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Press Release

ROFIN's compact laser for TFT cutting

High magnification of the cutting area

01.12.2009
Tailored Solution for TFT Cutting

ROFIN’s PowerLine SL 8 IC – a tailored solution

Competitive edge thanks to flexible product development and proximity to customers: ROFIN develops a new laser beam source for TFT cutting

Whether only a few centimetres big or screen sizes of over 50 inches – hardly any electronic device can do without an LCD display these days. In the vast majority of cases, TFT technology makes sure that every pixel is activated. The columns and rows of the pixel matrix are activated using transparent indium tin oxide (ITO) conductive paths. For efficient production of TFT displays, a conductive connection must be established between the columns and rows of the matrix – an intentional short circuit, as it were. In a later stage of the production, this step must be carefully undone.  A laser is the best tool for this.

ITO ablation with line widths of 35 µm at 400 mm/sec.

Leading screen manufacturers demand a processing speed of at least 400 mm/sec. Each group of conductive paths, only a few µm wide, has to be cut accurately and absolutely reliably with a line width of 35 ± 5 µm. Gabriele Fischer, Manager of the semiconductor industry segment at ROFIN, knows of these requirements and passes them on to the application laboratory in Guending. Speed is important, but so is the ability to integrate, since the laser beam sources will be moved by motor over great distances in at least one direction. The panel edge is sometimes over a metre long and the connection groups are distributed over the whole length.  If galvo deflection heads are used to position the beam in a processing field of this size, this will make the spot diameters too large, which means that the required line widths cannot be ensured. Therefore, fixed optics are used and the laser and panel are normally moved in one axis each.

Manfred Schadi, applications engineer at ROFIN, achieves excellent results with new PowerLine SL 8 IC, which has been optimized especially for cutting TFTs.  The beam source was developed to meet strict requirements for beam quality and pulse to pulse stability at high frequencies. A temperature management system with independent thermal monitoring, stabilization of all relevant optical components and heat dissipation via a cooling plate, ensures long-term stability and performance, which is necessary for reliable 24/7 operation.

PowerLine SL 8 IC reliably cuts ITO conductive paths with a line width of 35 µm. The laser power ensures much higher speeds than the required 400 mm/sec. The excellent beam properties make the new beam source interesting for other applications, too. For instance, Gabriele Fischer envisages structuring of wafers when producing MEMS, a product technology with great growth potential.