Target cooling device and cooling method in PVD

Abstract

The application provides a target cooling device and a cooling method in PVD, and belongs to the technical field of semiconductor manufacturing. The device comprises a magnetron assembly arranged in a cavity of a magnetron sputtering device, the magnetron assembly comprises a rotating shaft connected to the top of the magnetron assembly, and an inner ring magnet and an outer ring magnet which are circularly distributed, and the bottom of the inner ring magnet and the outer ring magnet is provided with a magnetic plate; the magnetron assembly is connected with a rotating driving assembly through the rotating shaft; a cooling flow channel is arranged in the magnetron assembly, and the magnetron assembly is in contact with a graphite layer. Since the cooling flow channel is arranged in the magnetron assembly, the cooling liquid is prevented from directly contacting the magnetron assembly, and the appropriate distance between the magnetron assembly and the target is ensured. When the graphite layer is gradually worn and thinned, the application adopts a gas cylinder combined with a moving block and a clever groove setting, and under the rotating action of the magnetron assembly, all the outer ring magnets are separated from the magnetic plates, so that the overall magnetic induction intensity is reduced, and the appropriate magnetic induction intensity is maintained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor manufacturing, and particularly relates to a target material cooling device and a cooling method in PVD. BACKGROUND

[0002] PVD (Physical Vapor Deposition) technology refers to a technology of vaporizing a material source (solid or liquid) surface into gaseous atoms / molecules or partially ionizing into ions under vacuum conditions by a physical method, and depositing a thin film with certain special functions on a 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 the magnetron sputtering needs to be cooled and cleaned by a cooling device after heat treatment to remove stains on the surface of the target material for the next step of processing. The existing target material cooling scheme mainly includes the following two kinds:

[0004] The chamber of the magnetron assembly is made into a sealed chamber, and cooling water is introduced into the chamber to cool the target backing plate, thereby realizing the cooling of the target material. However, this method has the following disadvantages: Since the cooling water directly contacts the magnetron assembly, it will corrode the magnetron assembly after a long period of use, causing the magnetron assembly to rust, thereby affecting the magnetic induction intensity and ultimately affecting the film plating. In addition, the chamber needs to be sealed in this method, which is difficult to design and manufacture, and has a high cost.

[0005] A cooling flow channel is designed in the target backing plate, and cooling water is introduced to cool the target material. This method also has defects: Since the flow channel needs to be designed in the backing plate, the backing plate must have sufficient thickness to accommodate the flow channel, which increases the distance from the magnetron assembly to the target material, thereby further affecting the magnetic induction intensity. SUMMARY

[0006] To solve the above problems, the present application provides a target material cooling device and a cooling method in PVD, which adopts a magnetron assembly with a cooling flow channel and cools the target material by heat conduction through a graphite layer.

[0007] To achieve the above purpose, the technical scheme of the present application is as follows:

[0008] The utility model provides a target cooling device in PVD, including the magnetron assembly that sets up in the cavity of magnetron sputtering equipment, the magnetron assembly includes the pivot that connects in the top of magnetron assembly, and the inner ring magnet and the outer ring magnet that distribute in circular array respectively, the inner ring magnet and the outer ring magnet all are provided with the magnetic plate at the bottom, the magnetron assembly is connected with the rotary drive assembly through the pivot, the cooling flow channel is set up in the magnetron assembly, and the magnetron assembly still is contacted with the graphite layer, the graphite layer sets up on the upper surface of target backing plate, the magnetron assembly is provided with the mounting groove with each outer ring magnet corresponds, and the outer ring magnet top is provided with the connecting head, and the connecting head is connected to the mounting groove in the magnetron assembly, the mounting groove is narrow in the middle, and each has the installation area for accommodating the connecting head on the upper and lower two ends, each outer ring magnet side is provided with the moving groove, and the cavity is also provided with the linear drive mechanism, and the moving block is connected with the linear drive mechanism action end, and the moving block can extend into the moving groove under the action of linear drive mechanism, the moving groove has the inclined plane.

[0009] Further, the rotary drive assembly includes a motor and a belt, and the motor is connected with the pivot through the belt.

[0010] Further, the inlet and outlet of the cooling flow channel are arranged in the pivot for connecting with the cooling pipeline.

[0011] Further, the cooling flow channel is communicated to the magnetic plate.

[0012] Further, the shoulder of each outer ring magnet is connected with the magnetic assembly through at least two elastic components.

[0013] Further, the mounting groove is made of elastic material.

