Gires-Tournois Interferometer mirrors (GTI)
BBO Crystals for THG of Ti:Sapphire lasers
Enhanced Watt Pilot Attenuator
National innovation prize 2010.
An industrial-research laser machine for c-Si solar cells. Equipped with cutting edge duet – femtosecond UV laser and nanosecond IR laser, Sollas is a multi-tasking system, designed for industrial-research or up to 3 MW/a capacity pilot manufacturing lines.
Laser processing of PV solar cells leads to:
- Thinner wafers
- Lower breakage rate
- Precise depth control
- ‘Cold processing’ using femtosecond lasers
- Easily adjustable parameters facilitate process development
- Selective ablation (due to different material response and controlled energy delivery)
Features:
- Optimized for 2.5 MW/a throughput industrial-research line
- Femtosecond UV and nanosecond IR laser sources
- Machine vision system detecting rotation and adjusting laser scanning field
- Precise laser beam control in space using high-performance galvanometer scanners
- 5″ and 6″ wafer processing
- Intuitive touch-screen user interface for simple production mode operation (SCA engineer)
- Full functionality software access in research mode (SCA engineer)
Sollas performs 4 technological processes:
- Selective SiNx/SiO2 removal
- Back contact laser firing
- Edge isolation
- Laser marking
- Other processes are integrated after feasibility tests
For selective SiNx/SiO2 removal, femtosecond UV laser source is used. This allows for very precise ablation of SiNx layer by causing minimal impact (direct or heat effect) on the Si layer – this extends the lifetime of carriers and allows avoiding micro cracks.
The other three processes are carried out by a nanosecond IR fiber laser, which is particularly characterized in fast processing.
Automated wafer handling and scanning system supports 5″ and 6″ diameter crystalline silicon (c-Si) wafers.
Integrated machine vision system and ability to adjust laser beam scanning field guarantees high repeatability and reliability.
System is equipped with a class-1 laser safety enclosure, integrated dust removal system to ensure dustless laser operation environment. Finally, system is controlled using flexible and user-friendly software ALTSE-SCA having production and research modes.
Femtosecond laser advantages
- Precise ablation due to selective absorbtion
- Minimal heat affected zone
Product is engineered and assembled in Lithuania (European Union).
SiNx layer ablated from monocrystaline wafer using UV femtosecond laser pulse.
