JP3411312B2 - Magnetron sputter cathode and method of adjusting film thickness distribution - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetron sputter cathode targeting a non-magnetic material, and in particular, a magnetron sputter cathode for uniformly depositing a non-magnetic target material on a substrate and adjustment of film thickness distribution. Regarding the method.

[0002]

2. Description of the Related Art FIG. 5 shows a side cross section of a round sputtering cathode 1'in a conventional magnetron type sputtering apparatus, which is not shown but is incorporated in a vacuum chamber in a known manner. There is. The part indicated by 17 in the figure is the wall of this vacuum chamber. Further, although not shown, a substrate to be formed a film and an anode electrode, which are arranged so as to face the sputter cathode 1 ′, are provided in the vacuum chamber.

In such a sputter cathode 1 ', in order to form a magnetic field in the space above the disk-shaped nonmagnetic target 2 to be sputtered, in FIG.
It has permanent magnets designated by 5, 6 and 7. The magnets are alternately inverted as shown in FIG. 5 and are concentrically arranged about the central axis z as shown in FIG. 6, and the lower ends thereof are fixed to the yoke plate 10 ′. That is, the central permanent magnet 4 has a columnar shape, and the other permanent magnets 5, 6 and 7 each have a cylindrical shape surrounding the magnets with the thicknesses shown in the drawing. On the permanent magnet 4 and the outermost permanent magnet 7 in the figure (that is, having the largest diameter among these permanent magnets), there are yokes 8 and 9 each having a substantially cylindrical shape and an annular shape (a part of which is shown in FIG. 6). (Indicated by a dotted line), which are made of pure iron, are magnetized by the permanent magnets 4 and 7 to form a magnetic field on the non-magnetic target 2 with their upper ends being the S pole and the N pole, respectively. On the other hand, the first permanent magnet 5 between them
The second permanent magnet 6 and the second permanent magnet 6 are fitted in the annular grooves 19 and 20 formed in the lower surface of the backing plate 3'which is fitted and supported by the yokes 8 and 9, respectively. A magnetic field is formed on top.

The backing plate 3'includes the target 2
Is a disk-shaped electrode concentrically arranged with a voltage applied by an applying means (not shown) to generate an electric field on the target 2 to cause magnetron discharge. Although not shown, a passage for introducing, circulating and discharging cooling water from the outside by a cooling water introducing means (not shown) is formed in the backing plate 3'in a known manner. 3 ′ Further, the target 2 is cooled.

In the drawing, 18 is a bolt for fixing the target 2, 15 is an earth shield which surrounds the outer peripheral portion of the sputter cathode 1'and which is at earth potential together with the vacuum chamber wall 17, and 16 is an earth shield. It is an insulator provided between the cathode frame body shown by the earth shields 15 and 13. As a result, the backing plate 3'side and the vacuum chamber side are insulated from each other, and as a whole, they are structured so as to maintain airtightness in the vacuum chamber and liquid-tightness of the passage in the target 2 (not shown). In addition, the cathode frame 13 is fixed to the yoke plate 10 ′ via the fixing member 14.
Is fixed, and the outer peripheral portion of the backing plate 3'that penetrates a part of the yoke 9 is in contact with the upper end surface thereof.

FIG. 7 shows the permanent magnets 4, 5, as described above.
The distribution of the magnetic field formed on the target 2 by 6 and 7 is shown in correspondence with the installation positions of the permanent magnets 4, 5, 6 and 7. However, since the permanent magnets 4, 5, 6 and 7 and the magnetic field generated by them are axisymmetric, only the right half portion in FIG. 5 is shown. That is, in the graph in FIG. 7A, the magnetic field distribution on the target 2 is shown with the ordinate representing the magnetic field strength and the abscissa representing the distance from the central axis z, of which the abscissa represents the permanent magnets 4 at the same time. The distance from the central axis z of each member is also shown in FIG. 7B, which is a schematic view of FIG. 5 showing only 5, 6, and 7 and the yokes 8 and 9.
In the graph of FIG. 7A, the magnetic field is divided into a vertical component Bv and a parallel (horizontal direction) component Bh with respect to the target 2, which are shown by a solid line and a dotted line, respectively. In addition, due to the magnetic field generated by the permanent magnets 5 and 6 described above, the vertical component Bv
The horizontal component Bh is corrected and distributed so that the position b becomes 0 at a position deviated from the center between the yoke 8 and the yoke 9, and the horizontal component Bh has its peak near the yokes 8 and 9. .

