The lateral resolution is 5µm and the image acquisition time is only 1.25s for the complete wafer. Image: Wickon Hightech

The lateral resolution is 5µm and the image acquisition time is only 1.25s for the complete wafer. Image: Wickon Hightech

Wickon Hightech has developed a new model of the ‘SPEEDFilm’ inspection platform specifically for PV manufacturers. The ‘SPEEDFilm Solar’ system ensures 100% inspection of screen printed paste structures with a very high throughput that is able to handle thinner and thinner printed structures on c-Si solar wafers.

Problem

The printed fingers and bars take the electrical energy from the wafer but any distortion in the printed layout, e.g. smearing of paste or contact dots somewhere on the surface or interrupted conductor lines can lead to a significant loss in module power. Providing PV manufacturers with a high-volume, accurate testing solutions in a small footprint is required to meet quality control requirements and the possibility of line integration to increase throughput and reduce the cost per-watt.

Solution

The SPEEDFilm Solar system takes two full resolution images to get a higher accuracy inspection result. Inspection is done with the printed layer upwards, while transporting from one segment to the next without loosing process time. The lateral resolution is 5µm and the image acquisition time is only 1.25s for the complete wafer. The image is pre-calculated with the Wickon Hightech ‘Dr.-M’ (data reduction module) to speed up all calculations. The Wickon Hightech ‘Wision’ software has been widely used in automotive screen printing production lines with the ability of inspecting very complex layouts. The system detects paste spots out of the printed layout starting with a minimal size of 5x5µm as well as smeared paste along the printed conductor lines and logically interrupted conductor lines, providing 100% of inspection.

Applications

Volume production inspection of screen printed paste structures on c-Si solar cells.

Platform

The SPEEDFilm Solar system deploys a sensor and the PC in a compact conveyor and can be integrated in nearly all available conveyor systems. This means that the maintenance costs and spare parts are used from existing equipment. The inspection program is based on the Gerber datas and is correcting the local distortions from the screen while printing. This makes it easy to integrate the system and run it in stable behavior. 

Availability

Commercial product rollout is planned for October 2017. 

Tags: wickon hightech, c-si manufacturing, solar cell, monocrystalline wafer, multicrystalline wafer, metallisation

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