Material Processing Using Femtosecond Lasers: Repairing Patterned Photomasks

MRS Bulletin ◽  
2006 ◽  
Vol 31 (8) ◽  
pp. 634-638 ◽  
Author(s):  
Richard Haight ◽  
Peter Longo ◽  
Alfred Wagner
Keyword(s):  
Semiconductor Industry ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Repair Process ◽  
Spot Size ◽  
Fused Silica ◽  
Ultrafast Laser Pulses ◽  
Light Pulses ◽  
Nanosecond Pulses ◽  
Silica Substrates

AbstractThe use of ultrafast laser pulses is having an impact on materials processing in profound ways. “Machining” with femtosecond pulses affords considerable advantages over nanosecond pulses, such as subdiffraction-limited material ablation, where ablated spot dimensions are below that achievable when longer pulses are focused to the minimum spot size dictated by optical physics. These properties have been exploited to address what had become a critical problem in the semiconductor industry, the repair of patterned photomasks. We will describe how the fundamentals of femtosecond laser ablation have been implemented in a machine designed to repair photomasks. We will also describe experiments designed to deposit Cr metal onto fused-silica substrates using 100-fs, 400-nm light pulses at atmospheric pressure. Multiphoton dissociation of Cr(CO)6 adsorbed on fused-silica substrates initiates Cr deposition. The mechanisms for deposition on both transparent (fused silica) and absorbing (Cr metal) substrates are discussed. Finally, we describe experiments that were carried out to extend the photomask repair process to shorter wavelengths (below 200 nm) using light generated by frequency-mixing of ultrashort, 30-fs pulses in an Ar-filled capillary.

scholarly journals Three-Dimensional Laser Printing of Macro-Scale Glass Objects at a Micro-Scale Resolution

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 565 ◽  
Author(s):  
Peng Wang ◽  
Wei Chu ◽  
Wenbo Li ◽  
Yuanxin Tan ◽  
Fang Liu ◽  
...  
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Laser Pulses ◽  
Fused Silica ◽  
Rapid Expansion ◽  
Ultrafast Laser Pulses ◽  
3D Objects ◽  
Macro Scale ◽  
Powerful Approach ◽  
3D Printing Technique

Three-dimensional (3D) printing has allowed for the production of geometrically complex 3D objects with extreme flexibility, which is currently undergoing rapid expansion in terms of materials, functionalities, as well as areas of application. When attempting to print 3D microstructures in glass, femtosecond laser-induced chemical etching (FLICE)—which is a subtractive 3D printing technique—has proved itself a powerful approach. Here, we demonstrate the fabrication of macro-scale 3D glass objects of large heights up to ~3.8 cm with an identical lateral and longitudinal feature size of ~20 μm. The remarkable accomplishment is achieved by revealing an unexplored regime in the interaction of ultrafast laser pulses with fused silica, which results in depth-insensitive focusing of the laser pulses inside fused silica.

A Two-Step Model for Multiple Picosecond and Femtosecond Pulses Ablation of Fused Silica

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Han Wang ◽  
Hong Shen ◽  
Zhenqiang Yao
Keyword(s):  
Light Intensity ◽  
Heat Affected Zone ◽  
Experimental Validation ◽  
Laser Pulses ◽  
Fused Silica ◽  
Ultrafast Laser ◽  
Damage Area ◽  
Ultrafast Laser Pulses ◽  
Step Model ◽  
Crater Morphology

The morphology of microchannels machined by multiple ultrafast laser pulses with 500 fs and 8 ps durations on fused silica plate is predicted by a two-step model with experimental validation in present work. A spike structure at crater boundary with different scales in 500 fs and 8 ps pulse ablation is found in the numerical investigation, which could be attributed to diffraction and attenuation of light intensity in both cases. To analyze the evolution of crater morphology and damaged area with an increasing number of pulses, the distribution of light intensity, lattice temperature, and self-trapped excitons density during certain pulses are studied. The results showed that 500 fs pulses lead to smoother crater boundary, smaller heat affected zone, and larger electrical damage area with respect to 8 ps pulses.

scholarly journals Three-Dimensional Laser Printing of Macro-Scale Glass Objects at a Micro-Scale Resolution

2019 ◽  
Author(s):  
Peng Wang ◽  
Wei Chu ◽  
Wenbo Li ◽  
Yuanxin Tan ◽  
Fang Liu ◽  
...  
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
Laser Pulses ◽  
Fused Silica ◽  
Ultrafast Laser Pulses ◽  
3D Objects ◽  
Macro Scale ◽  
Powerful Approach ◽  
Printing Technique ◽  
3D Printing Technique

Three-dimensional (3D) printing has allowed for production of geometrically complex 3D objects with extreme flexibility, which is currently undergoing rapid expansions in terms of materials, functionalities, as well as areas of application. When attempting to print 3D microstructures in glass, femtosecond laser induced chemical etching (FLICE) – which is a subtractive 3D printing technique – has proved itself a powerful approach. Here, we demonstrate fabrication of macro-scale 3D glass objects of large heights up to ~3.8 cm with an identical lateral and longitudinal spatial resolution of ~20 μm. The remarkable accomplishment is achieved by revealing an unexplored regime in the interaction of ultrafast laser pulses with fused silica which results in aberration-free focusing of the laser pulses deeply inside fused silica.

Experiment-Based Quantitative Analysis of Picosecond Pulse-Induced Morphological Changes in Fused Silica

2018 ◽  
Vol 6 (4) ◽  
Author(s):  
Jingwen Yan ◽  
Han Wang ◽  
Hong Shen
Keyword(s):  
Morphological Changes ◽  
Laser Pulses ◽  
Processing Parameters ◽  
Industrial Applications ◽  
Fused Silica ◽  
Picosecond Pulse ◽  
Simple Experiment ◽  
Incubation Effect ◽  
Ultrafast Laser Pulses ◽  
The Relationship

Due to its excellent quality, fused silica has been widely used in various industrial applications. The nonlinear absorptive nature of ultrafast laser pulses enables the induction of morphological changes within the bulk transparent materials. In this study, the interior modification of fused silica is induced by a picosecond pulsed laser, and the relationship between processing parameters and the modification geometry is demonstrated. Three different patterns are identified according to the geometric characteristics of the modification. Furthermore, a simple experiment-based model considering the incubation effect is put forward to predict picosecond pulse-induced morphological changes in fused silica.

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