A method for preparing high-precision super-micro prisms based on vapor deposition whiskers

Abstract

This invention relates to a high-precision ultra-micro prism fabrication method based on vapor-phase deposition whiskers in the field of optical component fabrication technology. The method includes the following steps: substrate pretreatment, which involves cleaning, removing impurities, and positioning the substrate; transferring the pretreated substrate from step one to a CVD device for directional whisker growth; whisker-substrate strengthening and bonding, where the grown substrate from step two is annealed to eliminate internal stress; and post-treatment, where the annealed product from step four is polished and inspected to obtain a qualified finished product. This invention achieves simultaneous attainment of micron-level precision, light transmittance, and mechanical properties, meeting the needs of high-end optoelectronic devices. The single-batch cycle is reduced to within 4 hours, breaking through the bottlenecks in mass production efficiency and stability. It ensures batch uniformity, high yield, and reduces production losses and costs.

Description

Technical Field

[0001] This invention belongs to the field of optical element fabrication technology and provides a method for fabricating high-precision ultra-micro prisms based on vapor-deposited whiskers. Background Technology

[0002] As optoelectronic devices develop towards miniaturization, high performance, and mass production, the production of microprisms faces the following challenges: 1. Under the trend of miniaturization (micrometer-level), due to the mutual incompatibility between precision, transmittance, and mechanical strength, it is difficult to simultaneously achieve a synergistic effect of high precision, high transmittance, and high mechanical reliability in microprisms, making it unsuitable for the stringent requirements of optoelectronic devices for core optical components; 2. Traditional processing methods struggle to balance efficiency and performance stability, resulting in a mass production bottleneck where "high-efficiency production inevitably leads to performance fluctuations"; 3. Excessive manual intervention leads to poor consistency in the performance parameters of microprisms during mass production, making it difficult to meet the batch production needs of the optoelectronic device industry. Therefore, a high-precision microprism fabrication method based on vapor-deposited whiskers is urgently needed to solve these problems. Summary of the Invention

[0003] In response to the above situation, the present invention aims to propose a high-precision ultra-micro prism fabrication method based on vapor-deposited whiskers, so as to achieve stable production of ultra-micro prisms with "high precision, high performance and high efficiency", and provide high-quality and compatible core optical components for optoelectronic devices.

[0004] A method for fabricating high-precision ultrafine prisms based on vapor-deposited whiskers includes the following steps:

[0005] Step 1: Substrate pretreatment. The substrate is cleaned and impurities are removed using plasma cleaning, and a mask is used to precisely position the substrate. Step 2: Directional growth of whiskers by vapor deposition. The pretreated substrate from Step 1 is transferred to the CVD equipment to start the growth process. Step 3: Strengthen the bond between whiskers and substrate. Anneal the substrate grown in Step 2 to eliminate internal stress. Step four, post-processing: The annealed products from step three are polished and then inspected to obtain qualified finished products. Qualified products are stored as finished products, while unqualified products are marked and discarded.

[0006] Preferably, in step one, the power of the plasma cleaning is 50-300W, and an argon-oxygen mixture with a volume ratio of 1:3 is introduced. The positioning accuracy of the mask is ±0.05μm, which realizes the removal of impurities and precise patterning of the substrate, and is compatible with ultra-micro prisms of different specifications.

[0007] Preferably, the reaction temperature in step two is 900-1100℃. Below 900℃, the silane decomposition rate is insufficient, resulting in a low whisker growth rate. Above 1100℃, the whiskers are prone to excessive lateral growth, leading to a decrease in prism apex angle accuracy. The pressure is 0.2-0.4 MPa, the magnetic field strength is 0.4-0.7 T, and the crystal growth rate is 0.3-0.8 μm / min. The purpose is to precisely guide the silicon whiskers to grow oriented along the preset prism apex angle, ensuring that the whisker growth direction perfectly matches the prism structure design angle, thereby improving the forming accuracy of the micro-prism.

[0008] Preferably, in step two, a gas is introduced, which is a mixture of silane and hydrogen or a mixture of silane, methane, and hydrogen, and the gas flow rate is 40-80 sccm.

