JPH10168566A - Sputtering equipment - Google Patents

Abstract

(57) [Problem] To provide a sputtering apparatus capable of increasing the erosion area of a target and increasing the use efficiency of the target for film formation. SOLUTION: A ring-shaped target 11 is arranged between a ring-shaped outer magnet 13 and an inner magnet 12, and the inner magnet 12 is moved in a target thickness direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus (specifically, a magnetic field focusing type magnetron sputtering apparatus).

[0002]

2. Description of the Related Art Conventionally, in a sputtering apparatus, a magnetron method can obtain a high-density plasma at a low voltage, and can form a thin film at a high speed with a small increase in the temperature of a substrate. Are often used to form a metal film or the like on a substrate.

In general, an inert gas such as argon is used in a magnetron sputtering apparatus, and argon is ionized by collision of gas molecules of the argon with electrons. It is important to have a high density and uniform distribution.
To this end, a feature of the magnetron method is that a method is used in which a magnetic field is formed by a magnet to converge a plasma and electrons are effectively collided with the plasma.

FIG. 11 is a schematic sectional view showing an example of a magnetron sputtering apparatus. For this device,
The operation is performed by the high frequency power supply Rf ₁ , and a high frequency bias is applied to the target 1 to sputter the target 1 to form a thin film of, for example, aluminum on the substrate 6. For example, the processing chamber 10 is evacuated by a vacuum pump connected to the discharge hole 10b, and argon is introduced from the introduction hole 10a.
Creating a plasma 7 by the combination of Rf _1, the magnet 2A, thereby increasing the plasma generation rate and density in a magnetic field due to 2B.

In such a sputtering apparatus, the magnetic flux generated from the plasma focusing magnets 2A and 2B captures ionized electrons and secondary electrons generated by sputtering on the surface of the target 1, so that the electron density on the surface of the target 1 is increased. And the probability of collision between these electrons and neutral gas molecules is increased, so that the plasma density can be increased.

FIG. 12 is an enlarged sectional view showing the target 1, the inner magnet 2A and the outer magnet 2B extracted from FIG. 11, and the magnetic flux emitted from the magnetic poles of the inner magnet 2A forms the magnetic force lines 3 as shown. And enters the magnetic pole of the outer magnet 2B.

However, in the sputtering apparatus as described above, the distribution of the magnetic field generated on the surface of the target 1 is not uniform as shown in the figure, and the intermediate portion between the inner magnet 2A for plasma convergence and the outer magnet 2B has There is a portion of the magnetic field on the surface of the target 1 where the component perpendicular to the surface of the target 1 becomes zero. In this portion, the plasma is converged and the target 1 surface is eroded in this portion.

FIG. 13 is a plan view of the target 1 showing the eroded state as described above, and FIG.
3 is a sectional view taken along line XIV-XIV of FIG. As shown in the figure, the eroded portion 4 on the surface of the target 1 is released and provided to the substrate 6 for film formation. The amount is determined by the volume ratio of the target 1 that contributes to the actual film formation and the target utilization rate. In this case, the utilization rate is very low, about 20 to 25% in many cases.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in view of the above circumstances, and is intended to increase the erosion area of a target and increase the efficiency of use of the target for film formation. It is intended to provide a device.

[0010]

Means for Solving the Problems The present inventor has made intensive studies to achieve the above object, and as a result, has found an effective method for enlarging the target erosion area and increasing its utilization efficiency. The present invention has been reached.

That is, according to the apparatus of the present invention, in a sputtering apparatus in which a magnetic field generator for plasma convergence is arranged on a target, the position of a magnetic field generated by the magnetic field generator is changed relative to the target. The present invention relates to a sputtering apparatus having means.

Thus, since the position of the magnetic field is relatively changed by the magnetic field generator and the target, for example, the erosion area of the target is increased, and the utilization efficiency of the target can be increased.

[0013]

In the apparatus according to the present invention, the magnetic field generator reciprocates relative to the target, and the reciprocation reduces the perpendicular component of the plasma converging magnetic flux with respect to the target. It is desirable to do.

In the above apparatus, the magnetic field generator includes a center magnet and a ring-shaped peripheral magnet surrounding the center magnet. The center magnet is disposed in a center hole of the ring-shaped target, and the thickness of the target in the thickness direction is reduced. It is preferable that the peripheral magnet surrounds the target around the ring-shaped target.

