Quartz mercury-filled microbubble and preparation method thereof

Abstract

The invention discloses a quartz mercury-filled microbubble and a preparation method thereof. Aiming at the problem of short service life of a traditional quartz mercury bubble caused by mercury ion bombardment, ultraviolet radiation and high-temperature sealing, a 20-50nm amorphous Al2O3 passive film is deposited on the inner wall of the quartz mercury bubble to block erosion, and meanwhile, an Al2O3 film in a bonding area is selectively stripped through femtosecond laser and is combined with argon plasma to activate and regenerate high-density silicon hydroxyl; and hydroxyl catalytic bonding low-temperature sealing is realized. According to the method, thermal-chemical conflicts between atomic layer deposition film formation and HCB bonding are decoupled, and high-strength interface bonding larger than or equal to 15 MPa is obtained while the global anti-aging performance of the inner cavity is guaranteed. The stability of the film layer is optimized through O3 pulse treatment and vacuum annealing, the service life of the device finally breaks through 10000 hours and is prolonged by more than three times compared with that of a traditional product, and the technical bottleneck that high chemical stability and high mechanical sealing performance are difficult to be compatible is solved.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic technology, especially the field of electric light source and microcavity device manufacturing technology, and specifically relates to a long-life quartz mercury-filled microbubble with excellent anti-aging properties and a high-strength sealing interface and its preparation method. Background Technology

[0002] Mercury-filled quartz microbubbles (or mercury bubbles) are an important ultraviolet light source widely used in fields such as spectral analysis, photochemistry, and disinfection. However, their actual lifespan is generally short, usually only about 3,000 hours, which severely restricts their application in long-term, high-reliability scenarios.

[0003] The main reasons for the limited lifespan include: 1) Mercury ion bombardment: During operation, internal mercury ions continuously bombard the inner wall of the quartz, destroying its Si-O-Si network structure, leading to the precipitation of impurity ions such as sodium and boron, which form color centers under ultraviolet light irradiation, reducing ultraviolet transmittance; 2) Ultraviolet radiation damage: The 185nm and 254nm high-energy ultraviolet rays emitted by the mercury lamp can directly break the chemical bonds of the quartz, causing photoaging and local crystallization of the material; 3) High-temperature sealing defects: Traditional processes use high-temperature (?~1000℃) sealing, which easily introduces microcracks and residual stress on the quartz surface, becoming a hidden danger for device sealing failure.

[0004] Existing technologies, such as adding external filters or bulk material doping (e.g., CeO2, TiO2), primarily work at the macroscopic level and are insufficient to effectively protect the inner surface of quartz directly exposed to harsh environments (mercury vapor, strong ultraviolet radiation). While atomic layer deposition (ALD) can prepare high-performance protective films such as Al2O3, its conventional process temperature (?~200℃) fundamentally conflicts with the low-temperature bonding processes (e.g., hydroxyl-catalyzed bonding, HCB) required for achieving high-strength seals. High-temperature ALD destroys the high-density silanol groups (Si-OH) on the quartz surface, which are essential active sites for HCB to achieve high-strength bonding at room temperature. If HCB encapsulation is performed before ALD deposition, the ALD precursor cannot diffuse and react uniformly within the closed microcavity, leading to uneven film formation or even deposition interruption.

[0005] Therefore, existing technologies are caught in a dilemma where it is difficult to achieve both "high chemical stability (inner wall protection)" and "high mechanical sealing (low temperature bonding)," which has become the core bottleneck restricting the development of long-life quartz mercury-filled microbubbles. Summary of the Invention

[0006] One object of the present invention is to provide a quartz mercury-filled microbubble.

[0007] The quartz mercury-filled microbubble of the present invention comprises a quartz microbubble body, the interior of which is filled with a predetermined dose of mercury. A nano-Al2O3 passivation film is deposited on the inner wall of the quartz microbubble body, the nano-Al2O3 passivation film being formed by a low-temperature atomic layer deposition process. The nano-Al2O3 passivation film is removed from the bonding regions of the quartz microbubble, exposing the quartz substrate. The bonding regions are then regenerated with silanol groups through surface activation treatment, and sealing is achieved through hydroxyl-catalyzed bonding.

[0008] Furthermore, the thickness of the nano-Al2O3 passivation film is 20–50 nm, preferably 25–35 nm, and it has an amorphous dense structure.

[0009] Another objective of this invention is to provide a method for preparing long-life quartz mercury-filled microbubbles. This technical solution, through an innovative process strategy of "first global deposition, then local removal and activation," successfully decouples the thermo-chemical conflict between high-performance passivation of the inner wall and high-strength low-temperature sealing, achieving synergistic optimization of the device's internal anti-aging performance and external sealing reliability.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] S1. A nano-Al2O3 passivation film is deposited on the inner wall of quartz microbubbles using atomic layer deposition technology at a deposition temperature of less than or equal to 80℃.

