考慮設計規則的符號式佈局到實體佈局的轉換

Abstract

現今的攜帶式產品大多具有微處理器，歸功於製程演進的快速及SoC (system-on-chip)的大量使用，而SoC優劣仰賴於Standard Cell的品質。因應市場需求使得製程間隔越來越短，佈局圖工程師(Layout Engineer)需要持續開發新的Standard Cell Libraries，在製程日漸複雜且需考慮的特殊形式Design Rules日漸趨多的情況下，對於佈局圖工程師來說，無疑是一個巨大的挑戰。

學者開始研究製程轉移(technology migration)，希望製程改變時減輕佈局圖工程師的負擔。我所了解的方式有兩種，一種是記錄原先佈局圖的拓墣關係(topology)，再經由壓縮及新製程的Design Rules產生新的佈局圖; 第二種是先將原佈局圖轉換成Symbolic Layout，再將Symbolic Layout透過新製程的Design Rules產生新的佈局圖。第一種方式可以盡量保有原先佈局圖的拓墣關係，但對於新世代製程來說，品質不一定比較好; 第二種方式先轉成Symbolic Layout (類似紀錄拓墣關係，但不會嚴謹地考慮Design Rules)，佈局圖元件上彼此距離關係也僅是相對位置，使其轉換過程更具彈性，產生的新佈局圖的品質較佳。

In the modern life, more and more portable devices contain embedded microprocessors because of process shrinking and popular use of SoC (system-on-chip). Quality of SoC depends heavily on hard IPs, so standard cells play an important role in SoC.

Process shrinking very quickly, generation of standard cells must catch up with the technology migration. For layout engineers, it is an extreme challenge to generate new style handcrafted standard cells in a small periods of time. Challenges include different numbers of metal layers used, different numbers of masks in a generation (e.g., double patterning / triple patterning), more and more specific design rules need to be considered…, etc.

More and more researchers focus on technology migration, hoping to lighten burdens on layout engineers. To the best of my knowledge, there are two types of technology migration: type 1 is to directly migrate the original layout topology with compaction and new design rules; type 2 is to transfer the original layout to symbolic layout first and then convert it to physical layout through new process.