解決工程改變中所產生之輸入扭轉違規與輸出負載違規

Abstract

為了縮短電子產品上市時間及減少在先進製程光罩上的巨額花費，繞線工程改變已成為具吸引力與實際的解決方案。在使用繞線工程改變時，由於電路上有限的備份電路單元造成新加入的電路常會造成時序上的輸入扭轉違規與輸出負載違規使得電路時序上出錯。這篇論文提出一個解決輸入扭轉違規與輸出負載違規的架構，藉由連接備份電路單元作為緩沖電路以解決新產生之電路延遲問題。我們提出兩種插入緩沖電路方法依序最小化所使用的緩沖電路及解決時序上有所違背的電路節點。這樣的架構已經在業界所使用的電路上驗證過。實驗數據表明我們所提出的架構相對於商業軟體可以使用更少的緩沖電路、更少的中央處理器運行時間去解決更多時序上延遲問題。整個架構建築在現有的自動繞線及擺放工具上並且可以方便的應用到不同的工具中。

To shorten the time-to-market and reduce the expensive cost of photomasks in advance process technologies, metal-only ECO has become a practical and attractive solution to handle incremental design changes. Due to limited spare cells in metal-only ECO, the new added netlist may often violate the input-slew and output-loading constraints and, in turn, delay or even fail the timing closure. This paper proposes a framework, named MOESS, to solve the input-slew and output-loading violations by connecting spare cells onto the violated nets as buffers. MOESS provides two buffer insertion schemes performed sequentially to minimize the number of inserted buffers and then to solve timing violations if there is any. This framework has been silicon-validated through industrial designs with more than 1-million instances. The experimental results demonstrate that MOESS can solve more violations with less inserted buffers and less CPU runtime compared to an EDA vendor’s solution. The whole framework is built based on a commercial APR tool and can be ported to any other APR tool offering open access to its design database.