In this case, it is desirable that the reciprocating center magnet has a smaller magnetic flux density on the magnetic pole surface than the peripheral magnet.

In the above apparatus, the magnetic field generator may be:
A first reciprocatingly arranged first end side of the target;
And a second magnet disposed on the other end side of the target.
It is preferable that the first magnet that reciprocates has a smaller magnetic flux density on the magnetic pole surface than the second magnet.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but it goes without saying that the present invention is not limited to the following embodiments.

FIG. 1 is a sectional view showing an arrangement of a magnet and a target of a magnetron sputtering apparatus (hereinafter simply referred to as an apparatus) according to an embodiment, and FIG. 2 is a plan view thereof.

As shown in the figure, the apparatus of the present embodiment has a ring-shaped target 1 outside an inner magnet 12 having a horizontally long cross section.
1 is arranged, and an outer magnet 13 having a ring-shaped vertically long cross section is arranged outside the outer magnet 13 so as to form a magnet for converging plasma. The magnetic pole surfaces of the inner magnet 12 and the outer magnet 13 are The position where the vertical component of the magnetic flux is reduced is moved by reciprocating the inner magnet 12 in a direction perpendicular to the above-mentioned plane, as shown by an arrow in the drawing.

In this case as well, the magnetic flux emitted from the magnetic pole of the inner magnet 12 for plasma convergence reaches the surface of the target 11 and enters the magnetic pole of the outer magnet 13 in the same manner as described above with reference to FIG. At this time, the component of the magnetic field on the surface of the target 11 that is perpendicular to the surface of the target 11 has a portion that is zero in an intermediate portion between the inner magnet 12 and the outer magnet 13. As a result, the plasma is converged in this portion, and the target 11 is eroded.

Therefore, as shown by a virtual line in FIG. 1, the inner magnet 12 or the outer magnet 13 is
By reciprocating in a direction perpendicular to one surface, a portion of the magnetic field where the component perpendicular to the surface of the target 11 becomes zero moves, so that the eroded portion of the target 11 is widened.

FIG. 1 shows the change of the magnetic field lines accompanying the reciprocation of the inner magnet 12, and the magnetic field lines 15A indicated by solid lines.
Is a magnetic field line locus at the lower position of the reciprocating motion of the inner magnet 12, and a broken magnetic line 15B is a magnetic field line locus at the upper limit position of the reciprocating motion of the inner magnet 12.

The reciprocating motion of the inner magnet 12 always operates during operation of the apparatus. Therefore, the position where the vertical component of the magnetic field becomes zero constantly moves, and as shown in FIG. 3, the surface of the target 11 can be eroded 14 evenly. In the figure, the phantom line indicates the target 1 before erosion.
1 represents the surface.

The mechanism by which the target erosion site is enlarged and averaged as the inner magnet 12 reciprocates as described above will be described with reference to FIG.

That is, as in the above-described conventional example, the position of the magnet 12 is fixed (therefore, there is no reciprocation).
In this case, the position where the vertical component of the magnetic field is zero on the surface of the target 11 is fixed at a fixed point between the distances L between the centers C and C ′ of the inner magnet 12 and the outer magnet 13, The erosion site is localized as shown in FIG. On the other hand, by reciprocating the inner magnet 12 as in the present embodiment, the position where the vertical component of the magnetic field becomes zero is determined by the inner magnet 12.
Is moved between O ₁ when it is in the lowered position and O ₂ when it is in the raised position.

In this case, the position where the vertical component of the magnetic field lines 15A and 15B of the magnetic field with respect to the target 11 becomes zero is:
These positions are O ₁ and O ₂ , respectively. At each of these positions, the erosion of the target 11 proceeds quickly by the converged plasma. Therefore, the position where the vertical component becomes zero constantly moves between O ₁ and O _{2 due to} the vertical movement of the inner magnet 12. As a result, the sputtering position of the plasma with respect to the target 11 is shown in FIG.
Are uniformly distributed on the surface of the target 11 as shown by the arrow shown in FIG.

As shown in FIG. 4, in order to change the arch shape of the line of magnetic force, the inner magnet 12 is formed to have a horizontally long cross section, so that the inner magnet 12 is formed.
Is effective in that the magnetic flux density at the surface of the outer magnet 13 is lower than the magnetic flux density at the narrow surface width of the outer magnet 13.

