JP5089962B2 - Magnetron sputtering electrode and sputtering apparatus provided with magnetron sputtering electrode - Google Patents

Description

  The present invention relates to a magnetron sputtering electrode for forming a predetermined thin film on a processing substrate by a magnetron sputtering method, and a sputtering apparatus provided with the magnetron sputtering electrode.

  In this type of sputtering apparatus, for example, a magnet assembly is provided to form a tunnel-like magnetic flux in front of a rectangular target (on the sputtering surface side). Then, when sputtering a target by applying a negative DC voltage or an AC voltage to the target, the electrons ionized in front of the target and secondary electrons generated by sputtering are captured to increase the electron density in front of the target, and these The plasma density is increased by increasing the collision probability between electrons and rare gas gas molecules introduced into the vacuum chamber. Thereby, for example, there is an advantage that the film forming speed can be improved without causing a significant temperature rise of the processing substrate, and it is often used for forming a metal film or the like on the processing substrate.

As a magnet assembly incorporated in this type of sputtering apparatus, a support plate (yoke) provided in parallel with the target, a central magnet arranged linearly in the longitudinal direction at the substantially upper center of the support plate, In addition, there is known one constituted by peripheral magnets arranged by changing the polarity on the target side so as to surround the periphery of the central magnet (Patent Document 1).
Japanese Patent Laid-Open No. 2000-248360 (for example, refer to the column of the prior art).

  By the way, when sputtering using the above sputtering apparatus, electrons in the plasma generated in a racetrack shape in front of the target are watched along the racetrack according to the polarity of the target side of the central magnet and the peripheral magnet. Exercise around or counterclockwise. Then, when it reaches the end of the target, it is bent by the electromagnetic field and changes its direction, but when it changes its direction, inertial motion remains, so electrons jump out to the target end.

  When electrons jump out to the target end side due to this inertial movement, the plasma spreads locally and the target erosion region extends to the target end side, so that the discharge becomes unstable and favorable thin film formation is inhibited. There is a fear. In addition, when the magnet assembly is reciprocated horizontally along the target in order to make the erosion area of the target as the sputtering progresses, the size and amount of movement of the magnet assembly can be reduced in consideration of the jumping out of the electrons. In this case, the non-erodible area becomes larger and the target utilization efficiency becomes worse.

  Therefore, in view of the above points, an object of the present invention is to provide a magnetron sputter electrode and a magnetron sputter electrode that can uniformly erode the outer peripheral edge of the target, can form a good thin film, and can increase the utilization efficiency of the target. It is providing the sputtering device provided with.

In order to solve the above problem, a magnetron sputtering electrode of the present invention comprises a target disposed opposite sense substrate, and a magnet assembly disposed behind the target to substrate and facing away, the magnet the assembly includes a central magnet disposed linearly, this so as to surround the periphery of the central magnet, is composed of a peripheral magnet disposed changing the polarity of the data Getto side, the direction in which the central magnet extends linearly as longitudinally, it has a straight portion extending parallel to the central magnet and the peripheral magnets on both sides of the respective longitudinal, vertical magnetic field of the magnetic flux generated in the tunnel-shaped with the straight portion of the central magnet and the peripheral magnet The position where the component becomes 0 is shifted to the central magnet side within a certain range from the central part of the magnet assembly at the longitudinal end part of the magnet assembly so as to prevent the electrons from jumping out to the target end side. construction was And wherein the door.

  According to the present invention, since the position where the vertical component of the magnetic field is 0 is locally shifted to the central magnet side within a certain range, the range where the position where the vertical component of the magnetic field is 0 is shifted, If it corresponds to the location where electrons jump out, even if an inertial movement remains when the electrons come to the end of the target and bend in the electromagnetic field and change its direction, the plasma does not jump out to the target end. Is prevented from spreading locally. As a result, it is possible to stably discharge during sputtering and to form a good thin film.

  The range in which the position where the vertical component of the magnetic field becomes 0 may be shifted to one side of the central magnet and alternately at both ends of the central magnet. Thereby, for example, when the magnet assembly is reciprocated, the position where the vertical component of the magnetic field becomes 0 only at the position where the electrons are ejected to the target end side by inertial movement in the reciprocating direction is opposite to the electron ejecting direction. The target erosion area can be made uniform with the progress of sputtering at the outer peripheral edge of the target, and the moving distance of the magnet assembly can be increased.

  In order to shift the position where the vertical component of the magnetic field becomes 0 within a certain range, for example, the magnetic force of at least one of the central magnet and the peripheral magnet may be locally increased or decreased.

