Processing of glass

The femtosecond laser micromachining technique has brought transparent materials processing to the next level. Complex structures can now be precisely fabricated by selectively removing material through drilling, cutting, and milling.

Glass Metal Polymer Other materials
Glass

Through glass vias (TGVs) fabrication

Formation of high aspect holes in glass substrates is becoming an increasingly important topic, especially in semiconductor field. With the help of femtosecond lasers it is possible to form low degree taper and high aspect ratio TGVs in glass with high quality – low chipping, absence of cracking and smooth hole inner wall.

FemtoLux 30 operating in GHz burst mode is used in producing high aspect ratio TGVs in glass substrates by performing percussion drilling. By splitting the single high energy pulse into 50 pulses in GHz burst, it is possible to not only to achieve high aspect ratio (up to 80 and more), but also precisely control the hole’s depth with resolution of 0.1 μm by carefully tuning the burst configuration. The technology for manufacturing TGVs was validated for different glass materials: AN100, BK7, BF33, D263, EXG and soda-lime.

Alternatively, TGVs can be formed by utilizing MHz+GHz burst mode and bottom-up milling technology. Taking advantage of zero-taper structure formation from bottom-up milling technology and process throughput increase from MHz+GHz burst mode, 200 um diameter hole matrix was formed in BF33 and D263 glass.

GHz burst assisted percussion drilling of high aspect ratio holes in EXG glass.

GHz burst assisted percussion drilling of high aspect ratio holes in EXG glass.

Courtesy of Akoneer.

Manufacturing examples

GHz burst assisted percussion drilling of high aspect ratio holes in EXG glass.

Courtesy of Akoneer.

GHz burst assisted percussion drilling of high aspect ratio holes in EXG glass.

Courtesy of Akoneer.

Bottom-up milling of 200 µm holes in SCHOTT BF33/D263 glass.

Courtesy of FTMC.

Selective laser etching (SLE) of through-glass vias in glass.

Courtesy of WoP.

Selective laser etching (SLE) of through-glass vias in glass.

Courtesy of WoP.

Selective laser etching (SLE) of through-glass vias in glass.

Courtesy of WoP.
TGVs formation FemtoLux

Formation of through-glass vias (TGVs) in glass substrates using femtosecond laser operating in MHz/GHz burst mode
D. Andriukaitis, V. Stankevič, E. Kažukauskas, and P. Gečys, in Lasers in Manufacturing Conference 2025, (WLT, 2025).

Recommended products

FemtoLux

Industrial Femtosecond Lasers
  • 50 W / >300 µJ at 1030 nm
  • 20 W / >50 µJ at 515 nm
  • 10 W / >25 µJ at 343 nm
  • < 400 fs – 1 ps
  • Single shot to 4 MHz (AOM controlled)
  • MHz, GHz, MHz+GHz burst modes

Similar applications

GHz burst assisted percussion drilling of high aspect ratio holes in EXG glass.

Through glass vias (TGVs) fabrication

Formation of high aspect holes in glass substrates is becoming an increasingly important topic, especially in semiconductor field. With the help of femtosecond lasers it is possible to form low degree taper and high aspect ratio TGVs in glass with high quality – low chipping, absence of cracking and smooth hole inner wall.
Micro-lens array fabricated with hybrid laser processing method using the FemtoLux 30

Hybrid Laser Processing of Micro-Lens Arrays

Micro-lens array fabricated by employing hybrid laser processing: a combination of burst mode and bottom-up milling. 
UVFS milling

Glass milling in GHz burst mode

Milling of glass by employing industrial femtosecond laser FemtoLux with GHz burst technology that increases the process throughput by dividing the high energy pulse into multiple ones.
Bottom-up milling of 200 µm holes in SCHOTT BF33/D263 glass.

Bottom-up milling of glass

Conventional laser milling strategy struggles to achieve high aspect ratio geometries, as ablation debris accumulates within the ablation area, preventing further material removal and resulting in saturation of ablated depth. Alternatively, in the bottom-up milling technique, the laser beam is focused at the bottom of a sample. This method allows all ablation products to be removed through the backside of the sample, enabling the formation of high aspect ratio geometries in glass.
Laser-based Bessel beam scribing of 4.8 mm soda-lime glass

Laser-based Bessel beam scribing

Bessel beam scribing is the most efficient laser-based, kerf-less method for scribing glass. This technique introduces intra-volume voids, followed by mechanical or thermal separation, resulting in smooth sidewall roughness and as it requres only a single laser pass, high scribing speeds can be achieved.
300 µm hole drilling in thin borosilicate glass.

Thin glass cutting

Processing glass substrates thinner than 0.5 mm presents significant challenges due to their fragility and susceptibility to cracking under excessive thermal loads. Femtosecond lasers are ideal for processing thin glass substrates because their ultra-short pulse duration minimizes thermal accumulation, resulting in superior quality.
Femtosecond laser induced selective etching of various diameter holes in fused-silica.

Femtosecond laser induced selective etching

Femtosecond laser induced selective etching is a two-step process where focused femtosecond laser pulses modify the material structure, followed by chemical etching that selectively removes the laser-modified regions. This technique enables precise taper-free 3D microfabrication in transparent materials, achieving superior surface roughness in the range of hundreds of nanometers and the capability to operate at wafer-level scales.
All applications