[0009] Preferably, the annealing temperature in step three is 500-800℃, the holding time is 1-3 hours, and the heating / cooling rate during the process is 5℃ / min. This ensures an impact strength ≥300MPa.

[0010] Preferably, the annealing treatment is performed at a temperature of 650-750℃ for a holding time of 2.5h.

[0011] Preferably, plasma polishing is used in step four, with a polishing time of 5-15 minutes, Ra≤0.5nm, and transmittance≥90%. The apex angle accuracy during inspection is ±0.01°, and defective products are rejected.

[0012] Preferably, the plasma polishing power is 180-220W and the polishing time is 10-15min.

[0013] In this invention, the mechanism of high-precision prism apex corner forming through the coordinated control of mask positioning and magnetic field guidance is as follows: First, the mask precisely positions the substrate surface, defining the two-dimensional nucleation region and bottom geometry for whisker growth. Second, during vapor deposition, a specific magnetic field of 0.4-0.7T acts on the plasma-state precursor molecules through Lorentz force and magnetohydrodynamic effects, altering their mean free path and strictly constraining the trajectory of the deposited particles. The two-dimensional bottom shape constraint coupled with the three-dimensional magnetic field-oriented deposition vector forces the deposited particles to accumulate and deposit along specific magnetic field line inclination angles (such as 60° or 90°). Simultaneously, temperature control within the 900-1100℃ range ensures that the crystal stacking rate matches the magnetic field deflection rate, thereby forming an ultra-micro prism structure with extremely high apex corner precision in a single step.

[0014] The beneficial effects of this invention are as follows: 1. Through collaborative design of various processes, micron-level precision, light transmittance, and mechanical properties are achieved simultaneously to meet the requirements of high-end optoelectronic devices.

[0015] 2. The cycle time for a single batch is reduced to within 4 hours, breaking through the bottlenecks in mass production efficiency and stability.

[0016] 3. Through modular design and preset parameter schemes, multiple materials and specifications can be switched without modifying core equipment, thus reducing the threshold for multi-specification production.

[0017] 4. Improved batch uniformity, increased the pass rate to over 98%, and reduced production losses and costs.

[0018] 5. It broadens the range of process adaptability, can be adapted to a variety of whisker materials, provides technical support for expanding product lines and covering more application fields, and has a wider application prospect. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the principle of Example 1; Figure 2 This is a flowchart illustrating the principle of Example 2. Detailed Implementation

[0020] The present invention will now be clearly described in conjunction with the accompanying drawings and specific embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art based on the embodiments of the present invention without inventive effort to obtain all other embodiments should be included within the scope of protection of the present invention.

[0021] Example 1 like Figure 1 As shown, a high-precision ultra-micro prism fabrication method based on vapor-deposited whiskers is applicable to the large-scale mass production of micron-sized silicon whisker ultra-micro prisms with a 60° apex angle commonly used in optoelectronic devices. First, preliminary preparations were made, and a parameter scheme for a "60° apex-angle silicon whisker ultra-micro prism" was preset. The specific core parameters were set as follows: silicon whisker growth temperature 950℃, reaction pressure 0.3MPa, silane-hydrogen gas (volume ratio 1:5), raw material gas flow rate 60sccm, magnetic field strength 0.5T, growth rate 0.6μm / min; annealing strengthening temperature 700℃, holding time 2.5h; plasma polishing power 200W, polishing time 12min. A mask adapted to the 60° apex-angle prism structure was replaced, and the mask was precisely positioned using the ±0.05μm precision visual alignment system of the substrate preprocessing submodule to ensure that the patterning accuracy met the standards.

[0022] The preparation process then proceeds, including the following steps: Step 1: Substrate pretreatment. The substrate is subjected to plasma cleaning at a power of 200W, with an argon-oxygen (volume ratio 1:3) mixture passed through it. The substrate surface is cleaned for 5 minutes to remove surface oil, impurities, and oxide layers, improving the adhesion between the whiskers and the substrate. After cleaning, a photomask is positioned to accurately pattern the 60° apex prism structure on the substrate surface.

