Global routing for modern large-scale circuit designs has attracted much attention in the recent literature. Most of the state-of-the-art academic global routers just work on a simplified routing congestion model that ignores the essential via capacity for routing through multiple metal layers. Such a simplified model would easily cause fatal routability problems in subsequent detailed routing. To remedy this deficiency, a more effective congestion metric that considers both the in-tile nets and the residual via capacity for global routing is presented. Experimental results show that our global router can achieve very high-quality routing solutions with more reasonable via usage.