100); An encoder (101) for detecting the position of the motor is mounted on the upper end of the output shaft of the servo motor (102) for feedback control of the DC servo motor; 'The eccentricity assembly (200) is mounted on the rotary drive assembly (100) Rotating motion The end, play a supporting role in regulating the magnetron and the magnetron tube and the rotation center distance;

The structure of the variable eccentricity component (200) is: The linear stepping motor (205) pushes the magnetron base (206) to slide on the guide rail (202) by an external driving nut (204), the magnetron base The seat (206) is suspended from the guide rail (202) by a slider (203), and the guide rail (202) is fixed on the rotating arm (201), that is, a linear stepping motor, an external driving nut, a magnetron base, a slider, The guide rail and the screw form a linear motion platform, and the forward and reverse rotation of the linear stepping motor increases or shortens the distance between the magnetron assembly and the rotation center; The magnetron assembly (300) is mounted on the variable eccentricity assembly (200) to form a magnetic field on the surface of the sputtering target to improve the utilization of the sputtering target and the quality of the deposited film on the surface of the sputtered material;

The structure of the magnetron assembly (300) is: an inner magnetic pole (303) and an outer magnetic pole (302) are fixed on the magnetic yoke (301), and the magnetic yoke (301) is fixed on the magnetic pole of the variable eccentric component (200). The tube base (206) enables the magnetron assembly to reciprocate linearly with the variable eccentric assembly while rotating the rotary drive assembly about the sputtering target axis.

2. A variable eccentric magnetron according to claim 1, wherein said inner magnetic pole (303) and outer magnetic pole (302) are horseshoe-shaped annular magnets of similar shape.

3. A variable eccentric magnetron according to claim 1, wherein when the magnetron assembly (300) moves inward, the first central point of the inner magnetic pole and the outer magnetic pole exceeds The center of the target is sputtered, and when the magnetron assembly (300) moves outward, the second center point of the inner and outer magnetic poles reaches the edge of the sputtering target, and the full coverage of the sputtering target surface by the magnetic field can be achieved.