Avoiding the requirement for pre-existing optical contact during picosecond laser glass-to-glass welding

Chen, Jianyong; Carter, Richard M.; Thomson, Robert R.; Hand, Duncan Paul

doi:10.1364/oe.23.018645

Cited by 56 publications

(31 citation statements)

References 18 publications

(25 reference statements)

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“…Figure 6 shows the measurement results of the surface roughness near the welding area by changing the etching time up to 40 min. According to published papers, optical contacted fused silica welding with ultrafast laser can bridge a 1 to 3 μm gap [20,35]. In conclusion, our etching time of 30 min, generating a surface roughness of 10 nm, which is still less than a hundredth of the wavelength of the welding laser, will not affect the welding efficiency [30].…”

Section: Resultsmentioning

confidence: 99%

Bonding Strength of a Glass Microfluidic Device Fabricated by Femtosecond Laser Micromachining and Direct Welding

Kim

Joung

et al. 2018

Micromachines

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We present a rapid and highly reliable glass (fused silica) microfluidic device fabrication process using various laser processes, including maskless microchannel formation and packaging. Femtosecond laser assisted selective etching was adopted to pattern microfluidic channels on a glass substrate and direct welding was applied for local melting of the glass interface in the vicinity of the microchannels. To pattern channels, a pulse energy of 10 μJ was used with a scanning speed of 100 mm/s at a pulse repetition rate of 500 kHz. After 20–30 min of etching in hydrofluoric acid (HF), the glass was welded with a pulse energy of 2.7 μJ and a speed of 20 mm/s. The developed process was as simple as drawing, but powerful enough to reduce the entire production time to an hour. To investigate the welding strength of the fabricated glass device, we increased the hydraulic pressure inside the microchannel of the glass device integrated into a custom-built pressure measurement system and monitored the internal pressure. The glass device showed extremely reliable bonding by enduring internal pressure up to at least 1.4 MPa without any leakage or breakage. The measured pressure is 3.5-fold higher than the maximum internal pressure of the conventional polydimethylsiloxane (PDMS)–glass or PDMS–PDMS bonding. The demonstrated laser process can be applied to produce a new class of glass devices with reliability in a high pressure environment, which cannot be achieved by PDMS devices or ultraviolet (UV) glued glass devices.

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Section: Resultsmentioning

confidence: 99%

Bonding Strength of a Glass Microfluidic Device Fabricated by Femtosecond Laser Micromachining and Direct Welding

Kim

Joung

et al. 2018

Micromachines

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“…The laser microwelding system enables the generation of weld seams at the interface of two glass plates, as demonstrated in References [ 41 , 42 ]. Previously, however, the welds were generated in relatively small areas (typically less than 5 mm × 5 mm).…”

Section: Resultsmentioning

confidence: 99%

“…This plasma expands and locally melts a small volume of surrounding glass that crosses into the bottom part of the cover glass (glass plate #1), and, when this solidifies on cooling, it forms a weld. Our previous work [ 42 ] showed that gaps smaller than 3 µm can be closed during the laser welding process.…”

Section: Resultsmentioning

confidence: 99%

“…In the past, we demonstrated that an ultrafast picosecond laser (Trumpf TruMicro 5×50, Trumpf Ltd., Ditzingen, Germany) can be an effective tool for the direct cutting, drilling, and micromachining of glass plates [ 39 , 40 ], and for joining glass to glass [ 41 , 42 ] or even glass to metal [ 41 ] without using any intermediate adhesive layers. In this article, we report on a combination of these processes to manufacture glass microfluidic devices.…”

Section: Introductionmentioning

confidence: 99%

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Rapid Laser Manufacturing of Microfluidic Devices from Glass Substrates

et al. 2018

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Conventional manufacturing of microfluidic devices from glass substrates is a complex, multi-step process that involves different fabrication techniques and tools. Hence, it is time-consuming and expensive, in particular for the prototyping of microfluidic devices in low quantities. This article describes a laser-based process that enables the rapid manufacturing of enclosed micro-structures by laser micromachining and microwelding of two 1.1-mm-thick borosilicate glass plates. The fabrication process was carried out only with a picosecond laser (Trumpf TruMicro 5×50) that was used for: (a) the generation of microfluidic patterns on glass, (b) the drilling of inlet/outlet ports into the material, and (c) the bonding of two glass plates together in order to enclose the laser-generated microstructures. Using this manufacturing approach, a fully-functional microfluidic device can be fabricated in less than two hours. Initial fluid flow experiments proved that the laser-generated microstructures are completely sealed; thus, they show a potential use in many industrial and scientific areas. This includes geological and petroleum engineering research, where such microfluidic devices can be used to investigate single-phase and multi-phase flow of various fluids (such as brine, oil, and CO2) in porous media.

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“…This degradation of the sealing quality can be mitigated by using ultrafast laser welding. Prior studies showed that ultrafast laser glass welding can effectively bond glass substrates by filling the interface gap up to 3 μm [46,47]. Figure 2B provides a schematic illustration of the ultrafast laser welding of a cover glass to the sensor substrate.…”

Section: Methodsmentioning

confidence: 99%

Characteristics of an Implantable Blood Pressure Sensor Packaged by Ultrafast Laser Microwelding

Kim

Park

et al. 2019

Sensors

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We propose a new packaging process for an implantable blood pressure sensor using ultrafast laser micro-welding. The sensor is a membrane type, passive device that uses the change in the capacitance caused by the membrane deformation due to applied pressure. Components of the sensor such as inductors and capacitors were fabricated on two glass (quartz) wafers and the two wafers were bonded into a single package. Conventional bonding methods such as adhesive bonding, thermal bonding, and anodic bonding require considerable effort and cost. Therefore CO2 laser cutting was used due to its fast and easy operation providing melting and bonding of the interface at the same time. However, a severe heat process leading to a large temperature gradient by rapid heating and quenching at the interface causes microcracks in brittle glass and results in low durability and production yield. In this paper, we introduce an ultrafast laser process for glass bonding because it can optimize the heat accumulation inside the glass by a short pulse width within a few picoseconds and a high pulse repetition rate. As a result, the ultrafast laser welding provides microscale bonding for glass pressure sensor packaging. The packaging process was performed with a minimized welding seam width of 100 μm with a minute. The minimized welding seam allows a drastic reduction of the sensor size, which is a significant benefit for implantable sensors. The fabricated pressure sensor was operated with resonance frequencies corresponding to applied pressures and there was no air leakage through the welded interface. In addition, in vitro cytotoxicity tests with the sensor showed that there was no elution of inner components and the ultrafast laser packaged sensor is non-toxic. The ultrafast laser welding provides a fast and robust glass chip packaging, which has advantages in hermeticity, bio-compatibility, and cost-effectiveness in the manufacturing of compact implantable sensors.

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Avoiding the requirement for pre-existing optical contact during picosecond laser glass-to-glass welding

Cited by 56 publications

References 18 publications

Bonding Strength of a Glass Microfluidic Device Fabricated by Femtosecond Laser Micromachining and Direct Welding

Bonding Strength of a Glass Microfluidic Device Fabricated by Femtosecond Laser Micromachining and Direct Welding

Rapid Laser Manufacturing of Microfluidic Devices from Glass Substrates

Characteristics of an Implantable Blood Pressure Sensor Packaged by Ultrafast Laser Microwelding

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