Magnetron sputtering utilizes a so-called "magnetron discharge", which forms a magnetic field orthogonal to an electric field and causes electrons to cycloidally move in this orthogonal region. This is due to the backing plate 3'in FIG. An electric field is generated in the space above the target 2 between the yoke 8 and the yoke 9 where the magnetic fields generated by the permanent magnets 4, 5, 6 and 7 are orthogonal to each other. However, as shown in A of FIG. 7, since the horizontal component Bh of the magnetic field orthogonal to the electric field is smaller than the vertical component Bv in the vicinity of the yokes 8 and 9, electrons cannot stably perform cycloid motion in this region,
That is, it is difficult to maintain the magnetron discharge, and in fact, most of the area between the position indicated by a (15 mm from the central axis z) and the position indicated by c (54 mm from the central axis z) in A of FIG. Magnetron discharge occurs. In such a magnetron discharge, the atmospheric gas introduced into the vacuum chamber is ionized one after another by the cycloidal motion of electrons to increase the plasma density, and the plasma density is at a position b (where the vertical component of the magnetic field is zero). The maximum is 44 mm from the central axis z. Therefore, since the target 2 is most actively sputtered at this position b, it becomes the erosion center of the target 2 at the same time. As a result, the erosion center is eroded deepest (erosion) and the target 2 is unevenly eroded, so that the use efficiency of the target 2 is deteriorated. Further, the nonuniformity of the erosion affects the scattering direction of the particles that fly out from the target 2 by sputtering, and makes the film thickness distribution of the thin film formed on the substrate nonuniform. Further, when forming various types of substrates having different diameters, it is necessary to change the film thickness distribution of the formed thin film for each substrate. Therefore, in order to make the erosion of the target 2 uniform and to change the film thickness distribution of the substrate in this way, the position of the erosion center is changed. Since the magnetic field generated by the permanent magnet 5 is greatly involved, the position of the erosion center can be changed by changing the installation position of the permanent magnet 5.

However, in the prior art, as shown in FIG. 5, the permanent magnet 5 is fixed to the same yoke plate 10 'together with the other permanent magnets 4, 6 and 7, and its N pole side is the backing plate 3'. Since it fits in the groove, in order to change the installation position of the permanent magnet 5, that is, to replace the permanent magnet 5 with one having a different diameter, not only the permanent magnet 5 but also the yoke plate 10 'or the yoke plate 10' is fixed. The permanent magnets 4, 6 and 7 present, as well as the backing plate 3 ', etc. must be replaced together. Therefore, the entire cathode must be replaced, which is costly.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is a magnetron capable of easily adjusting the film thickness distribution of a substrate by replacing the first magnet without replacing the entire cathode. -The purpose is to provide a sputtering cathode and a method of adjusting the film thickness distribution.