[0014] The utility model also provides a target cooling method in PVD, including the following steps:

[0015] The rotary drive assembly drives the magnetron assembly to rotate, the magnetic plate in the magnetron assembly is contacted with the graphite layer, the cooling liquid flows into the cooling flow channel through the inlet, and flows out through the outlet after a cycle;

[0016] When the graphite layer is worn, the moving block is inserted into the moving groove of the outer ring magnet by using the air cylinder, the moving block makes the outer ring magnet rise, the connecting head on the top of the outer ring magnet moves up and is extruded into the upper installation area of the mounting groove, the position of the outer magnet moves up and is separated from the magnetic plate.

[0017] The utility model has the advantages of:

[0018] 1. Since the cooling flow channel is arranged in the magnetron assembly, and the target is cooled by the contact and heat conduction between the magnetron assembly and the graphite layer, the cooling liquid is avoided from directly contacting with the magnetron assembly, and the appropriate distance between the magnetron assembly and the target is ensured.

[0019] 2. As the graphite layer gradually wears down and thins, this invention uses a cylinder combined with a moving block and a cleverly designed groove. Under the rotation of the magnetic control component, all the outer ring magnets are disengaged from the magnetic plate, thereby reducing the overall magnetic induction intensity and maintaining a suitable magnetic induction intensity at all times. Attached Figure Description

[0020] Figure 1 A cross-sectional schematic diagram and a partial enlarged view of a magnetron sputtering equipment with a target cooling device installed in PVD.

[0021] Figure 2 This is a schematic diagram of the cross-sectional structure of the magnetron control component.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1-Cavity, 2-Target material, 3-Magnetic control 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 material backplate. Detailed Implementation

[0024] The technical solutions provided by the present invention will be described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0025] like Figure 1 As shown, the target cooling device in PVD provided by this invention is installed inside the cavity 1 of the magnetron sputtering equipment. In this invention, a graphite layer 4 with a thickness of 2mm is provided on the upper surface of the target backplate 21 connected to the target 2. The magnetron assembly 3 includes a rotating shaft 5 at the top, several inner ring magnets 6, and several outer ring magnets 7. Magnetic plates 8 are provided at the bottom of both inner and outer ring magnets, and the magnetic plates 8 are connected to the main frame of the magnetron assembly 3. The rotating shaft 5 is connected to a motor 16 via a belt 15, and the motor 16 can drive the magnetron assembly 3 to rotate. The rotating shaft 5 is connected to a mounting plate inside the cavity 1 via a bearing 20. Due to the belt drive structure, the motor can be installed on the other side of the rotating shaft, facilitating the installation of cooling pipes. The motor and belt can be replaced with other devices with rotational drive functions. A cooling channel 9 is provided inside the main frame of the magnetron assembly 3. The coolant in the cooling channel can cool each inner and outer ring magnet, and simultaneously cool the magnetic plates through thermal conductivity. Furthermore, the cooling channel can also be connected to the bottom magnetic plate 8 through the channel within the frame of the magnetic control assembly 3, thereby directly cooling the magnetic plate 8. The cooling channel inlet 10 and the cooling channel outlet 11 are both located inside the rotating shaft for introducing and discharging coolant, and are connected to an external coolant supply device through pipes.

[0026] The outer ring magnet 7 of the magnetic control assembly 3 is provided with a circular connector 19 at its top (the connector has a smooth, protruding curved surface, or it can be elliptical). The outer ring magnet mounting groove 17 of the magnetic control assembly 3 is gourd-shaped, narrow in the middle and wider at the top and bottom. The groove 17 has mounting areas at both the top and bottom that are adapted to the size of the circular connector. The groove is made of an elastic material, allowing the circular connector to enter another mounting area of ​​the groove through the middle under external force. Multiple slits should be provided at the bottom of the mounting groove. The slits allow the mounting groove to expand to a certain extent under external force, making it easier for the connector to be inserted and connected. A cylinder 12 is provided next to the magnetic control assembly 3 inside the cavity 1. The actuating end of the cylinder 12 is connected to a moving block 13. Each outer ring magnet has a moving groove 14 on its side, and 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 of the movable block 13 that contacts the movable groove is located at the middle or upper part of the inclined surface inside the movable groove. Driven by the cylinder 12, the movable block 13 can extend into the upper or middle part of the movable groove 14. Under the action of the cylinder, the movable block extends further in. Due to the shape 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. Specifically, in this embodiment... Figure 1 In the design, both the moving groove 14 and the moving block 13 have triangular cross-sections. The moving block 13 is slightly higher than the moving groove 14, and its bottom is lower than the upper edge of the moving groove 14. The cylinder 12 can also use other mechanisms capable of linear motion, such as a linear motor. The shoulders of the outer ring magnet 7 (i.e., both sides of the circular connector 19) are connected to the main body of the magnetic control assembly via springs 18. The magnetic plate 8 is made of stainless steel and attracts the magnet. The rest of the frame of the magnetic control assembly 3 is made of stainless steel. When the circular connector 19 of the outer ring magnet 7 is located in the mounting area below the mounting groove 17, the outer ring magnet 7 is attracted to the magnetic plate 8, and the spring 18 is stretched. When the moving block 13 raises the outer ring magnet, the spring 18 retracts, assisting the circular connector 19 of the outer ring magnet 7 in resisting the magnetic force of the magnetic plate 8 and entering the mounting area above the mounting groove 17. The upper mounting area of ​​the mounting groove 17, combined with the narrow central area, can hold the circular connector of the outer ring magnet 7 in place, and the spring 18 also serves as an auxiliary limiting mechanism. Spring 18 can also be replaced with other elastic components with restoring force. When the outer magnet 7 needs to descend and re-attach to the magnetic plate 8, a larger external force can be applied.