[0012] S2. In the bonding region of quartz microbubbles, the deposited nano-Al2O3 passivation film is removed by femtosecond laser method to expose the underlying quartz surface;

[0013] S3. Perform plasma activation treatment on the exposed quartz surface to regenerate silanol groups;

[0014] S4. Low-temperature bonding and sealing between quartz components is performed at room temperature using hydroxyl catalytic bonding technology;

[0015] S5. Perform mercury compatibility verification and mercury-filled encapsulation.

[0016] Furthermore, in step S1, trimethylaluminum and deionized water are used as precursors in the atomic layer deposition process, and an ozone pulse treatment is introduced after every 30 to 60 deposition cycles to stabilize the chemical state of the film surface, inhibit crystallization, and reduce internal stress.

[0017] Furthermore, in step S1, after depositing the nano-Al2O3 passivation film, it is annealed at 120-180°C in a vacuum environment to release residual stress, and the annealing time is 15-30 minutes.

[0018] Furthermore, in step S2, the single-pulse energy density of the femtosecond laser is higher than the stripping threshold of the nano-Al2O3 passivation film and lower than the damage threshold of the quartz substrate, achieving highly selective removal without damaging the substrate. The single-pulse energy density of the femtosecond laser is 0.15–0.35 J / cm². 2 .

[0019] Furthermore, in step S3, the exposed quartz surface is bombarded with argon plasma with an energy of 50–100 eV to perform surface activation treatment, so that the density of silanol groups reaches greater than or equal to 14 nm. -2 .

[0020] Furthermore, in step S4, the hydroxyl catalytic bonding uses a sodium silicate nonahydrate solution with a pH of 11.2 as a catalyst, and the interfacial shear strength formed by the bonding is greater than or equal to 15 MPa.

[0021] This invention also provides a hydroxyl-catalytic bonding system for preparing the aforementioned mercury-filled quartz microbubbles, comprising: a nano-Al2O3 passivation film deposited on the inner wall of the quartz microbubble, formed by a low-temperature atomic layer deposition process; a locally removed film structure located in the bonding region of the microbubble, wherein the nano-Al2O3 passivation film is removed to expose the quartz substrate; the exposed quartz substrate surface is regenerated with high-density silanol groups through plasma activation treatment; and room-temperature hydroxyl-catalytic bonding is achieved between the high-density silanol groups and the surface of another similarly treated quartz component under the action of a catalyst, thereby spatially separating the passivation film region and the bonding region to jointly constitute the microbubble. The core of the system lies in achieving spatial and functional separation and synergy between the "protective film region" and the "bonding region".

[0022] The beneficial effects of this invention are as follows:

[0023] Ultra-long lifespan: The dense nano-Al2O3 passivation film on the inner wall effectively blocks mercury ion bombardment and high-energy ultraviolet photons, fundamentally inhibiting the aging of quartz materials, enabling the device to operate for more than 10,000 hours, which is more than 3 times longer than traditional products.

[0024] High-strength low-temperature sealing: By locally removing the passivation film and regenerating the highly active quartz surface, a room-temperature high-strength seal (interfacial bonding strength ≥15MPa) based on hydroxyl catalytic bonding is achieved, avoiding microcracks and residual stress caused by high-temperature sealing.

[0025] Process compatibility innovation: The proposed "film formation first, local treatment later" strategy successfully resolved the fundamental contradiction between the high-temperature film formation requirements of ALD and the low-temperature active surface requirements of HCB, providing a new approach for the fabrication of high-performance microcavity devices.

[0026] High reliability: The entire process chain is completed at low or room temperature, which minimizes the introduction of thermal stress and improves the long-term reliability of the device. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of the quartz mercury-filled microbubble of the present invention;

[0028] Figure 2 for Figure 1 Schematic diagram of the AA-direction section;

[0029] Figure 3 This is a schematic diagram of the process flow of the present invention;

[0030] Figure 4 A schematic diagram of femtosecond laser selective removal of Al2O3 film in the bonding region;

[0031] Figure 5 This is a schematic diagram of the hydroxyl catalytic bonding (HCB) process. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0033] A type of quartz mercury-filled microbubble, such as Figure 1 and 2 As shown in the figure: 1-quartz microbubble body, 2-nano Al2O3 passivation film, 3-bonding region (Al2O3 film removed), 4-quartz cover plate, 5-hydroxyl catalytic bonding interface. This mercury-filled quartz microbubble includes a quartz microbubble body 1, which is filled with a predetermined dose of mercury. A nano Al2O3 passivation film 2 is deposited on the inner wall of the quartz microbubble body, formed by a low-temperature atomic layer deposition process. The nano Al2O3 passivation film is removed from the bonding region 3 of the quartz microbubble, exposing the quartz substrate. The bonding region is regenerated with silanol groups through surface activation treatment, and sealing is achieved through hydroxyl catalytic bonding. The thickness of the nano Al2O3 passivation film is 20–50 nm, preferably 25–35 nm, and it has an amorphous dense structure. In this embodiment, the thickness of the nano Al2O3 passivation film is 30 nm.