[0010]

The above object is to provide a flat non-magnetic target, a backing plate disposed on one surface side of the non-magnetic target, and a backing plate spaced apart from the backing plate. A yoke plate, a columnar central magnet whose both magnetic poles are fixed to the central portions of the backing plate and the yoke plate, respectively, and both magnetic poles are concentric with the central magnet and the magnetism of both magnetic poles is reversed relative to the central magnet. A cylindrical outer peripheral magnet, which is arranged and has both magnetic poles fixed to the outer peripheral portions of the backing plate and the yoke plate, respectively, and is arranged concentrically with the central magnet between the central magnet and the outer peripheral magnet. A pair of cylindrical first members that are fixed to the yoke plate by inverting the magnetism of each other and inverting the magnetism of the central magnet and the magnet of the outer peripheral portion. In the magnetron sputter cathode consisting of the second magnet and the second magnet, the yoke plate is arranged so that the position where the vertical magnetic field component on the target surface becomes zero can be arbitrarily moved without changing the magnetron discharge region. It is divided into a first plate for fixing the central magnet and the first magnet, and a second plate for fixing the second magnet and the outer peripheral magnet, and the central magnet and the front plate.
A plurality of first magnets with different distances from the first magnet.
Prepare the rate in advance, and select one of them from the second
It is achieved by a magnetron spatter cathode, which is attachable to a plate .

[0011]

[Operation] Remove the first plate from the second plate ,
Instead, another first plate with a first magnet at a different distance from the central magnet is attached to the second plate.
As a result, the magnetic field distribution formed on the non-magnetic target is changed, and the erosion in magnetron sputtering is performed by moving only the center from the position in the sputtering before the exchange of the first magnet without changing the area. . Therefore, the film thickness distribution of the thin film formed on the substrate to be formed changes, and the film thickness distribution can be adjusted by appropriately selecting the diameter of the first magnet to be replaced.

[0012]

EXAMPLE A magnetron according to an example of the present invention will be described below.
The sputter cathode will be described with reference to FIGS. 1 to 4. The same components as those in the conventional example are designated by the same reference numerals, and the details thereof will be omitted.

FIG. 1 shows a side cross section of a magnetron sputter cathode 1, which is fixed to a wall 17 of a vacuum chamber (not shown) as in the conventional case. Further, in the magnetron sputter cathode 1 according to the present embodiment, the permanent magnets 4, 5, 6 and 7 are concentrically arranged as shown in FIG. It is divided into one yoke plate (first plate) 11 and second yoke plate (second plate) 10 . That is, a circular recess 22 is formed concentrically with the second yoke plate 10, and the first yoke plate 11 is removably fitted in the recess 22 to allow the bolt 12 to be screwed. It is integrated by wearing. The central permanent magnet 4 and the first permanent magnet (first magnet) 5 are fixed to the first yoke plate 11, and the second permanent magnet (second magnet) 6 and the outermost permanent magnet 7 are the second permanent magnet. York plate 1
It is fixed at 0. The second yoke plate 10
The diameter of the circular recess 22 is sufficiently larger than the diameter of the permanent magnet 5, so that the first yoke plate to which the permanent magnet 5 having the larger diameter shown in the figure is fixed can be attached. Further, unlike the conventional case, no groove is formed in the backing plate 3 for applying an electric field to the non-magnetic material target 2, and the permanent magnet 5 is joined to this only at its upper end surface. The other structure of the backing plate 3 is the same as the conventional one, and the structures other than the above description such as the yokes 8 and 9 are also the same as the conventional one.

The magnetic field formed on the target 2 by the permanent magnets 4, 5, 6 and 7 as described above is
Since 5, 6 and 7 are similar to the conventional example, they are distributed as shown in A of FIG. Therefore, in order to form an electric field orthogonal to such a magnetic field, the backing plate 3
When a negative voltage is applied to the target 2 and magnetron sputtering is performed as is known, the target 2 is eroded with b in FIG. 7A as the erosion center, and the particles of the constituent elements of the target 2 are ejected from there to sputter the cathode. 1 is attached to a substrate provided in the vacuum chamber so as to face 1.

Next, the change in the magnetic field distribution formed on the target 2 when the permanent magnet 5 is replaced with one having a different diameter will be described.