[0023] Step 2: Directional growth of silicon whiskers. The pretreated substrate is transferred to a CVD (CVD) machine. The CVD machine is evacuated to 0.01 MPa, and nitrogen carrier gas is introduced to purge for 3 minutes to remove residual air and avoid affecting the whisker growth quality. Subsequently, the temperature is increased to 950°C at a rate of 5°C / min and the pressure is stabilized at 0.3 MPa. A silane-hydrogen feed gas with a volume ratio of 1:5 is introduced, and the silicon whiskers are guided to grow at a preset angle of 60° with a magnetic field strength of 0.5T. The growth time is set to 80 minutes to ensure that multiple silicon whiskers grow together with a spacing error ≤ ±0.1 μm, forming a prism structure that meets the requirements.

[0024] Step 3, Whisker-Substrate Strengthening and Bonding: After the silicon whiskers are grown, the substrate undergoes annealing strengthening treatment. The temperature is set to 700℃ and held for 2.5 hours, with slow heating and cooling at a rate of 5℃ / min. This effectively eliminates the internal stress generated during whisker growth, ensuring the finished product has an impact resistance strength ≥300MPa and improving product stability.

[0025] Step four: After annealing and strengthening, the substrate is subjected to 200W plasma polishing for 12 minutes to remove burrs from the silicon whisker surface, ensuring a surface roughness Ra≤0.5nm and a transmittance≥90%, meeting optical performance requirements. After polishing, a comprehensive inspection of the finished product's apex tolerance, transmittance, and surface morphology is conducted. Qualified products are transferred to the finished product storage area by an automated unloading mechanism, while unqualified products are automatically marked and rejected.

[0026] In this embodiment, 100 60° apex angle silicon whisker micro prisms can be produced in a single batch, with a total production time of 3.8 hours per batch. The transmittance of the batch products fluctuates by ≤1%, the apex angle tolerance fluctuates by ≤±0.02°, and the pass rate reaches 98.5%, meeting the needs of large-scale mass production.

[0027] Example 2 like Figure 2 As shown, a high-precision ultrafine prism fabrication method based on vapor-phase deposition whiskers is applicable to the customized production of 90° apex angle, high mechanical strength silicon carbide whisker ultrafine prisms for special optoelectronic devices. By flexibly adjusting the device parameters of this invention to adapt to the growth characteristics of silicon carbide whiskers, the performance of customized products is ensured to meet the standards. The specific steps, parameters, and technical details are as follows: First, configure the parameters: create a new parameter scheme for a "90° apex angle silicon carbide whisker microprism" and save it. The core parameters are set as follows: silicon carbide whisker growth temperature 1050℃, reaction pressure 0.35MPa, silane-methane-hydrogen (volume ratio 1:0.5:5) feed gas flow rate 50sccm, magnetic field strength 0.6T, growth rate 0.4μm / min; annealing strengthening temperature 750℃, holding time 3h; plasma polishing power 220W, polishing time 15min. Replace the mask with one suitable for the 90° apex angle and use a silicon carbide substrate as the growth substrate to improve the compatibility between the whiskers and the substrate.

[0028] The preparation process then proceeds, including the following steps: Step 1, substrate pretreatment: The substrate (silicon carbide substrate) is plasma cleaned at a power of 250W, and a mixed gas of argon-oxygen (volume ratio 1:3) is introduced for 6 minutes to thoroughly remove surface impurities; after cleaning, the mask is positioned to complete the surface patterning of the 90° apex prism structure.

[0029] Step 2, directional growth of silicon carbide whiskers: The pretreated substrate is transferred to the CVD equipment. After the CVD equipment is evacuated to 0.01 MPa, nitrogen carrier gas is introduced for 5 min. The temperature is raised to 1050℃, the pressure is adjusted to 0.35 MPa, and a silane-methane-hydrogen mixed raw material gas is introduced. The silicon carbide whiskers are guided to grow at a 90° angle with a magnetic field strength of 0.6T. The growth time is set to 120 min to ensure the uniformity of whisker growth and the integrity of the interface.

[0030] Step 3, whisker-substrate strengthening: After the silicon whiskers are grown, the substrate is annealed at 750℃ for 3 hours to eliminate internal stress.