[0027] During the working process of the magnetron sputtering device, the motor 16 drives the belt 15 to drive the rotating shaft 5 to rotate, 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 2mm, the distance between the magnetron assembly and the back plate is 2mm, and the magnetron assembly generates a suitable magnetic induction intensity on the target material. The cooling liquid flows into the cooling flow channel through the cooling flow channel inlet, circulates, and then flows out through the cooling flow channel outlet, forming a complete cooling circulation loop. Since the graphite layer is installed on the upper surface of the target material and is in contact with the magnetic plate, through heat transfer, the cooling circulation loop can cool the target material. At the same time, graphite has a lubricating effect, so it will not affect the rotation of the magnetron assembly. Because the magnetron assembly rotates continuously, the cooling effect of the cooling circulation loop on the target material is more uniform.

[0028] Since the graphite layer will gradually wear out, the overall magnetron assembly will gradually decrease slightly, and when the magnetron assembly decreases, 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 controls the moving block to insert into the moving groove on the side of the magnet, and through the corresponding shape setting, the moving block will make the magnet rise as a whole. Since the installation groove 17 of the outer ring magnet is elastic, the circular connector 19 at the top of the outer ring magnet 7 will be squeezed upward into the installation area at the upper part of the installation groove 17, so that the position of the outer magnet is moved upward and separated from the magnetic plate. Since the magnetron assembly continues to rotate, 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 number of outer ring magnets to be separated should be selected according to the degree of wear of the graphite layer to control the magnetic induction intensity to a reasonable value.

[0029] It should be noted that the above content only illustrates the technical idea of the present application and cannot limit the protection scope of the present application. For ordinary skilled persons in the technical field, they can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements all fall within the scope of the claims of the present application.

Claims

1. A target cooling device in PVD, characterized in that The magnetron assembly is arranged in the cavity of a magnetron sputtering device, and includes a rotating shaft connected to the top of the magnetron assembly, and inner and outer ring magnets arranged in a circular array, respectively, and each provided with a magnetic plate at the bottom; the magnetron assembly is connected to a rotating drive assembly through the rotating shaft; a cooling flow channel is arranged in the magnetron assembly, and the magnetron assembly is in contact with a graphite layer arranged on the upper surface of a target backing plate; the magnetron assembly is provided with mounting grooves corresponding to each outer ring magnet, and the top of each outer ring magnet is provided with a connecting head connected into the mounting groove of the magnetron assembly; the mounting groove is narrow in the middle and has mounting areas at both ends for accommodating the connecting head; each outer ring magnet is provided with a moving groove at the side, and a linear drive mechanism is further arranged in the cavity, and a moving block is connected to the action end of the linear drive mechanism, which 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 rotating drive assembly includes a motor and a belt, and the motor is connected to the rotating shaft through the belt.

3. The target cooling apparatus 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 connection with a cooling pipe.

4. The target cooling apparatus in PVD according to claim 1, characterized in that, The cooling flow channel is communicated to the magnetic plate.

5. The target cooling apparatus in PVD according to claim 1, wherein, The shoulder of each outer ring magnet is connected to the magnetic assembly through at least two elastic components.

6. The target cooling apparatus in PVD according to claim 1, wherein, The mounting groove is made of elastic material.

7. A target cooling method in PVD, characterized by The target cooling device in PVD is realized by the method of any one of claims 1-6, including the following steps: The rotating drive assembly drives the magnetron assembly to rotate, the magnetic plate in the magnetron assembly is in contact with the graphite layer, the cooling liquid flows into the cooling flow channel through the inlet, and flows out through the outlet after one cycle; When the graphite layer is worn, the moving block is inserted into the moving groove of the outer ring magnet by using a cylinder, the moving block makes the outer ring magnet rise, the connecting head at the top of the outer ring magnet moves upward and is pressed into the upper mounting area of the mounting groove, the position of the outer magnet moves upward and is separated from the magnetic plate.

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