That is, in this embodiment, since the first yoke plate 11 can be attached to and detached from the second yoke plate 10, the first permanent magnet 5 having the diameter shown in FIG.
The one yoke plate 11 is removed from the second yoke plate 11 , and the permanent magnets with different diameters are replaced with the permanent magnets 5.
Another first yoke plate exchanged with is attached to the second yoke plate 10. The diameter of the permanent magnet 5 is smaller than that of the permanent magnet 5 shown in FIG. 5 by 5 mm (from the outer peripheral surface of the permanent magnet 4 to the permanent magnet 5). The distance to the outer peripheral surface of'is 16 mm)
A magnetic field distribution on the target 2 when the permanent magnet 5 ′ is attached is shown in A of FIG. That is, since the position of the N pole of the permanent magnet 5 is moved radially inward by 5 mm, the positions of a and c in the graph do not change and the position of b where the magnetic field Bv = 0 is b in the graph of A in FIG. 3 mm to the right of the position. Therefore, when the magnetron sputtering is performed with such a magnetic field distribution as described above, the erosion region, that is, the magnetron discharge region does not change, and only the center of the region moves radially outward by 3 mm, and the target 2 is eroded, and A thin film having a distribution different from the film thickness distribution formed by the above-mentioned sputtering in the magnetic field distribution shown in the graph of FIG. 7A is formed.

Further, a permanent magnet 5 "having a diameter of 5 mm larger than that of the permanent magnet 5 in FIG. 5 (the distance from the outer peripheral surface of the permanent magnet 4 to the outer peripheral surface of the permanent magnet 5" is 26 mm) is further fixed.
When the first yoke plate of 1 is attached to the second yoke plate 10, the magnetic field distribution on the target 2 becomes as shown in A of FIG. That is, since the position of the N pole of the permanent magnet 5 is moved radially outward by 5 mm, the positions of a and c in the graph hardly change (c is moved by 1 mm compared to the graph of A in FIG. 7). The position of b at which Bv = 0 is 2 to the left of the position of b in the graph of A of FIG.
It has moved mm. Therefore, with such a magnetic field distribution, the erosion region hardly changes, the center moves inward by 2 mm, the target 2 is sputtered, and the film thickness distribution of the thin film formed on the substrate changes. It should be noted that FIGS. 3 and 4 show the magnetic field distribution of the non-magnetic target in correspondence with the installation positions of the respective members of FIG. 1, as in FIG.

As described above, in this embodiment, the permanent magnets 4,
Unlike the conventional yoke plate 10 ′, the yoke plate fixing the 5, 6 and 7 is different from the first yoke plate 1
1 and since the second yoke plate 10 is divided into two parts, it can be replaced permanent magnet 5 having different diameters by exchanging only the first yoke plate 11. Therefore, in
The distance between the central permanent magnet 4 and the first permanent magnet 5 is
Prepare a plurality of different first yoke plates 11 in advance
Then, one of them is used as the second yoke plate 10
The erosion center can be easily changed without replacing the entire magnetron sputter cathode as in the conventional case, which is superior in cost to the conventional case. Further, by replacing only the permanent magnet 5, the position movement of the erosion center can be performed without changing the magnetron discharge area (erosion area), so that the plasma to the peripheral portion of the magnetron / sputter cathode 1 is generated by sputtering. It does not change the impact. That is, the discharge region does not move with the movement of the erosion center, and the peripheral portion of the magnetron sputtering cathode 1 is not sputtered.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, permanent magnets 4, 5, 6, 7 are used as magnets for forming a magnetic field on the target 2.
However, instead of this, an electromagnet may be used.

Further, although the round magnetron sputter cathode 1 has been described in the above embodiments, the present invention is also applicable to a square magnetron sputter cathode.

Further, in the above embodiment, unlike the conventional example, the annular groove into which the permanent magnet 5 is fitted is not formed in the backing plate 3, but a groove having a diameter corresponding to a plurality of permanent magnets 5 having different diameters is formed. A plurality of backing plates 3 may be formed so that when the permanent magnets 5 having different diameters are replaced and installed, any of the above grooves fits into the permanent magnets 5.

