Industrial Challenges and Opportunities in Glass-to-Glass Welding Using Ultrashort Pulsed Lasers
Business challenge
Process Innovation
Product Innovation
Growth & Scaling
Sector
Electrification
Wind, Maritime & Solar
Technology or capability
Laser Processing
Project Challenges
Glass to glass welding has emerged as a critical enabling technology across a diverse range of industries, including consumer electronics, microfluidics (lab on chip), micro-optics assembly, hermetic wafer level encapsulation, photovoltaic (PV) module sealing, and medical device packaging. These sectors demand high precision, contamination free bonding solutions that traditional methods such as anodic bonding, brazing, and adhesive based techniques struggle to deliver. Common drawbacks of these conventional approaches include long curing times, material creep, outgassing, and ageing, all of which compromise long term reliability and scalability.
In recent years, ultrashort pulsed (USP) laser welding has gained prominence as a promising alternative. This technique offers several advantages including high peak power, localised heating, flexible processing, and the ability to achieve direct micro welding without the need for intermediate layers.
Despite its technical potential, the current state of the art implementation of USP laser welding is constrained by several factors. Most systems operate with low average laser power (less than 6 W), fixed optics with short focal lengths (less than 20 mm), and translation stages with limited scanning speeds (2 to 100 mm/s). These limitations significantly reduce productivity and pose challenges for industrial scale adoption.
MTC's Solution
MTC implemented a high-power ultrashort pulsed laser system to explore scalable glass-to-glass welding. The setup featured a 250 W, 10 picosecond ultrashort pulsed laser, integrated with a 10 m/s high-speed galvoscanner. A suitable beam optic configuration was chosen to achieve the necessary peak power for nonlinear absorption while minimising thermal effects. A custom jig with a pneumatic piston ensured close contact between glass samples, which were thoroughly cleaned to prevent contamination.
The experimental trials focused on 1.1 mm and 3 mm borosilicate glass and investigated the influence of scan speed, frequency, average power, and focal position. The trials were divided into two phases: bulk glass modification (to investigate weld morphology) and glass-to-glass welding. Each phase was systematically analysed using optical microscopy, scanning electron microscopy (SEM), and water leak testing to assess weld morphology and bonding integrity. This approach allowed MTC to evaluate the process window for high-speed, high-power USP laser welding and its potential for industrial adoption in precision glass bonding applications.
By combining high power ultrashort pulsed laser technology with precision engineering, we successfully demonstrated a scalable hermetic glass to glass welding process that paves the way for industrial adoption in microfluidics and advanced device packaging.
David Gilbert, Technology Manager - MTC
The Outcome
- Successfully configured a high-power ultrashort pulsed laser system and designed a custom welding jig for bulk glass modification and glass-to-glass welding.
- Conducted systematic trials to study the effects of laser parameters including frequency, scan speed, average power, and focal position on weld morphology.
- Achieved effective bonding of 1.1 mm and 3 mm borosilicate glass.
- SEM analysis confirmed strong, defect-free bonding with no evidence of cracking.
- Demonstrated industrial relevance by fabricating a microfluidic device using laser machining and subsequent glass welding.
- Water leak testing validated the hermetic seal, showing no leakage and confirming the process’s suitability for precision applications.
Benefits to the Client
- Enhanced Manufacturing Efficiency: The scalable glass-to-glass welding process enables faster, cleaner, and more reliable bonding without the need for adhesives or intermediate layers. This reduces production time and simplifies assembly, especially for high-precision components.
- Industrial Readiness and Versatility: By demonstrating hermetic sealing and crack-free bonding, the technology proves its suitability for demanding applications such as microfluidics, medical devices, and optical packaging. It opens new possibilities for compact, leak-proof designs in sectors where reliability and miniaturisation are critical.