以最小成本選用備用標準元件實現設計變更

Abstract

Metal-only ECO 係利用只修改金屬層的光罩來實現最後一刻之設計變更，由於spare cells是在placement階段事先埋入，因此在數量以及種類上均受到限制，使得這項工作十分具有挑戰性。本論文將spare cell selection這個問題簡化為stable marriage problem，並利用名為stable matching的matching-based演算法正確地以可得的sapre cells實作出所要求的設計變更，同時也試著降低所費不貲之光罩成本。在實驗中經由五個工業界的實際例子驗證，對全部的例子來說，相較於廣泛被採用的手動編修的方式，或是與其自動化的版本相比，stable matching皆能以較低之光罩成本來完成所需之設計變更。

Metal-only ECO realizes the last-minute design changes by revising the photomasks of metal layers only. This task is challenging because the pre-injected spare cells are limited both in number and in cell types. This paper reduces the spare cell selection problem into stable marriage problem and uses a matching-based algorithm, named stable matching, that correctly implements the incremental design changes using the available space cells as well as tries to reduce the prohibitive photomask cost at the same time. The experiments are conducted on five industrial testcases. The results shows stable matching uses less photomask costs to complete design changes for all cases than the direct method that transforms the widely-used hand-editing procedure into an automatic one.