Etch-hole design in encapsulation for better robustness

This paper reports various etch-hole schemes based on the location and quantities of etch holes to improve robustness of the Thin Film Encapsulation (TFE). In order to achieve robust TFE, different etch hole mapping is performed on the cap layer and robustness of TFE was evaluated by measuring the height of the TFE using optical profiler measurement after sealing. For demonstrating the TFE, amorphous Si and AlN (or SiO2) were used as a sacrificial layer and the cap layer, respectively. Etching of a-Si sacrificial layer was performed with help of XeF₂. Experimental result shows that the quantity of etch holes and their location on the cap layer influence the downward deformation of the TFE after sealing process. A uniformly distributed etch holes scheme is effective in controlling the stress of encapsulation which results in low downward deformation..