A sputtering process for improving the uniformity of coating of waveguide electrodes

Abstract

The application relates to the field of coating technology, in particular to a sputtering process for improving the uniformity of waveguide electrode coating, which comprises the following steps: S1, substrate pretreatment; S2, dynamic mask design and installation; S3, process equipment and parameter setting; S4, sputtering deposition under intelligent control; S5, uniformity and edge transition synergistic regulation; and S6, post-treatment. The application realizes the consistency control of coating composition, thickness uniformity, adhesion and microstructure by adopting a dynamic mask with an edge gradual light transmission structure and combining an intelligent control system to realize real-time monitoring and dynamic adjustment of process parameters, effectively inhibits edge peak and step coverage mutation, and obtains a high-uniformity and defect-free film.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a sputtering process for improving the uniformity of waveguide electrode coating. Background Technology

[0002] As the core component of optical waveguide devices, the coating quality of waveguide electrodes directly affects the electro-optical performance, transmission loss, and lifespan of the devices. In the fabrication process of waveguide electrodes, the uniformity of the coating is one of the key indicators that determines the performance of the devices.

[0003] However, traditional sputtering deposition processes suffer from the following problems in practical applications: First, the uneven deposition rate distribution of sputtered particles on the substrate surface leads to poor coating thickness consistency, especially at substrate edges where spike effects or abrupt step coverage changes can occur, affecting the uniformity of the electric field distribution of the electrodes. Second, traditional masking techniques use hard boundary shielding, resulting in significant thickness jumps at the boundary between the coated and uncoated areas, leading to concentrated electric fields at the edges and reducing the device's withstand voltage performance and reliability. Furthermore, existing processes lack real-time monitoring and intelligent control capabilities for the deposition process, making it difficult to adapt to fluctuations in the state of different batches of substrates and targets, resulting in poor process repeatability and low yield.

[0004] Therefore, there is an urgent need for a sputtering process to improve the uniformity of waveguide electrode coating in order to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a sputtering process that improves the uniformity of waveguide electrode coating, thereby solving the problems of poor coating thickness uniformity, obvious edge spike effect, and low process repeatability mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a sputtering process for improving the uniformity of waveguide electrode coating, comprising the following steps:

[0007] S1: Substrate pretreatment: The waveguide electrode substrate to be coated is surface treated to improve the adhesion of the coating.

[0008] S2: Dynamic mask design and installation. Design and fabricate a dynamic mask with a gradient edge transparency structure. The mask is used to cover the non-coated area of ​​the waveguide electrode and form a transition zone with a natural transition of coating thickness at the boundary of the target coated area.

[0009] S3: Process equipment and parameter settings, providing a magnetron sputtering device with multi-target co-sputtering function, including a vacuum chamber, a gas control system, a rotatable sample holder and an intelligent control system, and preset initial process parameters;

[0010] S4: Intelligent sputtering deposition, using radio frequency magnetron sputtering to deposit the coating. The intelligent control system monitors and dynamically adjusts the process parameters in real time to ensure the consistency of coating composition, thickness uniformity, adhesion and microstructure.

[0011] S5: Coordinated regulation of uniformity and edge transition. During the sputtering process, the intelligent control system executes a coordinated regulation strategy to dynamically match the target-substrate distance, scanning path and plasma distribution, thereby achieving coordinated regulation of film uniformity and edge transition region.

[0012] S6: Post-treatment, the coating is annealed in an inert gas environment to eliminate stress and improve density and crystal quality. Then, it is naturally cooled to room temperature and the coated waveguide electrode is removed.

[0013] Preferably, the substrate pretreatment in S1 specifically includes:

[0014] The substrate is immersed in an organic solvent and cleaned using an ultrasonic cleaner to remove surface grease and impurities.

[0015] Rinse with deionized water and dry with inert gas;

[0016] The substrate surface is activated using a plasma cleaner to enhance coating adhesion.

[0017] Preferably, the edge gradient light-transmitting structure of the dynamic mask in S2 is one or more of the following: a sawtooth edge structure, a micro-pore array edge structure, and a thickness gradient edge structure.

[0018] Preferably, the initial process parameters in S3 include: a background vacuum level of less than 10. -4 Pa, sputtering power 50~500W, working gas pressure 0.1~2.0Pa, target distance 50~200mm, Ar flow rate 10~50sccm.

[0019] Preferably, the sample holder includes a revolution mechanism, a rotation mechanism, and an angle decoupling control unit.

