Strip-shaped planar magnetron cathode with high target utilization

Abstract

The application belongs to the technical field of ion plating and specifically relates to a strip-shaped planar magnetron cathode with high target material utilization, which comprises a strip-shaped target material, a back plate, inner magnetic steels and outer magnetic steels, wherein the strip-shaped target material is fixed on the back plate, the outer magnetic steels are arranged on the side of the back plate opposite to the strip-shaped target material and contain at least one N-S magnetic pole pair, and the inner magnetic steels are completely embedded in the back plate, and each inner magnetic steel is 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, and the inner magnetic steel between the N-S magnetic pole pair generates a second parallel magnetic field B2 on the surface of the strip-shaped target material, which is opposite to the direction of the first parallel magnetic field B1, and B1>B2. The inner magnetic steels with a specific magnetic field design are embedded in the back plate, the effect that the etching surface parallel magnetic field decreases with the increase of etching depth is achieved by embedding the inner magnetic steels, the target material is uniformly etched, and the target material utilization is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ion plating and particularly relates to a strip-shaped planar magnetron cathode with high target material utilization. BACKGROUND

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

[0003] Among various magnetron target structures, the strip-shaped planar magnetron target structure is the simplest and most reliable, and has the lowest cost, but the target material utilization is relatively low. The main factors causing low utilization are as follows: first, the magnetic field is unevenly distributed on the surface of the target material, causing discharge and sputtering to occur only in part of the target material; second, in the traditional magnetic field design, the deeper the target material etching, the stronger the magnetic field on the target material etching surface, so that the discharge and etching are further concentrated in the local area where the magnetic field is strong on the etching surface, eventually forming a V-shaped etching groove in the cross section, causing the target material to be etched through too early and scrapped. More optimization is made for the former, but for the latter, mechanical means such as rotation and scanning are mostly used, which increases the complexity and cost of the system and reduces the reliability.

[0004] CN119980166A discloses a magnetron target structure and a magnetron sputtering device, wherein the magnetron target structure comprises inner magnetic steel and 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 to a certain extent through the idea of extending the parallel field, but in actual application, as the target material etching process advances, the discharge position changes dynamically, and the width and uniformity of the parallel magnetic field are difficult to maintain continuously throughout the etching process, ultimately leading to the formation of a V-shaped etching groove in the cross section of the target material, and the improvement of the target material utilization is limited.

[0005] CN103147056A is a dynamic magnetic field vacuum coating magnetron sputtering source, which improves the magnetic field uniformity through a ring-shaped magnetic field that revolves and rotates simultaneously, but relies on mechanical transmission devices to realize magnetic field scanning, which significantly increases the complexity and manufacturing cost of the system, and the increased mechanical devices greatly reduce the overall reliability and maintenance convenience of the equipment.

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

[0007] Therefore, existing technologies may suffer from limited utilization due to the difficulty in maintaining magnetic field uniformity throughout the process, resulting in the formation of V-shaped etching grooves on the target material. Alternatively, they may rely on mechanical scanning / adjustment methods, which may increase system complexity and cost and reduce reliability. Summary of the Invention

[0008] To address the problems existing in the prior art, the main objective of this invention is to propose a strip-shaped planar magnetron cathode with high target utilization. Based on the external magnetic field of a traditional strip-shaped magnetron target, an internal magnet with a specific magnetic field design is embedded in the back plate. This allows the parallel magnetic field strength in the target area to decrease with increasing etching depth while still meeting the requirements of magnetron discharge, thereby preventing V-shaped etching channels from appearing on the target and achieving uniform etching of the target, thus improving the target utilization rate. At the same time, it avoids the complexity, high cost, and reliability issues of mechanical adjustment methods.

[0009] This invention provides the following technical solution:

[0010] A strip-shaped planar magnetron cathode with high target utilization rate includes a strip target, a backplate, an inner magnet, and an outer magnet, wherein:

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

[0012] The outer magnet is disposed on the side of the back plate opposite to the strip target and includes at least one N-S magnetic pole pair;

[0013] The inner magnet is completely embedded in the back plate, and each inner magnet is positioned between the N pole outer magnet and the S pole outer magnet of the NS pole pair.

