THINFILM
Scribing the right motion
With recent disruptions from global economic issues and changes to government incentives manufacturers need to take advantage of every incremental opportunity to create a competitive advantage in an increasingly challenging market place. John Lindell of Aerotech discusses how picking the right motion control partner with the right technology can help improve quality while reducing costs.
S
econd generation solar cells take advantage of improved materials that are applied as thin films to a variety of substrates. These new materials provide higher conversion efficiencies while lower-cost substrates significantly reduce manufacturing costs. Because of these efficiency and cost savings thin-film methods are increasingly popular with PV manufacturers. Third generation cells also take advantage of thin-film technologies and hold the promise of even greater conversion efficiencies and even lower production costs. This cycle of continuous improvement is considered absolutely necessary to drive solar power to be cost-competitive with current non- renewable energy sources.
In the push for clean, renewable energy at a price point that is equivalent to current grid prices, photovoltaic (PV) manufacturers require production systems that provide exceptionally high throughput as well as the highest possible uptime. One process tool key to reducing cost by increasing throughput is the scribing platform. Focusing on key technologies and selecting a partner that is familiar with these technologies is vital to providing a scribing system with the lowest total cost of ownership.
Scribing Methods
The basic thin-film manufacturing operation relies on a process known as scribing. After application of individual thin-film layers, panel scribing is used to selectively remove material in areas that will be electrical interconnects or isolation areas. Because it is a key process step, scribing must be strictly controlled to ensure proper function of the finished panel.
Two methods are used for the scribing process — mechanical and laser scribing. Each method provides specific benefits and presents unique challenges for material scribing. Mechanical scribing is less film-material-dependent than laser scribing but is limited in throughput as well as scribe quality, while lasers have throughput and quality advantages but their application is limited by the materials being scribed. Regardless of the method used, the scribing motion platform must accommodate the technology as well as provide extremely high throughput
System Level Approach
The best approach for developing a solar panel scribing solution is to consider the scribing platform as a whole. Simply looking at the primary scan axis will only tell part of the story. Yes, scan axis dynamic straightness, peak acceleration and peak velocity are very important, but there are other design elements that come into play.
Figure 1. XY, split axis, and gantry-style solar- panel scribing solutions
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www.solar-pv-management.com Issue III 2010
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