Target material cooling device and cooling method in PVD (Physical Vapor Deposition)

Abstract

The invention provides a target material cooling device and a cooling method in PVD (Physical Vapor Deposition), and belongs to the technical field of semiconductor manufacturing. The device comprises a magnetic control assembly arranged in a cavity of magnetron sputtering equipment, the magnetic control assembly comprises a rotating shaft connected to the top of the magnetic control assembly, an inner-ring magnet and an outer-ring magnet, the inner-ring magnet and the outer-ring magnet are circularly distributed, and magnetic plates are arranged at the bottoms of the inner-ring magnet and the outer-ring magnet; the magnetic control assembly is connected with the rotation driving assembly through a rotating shaft. A cooling flow channel is arranged in the magnetic control assembly, and the magnetic control assembly is further in contact with the graphite layer. Due to the fact that the cooling flow channel is arranged in the magnetic control assembly, direct contact between cooling liquid and the magnetic control assembly is avoided, and the proper distance between the magnetic control assembly and the target material is guaranteed. When the graphite layer is gradually abraded and thinned, all the outer ring magnets are separated from the magnetic plate under the rotation action of the magnetic control assembly by combining the air cylinder with the moving block and ingeniously arranging the groove, so that the overall magnetic induction intensity is reduced, and the proper magnetic induction intensity is always kept.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a target material cooling device and a cooling method in PVD. Background Art

[0002] PVD (Physical Vapor Deposition) technology refers to the technology of using physical methods to vaporize the surface of the material source (solid or liquid) into gaseous atoms / molecules, or partially ionize into ions under vacuum conditions, and deposit a thin film with some special functions on the substrate surface through a low-pressure gas (or plasma) process. PVD is one of the main substrate surface treatment technologies.

[0003] The target material of magnetron sputtering needs to be cooled and cleaned by a cooling device after the heat treatment process to remove stains on the surface of the target material for the next step of processing. The existing target material cooling solutions are mainly divided into the following two types: The chamber of the magnetron component is made into a sealed chamber, and cooling water is passed into the chamber to cool the target back plate, thereby achieving cooling of the target. However, this method has the following disadvantages: since the cooling water is in direct contact with the magnetron component, it will corrode the magnetron component after long-term use, causing the magnetron component to rust, thereby affecting the magnetic induction intensity and ultimately affecting the coating. In addition, this method requires the chamber to be sealed, which is difficult to design and manufacture and has high costs.

[0004] A cooling channel is designed in the target backing plate, and cooling water is passed through to cool the target. This method also has defects: since the channel must be designed in the backing plate, the backing plate must be thick enough to accommodate the channel, which increases the distance from the magnetron assembly to the target, further affecting the magnetic induction intensity. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a target material cooling device and a cooling method in PVD, which adopts a magnetron component with a cooling channel to cool the target material through heat conduction of a graphite layer.

[0006] To achieve the above object, the technical solution of the present invention is as follows: The target material cooling device in PVD comprises a magnetron assembly arranged in the cavity of a magnetron sputtering device, wherein the magnetron assembly comprises a rotating shaft connected to the top of the magnetron assembly, and inner ring magnets and outer ring magnets respectively distributed in a circular array, and magnetic plates are arranged at the bottom of the inner ring magnets and the outer ring magnets; the magnetron assembly is connected to the rotary drive assembly through the rotating shaft; a cooling flow channel is arranged in the magnetron assembly, and the magnetron assembly is also in contact with a graphite layer, and the graphite layer is arranged on the upper surface of the target material back plate; the magnetron assembly is provided with mounting grooves corresponding to each outer ring magnet, and a connector is arranged on the top of the outer ring magnet, and the connector is connected to the mounting groove of the magnetron assembly; the mounting groove is narrow in the middle, and has mounting areas for accommodating the connector at both ends; a moving groove is arranged on the side of each outer ring magnet, and a linear drive mechanism is also arranged in the cavity, and a moving block is connected to the action end of the linear drive mechanism, and the moving block can extend into the moving groove under the action of the linear drive mechanism, and the moving groove has an inclined surface.

