Strip-shaped plane magnetic control cathode with high target material utilization rate

Abstract

The invention belongs to the technical field of ion plating, and particularly relates to a strip-shaped planar magnetic control cathode with high target material utilization rate, which comprises a strip-shaped target material, a back plate, inner magnetic steel and outer magnetic steel, the strip-shaped target material is fixed on the back plate, and the outer magnetic steel is arranged on one side, back to the strip-shaped target material, of the back plate and comprises at least one N-S magnetic pole pair; the inner magnetic steel is completely embedded in the back plate, and each inner magnetic steel is correspondingly arranged between the N-pole outer magnetic steel and the S-pole outer magnetic steel of the N-S magnetic pole pair; each N-S magnetic pole pair generates a first parallel magnetic field B1 on the surface of the strip-shaped target material, the inner magnetic steel located between the N-S magnetic pole pairs generates a second parallel magnetic field B2 on the surface of the strip-shaped target material, the direction of the second parallel magnetic field B2 is opposite to that of the first parallel magnetic field B1, and B1 is larger than B2. The inner magnetic steel with a specific magnetic field design is embedded in the back plate, and the effect that the parallel magnetic field of the etching surface is reduced along with the increase of the etching depth is achieved by embedding the inner magnetic steel, so that the target material is uniformly etched, and the utilization rate of the target material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ion plating, and in particular relates to a strip-shaped planar magnetron cathode with high target material utilization rate. Background Art

[0002] Magnetron sputtering is one of the physical vapor deposition methods. It has the advantages of simple equipment, easy control, large coating area and strong adhesion. It achieves high speed, low temperature and low damage during coating.

[0003] Among various magnetron target structures, the strip-shaped planar magnetron target is the simplest, most reliable, and most cost-effective, but it also suffers from low target material utilization. The main factors contributing to this low utilization are: first, the uneven distribution of the magnetic field across the target surface, which results in discharge and sputtering occurring only in certain areas of the target; second, in traditional magnetic field designs, the deeper the target is etched, the greater the magnetic field intensity on the etched surface, further concentrating discharge and etching in localized areas of the etched surface where the magnetic field is stronger. This ultimately creates V-shaped etched grooves, causing the target to be etched through prematurely and rendered useless. While more magnetic field optimization is employed for the former, mechanical methods such as rotation and scanning are often employed for the latter, increasing system complexity and cost while reducing reliability.

[0004] CN119980166A discloses a magnetron target structure and magnetron sputtering equipment, wherein the magnetron target structure includes an inner magnetic steel and an outer magnetic steel, and the inner magnetic steel is arranged at the center of the outer magnetic steel. This patent improves the target material utilization rate to a certain extent by extending the parallel field. However, in actual applications, as the target material etching process advances, the discharge position changes dynamically, and the breadth and uniformity of the parallel magnetic field strength are difficult to maintain continuously throughout the etching process, which ultimately leads to the formation of a V-shaped etching groove in the cross section of the target material, and the improvement in the target material utilization rate is limited.

[0005] CN103147056A discloses a dynamic magnetic field vacuum coating magnetron sputtering source, which improves magnetic field uniformity through a circular magnetic field that revolves and rotates. However, it relies on a mechanical transmission device to achieve magnetic field scanning, which significantly increases system complexity and manufacturing costs. The added mechanical devices greatly reduce the overall reliability and maintenance convenience of the equipment.

[0006] CN111020510A discloses a new type of magnetic steel adjustable planar cathode, which uses an upper and lower inner and outer ring permanent magnet arrangement with the outer ring 8mm higher than the inner ring to weaken the vertical magnetic field component near the target surface. However, as the etching proceeds, this method requires continuous change of the magnetic field strength at each point to maintain uniformity. The adjustment mechanism of this patent relies on the deformation of the magnetic steel base to drive the magnet to fine-tune the lifting and lowering. This mechanical position adjustment not only increases the difficulty of adjustment, but also significantly increases the time cost and maintenance complexity of equipment use. In particular, if manual adjustment is used, the inconvenience of operation and low efficiency will be more prominent. The overall design has obvious limitations in the convenience and economy of dynamic control of the magnetic field.

[0007] Therefore, the existing technology may cause the target material to form a V-shaped etching groove due to the difficulty in maintaining the uniformity of the magnetic field throughout the entire process, resulting in limited improvement in utilization rate, or rely on mechanical scanning / adjustment methods to increase system complexity and cost and reduce reliability. Summary of the Invention

[0008] In order to solve the problems existing in the above-mentioned prior art, the main purpose of the present invention is to propose a strip-shaped planar magnetron cathode with high target material utilization. On the basis of the external magnetic steel magnetic field of the traditional strip-shaped magnetron target, an internal magnetic steel with a specific magnetic field design is embedded in the back plate, so that the parallel magnetic field strength in the target area decreases with the increase of etching depth on the basis of meeting the magnetron discharge requirements, thereby preventing the appearance of V-shaped etching channels in the target material, achieving the purpose of uniformly etching the target material and improving the target material utilization, while avoiding the complexity, high cost and reliability problems of mechanical adjustment means.

