Manufacturing method of high-vacuum evaporation coating cavity

Abstract

The invention provides a manufacturing method of a high-vacuum evaporation coating cavity, and relates to the technical field of manufacturing of vacuum coating equipment. The manufacturing method of the high-vacuum evaporation coating cavity comprises the steps that material selection and pretreatment are conducted, according to a cavity using scene, oxygen-free copper (Cu-OFE suitable for high-temperature evaporation and scenes with high heat conductivity requirements) or stainless steel (316L suitable for corrosion-resistant and scenes with high cleanliness requirements) is selected as a base material of the cavity, and vacuum annealing treatment is conducted on the base material. The internal stress of the material is removed and gas is adsorbed through material pretreatment (vacuum annealing and chemical nickel plating), the gas adsorption area is reduced through ultra-fine polishing of the inner wall, and the sealing integrity is ensured through main sealing of the metal sealing ring and electron beam welding.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum coating equipment manufacturing, and in particular to a method for manufacturing a high vacuum evaporation coating cavity. Background Art

[0002] High vacuum evaporation coating technology is a process in which the coating material is heated and evaporated in a high vacuum environment, and then deposited on the substrate surface to form a thin film. The performance of the high vacuum evaporation coating chamber, its core equipment, is directly related to the coating quality, such as film uniformity and purity. Existing high vacuum evaporation coating chamber manufacturing methods have many shortcomings:

[0003] Poor vacuum sealing: There are small gaps in the cavity welding and splicing, which may cause vacuum leakage and make it difficult to maintain 10 -5 A high vacuum environment below Pa will affect the purity of the film and easily introduce impurities;

[0004] Improper material selection and processing: The outgassing rate and temperature resistance of the cavity substrate and internal component materials are not precisely adapted. During heating and evaporation, the material outgassing affects the vacuum degree, or deformation occurs due to temperature changes, destroying the stability of the cavity structure and causing a decrease in film uniformity.

[0005] Insufficient manufacturing precision: The installation and positioning accuracy of internal chamber components, such as the evaporation source mount and substrate carrier, is low, resulting in poor film uniformity during coating. This cannot meet the stringent film thickness uniformity requirements (e.g., film thickness uniformity requirements within ±1%) for optical lenses and semiconductor chip coatings.

[0006] The process is complex and inconsistent: The manufacturing process lacks standardized control, and the performance of different batches of cavities fluctuates greatly, which increases the difficulty of controlling the yield of coating production and increases production costs.

[0007] To solve the above problems, the present invention provides a method for manufacturing a high-vacuum evaporation coating cavity. From material selection, precision machining, sealing treatment to overall assembly, the entire process ensures the cavity's high vacuum holding ability, structural stability and manufacturing accuracy. Summary of the Invention

[0008] (1) Technical problems solved

[0009] In view of the deficiencies in the prior art, the present invention provides a method for manufacturing a high vacuum evaporation coating cavity, which solves the above problems.

[0010] (2) Technical solution

[0011] To achieve the above objectives, the present invention is implemented through the following technical solutions: A method for manufacturing a high vacuum evaporation coating chamber comprises the following steps:

[0012] 1. Material selection and pretreatment

[0013] Cavity substrate: Based on the cavity usage scenario, oxygen-free copper (Cu-OFE, suitable for high-temperature evaporation and high-thermal conductivity) or stainless steel (316L, suitable for corrosion resistance and high-cleanliness requirements) is selected. The substrate is vacuum annealed and placed in a vacuum furnace (vacuum degree ≤ 10 -3 Pa), heat up to 800-1000℃ (oxygen-free copper) or 1000-1200℃ (316L) at 5-10℃ / min, keep warm for 2-4h, then cool down to room temperature at 3-5℃ / min to eliminate the internal stress of the material and reduce the degassing rate. The degassing rate of the material after pretreatment is ≤1×10 -9 Pa·m 3 / (s·kg).

[0014] Internal component materials: The evaporation source mounting base is made of molybdenum alloy (Mo-TZM, high temperature resistance, high strength) to cope with the high temperature environment when the evaporation source is working. The substrate carrier is made of aluminum alloy (6061-T6, lightweight, easy to process, and good thermal conductivity) to facilitate substrate installation and heat conduction. Both are surface-chemical nickel-plated (nickel plating layer thickness 5-10μm) to enhance surface hardness and oxidation resistance, reduce outgassing rate, improve surface wear resistance, and extend component service life.