[0007] Furthermore, the rotary drive assembly includes a motor and a belt, and the motor is connected to the rotating shaft through the belt.

[0008] Furthermore, the inlet and outlet of the cooling channel are arranged in the rotating shaft for connection with the cooling pipeline.

[0009] Furthermore, the cooling channel is connected to the magnetic plate.

[0010] Furthermore, each outer ring magnet shoulder is connected to the magnetic assembly through at least two elastic components.

[0011] Furthermore, the installation groove is made of elastic material.

[0012] The present invention also provides a target material cooling method in PVD, comprising the following steps: The rotating drive assembly drives the magnetostrictive assembly to rotate, the magnetic plate in the magnetostrictive assembly contacts the graphite layer, the coolant flows into the cooling channel through the cooling channel inlet, and flows out through the cooling channel outlet after one cycle; When the graphite layer is worn, the cylinder is used to control the moving block to be inserted into the moving groove of the outer ring magnet. The moving block makes the outer ring magnet rise, and the connecting head on the top of the outer ring magnet moves up and squeezes into the upper installation area of ​​the installation groove. The position of the external magnet moves up and separates from the magnetic plate.

[0013] The beneficial effects of the present invention are: 1. Since a cooling channel is set in the magnetron assembly, and the contact between the magnetron assembly and the graphite layer and heat conduction are used to cool the target material, direct contact between the coolant and the magnetron assembly is avoided, and a suitable distance between the magnetron assembly and the target material is ensured.

[0014] 2. When the graphite layer gradually wears and becomes thinner, the present invention adopts a cylinder combined with a moving block and an ingenious groove setting, and under the rotation of the magnetic control component, all outer ring magnets are separated from the magnetic plate, thereby reducing the overall magnetic induction intensity and always maintaining a suitable magnetic induction intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the cross-sectional structure of a magnetron sputtering device with a target material cooling device installed in PVD and a partial enlarged diagram; Figure 2 This is a schematic diagram of the cross-sectional structure of the magnetron component.

[0016] Description of reference numerals: 1- cavity, 2- target material, 3- magnetron assembly, 4- graphite layer, 5- rotating shaft, 6- inner ring magnet, 7- outer ring magnet, 8- magnetic plate, 9- cooling channel, 10- cooling channel inlet, 11- cooling channel outlet, 12- cylinder, 13- moving block, 14- moving groove, 15- belt, 16- motor, 17- mounting groove, 18- spring, 19- connector, 20- bearing, 21- target back plate. DETAILED DESCRIPTION

[0017] The technical solution provided by the present invention will be described in detail below in conjunction with specific embodiments. It should be understood that the following specific implementation methods are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0018] like Figure 1 As shown, the target material cooling device in the PVD provided by the present invention is arranged in the cavity 1 of the magnetron sputtering equipment. In the present invention, a graphite layer 4 is arranged on the upper surface of the target material back plate 21 connected to the target material 2, and the thickness of the graphite layer 4 is 2 mm. The magnetron assembly 3 includes a rotating shaft 5 arranged at the top, a plurality of inner ring magnets 6, and a plurality of outer ring magnets 7. A magnetic plate 8 is arranged at the bottom of the inner and outer ring magnets, and the magnetic plate 8 is connected to the main frame of the magnetron assembly 3. The rotating shaft 5 is connected to the motor 16 through a belt 15, and the motor 16 can drive the magnetron assembly 3 to rotate. The rotating shaft 5 is connected to the mounting plate in the cavity 1 through a bearing 20. Due to the use of a belt drive structure, the motor can be installed on the other side of the rotating shaft, which is convenient for installing a cooling pipe. The motor and the belt can be replaced by other devices with a rotation drive function. A cooling channel 9 is arranged in the main frame of the magnetron assembly 3, and the coolant in the cooling channel can cool the inner and outer ring magnets, and at the same time cool the magnetic plate under the action of heat conduction. Furthermore, the cooling channel can also be connected to the bottom magnetic plate 8 through the channel in the frame of the magnetron assembly 3, so as to directly cool the magnetic plate 8. The cooling channel inlet 10 and the cooling channel outlet 11 are both arranged in the rotating shaft for passing the coolant in and out, and are connected to the external coolant supply device through a pipeline.