[0034] The specific preparation process is as follows: Figure 3 As shown.

[0035] Example 1.

[0036] S1. Cleaning and ALD Deposition:

[0037] Cylindrical microbubble bodies (8 mm wall thickness) were fabricated using high-purity synthetic quartz. After ultrasonic cleaning and drying with acetone, ethanol, and deionized water, they were placed in a hot-wall type ALD system. Deposition was carried out at 60 °C using trimethylaluminum (TMA) and deionized water (H2O) as precursors and argon as carrier gas.

[0038] Each cycle consisted of a 0.1s TMA pulse followed by a 15s purge, then a 0.2s H2O pulse followed by a 15s purge. A total of 400 cycles were performed, with a 5ms O3 pulse applied after every 50 cycles. This resulted in the deposition of an approximately 30nm thick amorphous Al2O3 passivation film.

[0039] It was then annealed at 150°C under vacuum for 25 minutes.

[0040] S2. Laser film removal:

[0041] like Figure 4 A ring-shaped bonding region with a width of approximately 7 mm was defined at the edge of the microbubble, using an 800 nm femtosecond laser (single pulse energy 50 nJ, spot size 8 nm, scanning speed 100 mm / s, energy density 0.25 J / cm²). 2 The region was scanned, and the Al2O3 film was selectively and completely removed, exposing a clean quartz substrate with no damage (Ra≈0.28nm).

[0042] S3. Plasma activation:

[0043] The sample was placed in a plasma processing device, and high-purity argon gas was introduced. It was treated at 100W radio frequency power for 60 seconds to regenerate high-density silanol groups on the exposed quartz surface (XPS measurement showed a -OH density of 14.5 nm). -2 ).

[0044] S4. Hydroxyl catalytic bonding:

[0045] like Figure 5 Prepare a quartz cover plate that has undergone the same laser coating removal and plasma activation treatment. Align the two plates and drop a sodium silicate nonahydrate (Na2SiO3·9H2O) solution with pH=11.2 between the bonding surfaces as a catalyst. Apply light pressure and let stand in a clean environment for 48 hours to complete room temperature bonding. The shear strength of the bonding interface was measured to be 16 MPa.

[0046] S5. Mercury compatibility verification and mercury filling:

[0047] The bonded device was vacuum dehydrated at 120°C for 48 hours. A trace amount of mercury vapor was then introduced, and the frequency drift was monitored using a quartz crystal microbalance (QCM). The drift was 1 Hz, confirming the good chemical inertness of the Al2O3 film. Precisely measured liquid mercury was then injected through a micropore, and the injection port was finally sealed with a focused laser.

[0048] Effect verification: The microbubbles prepared in this example were tested in simulated Hg... 2+ Bombardment (dose 1×10) 16 cm -2 After that, no Na was detected. + Deposition was observed; after 500 hours of continuous irradiation with 185nm ultraviolet light, the transmittance decreased by only 0.9% (compared to 8% in the uncoated control group). The device's operational lifetime exceeded 10,000 hours.

[0049] Example 2.

[0050] Ellipsoidal quartz microbubbles (8mm³) were selected. 3 The main steps are similar to those in Example 1, with the following differences:

[0051] (1) The ALD deposition temperature was 50℃, and the cycle was 300 times. After every 30 cycles, a 4ms O3 pulse was introduced to deposit an amorphous Al2O3 passivation film with a thickness of about 22nm. After depositing the nano Al2O3 passivation film, it was annealed at 120℃ in a vacuum environment for 15 minutes.

[0052] (2) The femtosecond laser has a wavelength of 343 nm, a pulse width of 100 fs, a single pulse energy of 10 nJ, and an energy density of 0.15 J / cm². 2 .

[0053] (3) Plasma activation: Process for 90 seconds at 80W radio frequency power.

[0054] (4) HCB standing time: 72 hours, bond strength 15.5MPa.

[0055] The final device life test exceeded 10,200 hours.

[0056] Example 3.

[0057] Spherical quartz microbubbles (9mm³) were selected. 3 The main steps are similar to those in Example 1, with the following differences:

[0058] (1) The ALD deposition temperature was 80℃, and the cycle was 300 times. After every 60 cycles, a 3ms O3 pulse was introduced to deposit an amorphous Al2O3 passivation film with a thickness of about 25nm. After depositing the nano Al2O3 passivation film, it was annealed at 180℃ in a vacuum environment for 30 minutes.