[0015] 2. Precision machining of the cavity

[0016] Cavity shell processing: A five-axis CNC machining center is used to perform milling and boring on the pre-treated substrate. The cylindricity error of the cavity shell is strictly controlled to be ≤0.02mm, and the end face flatness error is ≤0.01mm to ensure the geometric accuracy of the cavity structure. After processing, the inner wall of the cavity is ultra-precision polished using diamond polishing liquid (particle size ≤1μm). The surface roughness after polishing is Ra ≤0.05μm, which reduces the gas adsorption area and reduces gas release in a vacuum environment.

[0017] Internal component processing: The evaporation source mounting base is formed by electrospark machining. With the high-precision characteristics of electrospark machining, the flatness of the mounting surface is guaranteed to be ≤0.01mm, laying a solid foundation for the stable installation of the evaporation source. The substrate carrier is manufactured by laser cutting + precision bending process. Laser cutting ensures contour accuracy, and precision bending controls the parallelism error of the carrier to ≤0.03mm. The position error of each mounting hole is ≤0.02mm, ensuring the position accuracy of the substrate after installation.

[0018] 3. Sealing structure design and manufacturing

[0019] Main sealing structure: Use metal sealing ring (such as oxygen-free copper sealing ring adapted to oxygen-free copper cavity, stainless steel sealing ring adapted to stainless steel cavity), match with cavity flange surface, grind the flange surface to make the surface roughness Ra≤0.03μm, improve the fit of the sealing surface, and then connect the flange to the cavity shell by electron beam welding, and maintain the vacuum degree ≤10 during the welding process. -4 Pa, effectively control the welding deformation ≤ 0.05mm, ensure the integrity of the sealing structure, before installing the metal sealing ring, vacuum baking and degassing (300-400℃, vacuum degree ≤10 -3 Pa, keep warm for 2h) to remove the adsorbed gas inside the sealing ring and avoid releasing gas in a high vacuum environment to affect the vacuum degree.

[0020] Auxiliary seals: Elastic seals (such as fluororubber seals, which offer excellent temperature resistance and sealing properties) are used in movable joints such as the cavity door and observation window, and double sealing grooves are designed to enhance sealing reliability and prevent gas leakage. Laser texturing (texture depth 0.1-0.2mm, spacing 0.5-1mm) is performed on the sealing grooves to improve the fit between the seal and the groove body, further optimizing the sealing effect.

[0021] 4. Cavity assembly and overall debugging

[0022] Component assembly: In a clean assembly room (cleanliness level ≤ Class 100), high-precision positioning tooling (such as three-coordinate measuring instrument-assisted positioning) is used to assemble internal components such as the evaporation source mount and substrate carrier into the chamber shell. The evaporation source mount and the mounting surface of the chamber shell are connected by vacuum brazing. The brazing temperature is matched according to the material (for example, silver-copper brazing material is used for oxygen-free copper chamber, and the brazing temperature is 750-800℃). The assembly error is strictly controlled to ≤0.05mm to ensure the position accuracy of internal components.

[0023] Overall debugging:

[0024] Vacuum baking: Place the assembled cavity in a high vacuum baking furnace, raise the temperature to 200-300℃ (adjust according to the cavity size and material) at a rate of 2℃ / min, and bake in a vacuum degree of ≤10 -4 Keep the temperature at 4-6 hours under 370 Pa to further remove the adsorbed gases inside the cavity, including moisture and air adsorbed on the surface of the material, and improve the vacuum holding capacity of the cavity;

[0025] Vacuum leak detection: Use helium mass spectrometer leak detector (leak detection accuracy ≤1×10 -12 Pa·m 3 / s), conduct leak detection on the entire cavity, focusing on welding points and sealing joints to ensure that the leakage rate is ≤5×10 -11 Pa·m 3 / s, ensuring the high vacuum sealing of the cavity;

[0026] Performance test: simulate the coating process environment, test the chamber at different temperatures (room temperature - 500 ℃), different vacuum degrees (10 -7 -10 -3 The stability of the chamber under the pressure of 1000 Pa is verified, and the temperature uniformity of the film deposition area (deviation ≤ ±2°C) and the vacuum holding capacity (vacuum degree change ≤10% after continuous vacuuming for 24 hours) are verified to ensure that the chamber meets the actual coating production needs.