[0020] Preferably, the parameters monitored in real time by the intelligent control system in S4 include the target material state, plasma spectrum, and film thickness information.

[0021] Preferably, the variables monitored in real time by the intelligent control system in S4 include: target voltage, target current, plasma emission spectrum, crystal film thickness signal, and automatically adjust power or gas flow rate according to deposition rate offset.

[0022] Preferably, the coordinated regulation strategy includes:

[0023] Dynamically match the target-base distance by adjusting the sample holder height or target angle.

[0024] The scanning path is optimized by using a combination of rotation and reciprocating translation.

[0025] Adjusting the magnetic field or auxiliary anode controls the plasma density distribution.

[0026] Preferably, the intelligent control system's execution of the collaborative control strategy further includes dynamic mask position fine-tuning and real-time thickness monitoring and feedback.

[0027] Preferably, the annealing process described in S6 is as follows: in an argon atmosphere, the temperature is raised to 300-600°C, held for 0.5-4 hours, and then naturally cooled to room temperature at a controllable rate.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] This invention creates a transition zone with gradually changing transmittance between the coated and uncoated areas by setting a dynamic mask with a gradient light-transmitting structure at the edge. This allows the coating thickness to transition naturally at the boundary, effectively suppressing edge spikes and abrupt changes in step coverage, and solving the problem of abrupt thickness changes at the boundary of traditional masks.

[0030] This invention achieves closed-loop control of the deposition process by setting up an intelligent control system to monitor the target material status, plasma spectrum and film thickness information in real time, and dynamically adjusts process parameters based on the monitoring data, which significantly improves the repeatability of the process and the consistency of the coating.

[0031] This invention achieves synergistic optimization of thin film uniformity and edge transition region by setting a synergistic control strategy, dynamically matching the target-substrate distance, optimizing the scanning path, and controlling the plasma distribution, while ensuring the density and crystal quality of the coating. Attached Figure Description

[0032] Figure 1 This is a flow chart of the sputtering process of the present invention;

[0033] Figure 2 This is a schematic diagram of the dynamic mask sawtooth edge structure of the present invention;

[0034] Figure 3 This is a schematic diagram of the edge structure of the dynamic mask micro-hole array of the present invention;

[0035] Figure 4 This is a schematic diagram of the dynamic mask thickness gradient edge structure of the present invention;

[0036] Figure 5 This is a diagram of the intelligent control logic framework of the dynamic intelligent control system of the present invention;

[0037] Figure 6 This is a schematic diagram illustrating the dynamic mask installation and intelligent control linkage of the present invention. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] The present invention provides a sputtering process for improving the uniformity of waveguide electrode coating, as shown in the following structure. Figure 1 As shown, it includes the following steps:

[0040] Step 1: Substrate Pretreatment (S1)

[0041] Immerse the waveguide electrode substrate to be coated in an organic solvent such as anhydrous ethanol or isopropanol, and clean it with an ultrasonic cleaner for 5-15 minutes to remove surface grease and impurities. Then rinse it with deionized water 2-3 times and dry it with an inert gas (such as nitrogen). Finally, use a plasma cleaner to activate the substrate surface for 1-5 minutes to enhance the adhesion of the coating. The pretreated substrate surface should be clean, activated, and uniform.

[0042] Step 2: Dynamic Mask Design and Installation (S2)

[0043] A dynamic mask with a gradient-edge transparent structure was designed and fabricated. This mask covers the non-coated area of ​​the waveguide electrode and forms a transition zone at the boundary of the target coating area where the coating thickness naturally changes. The dynamic mask is installed between the substrate and the target material and connected to an intelligent control system, allowing for fine-tuning of its position based on real-time feedback during the coating process. The gradient-edge transparent structure of the dynamic mask can be one or a combination of serrated edge structures, micro-pore array edge structures, and thickness-gradient edge structures.

[0044] Serrated edge structure: such as Figure 2 As shown, the mask edge is serrated, with a tooth height to tooth width ratio of 1:2 to 1:5 and a tooth tip angle of 30° to 60°, so that sputtered particles form discontinuous shielding in the edge area, achieving a gradient distribution of coating thickness.

[0045] During implementation, sputtered particles create discontinuous shielding at the edge of the serrations, with strong shielding at the tip of the serration (thin deposition) and weak shielding at the valley (thick deposition). The average deposition thickness is distributed along the boundary gradient, achieving a natural transition.

