Laser structuring of ITO layers

ITO layers (indium tin oxide) have a wide range of applications as electrode material in display technology, touch screens, electroluminescence diodes, OLEDs (organic light emitting diodes) etc. These layers are electrically conductive and optically transparent.

The coatings are usually created using the sputtering technique. The electrical and transparency properties depend on various factors including the precise control of the oxygen content during the coating procedure. It is also possible to modify the properties of the ITO layers by changing the indium to tin ratio in the oxide.

This material can be coated onto a very wide range of substrates such as PET (polyethylenetherephthalate, cellulose-triacetate, PEN (polyethylenenaphthenate), glass etc.

ITO layer, laser structured, electrode separations min. 25 µm (material: T-MOX-60, on PET film, manufacturer Bekaert / Belgium).

Laser structuring

The applications for ITO layers referred to above depend on structuring which can be realised on a very wide spectrum of structuring methods such as sputtering over masks, lithography, printing etc.

Structuring using lasers has proven to be a very simple and effective method. LPKF Laser & Electronics AG has developed a process for this purpose which achieves excellent results on the basis of mask projections. This technique is suitable for batch and roll-to-roll methods. Laser ablation is very effective because it uses the “single shot method": the ITO layer is ablated by just one laser pulse. Energy densities (fluencies) of approx. 200mJ/cm² are required for ablation.