[0059] (2) The femtosecond laser has a wavelength of 385 nm, a pulse width of 100 fs, a single pulse energy of 10 nJ, and an energy density of 0.35 J / cm². 2 .

[0060] (3) Plasma activation: Process for 90 seconds at 80W radio frequency power.

[0061] (4) HCB standing time: 60 hours, bond strength 15MPa.

[0062] The final device life test exceeded 10,500 hours.

[0063] Example 4. A film approximately 35 nm thick was prepared by 450 ALD cycles at 70 °C. HRTEM and SAED characterization confirmed its amorphous state. XPS showed an Al 2p binding energy of 74.3 eV, indicating a pure film. This film exhibits resistance to Hg. 2+ It performed well in bombardment and 185nm UV irradiation tests, and had strong adhesion (critical load 30mN).

[0064] Example 5. This example describes a complete HCB system, the core of which is the implementation of spatial functional partitioning: the Al2O3 passivation film (deposited at 60°C) on the inner wall is responsible for protection; the Al2O3 film in the edge annular bonding region (8 mm wide) is protected by a femtosecond laser (343 nm, 300 fs, 40 nJ, 0.22 J / cm²). 2 After removing and regenerating the -OH through argon plasma activation, it is used for HCB sealing with another activated quartz component. This system successfully integrates two high-performance processes, resulting in a final device life exceeding 10,100 hours.

[0065] The above description is only a preferred embodiment 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 quartz mercury-filled microbubble, characterized in that: The device includes a quartz microbubble body, which is filled with a predetermined dose of mercury. A nano-Al2O3 passivation film is deposited on the inner wall of the quartz microbubble body, which is formed by a low-temperature atomic layer deposition process. The nano-Al2O3 passivation film is removed from the bonding region of the quartz microbubble to expose the quartz substrate. The bonding region is regenerated with silanol groups through surface activation treatment, and sealing is achieved through hydroxyl-catalyzed bonding.

2. The quartz mercury-filled microbubble as described in claim 1, characterized in that: The thickness of the nano-Al2O3 passivation film is 20-50 nm, and it has an amorphous dense structure.

3. The quartz mercury-filled microbubble as described in claim 2, characterized in that: The thickness of the nano-Al2O3 passivation film is 25–35 nm.

4. The method for preparing mercury-filled quartz microbubbles according to any one of claims 1-3, characterized in that, The method includes the following steps: S1. A nano-Al2O3 passivation film is deposited on the inner wall of quartz microbubbles using atomic layer deposition technology at a deposition temperature of less than or equal to 80℃. S2. In the bonding region of quartz microbubbles, the deposited nano-Al2O3 passivation film is removed by femtosecond laser method to expose the underlying quartz surface; S3. Perform plasma activation treatment on the exposed quartz surface to regenerate silanol groups; S4. Low-temperature bonding and sealing between quartz components is performed at room temperature using hydroxyl catalytic bonding technology; S5. Perform mercury compatibility verification and mercury-filled encapsulation.

5. The method for preparing mercury-filled quartz microbubbles as described in claim 4, characterized in that: In step S1, trimethylaluminum and deionized water are used as precursors in the atomic layer deposition process, and an ozone pulse treatment is introduced after every 30 to 60 deposition cycles.

6. The method for preparing mercury-filled quartz microbubbles as described in claim 4, characterized in that: In step S1, after depositing the nano-Al2O3 passivation film, it is annealed at 120-180℃ in a vacuum environment for 15-30 minutes.

7. The method for preparing mercury-filled quartz microbubbles as described in claim 4, characterized in that: In step S2, the single-pulse energy density of the femtosecond laser is higher than the peeling threshold of the nano-Al2O3 passivation film and lower than the damage threshold of the quartz substrate.

8. The method for preparing mercury-filled quartz microbubbles as described in claim 7, characterized in that: The single-pulse energy density of the femtosecond laser is 0.15–0.35 J / cm². 2 .

9. The method for preparing mercury-filled quartz microbubbles as described in claim 4, characterized in that: In step S3, surface activation treatment is performed using argon plasma with an energy of 50–100 eV to achieve a silicon hydroxyl density of greater than or equal to 14 nm. -2 .

10. The method for preparing mercury-filled quartz microbubbles as described in claim 4, characterized in that: In step S4, the hydroxyl catalytic bonding uses a sodium silicate nonahydrate solution with a pH of 11.2 as a catalyst, and the interfacial shear strength formed by the bonding is greater than or equal to 15 MPa.

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