  In this case, if a magnetic shunt having a predetermined length is attached to the side surfaces of both sides in the longitudinal direction of the central magnet, the magnetic force in the range where the magnetic shunt is provided in the central magnet is locally weakened, and the magnet assembly itself Without changing the form, the position where the vertical component of the magnetic field becomes 0 may be shifted within a certain range to the side opposite to the electron emission direction.

  If drive means for reciprocating the magnet assembly in parallel along the back surface of the target is provided, the target erosion area can be made uniform as sputtering proceeds at the outer peripheral edge of the target. As a result, a high utilization efficiency of the target can be achieved.

In order to solve the above-described problem, the sputtering apparatus of the present invention includes any one of the above-described magnetron sputtering electrodes disposed in a sputtering chamber that can be evacuated, and gas introduction means for introducing a predetermined gas into the sputtering chamber; A sputtering power supply that enables power supply to the target is provided.

  As described above, in the magnetron sputtering electrode of the present invention and the sputtering apparatus equipped with this magnetron sputtering electrode, the outer peripheral edge of the target can be evenly eroded, the target utilization efficiency is high, and the discharge is stabilized. There is an effect that a good thin film can be formed.

  Referring to FIG. 1, 1 is a magnetron type sputtering apparatus (hereinafter referred to as “sputtering apparatus”) having a magnetron sputtering electrode C of the present invention. The sputtering apparatus 1 is, for example, an in-line type, and includes a sputtering chamber 11 that can be maintained at a predetermined degree of vacuum through vacuum exhausting means (not shown) such as a rotary pump or a turbo molecular pump. A substrate transfer means 2 is provided in the upper space of the sputtering chamber 11. The substrate transport unit 2 has a known structure, for example, has a carrier 21 on which the processing substrate S is mounted, and intermittently drives the driving unit to sequentially transport the processing substrate S to a position facing a target described later. it can.

  A gas introducing means 3 is provided in the sputtering chamber 11. The gas introducing means 3 communicates with a gas source 33 through a gas pipe 32 provided with a mass flow controller 31, and introduces a sputtering gas such as argon or a reactive gas used in reactive sputtering into the sputtering chamber 11 at a constant flow rate. it can. The reaction gas is selected according to the composition of the thin film to be formed on the processing substrate S, and oxygen, nitrogen, carbon, hydrogen-containing gas, ozone, water, hydrogen peroxide, or a mixed gas thereof is used. It is done. A magnetron sputtering electrode C is disposed below the sputtering chamber 11.

  The magnetron sputtering electrode C has a single target 41 having a substantially rectangular parallelepiped shape (rectangular in top view) provided so as to face the sputtering chamber 11. The target 41 is produced by a known method according to the composition of a thin film to be formed on the processing substrate S such as Al alloy, Mo, or ITO, and the area of the sputter surface 411 is set larger than the outer dimension of the processing substrate S. Has been. The target 41 is also bonded to a backing plate 42 that cools the target 41 through a bonding material such as indium or tin during sputtering, and the sputtering surface 411 of the target 41 is treated with the target 41 bonded to the backing plate 42. It is attached to the frame 44 of the magnetron sputtering electrode C through the insulating plate 43 so as to face the substrate S. When the target 41 is mounted, a shield (not shown) serving as an anode grounded to the ground is attached around the target 41.

  The magnetron sputtering electrode C has a magnet assembly 5 located behind the target 41 (on the side opposite to the sputtering surface 411). The magnet assembly 5 includes a support plate (yoke) 51 formed so as to extend on both sides of the target 41 along the longitudinal direction. The support plate 51 is composed of a flat plate made of a magnetic material that amplifies the attractive force of the magnet. Further, on the support plate 51, a central magnet 52 (for example, the polarity on the target 41 side is S) arranged on the center line extending in the longitudinal direction of the support plate 51 and the periphery of the central magnet 52 are surrounded. In addition, a peripheral magnet 53 (the polarity on the target 41 side is N) arranged in an annular shape along the outer periphery of the upper surface of the support plate 51 is provided with the polarity on the target 41 side changed.

  The peripheral magnet 53 includes straight portions 53a and 53b extending in parallel along the central magnet 52, and folded portions 53c on both sides in the longitudinal direction that bridge between the straight portions 53a and 53b. In this case, the distance between the central magnet 52 and the linear portions 53a and 53b is constant, and the volume when converted to the same magnetization of the central magnet 52 is converted to the same magnetization of the peripheral magnet 53 surrounding the periphery. The volume is designed to be about the sum of the volume (peripheral magnet: center magnet: peripheral magnet = 1: 2: 1 (see FIG. 1)). Thereby, a balanced closed-loop tunnel-shaped magnetic flux is formed in front of the target 41 (on the sputtering surface 411 side), and the ions ionized in front of the target 41 and the secondary electrons generated by sputtering are captured. The plasma density can be increased by increasing the electron density in front of the target 41.

