Laser Structuring of  ITO Layers

Material

ITO layers (Indium Tin Oxides) have found a broad application field as electrode material in display technology for touch screens, electro luminescent diodes, OLEDs (Organic Light Emitting Diodes) etc.. These layers are electrically conductive and optically transparent.

As a standard coating procedure sputtering technology is usually used. The electrical and transparent characteristics depend, among other things, on precise control of the oxygen content during the coating process. Furthermore the characteristics of the ITO layers can be varied by the relationship of  Indium to tin in the oxide. For example if the tin portion is lowered, then the electrical conductivity increases.

It is possible to apply this material on most different substrate materials, like PET (polyethylenetherephthalate, cellulose triacetate, PEN (polyethylenenaphthenate), glass etc.

Laser structuring

The areas of application mentioned above for ITO layers all require structuring. Different structuring procedures, for example sputtering over masks, lithography, printing etc. can be used, but a simple and effective procedure for structuring is means of lasers. Here the company LPKF laser & Electronics AG developed a procedure, which obtains very good results on basis mask projection. This procedure can be offered both in batch and in reel to reel procedures. The laser ablation works so effectively, because it is operated in the so-called one shot mode, i.e., the ITO layer is completely removed with only one laser pulse.