FIGS. 5 to 7 show examples of the movement of the magnet. FIG. 5 shows a lowered position where the upper surface of the inner magnet 12 and the upper surface of the outer magnet 13 are flush with each other. A measurement result of the magnetic flux density at a position where the distance d from the upper surface of the outer magnet 13 is 25 mm in this state will be described later.

FIG. 6 shows a raised position in which the upper surface of the inner magnet 12 has moved toward the target 11 by 15 mm from the upper surface of the outer magnet 13. The magnetic flux density measurement result at a position where the distance d from the upper surface of the outer magnet 13 is 25 mm in this state will be described later.

In the above-described embodiment, the inner magnet 12 is moved, but as shown in FIG. 7, the outer magnet 13 can be moved. Also in this case, the position where the vertical component of the magnetic field becomes zero can be moved in the same manner as when the inner magnet 12 is moved.

FIG. 8 is a schematic sectional view showing the entire apparatus according to the above-described embodiment. As shown in the figure, the moving mechanism of the inner magnet 12 may be, for example, a mechanism that couples the inner magnet 12 to a rod 16 connected to a driving source (not shown) provided outside the processing chamber 20.

In the case of this apparatus as well, the discharge hole 20b and the vacuum pump are connected to each other in the same manner as in FIG.
If the inside is evacuated and, for example, argon is introduced from the introduction hole 20a and operated by a power supply (not shown), the plasma 9 is formed as shown in the figure and electrons can be distributed at a high density on the surface of the target 11.

FIGS. 9 and 10 correspond to FIGS. 5 and 6 described above.
7 is a graph of data obtained as a result of measuring the magnetic flux density in FIG.

That is, FIG. 9 shows that, as shown in FIG.
The magnetic flux density at a position 5 mm above, reference numeral 18A is the density of the parallel component of the magnetic field parallel to the target 11, and reference numeral 19A is the density of the vertical component of the magnetic field.

FIG. 10 shows the magnetic flux density at a position 25 mm above the upper surface of the outer magnet 13 when the inner magnet 12 is in the raised position, as shown in FIG. 6, and reference numeral 18B denotes the density of the parallel component of the magnetic field parallel to the target 11. 19B
Is the density of the vertical component of the magnetic field.

According to this, as shown in FIG. 9, when the upper surface of the inner magnet 12 is flush with the upper surface of the outer magnet 13, the lower position of the reciprocating motion of the inner magnet 12 (see FIG. 5). , occurs part O ₁ of the vertical component of the magnetic field when the distance is about 63mm from the center C from the center C in the region to the center C 'of the outer magnet 13 of the inner magnet 12 is zero. On the other hand, the parallel component of the magnetic field has a substantially stable density until the distance from the center C is close to 80 mm.

As shown in FIG. 10, the upper surface of the inner magnet 12 is 15 mm from the upper surface of the outer magnet 13.
Elevated in the raised position (see FIG. 6), caused partial O ₂ of the vertical component distance of the magnetic field of about 33mm from the center C of the inner magnet 12 is zero, and the center the vertical component is zero in the region It occurs over a range of 33 mm to 63 mm from C. On the other hand, it can be seen that the horizontal component of the magnetic field decreases until the distance from the center C to about 47 mm, but thereafter shows a stable tendency as in the case of FIG.

As is clear from FIGS. 9 and 10 described above, the effective distance between cc 'and the cc' where the component perpendicular to the surface of the target 11 in the magnetic field becomes zero is 63 mm to 33 mm. . Therefore, the inner magnet 1
By reciprocating 2 by 15 mm, the erosion of the target 11 can be uniformly generated throughout the entire period. In other words, it is preferable to set the width between the inner circumference and the outer circumference of the target 11 in the range of 33 mm to 63 mm and move the inner magnet 12 up and down by 15 mm.

According to this embodiment, by reciprocating the inner magnet 12, the position where the vertical component of the magnetic field generated between the inner magnet 12 and the outer magnet 13 becomes zero always moves. The erosion position of the target 11 to be eroded always changes, and the erosion area increases. Therefore, the use efficiency of the target 11 used for film formation can be dramatically improved.

