由於近代積體電路的製造技術有快速的進步，而且設計的複雜度增加得非常快，導致在晶片上的黏著墊(Bond pad)數量大幅增加。為了讓焊錫球點網狀陣列(Ball Grid Array)上數量眾多的連接到晶片(IC)的邊界，在逃脫繞線上使用多層板是必要的趨勢。由於印刷電路板上的繞線層數對於成本與產出會有很大的影響，發展高速且有效的方法以減低繞線層數變得非常重要。然而，大多數工業設計仍是由工程師手動繞線，這導致完成設計所需花費的時間會花得很長，而且往往需要花費更多的繞線層數。 因此，我們提出了一個針對極大規模的焊錫球點網狀陣列的多層繞線方法。
由於BGA球點(Balls)的繞線序列會影響到需要的繞線層數，我們提出了十字切割法以增加每一個繞線層可以逃脫繞線的球點數量。此外，我們提出了一個高效的多方向搜尋方法對每一個球點尋找逃脫路徑，同時在繞線可以避免產生銳角。實驗結果顯示我們提出的多方向搜尋方法是非常快速且在繞線不會產生銳角。藉由提出的多方向搜尋方法以及十字切割法，我們的方法可以在相同的層數下，比最先進的方法還要迅速。

The complexity of modern IC design is increasing in a dramatic speed, which makes the number of pads in a chip grow exponentially. To enable a large amount of pads to connect to the boundaries of the pad matrix, the trend of using multiple layers to complete escape routing becomes necessary. Since cost and yields of a PCB are greatly impacted by layer number, developing an efficient and effective methodology to minimize routing layers becomes very important. However, most of designs in industry are still routed manually. It not only increases time-to-market but also consumes more routing layers. Therefore, we propose a new methodology to complete multi-layer escape routing for a large scale pad matrix. Since routing sequence of pads has a lot to do with required layer number, a novel cross patten is proposed to divide a pad matrix such that boundary channels in each layer can be increased. Besides, we propose an efficient and effective multi-direction search method to route each pad, which can avoid generating angle wires. The experimental results show that EDSM algorithm can be faster and no acute angle wires. With EDSM algorithm and cross pad division pattern, our routing methodology can achieve the same routing layers compared to Wang et. al. [18] in a very fast runtime. A 80 * 80 pad matrix can be routed by our algorithm in 4.84 sec.

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