[0046] Micropore array edge structure: such as Figure 3As shown, the mask edge region is distributed with a micropore array whose aperture gradually increases from the inside to the outside. The micropore diameter ranges from 0.1 to 0.5 mm, and the porosity increases linearly from 0% to 80%. The coating thickness can be controlled by controlling the transmittance.

[0047] During implementation, by controlling the linear increase of the micropore diameter and areal density, the flux of sputtered particles passing through the mask is gradually changed from 100% to 20%, thereby precisely controlling the coating thickness gradient.

[0048] Gradual thickness edge structure: such as Figure 4 As shown, the thickness of the mask edge region decreases linearly or exponentially from the center to the edge, the width of the thickness decrease region is ≥2mm, and the thickness at the thinnest point is 5% to 20% of the thickness of the mask body. The natural transition of the coating thickness is achieved by utilizing the difference in the mask's own shading effect.

[0049] During implementation, the change in the thickness of the mask itself directly alters the penetration probability of sputtered particles. The thinner the mask, the higher the transmittance and the thicker the deposition; the thicker the mask, the stronger the shielding and the thinner the deposition. Linear or exponential decay ensures that the thickness change is continuous without abrupt changes.

[0050] Step 3: Process Equipment and Parameter Settings (S3)

[0051] A magnetron sputtering apparatus with multi-target co-sputtering capability is provided, comprising a vacuum chamber, a gas control system, a rotatable sample holder, and an intelligent control system; and preset initial process parameters including sputtering power, working gas pressure, and target-substrate distance. Furthermore, the rotatable sample holder includes a revolution mechanism, a rotation mechanism, and an angle decoupling control unit to achieve uniform deposition incident angles at various points on the substrate surface, significantly improving the uniformity of the coating thickness, with thickness deviation controllable within ±3%.

[0052] The orbital mechanism: The sample holder revolves around the central axis of the sputtering cavity at a speed of 1 to 10 rpm, which is used to achieve time-averaged deposition of the substrate under different target orientations;

[0053] Rotation mechanism: Each substrate fixture rotates independently at a speed of 10-30 rpm. The rotation direction is the same as or opposite to the revolution direction, which is used to dynamically change the deposition incident angle of each point on the substrate surface relative to the target.

[0054] Angle decoupling control unit: The intelligent control system independently adjusts the rotation speed ratio between the revolution and the rotation, with a speed ratio range of 1:2 to 1:10. By adjusting the speed ratio, the time average of the deposition incident angle is uniformized, so that the total deposition rate of each point on the substrate surface tends to be consistent throughout the entire deposition cycle.

[0055] Furthermore, the initial process parameters include: a background vacuum level of less than 10... -4Pa, sputtering power 50-500W, working gas pressure 0.1-2.0Pa, target-substrate distance 50-200mm, Ar flow rate 10-50sccm. The specific steps for setting the initial process parameters in this invention include:

[0056] Vacuum conditions: Evacuate the vacuum chamber to a background vacuum level of 10. -5 ~10 -6 the following.

[0057] Sputtering power: Set the sputtering power to 100~300W.

[0058] Target arrangement: 2 to 4 target positions are symmetrically arranged in the cavity. The distance between the target and the substrate is 80 to 150 mm. The angle between the target normal and the substrate's revolution axis is 0° to 30°. The symmetrical arrangement of multiple targets further homogenizes the distribution of the deposition particle flow.

[0059] Sample holder setup: The pretreated waveguide electrode substrate is fixed on a rotatable sample holder, ensuring that the substrate surface is parallel to the sputtering target. The sample holder rotates during the coating process at a speed of 5–30 rpm.

[0060] Gas introduction: The working gas, argon (Ar), is introduced into the cavity through a mass flow controller. The flow rate is controlled between 10 and 50 sccm, and the working pressure is kept stable between 0.2 and 1.0 Pa.

[0061] Step 4: Sputter deposition under intelligent control (S4)

[0062] The coating is deposited using radio frequency (RF) magnetron sputtering. During the deposition process, an intelligent control system monitors variables such as target voltage, target current, plasma emission spectrum, and crystal oscillator film thickness signal in real time, and automatically adjusts the power or gas flow rate according to the deposition rate deviation.

[0063] In practice, when a decrease in deposition rate is detected, the system automatically increases sputtering power or adjusts gas flow to maintain a stable deposition rate. The intelligent control system ensures the consistency of coating composition, thickness uniformity, adhesion and microstructure, while responding in real time to the target material status and cavity environment fluctuations to achieve low-defect, repeatable high-performance deposition.

