A selective substrate bias control device for a magnetron sputtering system and a multilayer film preparation method

Abstract

A selective substrate bias control device for magnetron sputtering system and a multilayer film preparation method, the device comprises a slide rail (1), a conductive slide rail (2) and a conductive rod (3). The slide rail (1) is fixed on the top of the vacuum chamber of the magnetron sputtering system, and the conductive slide rail (2) is detachably installed on the slide rail (1). The distance between the installation starting point of the conductive slide rail (2) and the film layer growth starting point is greater than or equal to d / 4, wherein d is the path length of the substrate assembly across a target material. The length of the conductive slide rail (2) is the corresponding path length from the installation starting point to the film layer growth ending point. The substrate assembly realizes electrical contact with the conductive slide rail (2) through the conductive rod (3). The device realizes selective regulation of the bias voltage of different film layers in the multilayer film system by designing the length and installation position of the conductive slide rail (2). By controlling the distance between the installation starting point of the conductive slide rail (2) and the film layer growth starting point to be greater than or equal to d / 4, the film layer flatness is improved while avoiding additional interface diffusion caused by bias voltage, thereby improving the optical performance of the multilayer film. The device is suitable for most planetary motion type magnetron sputtering equipment, is not limited by the shape of the substrate, and can be widely applied to the deposition of various material film layers.

Description

Technical Field

[0001] The present invention relates to the research field of magnetron sputtering coating technology, and in particular to a selective substrate bias control device for a magnetron sputtering system and a multilayer film preparation method. Background Art

[0002] Magnetron sputtering is a common method for depositing multilayer films, attracting widespread attention for its efficient and high-quality thin film deposition capabilities. Multilayer film applications, particularly in optics, electronics, and magnetic materials, place extremely stringent requirements on the surface and interface roughness of the films. During magnetron sputtering, applying a base bias voltage can effectively reduce the surface and interface roughness of multilayer films. There are two traditional bias application methods: one applies a uniform bias to all layers of the multilayer; the other applies a bias to only a subset of the layers. Both bias application methods maintain a constant bias voltage for a specific layer throughout the deposition process. However, the additional ion bombardment caused by the bias can cause intermixing of material atoms at the interface, leading to interfacial diffusion and ultimately degrading the optical performance of the multilayer. To address this issue, selective bias control is required for specific layers. Currently, researchers typically use multiple targets of the same material to deposit specific layers, applying a bias voltage during sputtering of a subset of the targets to achieve segmented bias control. However, this approach faces several challenges: first, the limited number of target materials available for coating equipment restricts the types of film materials that can be manipulated; second, the limited control modes for specific film layers cannot meet the diverse needs of process research. The urgent challenge is how to achieve selective control of substrate bias voltage without increasing the number of target materials, thereby reducing the surface roughness of multilayer films while avoiding interfacial diffusion and, therefore, improving their quality. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a selective substrate bias control device for a magnetron sputtering system and a method for preparing a multilayer film. The device includes a slide rail, a conductive slide rail and a conductive rod. The slide rail is fixed on the top of the vacuum chamber of the magnetron sputtering system, and the conductive slide rail is detachably mounted on the slide rail; the distance between the installation starting point of the conductive slide rail and the starting point of the film growth is ≥d / 4, where d is the path length of the substrate assembly passing over a target material. The length of the conductive slide rail is the path length corresponding to the installation starting point to the end point of the film growth. The substrate assembly is electrically contacted with the conductive slide rail through the conductive rod. The present invention realizes a bias device with a simple structure and flexible adjustment, which can significantly reduce the surface and interface roughness of magnetron sputtering multilayer films.

[0004] The technical solutions of the present invention are as follows:

[0005] A selective substrate bias control device for a magnetron sputtering system, comprising:

[0006] Slide rail, fixed on the top of the vacuum chamber of the magnetron sputtering system;

[0007] A conductive slide rail is detachably mounted on the slide rail, wherein the horizontal distance between the installation starting point of the conductive slide rail and the film growth starting point is ≥ d / 4, where d is the path length of the substrate assembly passing over the single target, and the length of the conductive slide rail is the path length from the installation starting point to the film growth end point;

[0008] The conductive rod is used to connect the base assembly and the conductive slide rail to ensure that the base assembly maintains elastic electrical contact with the conductive slide rail during movement.

[0009] The installation position and length of the conductive slide rail are set in sections according to the target material distribution and the film growth path, so as to achieve selective regulation of the bias voltage of different film layers in the multilayer film system.

[0010] The conductive rod includes a ball, a spring and a rod body, wherein the ball maintains contact with the surface of the conductive slide rail through the elastic force of the spring, thereby ensuring the stability of the electrical connection.

[0011] The conductive slide rail is locked on the slide rail by a fixer to achieve detachable installation.

[0012] The conductive slide rail is provided with a U-shaped track, and the balls slide along the U-shaped track.

[0013] Both ends of the conductive slide rail are provided with chamfers to prevent the balls from scratching against the conductive slide rail.

[0014] The length of the conductive slide rail covers the entire or partial path of the film growth, specifically 1 / 4 to 3 / 4 of the film growth path corresponding to the target material.