  Then, the processing substrate S is transported to a position facing the target 41, a predetermined sputtering gas or reaction gas is introduced through the gas introducing means 3, and then the sputtering substrate is connected to the target 41 through a sputtering power source (not shown). Then, when a negative DC voltage or a high frequency voltage is applied, an electric field perpendicular to the processing substrate S and the target 41 is formed, and a racetrack-like plasma is generated in front of the target 41 and the target 41 is sputtered. A predetermined thin film is formed on the processing substrate S.

  When the magnet assembly 5 is provided as described above, the plasma density above the central magnet 52 and the peripheral magnet 53 is low, and the amount of erosion of the target 41 accompanying the progress of sputtering is reduced as compared with the periphery. Therefore, the lateral width of the support plate 51 is made smaller than the width of the target 41, and driving means 6 such as an air cylinder or a motor is provided, and the magnet assembly 5 is attached to the driving shaft 61 of the driving means 6. Then, during sputtering, the magnet assembly 5 is reciprocated in parallel at two horizontal positions along the width direction of the target 41 (direction perpendicular to the longitudinal direction of the central magnet 52), so that the position of the tunnel-like magnetic flux is determined. I try to change it. Thereby, the entire surface including the outer peripheral edge portion of the target 41 can be eroded almost uniformly, and the utilization efficiency of the target 41 can be further enhanced by two-dimensional reciprocation.

  By the way, as shown in FIG. 2, when the magnet assembly 5 is configured and a racetrack-like plasma is generated in front of the target 41, the polarity of the central magnet 52 on the target 41 side is S, and the target of the peripheral magnet 53 is When the polarity on the 41 side is N, the electrons in the plasma are moving clockwise along the race track T1 when viewed from the back side of the target 41. And when it reaches the end of the target 41, it is bent by the electromagnetic field and changes its direction, but since inertial motion remains when changing the direction, electrons jump out to the end of the target 41 and the racetrack-like plasma is generated. A portion locally expands to the end side of the target 41 (as shown in FIG. 2A, for example, the lower left side of the target 41 protrudes downward (X direction), while the upper right side of the target 41 (not shown) Jump out in the direction).

  When the magnet assembly 5 is reciprocated in such a state, a part of the erosion region E1 of the target 41 locally extends to the end side of the target 41 (region indicated by reference sign R in FIG. 2B). Discharge becomes unstable and good thin film formation is hindered. Considering such jumping out of electrons, it is conceivable to reduce the size and moving amount of the magnet assembly 5, but in this case, the non-erosion area becomes larger and the utilization efficiency of the target 41 becomes worse.

  In the present embodiment, as shown in FIG. 3A, the plate-like magnetic shunt 7 is provided on the side surface of the center magnet 52 that is located in the electron jump-out direction X (that is, at the center). Magnetic shunts 7 are attached to the staggered sides at both ends of the magnet). In this case, for example, when the target 41 has a size of 200 × 2500 mm, electrons jump up to about 20 mm at a position in the range of 100 to 250 mm from the end of the target 41, and in such a case, The magnetic shunt 7 may be provided with a predetermined length from both ends of the central magnet 52 (length from both ends in the longitudinal direction of the magnet assembly 5 to 350 mm).

  The magnetic shunt 7 may be any material having a high maximum magnetic permeability and rigidity. For example, stainless steel having magnetism such as SUS430, metals such as pure iron and nickel that can enhance the magnetic field attenuation effect, permalloy, supermalloy An alloy having a high magnetic permeability such as can be used, and the thickness thereof is set in the range of 1.0 to 5.0 mm.

  Thereby, the magnetic force in the range where the magnetic shunt 7 is provided in the central magnet 52 is locally weakened, so that the tunnel between the central magnet 52 and the peripheral magnet 53 is not changed without changing the form of the magnet assembly 5 itself. Among the magnetic fluxes generated in the shape of the magnetic field, the position where the vertical component of the magnetic field is zero although it is located in the region between the central magnet 52 provided with the magnetic shunt 7 and one linear portion 53a (the plasma has the highest density). , A position contributing to sputtering of the target) is locally shifted toward the central magnet 52 within the range of the length of the magnetic shunt 7. That is, when the track-like lines L1 that respectively pass through the positions where the vertical component of the magnetic field is 0, portions that are alternately positioned on one side of the central magnet 52 and at both ends of the central magnet 52 are shown. , And shifts locally to the central magnet 52 side, resulting in a line L1 as shown in FIG. For this reason, when plasma is generated in front of the target 41, even if an inertial movement remains when electrons come to the end of the target 41 and are bent by an electromagnetic field and change its direction, they jump out to the end of the target 41. Is prevented, and the plasma does not spread locally.