Although the embodiments of the present invention have been described above, the above embodiments can be variously modified based on the technical idea of the present invention.

For example, the movement of the magnets may be such that the inner magnet 12 and the outer magnet 13 are simultaneously moved in opposite directions or in the same direction.

Further, the inner magnet 12 and the outer magnet 13 may be fixed, and the target 11 may be moved in the horizontal or vertical direction.
And the target 11 can be moved together. The position of the magnet is not limited to the side of the target, but may be below. The shape of the target can be variously changed.

The magnet may be a permanent magnet or an electromagnet. The shape of the magnet is not limited to the ring shape, but may be a triangle, a quadrangle, or a polygon having more than that. Further, a bar magnet may be used, in which case one of the outer magnets may be omitted and one target may be positioned laterally to one target.
The book magnets can be arranged to be vertically movable, and fixed magnets can be arranged on the other side of the target.

The moving means may be of a mechanical type such as a cam type or a screw type, or various types such as an electromagnetic type.

[0045]

According to the present invention, as described above, a sputtering apparatus in which a magnetic field generator for plasma convergence is arranged on a target is used to position the magnetic field generated by the magnetic field generator relative to the target. Since there is a means for changing the target, it is possible to arbitrarily change a region in which erosion is likely to occur on the target, enlarge the erosion area of the target, and improve the use efficiency of the target.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magnet and a target of a magnetron sputtering apparatus according to an embodiment of the present invention (FIG. 2).
FIG. 2 is a sectional view taken along line II of FIG.

FIG. 2 is a plan view of FIG.

FIG. 3 is a cross-sectional view of a target after sputtering by a magnetron sputtering apparatus.

FIG. 4 is a principle diagram showing an enlarged part of FIG. 1;

FIG. 5 is a sectional view showing a lowered position of an inner magnet of the magnetron sputtering apparatus.

FIG. 6 is a cross-sectional view showing a raised position of an inner magnet of the magnetron sputtering apparatus.

FIG. 7 is a cross-sectional view showing a state where an outer magnet of the magnetron sputtering apparatus is moved.

FIG. 8 is a schematic sectional view of the same magnetron sputtering apparatus.

FIG. 9 is a graph showing the magnetic flux density in the state of FIG.

FIG. 10 is a graph showing the magnetic flux density in the state of FIG.

FIG. 11 is a schematic sectional view showing an example of a conventional magnetron sputtering apparatus.

FIG. 12 is a sectional view showing a magnet and a target of the magnetron sputtering apparatus.

FIG. 13 is a plan view of the target after sputtering by the magnetron sputtering apparatus.

14 is a sectional view taken along line XIV-XIV of FIG.

[Explanation of symbols]

11 target, 12 inner magnet, 13 outer magnet, 14 erosion portion, 15A, 15B magnetic line of force, 16 rod, 18A, 18B horizontal component, 19
A, 19B: vertical component, 20: processing chamber, 20a: introduction hole, 20b: discharge hole, Rf ₁ : high frequency power supply, L: distance

Claims (7)

[Claims] 1. A sputtering apparatus in which a magnetic field generator for plasma convergence is disposed with respect to a target, comprising: means for changing a position of a magnetic field by the magnetic field generator relative to the target. A sputtering apparatus. 2. The apparatus of claim 1, wherein said magnetic field generator reciprocates relative to said target. 3. The apparatus according to claim 2, wherein the reciprocating motion of the magnetic field generator reduces a perpendicular component of the plasma converging magnetic flux with respect to the target. 4. The magnetic field generator comprises a center magnet and a ring-shaped peripheral magnet surrounding the center magnet. The center magnet is disposed in a center hole of the ring-shaped target and reciprocates in the thickness direction of the target. 3. The apparatus according to claim 2, wherein the peripheral magnet surrounds the target in a ring-shaped outer periphery. 5. The apparatus according to claim 4, wherein the reciprocating center magnet has a lower magnetic flux density at the pole face than the peripheral magnet. 6. The magnetic field generator includes a first magnet disposed on one end side of the target and reciprocating, and a second magnet disposed on the other end side of the target. An apparatus according to claim 2. 7. The apparatus according to claim 7, wherein the first magnet reciprocatingly moves comprises the second magnet.
Has a smaller magnetic flux density on the pole face than the magnet of
An apparatus according to claim 6.