JP5049561B2 - 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 Unexamined Patent Publication 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 problems, the magnetron sputtering electrode according to claim 1 includes a magnet assembly behind a target disposed opposite to the processing substrate, and the magnet assembly is linear along the longitudinal direction. A central magnet arranged in parallel with each other, and a peripheral magnet composed of a linear portion extending in parallel on both sides of the central magnet and a folded portion that bridges between the two linear portions, with the polarity on the target side changed, and the central magnet Each linear part of the peripheral magnet is equidistant, and the distance between the central magnet and each linear part is narrower than that in the central region of the magnet assembly at both longitudinal ends of the magnet assembly. .

  According to the present invention, since the distance between the central magnet and each linear portion is locally narrowed at both longitudinal ends of the magnet assembly, each magnetic flux generated in a tunnel shape between the central magnet and the peripheral magnets. Among these, the position where the vertical component of the magnetic field is 0, although located in a region where the interval is locally narrowed, is locally shifted to the central magnet side within a certain range. For this reason, when plasma is generated in front of the target, even if an inertial motion remains when electrons come to the end of the target and bend in the electromagnetic field and change direction, it is prevented from jumping out to the target end. The plasma is prevented from spreading locally. As a result, it is possible to stably discharge during sputtering and to form a good thin film.

  In this case, depending on the polarity on the target side, one end of the linear portion and both end portions of the central magnet are moved to the other linear portion side to narrow the interval, and if the both end portions are rotationally symmetric, the magnet When the assembly is reciprocated, the position where the vertical component of the magnetic field is 0 is the opposite side of the electron emission direction within a certain range only at the location where electrons are emitted to the target end side by inertial movement in the reciprocating direction. The target erosion area can be made uniform as the sputtering progresses at the outer peripheral edge of the target.

  For example, when one of the linear portions and a part of both sides of the central magnet are moved to the other linear portion side to narrow the interval, the magnetic field located on the opposite side of the electron jumping direction is caused by this. In some cases, the position where the vertical component becomes 0 is locally shifted to the target end side. In this case, a part of the plasma generated in a racetrack shape spreads to the target end side. In this case, if a magnetic shunt is provided on the side surface of the other linear portion of the both ends of the central magnet, the magnetic force at the location where the magnetic shunt is provided in the central magnet is locally weakened, and the electrons jump out. It may be possible to perform re-correction by shifting the position where the vertical component of the magnetic field becomes 0 in a direction within a certain range.

  On the other hand, in order to recorrect the position where the vertical component becomes 0, in addition to or instead of the above, at least one of the portions of the other linear portion facing both ends in the longitudinal direction of the magnet assembly. The part may be moved to the central magnet side.

  In addition, an auxiliary magnet is added to at least a part of the upper surface of a portion of the other linear portion that faces both ends in the longitudinal direction of the magnet assembly to locally increase the magnetic force of a part of the peripheral magnet. Then, the position where the vertical component of the magnetic field becomes 0 in the electron emission direction may be shifted and re-corrected.

  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-mentioned problems, according to a sixth aspect of the present invention, the magnetron sputter electrode according to the first to fifth aspects is arranged in a sputter chamber that can be evacuated, and a predetermined gas is introduced into the sputter chamber. A gas introduction means and a sputtering power source that enables power supply to the target are 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 gas containing oxygen, nitrogen, carbon, hydrogen, ozone, water, hydrogen peroxide, or a mixed gas thereof is used. . 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 sputtering surface 411 is set larger than the outer dimension of the processing substrate S. ing. 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 as in the prior art 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, Assuming that the polarity of the peripheral magnet 53 on the target 41 side is N, 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 becomes a target when electrons jump out to the end side of the target 41 (or to the outside of the end of the target 41). 41 extends to the end side (a region indicated by symbol R in FIG. 2B), and the discharge becomes unstable, thereby preventing good thin film formation. 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.

  As shown in FIG. 3, in the present embodiment, the distance between the central magnet 52 and the linear portions 53a and 53b of the peripheral magnet 53 is kept constant at both ends in the longitudinal direction of the magnet assembly 5. The interval between the central magnet 52 and each linear portion 53a, 53b is narrower than that in the central region of the magnet assembly 5, and both end portions in the longitudinal direction of the magnet assembly 5 with this interval narrowed are rotationally symmetric. A magnet assembly 5 was constructed. That is, both end portions 521 and 522 of the central magnet 52 and both end portions 531 and 532 of one linear portion 53a (the other linear portion 53b at the other end of the central magnet) are placed on the opposite side to the electron projecting direction X. It is moved stepwise toward the other linear portion 53b (one linear portion 53a at the other end of the central magnet), and the distance D2 from the distance D1 in the central region of the magnet assembly 5 toward the both sides in the longitudinal direction. D3 was made narrower.

  For example, when the target 41 has a size of 200 × 2500 mm, a maximum of about 20 mm of electrons are emitted at a position in the range of 100 to 250 mm from the end of the target 41. The range of about 350 mm from both ends in the longitudinal direction of 5 is defined as both ends in the longitudinal direction of the magnet assembly 5, and the distances D2 and D3 are narrowed by a width (for example, 30 mm or less) corresponding to the electron jump-out distance. . In this case, when the distance from both ends in the longitudinal direction is longer than 350 mm, the non-erodible region is expanded.

  As a result, among the magnetic fluxes generated in a tunnel shape between the central magnet 52 and the peripheral magnet 53, the position where the vertical component of the magnetic field is zero in the region where the interval is locally narrowed (most plasma is generated). The density increases and the position contributing to sputtering of the target locally shifts to the central magnet 52 side within a certain range. That is, as shown in FIG. 3B, when looking at the track-like lines L1 passing through the positions where the vertical component of the magnetic field is 0, both end portions 521 and 522 of the central magnet 52 and one linear portion 53a By moving both end portions 531 and 532 to the other straight line portion 53b located on the opposite side to the electron jumping direction X, it is located on the one straight line portion 53a side of the line L1 in the moved region. What is to be shifted shifts to the central magnet 52 side.