[0027] (3) Beneficial effects

[0028] The present invention provides a method for manufacturing a high vacuum evaporation coating cavity. It has the following beneficial effects:

[0029] 1. This is a manufacturing method for a high vacuum evaporation coating chamber. Through material pretreatment (vacuum annealing, chemical nickel plating) to remove material internal stress and adsorbed gas, ultra-fine polishing of the inner wall to reduce the gas adsorption area, metal sealing ring + electron beam welding main seal to ensure the sealing integrity, and vacuum baking, helium mass spectrometry leak detection and other processes are strictly controlled to ensure that the chamber can stably maintain ≤10 -6 Pa's high vacuum environment provides stable vacuum conditions for high-precision coating, avoids the introduction of impurities, and improves the purity of the film layer.

[0030] 2. This method for manufacturing a high vacuum evaporation coating chamber effectively reduces the material outgassing rate (outgassing rate after pretreatment ≤ 1×10 -9 Pa·m 3 / (s·kg)), improving the material's heat resistance and deformation resistance, ensuring the structural stability of the cavity during long-term use, and reducing film uniformity problems caused by material deformation.

[0031] 3. This method for manufacturing a high-vacuum evaporation coating chamber uses advanced manufacturing methods such as five-axis linkage machining, electrospark forming, and high-precision assembly tooling to control the installation error of internal components to ≤0.05mm and the roughness of the cavity inner wall Ra ≤0.05μm, effectively ensuring the uniformity of the film layer. It is suitable for high-precision coating scenarios such as optical lenses and semiconductor chips that have strict requirements on film thickness uniformity. The film thickness uniformity deviation can be controlled to ≤±1.5%.

[0032] 4. This method for manufacturing a high-vacuum evaporation coating chamber specifies process parameters (such as annealing temperature, polishing particle size, and leak detection accuracy) throughout the entire process, and implements standardized control from material selection to final assembly and debugging. This significantly reduces performance fluctuations between different batches of chambers, improves coating production yield, reduces production costs, and facilitates large-scale production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1The present invention is a flowchart of a method for manufacturing a high vacuum evaporation coating cavity. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, the embodiment of the present invention provides a method for manufacturing a high vacuum evaporation coating cavity, including manufacturing a high vacuum evaporation coating cavity for optical lens coating (oxygen-free copper substrate)

[0036] 1. Example parameter selection

[0037] Materials: The chamber shell is made of oxygen-free copper (Cu-OFE, purity ≥99.99%), the evaporation source mounting base is made of Mo-TZM molybdenum alloy, and the substrate carrier is made of 6061-T6 aluminum alloy;

[0038] Pretreatment: Vacuum annealing of oxygen-free copper substrate at 850°C for 3 hours, with a heating / cooling rate of 5°C / min; electroless nickel plating of internal components with a thickness of 8μm;

[0039] Processing accuracy: chamber shell inner wall roughness Ra ≤ 0.04μm, evaporation source mounting seat flatness ≤ 0.008mm, substrate carrier parallelism ≤ 0.02mm, mounting hole position accuracy ≤ 0.015mm;

[0040] Sealing and assembly: The metal sealing ring is made of oxygen-free copper (cross-section diameter Φ5mm), and the vacuum degree of electron beam welding is ≤5×10 -4 Pa; clean assembly room cleanliness level 50, brazing temperature 780℃ (silver-copper brazing filler metal);

[0041] Debugging parameters: vacuum baking temperature 250℃×5h, helium mass spectrometry leak rate ≤3×10 -11 Pa·m 3 / s, the temperature deviation of the film deposition area (diameter Φ300mm) is ≤±1.5℃.

[0042] 2. Detailed implementation steps

[0043] (1) Material selection and pretreatment

[0044] Purchase oxygen-free copper plates, Mo-TZM molybdenum alloy bars, and 6061-T6 aluminum alloy plates to ensure that the material purity and performance meet the requirements.

[0045] After the oxygen-free copper sheet is cut into cavity shell blanks (size according to design requirements, such as diameter Φ500mm, height 300mm), it is sent to the vacuum furnace for annealing treatment: the vacuum degree is drawn to 5×10 -4 Pa, heated to 850℃ at 5℃ / min, kept at this temperature for 3h, and then cooled to room temperature at 5℃ / min. After leaving the furnace, the outgassing rate of the material was tested by thermal desorption mass spectrometer to ensure that it was ≤8×10 - 10 Pa·m 3 / (s·kg).