[0064] Step 5: Coordinated Regulation of Uniformity and Edge Transition (S5)

[0065] During the sputtering process, such as Figure 5As shown, the intelligent control system executes a coordinated regulation strategy, dynamically matching the target-substrate distance, scanning path, and plasma distribution to achieve coordinated regulation of film uniformity and edge transition zone, ensuring global optimization of deposition rate distribution and film thickness consistency, while suppressing abrupt changes in edge peaks and step coverage, ultimately obtaining a highly uniform and defect-free film.

[0066] The intelligent control system implements coordinated control strategies including: dynamically matching the target-base distance by adjusting the sample holder lifting or target angle; optimizing the scanning path by using a combination of rotation and reciprocating translational motion; and adjusting the magnetic field or auxiliary anode to control the plasma density distribution.

[0067] The intelligent control system of the present invention also includes dynamic mask position fine-tuning, real-time thickness monitoring and feedback, and multi-target collaborative sputtering in executing the collaborative control strategy.

[0068] Dynamic mask position fine-tuning: Based on the three-dimensional model of the substrate and real-time deposition rate feedback, the intelligent control system dynamically adjusts the relative position of the mask and the substrate to ensure that the width of the transition zone formed by the coating at the boundary of the target area is ≥2mm, and the coating thickness in the transition zone shows an exponential or linear decay law, and the angle between the edge and the substrate surface is controlled within 5°~15°.

[0069] Real-time thickness monitoring and feedback: Using a crystal oscillator thickness monitor or an in-situ optical monitoring system, the film thickness in different areas of the substrate is measured in real time; when the thickness deviation exceeds the preset threshold (e.g., ±2%) or the shape of the transition zone deviates from the target, the intelligent control system automatically adjusts the sputtering power, gas flow rate, sample holder rotation speed or mask position for dynamic compensation.

[0070] Multi-target co-sputtering: For large-sized or highly irregularly shaped waveguide electrodes, the multi-target co-sputtering function is activated, which utilizes multiple symmetrically arranged targets to sputter simultaneously. By adjusting the independent power of each target, the spatial distribution of the electric field and deposited particles is optimized.

[0071] This invention achieves uniform coating on large-size or irregularly shaped substrates by setting up a multi-target co-sputtering function, utilizing multiple symmetrically arranged targets for simultaneous sputtering, and adjusting the independent power of each target, thereby enhancing the applicability of the process.

[0072] like Figure 5 as well as Figure 6 As shown, the following are the fine-tuning rules for controlling the position of the dynamic mask when the intelligent control system detects anomalies:

[0073]

[0074] Step Six: Post-processing (S6)

[0075] The coating is annealed in an inert gas (such as argon) environment to eliminate internal stress, improve density and crystal quality, and then naturally cooled to room temperature before the waveguide electrode with coating is removed.

[0076] The annealing process is as follows: in an argon atmosphere, the temperature is raised to 300-600°C, held for 0.5-4 hours, and then naturally cooled to room temperature at a controllable rate. Preferably, in an argon atmosphere, the temperature is raised to 400-500°C, held for 1-3 hours, and then naturally cooled to room temperature at a rate of ≤5°C / min.

[0077] This invention, by setting up a post-annealing treatment process, involves heating and cooling at a controllable rate in an argon atmosphere, which effectively eliminates internal stress in the coating, improves density and crystal quality, and extends the service life of the waveguide electrode.

[0078] The invention also includes coating inspection. After coating is completed, the waveguide electrode is inspected in four dimensions: geometric morphology, electrical performance, optical performance, and comprehensive performance verification. This ensures that the coating meets the uniformity index and electric field control function required by the design, thereby improving the yield and reliability of the product.

[0079] Geometric morphology inspection: including coating thickness uniformity inspection and coating edge morphology inspection, to ensure that the thickness deviation is within ±3% and the transition zone width is ≥2mm.

[0080] Electrical performance testing: including insulation resistance testing (requirement ≥10 ohms) 12 Ω), dielectric strength test (required ≥15kV / mm), and surface resistivity distribution scan of the coating.

[0081] Optical performance testing: including transmittance testing (≥90%) and absorptivity testing (≤5%).

[0082] Comprehensive performance verification includes electric field distribution simulation verification, discharge stability testing, and environmental reliability testing (high temperature and humidity, temperature cycling, etc.).