  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, it jumps out toward 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.

  By the way, when the magnet assembly 5 is configured as described above, due to this, the position at which the perpendicular component of the magnetic field is 0 on the side opposite to the electron emission direction is within a certain range and the electron emission direction. There may be a local shift to the other side. That is, as shown in FIG. 3 (b), when the track-like lines L1 passing through the positions where the vertical component of the magnetic field is 0 are seen, in the region where the central magnet 52 and one linear portion 53a are moved, A range La located on the other linear portion 53b side of L1 is shifted so as to swell toward the opposite side to the electron projecting direction X. In this case, a part of the plasma generated in a racetrack shape may spread toward the end of the target 41, and the erosion area E2 may extend slightly toward the end of the target 41. Therefore, as shown in FIG. 4A, it is preferable to provide the magnetic shunt 7 on the side surface of the portion 522 of the central magnet 52 that has been moved to the other linear portion 53b side.

  This locally weakens the magnetic force of the central magnet 52 where the magnetic shunt 7 is provided, and shifts the position where the vertical component of the magnetic field becomes 0 in the electron ejection direction, thereby recorrecting the bulge. . That is, in the line L1, a region La that swells outward from the other straight line portion 53b is shifted to the central magnet 52 side to form a racetrack-like line L2 as shown in FIG. As a result, the erosion region of the target 41 accompanying the progress of sputtering at the outer peripheral edge of the target 41 can be made more linear along the longitudinal direction of the target 41.

  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, for example, can be used, and its thickness is set in the range of 1.0 to 5.0 mm. For example, it is attached over the entire length of the portion 522 moved to the linear portion 53b side. It is done.

  On the other hand, as shown in FIG. 5, in order to recorrect the bulge of the racetrack-like line L1, in addition to or instead of the above, the length of the magnet assembly 5 in the other linear portion 53b is changed. At least a part 530 of the part facing both ends in the direction, preferably a part corresponding to the swelled area La of the line L1, may be moved to the central magnet 52 side. As a result, the bulge is shifted and corrected again in the direction of the central magnet 52, resulting in a racetrack L3 as shown in FIG.

  Further, as shown in FIG. 6, in order to recorrect the bulge of the racetrack-like line L1, in addition to or instead of the above, both ends in the longitudinal direction of the magnet assembly of the other linear portion 53b. The auxiliary magnet 8 may be added to at least a part of the part facing the part, preferably the upper surface of the part corresponding to the swelled area La of the line L1. Thereby, the magnetic force of the location where the auxiliary magnet 8 is provided is locally increased, the position where the vertical component of the magnetic field becomes 0 is shifted, and the bulge is corrected again.

  In the present embodiment, considering the production of the magnet assembly 5, both ends 521 and 522 of the central magnet 52 and both ends 531 and 532 of one linear portion 53a are connected to the other linear portion 53b side. However, the present invention is not limited to this, and the interval changes continuously as it goes to both ends in the longitudinal direction of the magnet assembly 5 according to the jumping width of the electrons. It may be.

  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 the magnet assembly based on a prior art. (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. (B) is a diagram for explaining the correction of the race track. (C) is a figure explaining the erosion area | region of the target accompanying progress of sputtering. (A) is a figure explaining the structure of the magnet assembly which concerns on the other form of this invention. (B) is a diagram for explaining the correction of the position of the racetrack-like line passing through the position where the magnetic field vertical component becomes zero. (A) is a figure explaining the structure of the magnet assembly which concerns on the other form of this invention. (B) is a diagram for explaining the correction of the position of the racetrack-like line passing through the position where the magnetic field vertical component becomes zero. (A) And (b) is a figure explaining the structure of the magnet assembly which concerns on the other form of this invention.

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 (7)

A magnet assembly is provided behind a target disposed opposite to the processing substrate. The magnet assembly includes a central magnet arranged linearly along the longitudinal direction, linear portions extending in parallel on both sides of the central magnet, and both. The magnet assembly has a peripheral magnet composed of a folded portion that bridges between the straight portions and changes the polarity on the target side, and the central magnet and each linear portion of the peripheral magnet are equally spaced. A magnetron sputter electrode, characterized in that the distance between the central magnet and each linear portion is narrower than that in the central region of the magnet assembly at both longitudinal ends of the magnet assembly. 2. The magnetron sputter electrode according to claim 1, wherein one end of the linear portion and both ends of the central magnet are moved toward the other linear portion to narrow the interval, and the both end portions are rotationally symmetric. The magnetron sputter electrode according to claim 2, wherein a magnetic shunt is provided on a side surface on the other straight portion side of both ends of the central magnet. 4. The magnetron sputtering according to claim 2, wherein at least a part of a portion of the other straight portion facing both ends in the longitudinal direction of the magnet assembly is moved to the center magnet side. electrode. 5. The auxiliary magnet is added to at least a part of the upper surface of a portion of the other linear portion facing both ends in the longitudinal direction of the magnet assembly. The magnetron sputter electrode as described. 6. The magnetron sputter electrode according to claim 1, further comprising driving means for reciprocating the magnet assembly in parallel along the back surface of the target. A magnetron sputtering electrode according to claim 1 is disposed in a sputtering chamber capable of being evacuated, a gas introducing means for introducing a predetermined gas into the sputtering chamber, and a sputtering power source capable of supplying power to the target. A sputtering apparatus characterized by being provided.

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