[0023]

As described above, according to the present invention , the mask
On the target surface without changing the Gnetron discharge area
The position where the vertical magnetic field component of
Set the yoke plate to the center magnet and the first magnet so that
Set the first plate, the second magnet and the outer magnet
Divide into a second plate to set the center magnet and the first magnet
Multiple first plates with different distances from
Prepare one of these and transfer one of them to the second plate.
By being attachable , the center can be changed without changing the entire cathode and without changing the erosion region of the non-magnetic target in magnetron sputtering. Further , the film thickness distribution of the thin film formed on the substrate can be easily adjusted.

[Brief description of drawings]

FIG. 1 is a side sectional view of a magnetron sputter cathode according to an embodiment of the present invention.

FIG. 2 is a plan view showing a cross section of the magnetron sputter cathode taken along line [2]-[2] in FIG.

FIG. 3A is a graph showing a magnetic field distribution on the surface of a non-magnetic material target in the same magnetron sputtering cathode, and B is a graph of FIG. 1 in which the abscissa axis of the graph corresponds to the mounting position of each member. It is a schematic diagram of the right half.

4 is a graph showing a magnetic field distribution on the surface of a non-magnetic target, and B is a schematic view of the right half of FIG. 1 showing the attachment positions of the respective members on the horizontal axis of the rough. .

FIG. 5 is a side sectional view of a magnetron sputter cathode according to a conventional example.

6 is a plan view showing a cross section taken along line [6]-[6] in FIG. 5 of the magnetron sputter cathode. FIG.

7 is a graph showing a magnetic field distribution on the surface of a non-magnetic target in the same magnetron sputter cathode, and B is a graph of FIG. 5 in which the horizontal axis of the graph corresponds to the mounting positions of the members. It is a schematic diagram of the right half.

[Explanation of symbols]

1 Magnetron Sputtering Cathode 2 Non-Magnetic Target 3 Backing Plate 4 Permanent Magnet 5 Permanent Magnet (First Permanent Magnet) 6 Permanent Magnet (Second Permanent Magnet) 7 Permanent Magnet 10 Second Yoke Plate 11 First Yoke plate

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Imamura 2500 Hagizono, Chigasaki-shi, Kanagawa, Japan, in Japan Sky Technology Co., Ltd. 56) References JP-A-2-34780 (JP, A) JP-A-4-276069 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C23C 14 / 00-14 / 58

Claims (2)

(57) [Claims] 1. A flat non-magnetic material target, a backing plate disposed on one surface side of the non-magnetic material target, a yoke plate spaced apart from the backing plate, and both magnetic poles. A columnar central magnet fixed to the central portions of the backing plate and the yoke plate, and concentrically with the central magnet, the magnetic poles of which are reversed in magnetism with respect to the central magnet. A cylindrical outer peripheral magnet fixed to the outer peripheral portion of the backing plate and the yoke plate, and a magnet arranged in concentric relation with the central magnet between the central magnet and the outer peripheral magnet to mutually invert the magnetism, and For the central magnet,
And a magnetron / sputter cathode consisting of a pair of cylindrical first and second magnets fixed to the yoke plate by reversing the magnetism with respect to the outer peripheral magnet, without changing the magnetron discharge region, A first plate that fixes the central magnet and the first magnet to the yoke plate so that the position where the vertical magnetic field component on the target surface becomes zero can be arbitrarily moved, the second magnet and the outer peripheral magnet And a second plate that fixes the central magnet and the first magnet.
Prepare multiple different first plates in advance, and
Any of the above can be attached to the second plate
Magnetron sour hawk Sword, characterized in that it was. 2. The magnetron sputter cathode according to claim 1, wherein among the plurality of first plates
Select one and leave the magnetron discharge area unchanged
The position where the vertical magnetic field component on the target surface becomes zero
Face the non-magnetic target by changing
A method for adjusting a film thickness distribution, which comprises adjusting a film thickness distribution of a substrate arranged in the same manner.