[0015] The installation direction of the slide rail is parallel to the movement plane of the magnetron sputtering system substrate assembly.

[0016] The slide rails, conductive slide rails and conductive rods are all made of materials with good hardness and conductivity, such as aviation duralumin.

[0017] A method for preparing a multilayer film based on a selective substrate bias control device of a magnetron sputtering system is characterized in that the substrate bias control device is used, and the method comprises the following steps:

[0018] Step 1. According to the target material type and film interface requirements, adjust the installation position and length of the conductive slide rail so that the conductive slide rail corresponding to the non-interface area covers a specified proportion of the entire film growth process;

[0019] Step 2: The base assembly is connected to the conductive rail via a conductive rod to achieve electrical contact.

[0020] Step 3. Turn on the bias power supply and use a multimeter to monitor the surface voltage of the conductive rail in real time to confirm that it is fully powered and the voltage is stable.

[0021] Step 4. Complete the multilayer film preparation according to the standard process of magnetron sputtering technology.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1) In view of the different growth paths of each film layer, the present invention adopts a segmented installation design of a detachable conductive slide rail, which can flexibly realize the selective regulation of the bias application position and ratio without adding additional target materials, while simplifying the process flow.

[0024] 2) The design of the elastic conductive rod in this invention enables it to adapt to substrates of various shapes, including flat and curved surfaces. This solves the problem of traditional bias devices being dependent on substrate shape and is suitable for most planetary magnetron sputtering equipment, greatly expanding its application scenarios. Furthermore, the device is low-cost and simple to operate.

[0025] 3) Based on in-depth research into film growth dynamics and interfacial diffusion mechanisms, the present invention designed the distance between the conductive rail installation point and the film growth point to ensure that this distance is at least one-quarter the length of the substrate's path over the target. This design suppresses atomic mixing and interfacial diffusion at the interface, reduces the film's surface roughness, and improves the optical performance of the multilayer film. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a top view of the selective substrate bias control device for a magnetron sputtering system according to the present invention.

[0027] Figure 2 It is a side view of the selective substrate bias control device for a magnetron sputtering system according to the present invention.

[0028] Figure 3 This is a schematic diagram of the conductive slide rail installation of the S3 sample in Example 1 of the present invention.

[0029] Figure 4 It is the measured reflectivity of three groups of Mo / Si / C multilayer film samples in Example 1 of the present invention.

[0030] Figure 1-3 Middle: 1-slide rail, 2-conductive slide rail, 3-conductive rod, 4-fixer, 5-U-shaped rail, 6-chamfer, 7-ball, 8-spring, 9-rod body, 10-conductive slide rail with a length of d / 2, 11-conductive slide rail with a length of d, 12-conductive slide rail with a length of d.

[0031] Figure 4 Middle: S1 is a multilayer film sample without added bias, S2 is a multilayer film sample with added bias to all film layers, and S3 is a multilayer film sample with a controlled bias ratio of 50% for the Si film layer. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the embodiments and drawings, but the scope of protection of the present invention should not be limited thereto.

[0033] like Figure 1 The selective substrate bias control device for a magnetron sputtering system provided by the present invention comprises a slide rail, a conductive slide rail, and a conductive rod. The method of the present invention is described by taking the preparation of a Mo / Si / C multilayer film as an example. The multilayer film structure is Substrate / [Si / C / Mo] 30 Si / Air. The film growth stage is defined as the angle range of ±θ / 2 centered on the target in the substrate motion trajectory, where θ is the angle between two adjacent target positions in the substrate motion trajectory, such as Figure 3 shown.

[0034] Example 1:

[0035] Step 1. Installation of slide rail 1 and conductive slide rail 2:

[0036] 1.1 Fix the slide rail 1 to the top of the vacuum chamber of the magnetron sputtering system with bolts, ensuring that it is parallel to the movement plane of the substrate assembly;

[0037] 1.2 According to the distribution position of the target materials (Mo, Si, C), three detachable conductive slide rails 2 are installed on the slide rail 1, such as Figure 3 As shown, the Mo and C targets use conductive rails 11 and 12 of length d (d is the length of the path the substrate passes over a single target), covering the entire film growth path (i.e., the entire path the substrate passes over the target). The Si target uses a conductive rail 10 of length d / 2, covering only the last 50% of the Si film growth path (i.e., from the midpoint to the end of the film growth).

[0038] The distance between the installation starting point of the conductive slide rail 10 used in the 1.3Si film layer and the film layer growth starting point is set to d / 2, and the three conductive slide rails 2 are locked on the slide rail 1 through the fixer 4.

[0039] Step 2. Connection of conductive rod 3:

[0040] The base assembly is electrically connected to the conductive rail 2 via a conductive rod 3. The conductive rod 3 includes a ball 7 and a spring 8. The ball 7 maintains elastic contact with the surface of the conductive rail 2 through the elastic force of the spring 8, ensuring the stability of the electrical connection of the base during planetary motion.