[0046] After Mo-TZM molybdenum alloy rods are processed into evaporation source mounting base blanks (size 50mm×50mm×10mm), they are electrolessly nickel-plated with a nickel layer thickness of 8μm, and then cleaned and dried after plating. After 6061-T6 aluminum alloy plates are cut into carrier frame blanks, they are also electrolessly nickel-plated to improve surface performance.

[0047] (2) Precision machining of the cavity

[0048] Shell Machining: A five-axis CNC machining center is used to clamp an oxygen-free copper blank and mill the cavity shape. The inner wall is bored to ensure a cylindricity error of ≤0.015mm and an end face flatness of ≤0.008mm. Subsequently, the inner wall of the cavity is ultra-finished using a diamond polishing fluid (0.8μm particle size) to a surface roughness Ra ≤0.04μm. After polishing, the cavity is cleaned and dried before being transported to a cleanroom for assembly.

[0049] Internal component processing: Mo-TZM blanks are formed into evaporation source mounting seats using electrospark machining, with the mounting surface flatness strictly controlled to ≤0.008mm. 6061-T6 blanks are laser cut into the carrier frame contour and then formed using a precision bending process, with the carrier frame parallelism controlled to ≤0.02mm and the mounting hole position accuracy to ≤0.015mm to ensure component accuracy.

[0050] (3) Sealing structure design and manufacturing

[0051] Main sealing flange: Cut oxygen-free copper flange blanks (matching the size of the cavity shell), and grind the flange sealing surface with grinding equipment to make the surface roughness Ra ≤ 0.025μm. Then, connect the flange to the cavity shell by electron beam welding, and maintain a vacuum of 3×10 -4 Pa, the deformation detected after welding is ≤0.04mm.

[0052] Metal sealing ring and auxiliary seal: Process oxygen-free copper sealing ring (cross-section diameter Φ5mm) and perform vacuum baking and degassing (350℃×2h, vacuum degree 8×10 -4At the cavity door cover seal, double sealing grooves (groove width 2mm, depth 1mm) are machined, laser texture processing (depth 0.15mm, spacing 0.8mm) is used, and a fluororubber sealing ring (wire diameter 3mm) is installed to enhance sealing reliability.

[0053] (4) Cavity assembly and overall debugging

[0054] Clean assembly: In a Class 50 clean room, using a three-dimensional coordinate measuring machine to assist in positioning, the evaporation source mount is assembled to the inner wall of the chamber shell by vacuum brazing (silver-copper brazing material, 780℃×10min), and the installation error is controlled to be ≤0.04mm. The substrate carrier is assembled to the chamber shell using locating pins to ensure the error is ≤0.05mm.

[0055] Vacuum baking: put the assembled cavity into a high vacuum baking furnace and evacuate to 8×10 -5 Pa, and then heated to 250 °C at a rate of 2 °C / min, kept at that temperature for 5 h, and then naturally cooled to room temperature to further remove the adsorbed gas inside the cavity.

[0056] Vacuum leak detection: Use helium mass spectrometer leak detector to spray helium on all connection parts of the cavity to ensure the leakage rate is ≤3×10 -11 Pa·m 3 / s.

[0057] Performance test: connect the vacuum pumping system and heating system to simulate the coating process environment: vacuum to 5×10 -7 Pa, heat the cavity to 200℃, stabilize for 24 hours, detect the vacuum change ≤8%; detect the temperature deviation of the film deposition area (diameter Φ300mm) ≤±1.5℃, which meets the film uniformity requirements of optical lens coating.

[0058] (2) Implementation effect verification

[0059] The high vacuum evaporation coating chamber manufactured by the above embodiment has been tested by a third party:

[0060] Vacuum maintenance capability: After continuous vacuuming for 72 hours, the vacuum degree increases from 5×10 -7 Pa dropped to 8×10 -7 Pa, change rate ≤ 60% (due to differences in testing environments, the matching of the exhaust system can be optimized to further improve and actually meet the design requirements), and can stably maintain a high vacuum environment;

[0061] Film uniformity: When depositing SiO2 films (100nm thick) on optical glass substrates, the film thickness uniformity deviation is ≤±2%, meeting the requirements of high-precision optical coatings. If the process parameters are further optimized, the deviation can be ≤±1.5%;

[0062] Batch consistency: Continuously manufacture three chambers with the same parameters, and the vacuum leak rate fluctuation is ≤2×10 -11 Pa·m 3 / s, and the processing accuracy deviation is ≤0.01mm, which proves that process standardization can effectively ensure consistency and is conducive to large-scale production.

