Photolithography Solution That Overcomes Significant Die Placement Error For Advanced Packaging

The requirement for smaller features and tighter die in advanced wafer level packaging (WLP) and advanced panel level packaging (PLP) makes it essential to develop more capable lithography systems. Nowadays, the requirements for advanced packaging systems with high yield goes beyond the simple inherent lens overlay, more advanced features, such as magnification (mag) and rotation(theta) correction is needed for the mismatch between the feature (or die) position/size on substrate and the reticle pattern. This paper describes the newly developed site-by-site mag and theta correction solution by adjusting the reticle chuck position in a 2X reduction photolithography system. This technology actively mitigates symmetric mag errors within a job for up to +/-400ppm, and theta errors up to +/-1.65mrad. Experimental results in this work prove that site by site mag and theta correction worked on the wafer. What is more compelling is that there is no throughput penalty to enable this capability.