In modern advanced packaging, redistribution layers (RDLs) are often used for signal transmission among chips, and vias are used for communication among different layers. Most existing RDL routers perform via planning before routing. However, since vias can be placed at arbitrary locations under the irregular via structure, via planning limits the solution space and reduces layout flexibility. This work proposes a new flow with a novel routing graph model for 90-and 135-degree routing, which allows dynamic via insertion during routing. The proposed algorithm enlarges the solution space by providing more choices during path-finding, achieving higher routing quality. The experimental results based on commonly used benchmark suites show that our router achieves shorter wirelength and runtime than state-of-the-art works, including an any-angle router.

In modern advanced packaging, redistribution layers (RDLs) are often used for signal transmission among chips, and vias are used for communication among different layers. Most existing RDL routers perform via planning before routing. However, since vias can be placed at arbitrary locations under the irregular via structure, via planning limits the solution space and reduces layout flexibility. This paper proposes a new flow with a novel routing graph model for 90- and 135-degree routing, which allows dynamic via insertion during routing. The proposed algorithm enlarges the solution space by providing more choices during path-finding, achieving higher routing quality. The experimental results based on commonly used benchmark suites show that our router achieves over 10% better wirelength with over 29X speedup over the state-of-the-art work and even achieves 0.4% better wirelength with 55X speedup over the state-of-the-art any-angle router.

Redistribution layers (RDLs) are widely applied for signal transmissions in advanced packages. Traditional redistribution layer (RDL) routers use only 90- and 135-degree turns for routing. With technological advances, routing in RDLs can be any obtuse angle, leading to larger routing solution spaces and shorter total wirelength. This paper proposes the first any-angle routing algorithm in the literature for multiple RDLs. We first give a novel global routing algorithm with accurate routing resource estimation. A multi-net access point adjustment method is then proposed based on dynamic programming and our partial net separation scheme. Finally, we develop an efficient tile routing algorithm to obtain valid routes with fixed access points. Experimental results show that our algorithm can achieve a 15.7% shorter wirelength compared with a traditional RDL router.