[0009] The present invention provides the following technical solutions:

[0010] A strip-shaped planar magnetron cathode with high target material utilization rate comprises a strip-shaped target material, a back plate, an inner magnetic steel and an outer magnetic steel, wherein:

[0011] The strip target is fixed on the back plate.

[0012] The outer magnetic steel is arranged on a side of the back plate facing away from the strip target and includes at least one NS magnetic pole pair;

[0013] The inner magnetic steel is completely embedded in the back plate, and each inner magnetic steel is correspondingly arranged between the N pole outer magnetic steel and the S pole outer magnetic steel of the NS magnetic pole pair;

[0014] The magnetic field strength on each surface is B 外 The NS magnetic pole pair generates a first parallel magnetic field B1 on the surface of the strip target, and the surface magnetic field strength between the NS magnetic pole pair is B 内 The internal magnetic steel generates a second parallel magnetic field B2 on the surface of the strip target material, which is opposite to the first parallel magnetic field B1, and B1>B2.

[0015] The magnetic field strength B on the surface of the external magnetic steel of the present invention 外 The higher the magnetic field strength, the stronger the parallel magnetic field B1 formed on the target surface. 内 The parallel magnetic field B2 formed on the target surface is weak and opposite to the magnetic field of the external magnetic steel. The parallel magnetic field B of the combined magnetic field is in the same direction as B1, and the intensity is ||B1|-|B2||. As the etching depth H of the target surface increases, the etched surface of the target decreases, and the intensities of B1 and B2 increase. Since the inner magnetic steel is very close to the target surface and the outer magnetic steel is far away from the target surface, at an appropriate B 外 and B 内Under this value, |dB2 / dH|>|dB1 / dH|, that is, as H increases, the increment of B2 is greater than the increment of B1, and at this time, B weakens with the increase of H. Since the discharge etching area of ​​the magnetron target is concentrated in the area with stronger B, the discharge etching will preferentially occur in the area with smaller H and stronger B, making the etching uniform.

[0016] Preferably, B 外 The value range is 3500-4500Gs, B 内 The value range is 500-1500Gs.

[0017] Preferably, the inner magnetic steel is embedded in a backing plate close to the strip target.

[0018] According to a specific embodiment of the present invention, the bar target is an indirectly cooled bar magnetron target, and cooling water channels are spaced apart on the side of the backing plate facing away from the bar target. The cooling water channels are spaced apart between adjacent N-pole outer magnetic steel and S-pole outer magnetic steel. The cooling water channels cool the backing plate.

[0019] Preferably, the central axis of the inner magnetic steel coincides with the central axis of the corresponding NS magnetic pole pair.

[0020] Preferably, the aspect ratio of the strip target is not less than 9:1, adapted to the long strip magnetic field distribution. For example, the length of the strip target is 200-2000 mm, the width is 90-150 mm, and the height is 3-10 mm.

[0021] Preferably, the back plate is made of copper, which has the function of protecting the magnetic steel and conducting heat. According to a specific embodiment of the present invention, the thickness of the back plate is 0.5 mm.

[0022] The beneficial effects of the present invention are as follows:

[0023] By embedding internal magnetic steel within the backplate of a conventional strip-shaped magnetron target, the present invention alters the magnetic field distribution of conventional planar strip-shaped magnetron targets. This results in the target surface area experiencing discharge etching gradually decreasing in parallel with increasing etching depth. Consequently, the parallel magnetic field intensity in deeper etched areas is actually lower than in shallower etched areas, allowing more discharge and etching to occur in these shallower areas. This achieves uniform etching and improves target utilization, while also avoiding the complexity, cost, and reliability issues associated with mechanical adjustment methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0025] Figure 1 This is a schematic diagram of the planed structure of a strip-shaped planar magnetron cathode with high target material utilization. DETAILED DESCRIPTION

[0026] The following will be a clear and complete description of the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0027] like Figure 1 As shown, the present invention provides a strip-shaped planar magnetron cathode with high target material utilization, comprising a strip target material 1, a backing plate 2, an inner magnetic steel 3 and an outer magnetic steel 4, wherein: the strip target material 1 is fixed on the backing plate 2, the outer magnetic steel 4 is arranged on the side of the backing plate 2 facing away from the strip target material 1, and comprises at least one NS magnetic pole pair; the inner magnetic steel 3 is completely embedded in the backing plate 2, and each inner magnetic steel 3 is correspondingly arranged between the N-pole outer magnetic steel 41 and the S-pole outer magnetic steel 42 of the NS magnetic pole pair; the surface magnetic field strength of each is B 外 The NS magnetic pole pair generates a first parallel magnetic field B1 on the surface of the strip target 1, and the surface magnetic field strength between the NS magnetic pole pair is B 内 The inner magnetic steel 3 generates a second parallel magnetic field B2 on the surface of the strip target 1 in the opposite direction to the first parallel magnetic field B1, and B1>B2. The strip target 1 is an indirect-cooled strip magnetron target, and cooling water channels 5 are spaced apart on the side of the back plate 2 facing away from the strip target 1. The cooling water channels 5 are spaced apart between the adjacent N-pole outer magnetic steels 41 and the S-pole outer magnetic steels 42. The cooling water channels 5 use cooling to cool the back plate 2. The central axis of the inner magnetic steel coincides with the central axis of the corresponding NS magnetic pole pair. The aspect ratio of the strip target is not less than 9:1, which is adapted to the long strip magnetic field distribution. The bottom of the inner magnetic steel 3 and the outer magnetic steel 4 are both equipped with a magnetic yoke (not shown in the figure) to prevent leakage magnetic discharge below.