[0083] After the above tests and verifications ensure that the coating meets the design requirements for uniformity and electric field control, the coated waveguide electrode can be put into subsequent use.

[0084] Example

[0085] This invention provides an embodiment: by employing a dynamic mask with a gradient-transmittance structure at the edges, a transition zone with gradually changing transmittance is formed between the coated and uncoated areas, resulting in a gradient distribution of sputtered particles at the boundary region. This achieves a coating edge with a natural thickness transition, effectively suppressing the spike effect and abrupt step coverage changes caused by traditional hard boundary masks. Simultaneously, an intelligent control system monitors the target state, plasma spectrum, and film thickness information in real time, and dynamically adjusts process parameters such as sputtering power, gas flow rate, and sample holder rotation speed based on the monitoring data, achieving closed-loop control of the deposition process. The combined motion of revolution and rotation, along with angle decoupling control, makes the deposition incident angle at each point on the substrate surface tend to be uniform, significantly improving the thickness uniformity of the coating. The synergistic control strategy, through dynamic matching of the target-substrate distance, optimization of the scanning path, and control of plasma distribution, achieves synergistic optimization of film uniformity and the edge transition zone, ultimately obtaining a highly uniform and defect-free film.

[0086] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A sputtering process for improving the uniformity of waveguide electrode coating, characterized in that, Includes the following steps: S1: Substrate pretreatment: The waveguide electrode substrate to be coated is surface treated to improve the adhesion of the coating. S2: Dynamic mask design and installation. Design and fabricate a dynamic mask with a gradient edge transparency structure. The mask is used to cover the non-coated area of ​​the waveguide electrode and form a transition zone with a natural transition of coating thickness at the boundary of the target coated area. S3: Process equipment and parameter settings, providing a magnetron sputtering device with multi-target co-sputtering function, including a vacuum chamber, a gas control system, a rotatable sample holder and an intelligent control system, and preset initial process parameters; S4: Intelligent sputtering deposition, using radio frequency magnetron sputtering to deposit the coating. The intelligent control system monitors and dynamically adjusts the process parameters in real time to ensure the consistency of coating composition, thickness uniformity, adhesion and microstructure. S5: Coordinated regulation of uniformity and edge transition: During the sputtering process, the intelligent control system executes a coordinated regulation strategy to achieve coordinated regulation of film uniformity and edge transition region. S6: Post-treatment, the coating is annealed in an inert gas environment to eliminate stress and improve density and crystal quality. Then, it is naturally cooled to room temperature and the coated waveguide electrode is removed.

2. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 1, characterized in that: The substrate pretreatment described in S1 specifically includes: The substrate is immersed in an organic solvent and cleaned using an ultrasonic cleaner to remove surface grease and impurities. Rinse with deionized water and dry with inert gas; The substrate surface is activated using a plasma cleaner to enhance coating adhesion.

3. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 1, characterized in that: The edge gradient light-transmitting structure of the dynamic mask described in S2 is one or more combinations of sawtooth edge structure, micro-pore array edge structure and thickness gradient edge structure.

4. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 1, characterized in that: The initial process parameters mentioned in S3 include: a background vacuum level of less than 10. -4 Pa, sputtering power 50~500W, working gas pressure 0.1~2.0Pa, target distance 50~200mm, Ar flow rate 10~50sccm.

5. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 1, characterized in that: The sample holder includes a revolution mechanism, a rotation mechanism, and an angle decoupling control unit.

6. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 1, characterized in that: The parameters monitored in real time by the intelligent control system described in S4 include the target material state, plasma spectrum, and film thickness information.

7. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 6, characterized in that: The intelligent control system described in S4 monitors variables in real time, including target voltage, target current, plasma emission spectrum, and crystal film thickness signal, and automatically adjusts power or gas flow rate according to deposition rate offset.

8. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 1, characterized in that: The coordinated regulation strategy includes: Dynamically match the target-base distance by adjusting the sample holder height or target angle. The scanning path is optimized by using a combination of rotation and reciprocating translation. Adjusting the magnetic field or auxiliary anode controls the plasma density distribution.

9. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 1, characterized in that: The intelligent control system's collaborative control strategy also includes dynamic mask position fine-tuning and real-time thickness monitoring and feedback.

10. The sputtering process for improving the uniformity of waveguide electrode coating according to claim 1, characterized in that: The annealing process described in S6 is as follows: in an argon atmosphere, the temperature is raised to 300–600°C, held for 0.5–4 hours, and then naturally cooled to room temperature at a controlled rate.

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