[0019] A circular connector 19 is provided on the top of the outer ring magnet 7 in the magnetron assembly 3 (the outside of the connector is a smooth protruding curved surface, and can also be set to an elliptical shape). The outer ring magnet mounting groove 17 in the magnetron assembly 3 is a gourd-shaped groove that is narrow in the middle and wider at the upper and lower ends. The groove 17 has mounting areas that are adapted to the size of the circular connector. The groove material is made of elastic material. Under the action of external force, the circular connector can enter the other mounting area of ​​the groove through the middle of the groove. A plurality of slits should be provided at the bottom of the mounting groove. The slit setting can allow the mounting groove to expand to a certain range under the action of external force, so that the connector can be inserted more easily for connection. A cylinder 12 is provided next to the magnetron assembly 3 in the cavity 1. A moving block 13 is connected to the action end of the cylinder 12. A moving groove 14 is provided on the side of each outer ring magnet. The shape and position of the moving block 13 are adapted to the moving groove 14. Specifically, the movable groove has an inclined surface, and the end height of the movable block 13 for contacting the movable groove is located at the middle or upper part of the inclined surface in the movable groove. The movable block 13 can be extended into the upper or middle part of the movable groove 14 under the drive of the cylinder 12. The movable block is further extended under the action of the cylinder. Through the shape setting of the movable groove 14, the movable block 13 gradually slides to the lower part of the movable groove 14, thereby raising the external magnet. Figure 1 In the figure, the cross-sections of the moving groove 14 and the moving block 13 are both triangular, the moving block 13 is slightly higher than the moving groove 14 as a whole, and the bottom of the moving block 13 is lower than the upper edge of the moving groove 14. The cylinder 12 can also adopt other mechanisms capable of linear motion, such as a linear motor. The two shoulder positions of the outer ring magnet 7 (i.e., the two sides of the circular connector 19) are connected to the main body of the magnetic control component through a spring 18. The magnetic plate 8 is made of stainless iron, which has an attraction effect on the magnet, and the rest of the frame of the magnetic control component 3 is made of stainless steel. When the circular connector 19 of the outer ring magnet 7 is located in the installation area at the lower part of the installation groove 17, the outer ring magnet 7 is adsorbed on the magnetic plate 8, and the spring 18 is in a stretched state. When the moving block 13 lifts the outer ring magnet, the spring 18 retracts to assist the circular connector 19 of the outer ring magnet 7 to enter the installation area at the upper part of the installation groove 17 against the magnetic force of the magnetic plate 8. The upper installation area of ​​the installation groove 17 cooperates with the narrow area in the middle to clamp the circular connector of the outer ring magnet 7, and the spring 18 can also play an auxiliary limiting role. The spring 18 may also be replaced by other elastic components with resilience. When the outer ring magnet 7 needs to be lowered and adsorbed onto the magnetic plate 8 again, a large external force can be applied to achieve this.

[0020] During the operation of the magnetron sputtering equipment, the motor 16 drives the belt 15 to rotate the rotating shaft 5, and finally drives the magnetron assembly 3 to rotate. The magnetic plate 8 in the magnetron assembly 3 is in contact with the graphite layer 4. Since the thickness of the graphite layer is 2 mm, the distance between the magnetron assembly and the back plate is 2 mm, and the magnetron assembly generates a suitable magnetic induction intensity for the target material. The coolant flows into the cooling channel through the cooling channel inlet, circulates once, and then flows out through the cooling channel outlet to form a complete cooling circulation loop. Since the graphite layer is installed on the upper surface of the target material and contacts the magnetic plate, the cooling circulation loop can cool the target material through heat transfer. At the same time, graphite has a lubricating effect, so it will not affect the rotation of the magnetron assembly. Since the magnetron assembly rotates continuously, the cooling effect of the cooling circulation loop on the target material is more uniform.