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

[0015] The magnetic field strength B on the surface of the external magnet of this invention 外 The magnetic field strength B1 on the target surface is relatively high, resulting in a strong parallel magnetic field. The magnetic field strength B on the surface of the internal magnet is also relatively high. 内 The parallel magnetic field B2 formed on the target surface is relatively weak and opposite to the magnetic field of the outer magnet. The parallel magnetic field B of the resultant magnetic field is in the same direction as B1, with a strength of ||B1|-|B2||. As the etching depth H of the target surface increases, the etched surface area decreases, and the strengths of both B1 and B2 increase. Because the inner magnet is very close to the target surface and the outer magnet is far from the target surface, at an appropriate B... 外 and B 内Under certain values, |dB2 / dH| can be made greater than |dB1 / dH|, meaning that as H increases, the increment of B2 is greater than the increment of B1, and B weakens as H increases. Since the magnetron-controlled target discharge etching region is concentrated in the region with stronger B, the discharge etching will preferentially occur in the region with smaller H and stronger B, resulting in uniform etching.

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

[0017] Preferably, the inner magnet is embedded in the back plate close to the strip target material.

[0018] According to a specific embodiment of the present invention, the strip target is an indirect-cooled strip magnetron target, and cooling water channels are spaced apart on the side of the back plate opposite to the strip target. The cooling water channels are spaced apart between adjacent N-pole and S-pole external magnets. The cooling water channels are used to cool the back plate.

[0019] Preferably, the central axis of the inner magnet coincides with the central axis of the corresponding N / S magnetic pole pair.

[0020] Preferably, the aspect ratio of the strip target is not less than 9:1, which is suitable for elongated 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 serves to protect the magnets and conduct 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 this invention are as follows:

[0023] This invention alters the magnetic field distribution of a traditional strip-shaped magnetron target by embedding an internal magnet within the backplate. This causes the parallel magnetic field strength to gradually decrease as the etching depth increases in the target surface. Therefore, the parallel magnetic field strength in the deeper etched areas is actually lower than that in the shallower etched areas, resulting in more discharge and etching occurring in the shallower regions. This achieves uniform etching, improves target utilization, and avoids the complexity, high cost, and reliability issues associated with mechanical adjustment methods. Attached Figure Description

[0024] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only represent some of the embodiments of the present application, and all other embodiments obtained by a person of ordinary skill in the art without any creative effort based on these drawings also belong to the protection scope of the present application.

[0025] Figure 1 A schematic view of a planar strip magnetron cathode with high target utilization rate. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments will be described clearly and completely below. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without any creative effort also belong to the protection scope of the present application.

[0027] As shown in the drawings, Figure 1 the present application provides a planar strip magnetron cathode with high target utilization rate, comprising a strip target 1, a back plate 2, inner magnetic steel 3 and outer magnetic steel 4, wherein: the strip target 1 is fixed on the back plate 2, the outer magnetic steel 4 is arranged on the side of the back plate 2 opposite to the strip target 1, and contains at least one N-S magnetic pole pair; the inner magnetic steel 3 is completely embedded in the back plate 2, and each inner magnetic steel 3 is arranged between the N-pole outer magnetic steel 41 and the S-pole outer magnetic steel 42 of the N-S magnetic pole pair; the surface magnetic field strength of each N-S magnetic pole pair is B 外 , and the first parallel magnetic field B1 is generated on the surface of the strip target 1; the surface magnetic field strength of the inner magnetic steel 3 between the N-S magnetic pole pair is B 内 , the second parallel magnetic field B2 opposite to the direction of the first parallel magnetic field B1 is generated on the surface of the strip target 1, and B1>B2. The strip target 1 is an inter-cooled strip magnetron target, and cooling water channels 5 are distributed at intervals on the side of the back plate 2 opposite to the strip target 1. The cooling water channels 5 are arranged at intervals between the adjacent N-pole outer magnetic steel 41 and S-pole outer magnetic steel 42. The cooling water channels 5 are used to cool the back plate 2 by cooling. The central axis of the inner magnetic steel coincides with the central axis of the corresponding N-S magnetic pole pair. The width-height ratio of the strip target is not less than 9:1, which is suitable for long strip magnetic field distribution. The bottom of the inner magnetic steel 3 and the outer magnetic steel 4 is provided with a magnetic yoke (not shown in the figure) to prevent discharge of the lower magnetic field.