[0041] Step 3. Bias power supply setting:

[0042] 3.1 Turn on the bias power supply and use a multimeter to monitor the voltage of the conductive rail 2 in real time. Confirm that the voltage is stable and adjust it to the target voltage of -50V.

[0043] 3.2 Confirm that the conductive slide rails 2 corresponding to the Mo target, C target and Si target are fully energized;

[0044] Step 4. Coating process:

[0045] The Mo / Si / C multilayer film was prepared on a flat substrate according to the standard operating procedures of the magnetron sputtering process. The sample number is S3.

[0046] Comparative Example:

[0047] No bias voltage was added during the coating process, and the prepared sample was numbered S1.

[0048] The length of the conductive slide rail corresponding to the Si target in step 1 was changed to d, and a -50V bias was applied to the Mo target, C target, and Si target throughout the film growth process. The prepared sample was numbered S2.

[0049] Performance testing:

[0050] The spectra were measured on a reflectometer at the National Synchrotron Radiation Laboratory's beamline spectral radiation standards and metrology station. The measurement wavelength was 12 nm to 15 nm, with a step size of 0.015 nm. Figure 4 The results of the extreme ultraviolet reflectivity spectra of the samples prepared by the selective substrate bias control device of the present invention and the control group samples are shown in FIG. The peak reflectivity of the samples prepared by the selective substrate bias control device of the present invention is 62.4%, which is higher than that of the other two groups of samples.

[0051] Example 2: Preparation of a multilayer film on a curved substrate

[0052] The flat substrate in Example 1 is replaced with a curved substrate, and the installation of the conductive rail 2 remains unchanged. The elastic coefficient of the spring 8 is adjusted to ensure that the curved substrate is in stable contact with the conductive rail 2 during planetary motion.

[0053] The coating process parameters are the same as those in Example 1, and a Mo / Si / C multilayer film with the same structure is prepared. The surface roughness of the film layer can be suppressed, and the device can still achieve interface diffusion suppression on curved substrates, thereby improving optical performance.

Claims

1. A selective substrate bias control device for a magnetron sputtering system, characterized in that: include: A slide rail (1) is fixed on the top of the vacuum chamber of the magnetron sputtering system; A conductive slide rail (2) is detachably mounted on the slide rail (1), wherein the horizontal distance between the installation starting point of the conductive slide rail (2) and the film growth starting point is ≥ d / 4, wherein d is the path length of the substrate assembly passing over the single target material, and the length of the conductive slide rail (2) is the path length corresponding to the installation starting point to the film growth end point; A conductive rod (3) is used to connect the base assembly and the conductive slide rail (2) to ensure that the base assembly maintains elastic electrical contact with the conductive slide rail (2) during movement; The installation position and length of the conductive slide rail (2) are set in sections according to the target material distribution and the film growth path, so as to achieve selective regulation of the bias voltage of different film layers in the multilayer film system; The installation direction of the slide rail (1) is parallel to the movement plane of the magnetron sputtering system substrate assembly.

2. The selective substrate bias control device for a magnetron sputtering system according to claim 1, characterized in that: The conductive rod (3) comprises a ball (7), a spring (8) and a rod body (9), wherein the ball (7) maintains contact with the surface of the conductive slide rail (2) through the elastic force of the spring (8), thereby ensuring the stability of the electrical connection.

3. The selective substrate bias control device for a magnetron sputtering system according to claim 1, characterized in that: The conductive slide rail (2) is locked onto the slide rail (1) via a fixer (4) to achieve detachable installation.

4. The selective substrate bias control device for a magnetron sputtering system according to claim 2, characterized in that: A U-shaped track (5) is provided on the conductive slide rail (2), and the ball (7) slides along the U-shaped track (5).

5. The selective substrate bias control device for a magnetron sputtering system according to claim 2, characterized in that: Both ends of the conductive slide rail (2) are provided with chamfers (6) to prevent the balls (7) from scraping against the conductive slide rail (2).

6. The selective substrate bias control device for a magnetron sputtering system according to any one of claims 1 to 5, characterized in that: The length of the conductive slide rail (2) covers the entire or partial path of film layer growth, specifically 1 / 4 to 3 / 4 of the film layer growth path corresponding to the target material.

7. The selective substrate bias control device for a magnetron sputtering system according to claim 1, characterized in that: The slide rail (1), the conductive slide rail (2) and the conductive rod (3) are all made of materials with good hardness and conductive properties.

8. A method for preparing a multilayer film based on a selective substrate bias control device of a magnetron sputtering system, characterized in that: The substrate bias control device according to any one of claims 1 to 7 comprises the following steps: Step 1. According to the target material type and the film interface requirements, the installation position and length of the conductive slide rail (2) are adjusted so that the conductive slide rail (2) corresponding to the non-interface area covers a specified proportion of the entire film growth process; Step 2. The base assembly is connected to the conductive rail (2) via the conductive rod (3) to achieve electrical contact; Step 3. Turn on the bias power supply and use a multimeter to monitor the surface voltage of the conductive rail (2) in real time to confirm that it is fully powered and the voltage is stable; Step 4. Complete the multilayer film preparation according to the standard process of magnetron sputtering technology.

Images