[0021] As the graphite layer will gradually wear out, the overall magnetron assembly will drop slightly. When the magnetron assembly drops, its magnetic induction intensity will also increase. Therefore, when the graphite layer is worn to a certain extent, a certain number of magnets need to be separated from the magnetic plate. At this time, the cylinder is used to control the moving block to be inserted into the moving groove on the side of the magnet. Through the corresponding shape setting, the moving block will make the magnet rise as a whole. Since the mounting groove 17 of the outer ring magnet is elastic, the circular connector 19 on the top of the outer ring magnet 7 will squeeze upward into the mounting area at the top of the mounting groove 17, so that the position of the external magnet moves up and separates from the magnetic plate. Since the magnetron assembly rotates continuously, all the outer ring magnets can be separated from the magnetic plate under the action of the moving block, thereby reducing the overall magnetic induction intensity. In actual application, the corresponding number of outer ring magnets should be selected to be separated according to the degree of wear of the graphite layer to control the magnetic induction intensity to an appropriate value.

[0022] It should be noted that the above content only illustrates the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications all fall within the protection scope of the claims of the present invention.

Claims

1. A target cooling device in PVD, characterized in that: The invention comprises a magnetron assembly arranged in a cavity of a magnetron sputtering device, wherein the magnetron assembly comprises a rotating shaft connected to the top of the magnetron assembly, and inner ring magnets and outer ring magnets respectively distributed in a circular array, and magnetic plates are arranged at the bottom of the inner ring magnets and the outer ring magnets; the magnetron assembly is connected to a rotary drive assembly through the rotating shaft; a cooling flow channel is arranged in the magnetron assembly, and the magnetron assembly is also in contact with a graphite layer, and the graphite layer is arranged on the upper surface of a target back plate; the magnetron assembly is provided with mounting grooves corresponding to each outer ring magnet, and a connector is arranged on the top of the outer ring magnet, and the connector is connected to the mounting groove of the magnetron assembly; the mounting groove is narrow in the middle, and has mounting areas for accommodating the connector at both the upper and lower ends; a moving groove is arranged on the side of each outer ring magnet, and a linear drive mechanism is also arranged in the cavity, and a moving block is connected to the action end of the linear drive mechanism, and the moving block can extend into the moving groove under the action of the linear drive mechanism, and the moving groove has an inclined surface.

2. The target cooling device in PVD according to claim 1, characterized in that: The rotary drive assembly comprises a motor and a belt, and the motor is connected to the rotating shaft via the belt.

3. The target cooling device in PVD according to claim 1, characterized in that: The inlet and outlet of the cooling flow channel are arranged in the rotating shaft for connecting with the cooling pipeline.

4. The target cooling device in PVD according to claim 1, characterized in that: The cooling channel is connected to the magnetic plate.

5. The target cooling device in PVD according to claim 1, characterized in that: Each outer ring magnet shoulder is connected to the magnetic assembly through at least two elastic components.

6. The target cooling device in PVD according to claim 1, characterized in that: The installation groove is made of elastic material.

7. A method for cooling a target in PVD, characterized in that: The target material cooling device in PVD according to any one of claims 1 to 6 is used, comprising the following steps: The rotating drive assembly drives the magnetostrictive assembly to rotate, the magnetic plate in the magnetostrictive assembly contacts the graphite layer, the coolant flows into the cooling channel through the cooling channel inlet, and flows out through the cooling channel outlet after one cycle; When the graphite layer is worn, the cylinder is used to control the moving block to be inserted into the moving groove of the outer ring magnet. The moving block makes the outer ring magnet rise, and the connecting head on the top of the outer ring magnet moves up and squeezes into the upper installation area of ​​the installation groove. The position of the external magnet moves up and separates from the magnetic plate.

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