Advantages of using DPSS nanosecond laser with a Gaussian beam shape for scribing thin film photovoltaic panels

Abstract

Laser scribing of various thin film materials is a key process in manufacturing of thin film photovoltaic (PV) panels. In recent years, PV industry has adopted the use of high-power nanosecond-pulse diode pumped solid state (DPSS) Q-switch lasers to increase precision and throughput of scribe processes. A major push for the use of lasers is made in order to increase the quality of scribes and hence the efficiency of a solar cell while reducing fabrication costs. This paper focuses on identifying advantages of using a Gaussian shaped laser beam from a DPSS Q-switch laser for thin film scribe processes. In particular, scribing with a Gaussian laser beam and a flattop shaped laser beam has been evaluated and compared. From a laser scribing system design perspective, the effect of beam intensity distribution on the process depth of focus has been characterized. In addition, scribing with a high quality low M 2 Gaussian beam from a DPSS q-switch laser and a beam from a high M 2 fiber laser has been compared. Again from a laser scribing design perspective, the effect of each laser on process depth of focus has been characterized.

Femtosecond laser scribing of Mo thin film on flexible substrate using axicon focused beam

“…Despite the advantage femtosecond laser offers in scribing CIGS solar cells, it faces one serious limitation: small depth of field. For example, the Rayleigh length for a laser with wavelength of 1 µm focused to a 10 µm spot size (in diameter) is less than 0.1 mm, which means consistent narrow line width during scribing is impossible to achieve when the height variation for a large moving flexible substrate is expected to be up to 3 mm (Tamhankar et al, 2009). In view of the fact that common beam shaping from Gaussian to flattop distribution renders an even shorter depth of field based on the study by Tamhankar et al (2009), the purpose of this paper is to study fs laser scribing with axicon focused beam.…”

“…For example, the Rayleigh length for a laser with wavelength of 1 µm focused to a 10 µm spot size (in diameter) is less than 0.1 mm, which means consistent narrow line width during scribing is impossible to achieve when the height variation for a large moving flexible substrate is expected to be up to 3 mm (Tamhankar et al, 2009). In view of the fact that common beam shaping from Gaussian to flattop distribution renders an even shorter depth of field based on the study by Tamhankar et al (2009), the purpose of this paper is to study fs laser scribing with axicon focused beam. Use of an axicon lens can generate an intense beam pattern which is referred to as a near-nondiffracting beam, i.e., a beam with much larger depth of focus in comparison to that generated by a conventional focusing lens.…”

Effects of CW CO<sub>2</sub> Laser Annealing on Indium Tin Oxide Thin Films Characteristics

“…Laser materials processing is an enabling technology in many industries. The most prominent are automotive, semiconductor technology, flat panel display production, solar cell technology and medicine [1]. Typical laserbased processes are welding, soldering, cutting, drilling and laser annealing [2] written by laser micromachining [3], ablation and micro-lithography.…”