[0028] The following is a detailed description of the embodiments of the present invention. Figure 1 The technical solution is further explained.

[0029] Example 1

[0030] Below the discharge etching area, an inner magnetic steel is added at the contact position between the strip target and the cooling back plate.

[0031] The length of the strip target is 2000 mm, the width is 150 mm, and the thickness is 10 mm.

[0032] The cooling back plate is made of copper and has a thickness of 0.5mm.

[0033] Surface magnetic field strength B of the external magnetic steel 外 4500Gs.

[0034] Surface magnetic field strength B of the inner magnetic steel 内 1500Gs.

[0035] A 1mm thick yoke is provided at the bottom to prevent magnetic flux leakage and discharge from the bottom.

[0036] After the target material was used up, the utilization rate was measured to be 60%.

[0037] Example 2

[0038] Below the discharge etching area, an inner magnetic steel is added at the contact position between the strip target and the cooling back plate.

[0039] The length of the strip target is 200 mm, the width is 90 mm, and the thickness is 3 mm.

[0040] The cooling back plate is made of copper and has a thickness of 0.5mm.

[0041] Surface magnetic field strength B of the external magnetic steel 外 3500Gs.

[0042] Surface magnetic field strength B of the inner magnetic steel 内 500Gs.

[0043] A 1mm thick yoke is provided at the bottom to prevent magnetic flux leakage and discharge from the bottom.

[0044] After the target material was used up, the utilization rate was measured to be 52%.

[0045] Example 3

[0046] Below the discharge etching area, an inner magnetic steel is added at the contact position between the strip target and the cooling back plate.

[0047] The length of the strip target is 1000 mm, the width is 90 mm, and the thickness is 10 mm.

[0048] The cooling back plate is made of copper and has a thickness of 0.5mm.

[0049] Surface magnetic field strength B of the external magnetic steel 外 4000Gs.

[0050] Surface magnetic field strength B of the inner magnetic steel 内 1000Gs.

[0051] A 1mm thick yoke is provided at the bottom to prevent magnetic flux leakage and discharge from the bottom.

[0052] After the target material was used up, the utilization rate was measured to be 57%.

[0053] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A strip-shaped planar magnetron cathode with high target material utilization, characterized in that: It includes a bar target, a back plate, an inner magnetic steel and an outer magnetic steel, wherein: The strip target is fixed on the back plate. The outer magnetic steel is arranged on a side of the back plate facing away from the strip target and includes at least one NS magnetic pole pair; The inner magnetic steel is completely embedded in the back plate, and each inner magnetic steel is correspondingly arranged between the N pole outer magnetic steel and the S pole outer magnetic steel of the NS magnetic pole pair; The magnetic field strength on each surface is B 外 The NS magnetic pole pair generates a first parallel magnetic field B1 on the surface of the strip target, and the surface magnetic field strength between the NS magnetic pole pair is B 内 The internal magnetic steel generates a second parallel magnetic field B2 on the surface of the strip target material, which is opposite to the first parallel magnetic field B1, and B1>B2.

2. The strip-shaped planar magnetron cathode with high target utilization according to claim 1, characterized in that: B 外 The value range is 3500-4500Gs, B 内 The value range is 500-1500Gs.

3. The strip-shaped planar magnetron cathode with high target utilization according to claim 1, characterized in that: The inner magnetic steel is embedded in a back plate close to the strip target.

4. The strip-shaped planar magnetron cathode with high target utilization according to claim 1, characterized in that: The strip target is an indirect-cooled strip magnetron target. Cooling water channels are spaced apart on the side of the back plate facing away from the strip target. The cooling water channels are spaced apart between adjacent N-pole outer magnetic steels and S-pole outer magnetic steels.

5. The strip-shaped planar magnetron cathode with high target utilization according to claim 1, characterized in that: The center axis of the inner magnetic steel coincides with the center axis of the corresponding NS magnetic pole pair.

6. The strip-shaped planar magnetron cathode with high target utilization according to claim 1, characterized in that: The aspect ratio of the strip target is not less than 9:

1.

7. The strip-shaped planar magnetron cathode with high target utilization according to claim 6, characterized in that: The strip target has a length of 200-2000 mm, a width of 90-150 mm, and a height of 3-10 mm.

8. The strip-shaped planar magnetron cathode with high target utilization rate according to claim 1, characterized in that: The back plate is made of copper.

9. The strip-shaped planar magnetron cathode with high target utilization according to claim 1, characterized in that: The bottoms of the inner magnetic steel and the outer magnetic steel are both equipped with magnetic yokes.

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