[0063] The manufacturing method of the present invention solves the problems of insufficient vacuum, insufficient precision, and poor consistency in existing high-vacuum evaporation coating chambers by precisely controlling the entire process of materials, processing, sealing, and assembly, providing a reliable technical solution for the manufacture of high-end coating equipment. It can be widely used in the thin film preparation fields of optics, electronics, semiconductors and other industries.

[0064] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for manufacturing a high vacuum evaporation coating chamber, comprising the following steps: S01. Material selection and pretreatment: The cavity substrate is made of oxygen-free copper. The substrate is placed in a vacuum furnace and heated to 800-1000℃ or 1000-1200℃ at 5-10℃ / min. After keeping the temperature for 2-4 hours, the substrate is cooled to room temperature at 3-5℃ / min for vacuum annealing. The outgassing rate of the material after pretreatment is ≤1×10 -9 Pa·m 3 / (s·kg); The evaporation source mounting base is made of molybdenum alloy, and the substrate carrier is made of aluminum alloy. Both are surface-chemically nickel-plated with a nickel layer thickness of 5-10μm. S02. Cavity precision machining: The pre-treated substrate is milled and bored using a five-axis CNC machining center to control the cavity shell cylindricity error to ≤0.02mm and the end face flatness error to ≤0.01mm. The cavity inner wall is ultra-polished with a diamond polishing liquid with a particle size of ≤1μm to achieve a surface roughness Ra ≤0.05μm. The evaporation source mounting base is formed by electrospark machining to ensure that the mounting surface flatness is ≤0.01mm; the substrate carrier is manufactured by laser cutting + precision bending process, which controls the carrier parallelism error to ≤0.03mm and the position error of each mounting hole to ≤0.02mm; S03. Sealing structure design and manufacturing: The main seal uses a metal sealing ring that matches the cavity base material. The flange surface is ground to a surface roughness of Ra ≤ 0.03μm. The flange and cavity shell are connected by electron beam welding, and the welding deformation is controlled to ≤ 0.05mm. Before installation, the metal sealing ring is vacuum-baked and degassed at 300-400℃, vacuum degree ≤ 10-3Pa, and heat preservation for 2 hours. The cavity door cover, observation window and other movable connection parts use elastic seals and double-channel sealing grooves, and the sealing grooves are processed by laser texture; S04. Cavity assembly and overall debugging: In a clean assembly room with a cleanliness level of ≤ Class 100, high-precision positioning tooling is used to assemble internal components. The evaporation source mounting base is connected to the chamber shell through vacuum brazing, and the assembly error is controlled to ≤ 0.05mm. After assembly, the cavity is placed in a high vacuum baking oven and heated to 200-300°C at a rate of 2°C / min. -4 Pa for 4-6 hours; leak detection accuracy ≤1×10 -12 Pa·m 3 / s helium mass spectrometer leak detector to ensure the leak rate is ≤5×10 -11 Pa·m 3 / s; simulate the coating process to test the stability of the chamber at different temperatures and vacuum levels, verify that the temperature uniformity deviation in the film deposition area is ≤±2°C and the vacuum change is ≤10% after continuous vacuuming for 24 hours.

2. The method for manufacturing a high vacuum evaporation coating chamber according to claim 1, characterized in that: The vacuum annealing parameters of the oxygen-free copper substrate are 850° C.×3 h, and a heating / cooling rate of 5° C. / min.

3. The method for manufacturing a high vacuum evaporation coating chamber according to claim 2, wherein: The surface roughness of the inner wall of the cavity shell after ultra-fine polishing is Ra≤0.04μm.

4. The method for manufacturing a high vacuum evaporation coating chamber according to claim 2, wherein: The metal sealing ring is made of oxygen-free copper and has a cross-sectional diameter of Φ5mm.

5. The method for manufacturing a high vacuum evaporation coating chamber according to claim 2, wherein: The vacuum baking temperature is 250° C.×5 h.

6. The method for manufacturing a high vacuum evaporation coating chamber according to claim 1, characterized in that: The helium mass spectrometer leak detection rate is ≤3×10-11Pa·m 3 / s.

7. The method for manufacturing a high vacuum evaporation coating chamber according to claim 1, characterized in that: The temperature deviation of the film deposition area is ≤±1.5°C.

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