The worldwide solar cell industry is booming and increasing its production volume year by year. With the unique non-contact ultrasound-air-bearing technology, ZS-Handling GmbH has established a completely new dimension for the handling of substrates in the photovoltaic industry.
We are adressing today´s challenges in Photovoltaic industry
Handling during all processes must be gentle enough to prevent microcracks and edge chipping.
Thinner and thinner substrates:
Realize transportation possibilities of substrates that may be bent by their own weight.
All processes must be tolerant to solar cells of varying thickness.
Very short cycle times:
Guarantee optimized cycle times for the interaction of several processes (up to 7000 wafers/h or 0,5 s/wafer).
Increased yield by minimizing breakage rates (< 70 ppm).
Integration of high speed measurement equipment.
Avoiding any kind of edge and surface stress while feeding only intact solar wafers through the production line.
At home in the photovoltaic industry. as well as in the semiconductor and FPD industry, ZS-Handling GmbH plays a trend-setting role in Europe, Asia and North America.
We provide a comprehensive range of products with several revolutionary novelties for non-contact and gentle handling of solar cells and wafers. These solutions are targeting yield increase as well as the profitability of your production lines.
Non-contact Picker Unit
The non-contact picker module represents an essential part of our production range.
While completely avoiding time intensive pick&place processes, a non-contact ultrasonic singulation is available for our customers to handle solar wafers gently, within a cycle time of 0.5 secounds per wafer. Moreover, the picker unit is suitable for different substrate sizes.
The wafer is attracted by a large scale, low pressure zone from distances up to 12 mm. At the same time, the ultrasound-air-bearing prevents any contact to the linear track. Wafers hover below the track's surface and can be moved and accelerated without any friction.
Non-contact Linear Track
The non-contact handling systems provided by Zimmermann & Schilp can be applied in any process environment. The ambient air or process gas is compressed by the ultrasound, so solar wafers or cells are levitated contactlessly along defined tracks.
The non-contact linear transfer track combines optimized transport speed and low cycle times with minimized wafer damage (< 70 ppm).The non-contact transport minimizes wafer stress due to the non-contact, full-surface gripping forces. A belt causes forward motion, while the edge-load is only a fraction of the weight of the solar cell.
In-process Quality Control
In modern solar plants, product quality is ensured by fast optical measurement systems. With our non-contact handling devices using glass sonotrodes, we offer the ideal solution for a two-sided substrate inspection. Wafers / Cells can be inspected either in the gap between the sonotrodes (ultrasound-air-bearings) as well as through a sonotrode made of glass.
Non-contact Sorter Module
Quality management becomes significantly more complex by the rapid progress in solar industry. With the non-contact solar cell sorter system, we offer a respective solution for the industry.
By means of the non-contact linear track, solar cells are held from the top side and transported to the correct position over the carrier. Reliability, speed and a very small energy footprint are some of the key benefits of the sorter system.
Non-contact Glass Handling
ZS-Handling not only provides devices for wafer / cell handling, we also offer grippers and conveyors for thin-film PV production.
The non-contact conveyors facilitate a smooth and friction free transport of substrates. The systems are designed as modules which can be assembled to arrays of any length and width.
The devices offer two approaches to realize double-sided inspection of substrates:
Intersection of the transfer system with a gap up to 20 mm. This gap can easily be crossed by the substrates, while the inspection can be done through this gap (e.g. by optical sensors, line cameras).
Using glass as material of the transfer systems, the substrate can be inspected by optical means through the glass.
Glass-grippers for Top-side Handling:
For top-side handling the repelling ultrasound forces are used in combination with attracting low-pressure forces. This technique enables an easy-to-use non-contact handling of parts, very much like the familiar top-side-gripping of parts. Additionally, flexible parts can be flattened and kept in position and geometry by this technique, without any contact to the handling tool. The substrates are centered by adjustable and moveable side-stops.
Ultrasound is a vibration at frequencies beyond the upper limit of human hearing (f > 20 kHz). It is generated by transducers which are powered by seperate power electronics.
Levitation, No Cleaning
The levitational effect of our ultrasound-air-bearing is not comparable to ultrasound-cleaning, which requires a fluid. Within that fluid, the ultrasound generates voids (partial vacuum bubbles) which are collapsing with enormous energy and leads to the removal of particles from the surface. In contrast to that, our ultrasound-air-film technology needs needs compressible fluids, like process gases or air, which is compressed within a gap between the part and the handling tool. The film of compressed air acts exactly like a conventional air-bearing, except for the loss of generating compressed air – no pumps, pipes or nozzles. The damping air film prevents the vibration of energy from being transferred to the part, so that there is basically no vibration of the part.
Squeezefilm Levitation: Repelling Forces
The physics of ultrasound-air-bearing derives more from fluid dynamics than from acoustic principles. The gas pressure in the gap between the workpiece and the vibrating surface of the sound generator rises, due to the cyclic compression and decompression of the thin gas film. Therefore, it is necessary to create a uniform vibration pattern in order to generate equal levitation forces throughout the whole vibrating surface.This is one of the core competences of Zimmermann & Schilp – We trim the sound! Using the squeezefilm, levitation significant repelling forces can be generated between the sound source and the workpiece, therefore, the workpiece can be moved without any friction. For pressure generation, ultrasound technology uses ambient air or (process) gas on the interface.
Combination of Physical Effects: Top-Side Handling
Many handling processes need the use of attracting and repelling forces at the same time, e.g. top-side handling. In these cases, repelling ultrasound forces are used in combination with attracting low-pressure forces.This technique enables an easy-to-use, non-contact handling of parts, very much like the familiar top-side-gripping of parts. Additionally, flexible parts can be flattened and kept in position and geometry by this technique, without any contact to the handling tool.