  As a result, the erosion region E2 of the target accompanying the progress of sputtering at the outer peripheral edge of the target 41 can be made substantially linear along the longitudinal direction of the target 41 (see FIG. 3C) and stable during sputtering. Can be discharged and a good thin film can be formed. Further, even if the magnet assembly 5 is reciprocated along the width direction of the target 41 during sputtering, the moving distance of the target of the magnet assembly 5 can be increased, so that the entire surface including the outer peripheral edge of the target 41 is covered. Therefore, the use efficiency of the target 41 can be further increased.

  In the present embodiment, the shape of the magnet assembly 5 itself is not changed, and the magnetic shunt 7 is provided on the side surface of the central magnet 52 in order to locally increase or decrease the magnetic force of at least one of the central magnet 52 or the peripheral magnet 53. However, the present invention is not limited to this, and only the portion of the one linear portion 53a of the peripheral magnet 53 that faces the position where the magnetic shunt 7 is provided is changed to a magnet having a strong magnetic force. Alternatively, an additional magnet may be attached to the upper surface of the portion, and the magnetic force of the peripheral magnet 53 may be locally increased.

  In the present embodiment, the magnetron sputter electrode C in which one target 41 is arranged has been described. However, the present invention is not limited to this, and a plurality of targets 41 arranged in parallel to the processing substrate S. The present invention can be applied. When a plurality of targets 41 are arranged side by side, if electrons jump out of the target end due to inertial movement, the electrons jump to the adjacent target to make the discharge unstable. By applying the present invention, Electron jumping is prevented, and discharge can be stabilized to form a good thin film.

The figure which illustrates typically the sputtering device of this invention. (A) is a figure explaining the structure of a magnet assembly. (B) is a diagram for explaining the jumping out of electrons. (A) is a figure explaining the structure of the magnet assembly which concerns on this invention. FIG. 6B is a diagram for explaining a racetrack-like line passing through a position where the magnetic field vertical component becomes zero. (C) is a figure explaining the erosion area | region of the target accompanying progress of sputtering.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetron sputtering apparatus 41 Target 5 Magnet assembly 52 Center magnet 53 Peripheral magnet 53a, 53b Linear part 53c Fold-up part C Magnetron sputter electrode S Processing substrate

Claims (6)

Comprising a target arranged opposite to the handle substrate, and a magnet assembly disposed behind the target to substrate and facing away,
The magnet assembly includes a central magnet arranged linearly, this so as to surround the periphery of the central magnet, is composed of a peripheral magnet disposed changing the polarity of the data Getto side,
With the direction in which the central magnet extends linearly as the longitudinal direction, the central magnet and the peripheral magnet have straight portions extending in parallel on both sides in the longitudinal direction,
The position where the vertical component of the magnetic field of the magnetic flux generated in a tunnel shape between the central magnet and the linear portion of the peripheral magnet becomes zero is more constant at the longitudinal end of the magnet assembly than the central portion of the magnet assembly . A magnetron sputter electrode, wherein the magnetron sputter electrode is configured to shift to the center magnet side within a range to prevent electrons from jumping out to the target end side .   2. The magnetron sputter electrode according to claim 1, wherein the range where the position where the vertical component of the magnetic field is 0 is shifted alternately at one side of the central magnet and at both ends of the central magnet.   3. The magnetron sputter electrode according to claim 1, wherein the magnetic force of at least one of the central magnet and the peripheral magnet is locally increased or decreased.   4. A magnetron sputter electrode according to claim 3, wherein a magnetic shunt having a predetermined length is attached to side surfaces of both end portions in the longitudinal direction of the central magnet. The magnetron sputter electrode according to any one of claims 1 to 4, further comprising drive means for reciprocating the magnet assembly in parallel along the back surface of the target. The magnetron sputtering electrode according to any one of claims 1 to 5 is arranged in a sputtering chamber capable of being evacuated, and gas introduction means for introducing a predetermined gas into the sputtering chamber and power supply to a target can be made possible. A sputtering apparatus comprising a sputtering power source.

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