[0028] The technical solutions will be further described below in combination with specific embodiments. Figure 1

[0029] Embodiment 1

[0030] Under the discharge etching area, the inner magnetic steel is added at the position where the strip target contacts the cooling back plate.​

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

[0032] The material of the cooling back plate is red copper, and the thickness is 0.5 mm.

[0033] The surface magnetic field strength B of the outer magnetic steel is 4500 Gs. 外 The surface magnetic field strength B of the outer magnetic steel is 4500 Gs.

[0034] The surface magnetic field strength B of the inner magnetic steel is 1500 Gs. 内 The surface magnetic field strength B of the inner magnetic steel is 1500 Gs.

[0035] A magnetic yoke with a thickness of 1 mm is arranged below to prevent discharge caused by magnetic leakage.

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

[0037] Example 2

[0038] An inner magnetic steel is arranged at the position where the bar-shaped target contacts the cooling back plate below the discharge etching area.

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

[0040] The material of the cooling back plate is red copper, and the thickness is 0.5 mm.

[0041] The surface magnetic field strength B of the outer magnetic steel is 3500 Gs. 外 The surface magnetic field strength B of the outer magnetic steel is 3500 Gs.

[0042] The surface magnetic field strength B of the inner magnetic steel is 500 Gs. 内 The surface magnetic field strength B of the inner magnetic steel is 500 Gs.

[0043] A magnetic yoke with a thickness of 1 mm is arranged below to prevent discharge caused by magnetic leakage.

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

[0045] Example 3

[0046] An inner magnetic steel is arranged at the position where the bar-shaped target contacts the cooling back plate below the discharge etching area.

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

[0048] The material of the cooling back plate is red copper, and the thickness is 0.5 mm.

[0049] The surface magnetic field strength B of the outer magnetic steel is 4000 Gs. 外 The surface magnetic field strength B of the outer magnetic steel is 4000 Gs.

[0050] The surface magnetic field strength B of the inner magnetic steel is 1000 Gs. 内 The surface magnetic field strength B of the inner magnetic steel is 1000 Gs.

[0051] A 1mm thick magnetic yoke is fitted at the bottom to prevent magnetic leakage discharge.

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

[0053] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within 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 strip target, a backplate, an inner magnet, and an outer magnet, wherein: The strip target material is fixed to the back plate. The outer magnet is disposed on the side of the back plate opposite to the strip target and includes at least one N-S magnetic pole pair; The inner magnet is completely embedded in the back plate, and each inner magnet is positioned between the N pole outer magnet and the S pole outer magnet of the NS pole pair. The magnetic field strength on each surface is B. 外 The N and S magnetic pole pairs generate a first parallel magnetic field B1 on the surface of the strip target, and the surface magnetic field strength between the N and S magnetic pole pairs is B. 内 The inner magnet generates a second parallel magnetic field B2 on the surface of the strip target material, which is opposite to the direction of the first parallel magnetic field B1, and B1 > B2. B 外 The value range is 3500-4500Gs, B 内 The value range is 500-1500Gs; The internal magnet is embedded in the back plate close to the strip target material; The central axis of the inner magnet coincides with the central axis of the corresponding NS pole pair.

2. The strip planar magnetron cathode with high target utilization rate according to claim 1, characterized in that, The strip target is an indirect-cooled strip magnetron target. Cooling water channels are distributed at intervals on the side of the back plate opposite to the strip target. The cooling water channels are arranged at intervals between adjacent N-pole outer magnets and S-pole outer magnets.

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

1.

4. The strip planar magnetron cathode with high target utilization rate according to claim 3, 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.

5. The strip planar magnetron cathode with high target utilization rate according to claim 1, characterized in that, The backplate is made of copper.

6. The strip planar magnetron cathode with high target utilization rate according to claim 1, characterized in that, Both the inner and outer magnets are equipped with magnetic yokes at their bottoms.

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