[0031] Step four: Perform plasma polishing on the annealed substrate at 220W power for 15 minutes to ensure a surface roughness Ra ≤ 0.5nm. After polishing, the finished product is inspected, focusing on the 90° apex angle accuracy, silicon carbide whisker interface bonding state, and light transmittance (≥90%). Qualified products are delivered as customized products, while unqualified products are marked and rejected.

[0032] This embodiment allows for flexible parameter adjustment to adapt to customized requirements, producing 20 90° apex-angle silicon carbide whisker micro prisms per batch, with a total production time of 4 hours per batch. The finished product has an impact resistance of ≥320MPa, meeting the customized requirements of special optoelectronic devices for high mechanical performance and prisms with specific angles.

[0033] The above embodiments have the following technical advantages: 1. Excellent performance synergy: Simultaneously achieves ultra-micro prism apex angle tolerance ≤ ±0.1°, light transmittance ≥90%, and impact resistance ≥300MPa, breaking through the bottleneck of the mutual exclusion of precision and performance in traditional technology; 2. High production efficiency: The production time for a single batch is reduced to ≤4 hours, which is a significant improvement compared to the 8-12 hours of traditional processes; 3. Good batch consistency: Improved automation and reduced manual intervention. The transmittance of batch products fluctuates by ≤1% and the apex angle tolerance fluctuates by ≤±0.05°, which is suitable for large-scale supporting needs.

[0034] 4. Achieve continuous processing of "substrate pretreatment - whisker directional growth - enhanced bonding", avoiding the inefficiency and pollution problems of traditional step-by-step processing, and providing a structural basis for multi-specification transformation.

[0035] 5. Based on the growth characteristics of silicon whiskers, key technologies such as magnetic field orientation control, precise delivery of raw material gas, and temperature gradient guidance can be designed. Combined with precise substrate patterning and high-precision finished product testing, the forming accuracy and optical and mechanical properties of the ultra-micro prism can be guaranteed.

[0036] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for fabricating high-precision ultrafine prisms based on vapor-deposited whiskers, characterized in that, Includes the following steps: Step 1: Substrate pretreatment. The substrate is cleaned and impurities are removed using plasma cleaning, and a mask is used to position the substrate. Step 2: Directional growth of whiskers by vapor deposition. The pretreated substrate from Step 1 is transferred to the CVD equipment to start the growth process. Step 3: Strengthen the bond between whiskers and substrate. Anneal the substrate grown in Step 2 to eliminate internal stress. Step four, post-processing: polish the annealed product from step three, and then inspect it to obtain a qualified finished product.

2. The method for preparing a high-precision ultrafine prism based on vapor-deposited whiskers according to claim 1, characterized in that, In step one, the power of the plasma cleaning is 50-300W, and an argon-oxygen mixture with a volume ratio of 1:3 is introduced during the cleaning process. The positioning accuracy of the mask is ±0.05μm.

3. The method for preparing a high-precision ultrafine prism based on vapor-deposited whiskers according to claim 1, characterized in that, The reaction temperature in step two is 900-1100℃, the pressure is 0.2-0.4 MPa, the magnetic field strength is 0.4-0.7 T, and the crystal growth rate is 0.3-0.8 μm / min.

4. The method for preparing a high-precision ultrafine prism based on vapor-deposited whiskers according to claim 1, characterized in that, In step two, a gas is introduced, which is a mixture of silane and hydrogen or a mixture of silane, methane, and hydrogen, with a flow rate of 40-80 sccm.

5. The method for fabricating a high-precision ultrafine prism based on vapor-deposited whiskers according to claim 1, characterized in that, The annealing process in step three is carried out at a temperature of 500-800℃ for 1-3 hours, with a heating / cooling rate of 5℃ / min.

6. The method for preparing a high-precision ultrafine prism based on vapor-deposited whiskers according to claim 5, characterized in that, The annealing process is carried out at a temperature of 650-750℃ for 2.5 hours.

7. The method for preparing a high-precision ultrafine prism based on vapor-deposited whiskers according to claim 1, characterized in that, In step four, plasma polishing is used, and the polishing time is 5-15 minutes.

8. The method for preparing a high-precision ultrafine prism based on vapor-deposited whiskers according to claim 7, characterized in that, The plasma polishing power is 180-220W, and the polishing time is 10-15min.

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